| blob | faa184a2bbdd3df8ff05b896e60eeadeb23db327 |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2018 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. */
87 /* Nonzero if we are folding constants inside an initializer; zero
88 otherwise. */
91 /* The following constants represent a bit based encoding of GCC's
92 comparison operators. This encoding simplifies transformations
93 on relational comparison operators, such as AND and OR. */
111 };
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 {
414 /* Steps don't prevent negation. */
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. */
464 /* Fall through. */
477 /* In general we can't negate A in A / B, because if A is INT_MIN and
478 B is not 1 we change the sign of the result. */
482 /* In general we can't negate B in A / B, because if A is INT_MIN and
483 B is 1, we may turn this into INT_MIN / -1 which is undefined
484 and actually traps on some architectures. */
493 /* Negate -((double)float) as (double)(-float). */
495 {
499 }
503 /* Negate -f(x) as f(-x). */
509 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
511 {
515 }
520 }
522 }
524 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
525 simplification is possible.
526 If negate_expr_p would return true for T, NULL_TREE will never be
527 returned. */
529 static tree
531 {
533 tree tem;
536 {
537 /* Convert - (~A) to A + 1. */
561 {
566 }
570 {
571 tree_vector_builder elts;
575 {
580 }
583 }
606 {
607 /* -(A + B) -> (-B) - A. */
609 {
613 }
615 /* -(A + B) -> (-A) - B. */
617 {
621 }
622 }
626 /* - (A - B) -> B - A */
637 /* Fall through. */
641 {
650 }
658 /* In general we can't negate A in A / B, because if A is INT_MIN and
659 B is not 1 we change the sign of the result. */
665 /* In general we can't negate B in A / B, because if A is INT_MIN and
666 B is 1, we may turn this into INT_MIN / -1 which is undefined
667 and actually traps on some architectures. */
679 /* Convert -((double)float) into (double)(-float). */
681 {
685 }
689 /* Negate -f(x) as f(-x). */
692 {
698 }
702 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
704 {
707 {
714 }
715 }
720 }
723 }
725 /* A wrapper for fold_negate_expr_1. */
727 static tree
729 {
736 }
738 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
739 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
740 return NULL_TREE. */
742 static tree
744 {
746 location_t loc;
759 }
760 \f
761 /* Split a tree IN into a constant, literal and variable parts that could be
762 combined with CODE to make IN. "constant" means an expression with
763 TREE_CONSTANT but that isn't an actual constant. CODE must be a
764 commutative arithmetic operation. Store the constant part into *CONP,
765 the literal in *LITP and return the variable part. If a part isn't
766 present, set it to null. If the tree does not decompose in this way,
767 return the entire tree as the variable part and the other parts as null.
769 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
770 case, we negate an operand that was subtracted. Except if it is a
771 literal for which we use *MINUS_LITP instead.
773 If NEGATE_P is true, we are negating all of IN, again except a literal
774 for which we use *MINUS_LITP instead. If a variable part is of pointer
775 type, it is negated after converting to TYPE. This prevents us from
776 generating illegal MINUS pointer expression. LOC is the location of
777 the converted variable part.
779 If IN is itself a literal or constant, return it as appropriate.
781 Note that we do not guarantee that any of the three values will be the
782 same type as IN, but they will have the same signedness and mode. */
784 static tree
788 {
796 /* Strip any conversions that don't change the machine mode or signedness. */
805 /* We can associate addition and subtraction together (even
806 though the C standard doesn't say so) for integers because
807 the value is not affected. For reals, the value might be
808 affected, so we can't. */
814 {
820 /* First see if either of the operands is a literal, then a constant. */
833 /* If we haven't dealt with either operand, this is not a case we can
834 decompose. Otherwise, VAR is either of the ones remaining, if any. */
839 else
842 /* Now do any needed negations. */
849 }
854 {
855 /* -1 - X is folded to ~X, undo that here. Do _not_ do this
856 when IN is constant. */
859 }
860 else
864 {
877 }
887 }
889 /* Re-associate trees split by the above function. T1 and T2 are
890 either expressions to associate or null. Return the new
891 expression, if any. LOC is the location of the new expression. If
892 we build an operation, do it in TYPE and with CODE. */
894 static tree
896 {
898 {
901 }
905 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
906 try to fold this since we will have infinite recursion. But do
907 deal with any NEGATE_EXPRs. */
911 {
913 {
926 }
928 {
931 }
935 }
939 }
940 \f
941 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
942 for use in int_const_binop, size_binop and size_diffop. */
944 static bool
946 {
953 {
962 }
967 }
969 /* Subroutine of int_const_binop_1 that handles two INTEGER_CSTs. */
971 static tree
974 {
975 wide_int res;
976 tree t;
985 {
1001 {
1005 else
1007 }
1010 /* It's unclear from the C standard whether shifts can overflow.
1011 The following code ignores overflow; perhaps a C standard
1012 interpretation ruling is needed. */
1014 else
1021 {
1025 else
1027 }
1031 else
1110 }
1118 }
1120 /* Combine two integer constants PARG1 and PARG2 under operation CODE
1121 to produce a new constant. Return NULL_TREE if we don't know how
1122 to evaluate CODE at compile-time. */
1124 static tree
1127 {
1134 {
1135 poly_wide_int res;
1140 {
1158 else
1165 else
1178 }
1183 }
1186 }
1188 tree
1190 {
1192 }
1194 /* Return true if binary operation OP distributes over addition in operand
1195 OPNO, with the other operand being held constant. OPNO counts from 1. */
1197 static bool
1199 {
1201 {
1212 }
1213 }
1215 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1216 constant. We assume ARG1 and ARG2 have the same data type, or at least
1217 are the same kind of constant and the same machine mode. Return zero if
1218 combining the constants is not allowed in the current operating mode. */
1220 static tree
1222 {
1223 /* Sanity check for the recursive cases. */
1231 {
1237 }
1240 {
1241 machine_mode mode;
1242 REAL_VALUE_TYPE d1;
1243 REAL_VALUE_TYPE d2;
1244 REAL_VALUE_TYPE value;
1245 REAL_VALUE_TYPE result;
1249 /* The following codes are handled by real_arithmetic. */
1251 {
1262 }
1270 /* Don't perform operation if we honor signaling NaNs and
1271 either operand is a signaling NaN. */
1277 /* Don't perform operation if it would raise a division
1278 by zero exception. */
1284 /* If either operand is a NaN, just return it. Otherwise, set up
1285 for floating-point trap; we return an overflow. */
1287 {
1288 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1289 is off. */
1293 }
1295 {
1296 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1297 is off. */
1301 }
1306 /* Don't constant fold this floating point operation if
1307 the result has overflowed and flag_trapping_math. */
1315 /* Don't constant fold this floating point operation if the
1316 result may dependent upon the run-time rounding mode and
1317 flag_rounding_math is set, or if GCC's software emulation
1318 is unable to accurately represent the result. */
1328 }
1331 {
1332 FIXED_VALUE_TYPE f1;
1333 FIXED_VALUE_TYPE f2;
1334 FIXED_VALUE_TYPE result;
1339 /* The following codes are handled by fixed_arithmetic. */
1341 {
1353 {
1360 }
1365 }
1372 /* Propagate overflow flags. */
1376 }
1379 {
1388 {
1399 mpc_mul);
1413 mpc_div);
1414 /* Fallthru. */
1420 {
1421 /* Keep this algorithm in sync with
1422 tree-complex.c:expand_complex_div_straight().
1424 Expand complex division to scalars, straightforward algorithm.
1425 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1426 t = br*br + bi*bi
1427 */
1428 tree magsquared
1432 tree t1
1436 tree t2
1443 }
1444 else
1445 {
1446 /* Keep this algorithm in sync with
1447 tree-complex.c:expand_complex_div_wide().
1449 Expand complex division to scalars, modified algorithm to minimize
1450 overflow with wide input ranges. */
1456 {
1457 /* In the TRUE branch, we compute
1458 ratio = br/bi;
1459 div = (br * ratio) + bi;
1460 tr = (ar * ratio) + ai;
1461 ti = (ai * ratio) - ar;
1462 tr = tr / div;
1463 ti = ti / div; */
1474 }
1475 else
1476 {
1477 /* In the FALSE branch, we compute
1478 ratio = d/c;
1479 divisor = (d * ratio) + c;
1480 tr = (b * ratio) + a;
1481 ti = b - (a * ratio);
1482 tr = tr / div;
1483 ti = ti / div; */
1495 }
1496 }
1501 }
1505 }
1511 {
1516 /* We can operate directly on the encoding if:
1518 a3 - a2 == a2 - a1 && b3 - b2 == b2 - b1
1519 implies
1520 (a3 op b3) - (a2 op b2) == (a2 op b2) - (a1 op b1)
1522 Addition and subtraction are the supported operators
1523 for which this is true. */
1526 /* We can operate directly on stepped encodings if:
1528 a3 - a2 == a2 - a1
1529 implies:
1530 (a3 op c) - (a2 op c) == (a2 op c) - (a1 op c)
1532 which is true if (x -> x op c) distributes over addition. */
1534 else
1535 /* Similarly in reverse. */
1537 tree_vector_builder elts;
1542 {
1548 /* It is possible that const_binop cannot handle the given
1549 code and return NULL_TREE */
1553 }
1556 }
1558 /* Shifts allow a scalar offset for a vector. */
1561 {
1564 tree_vector_builder elts;
1569 {
1574 /* It is possible that const_binop cannot handle the given
1575 code and return NULL_TREE. */
1579 }
1582 }
1584 }
1586 /* Overload that adds a TYPE parameter to be able to dispatch
1587 to fold_relational_const. */
1589 tree
1591 {
1595 /* ??? Until we make the const_binop worker take the type of the
1596 result as argument put those cases that need it here. */
1598 {
1615 {
1620 }
1625 {
1641 {
1651 }
1654 }
1660 {
1683 {
1696 }
1699 }
1702 }
1707 /* Make sure type and arg0 have the same saturating flag. */
1712 }
1714 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1715 Return zero if computing the constants is not possible. */
1717 tree
1719 {
1720 /* Don't perform the operation, other than NEGATE and ABS, if
1721 flag_signaling_nans is on and the operand is a signaling NaN. */
1730 {
1731 CASE_CONVERT:
1738 /* If the source address is 0, and the source address space
1739 cannot have a valid object at 0, fold to dest type null. */
1750 {
1751 /* Can't call fold_negate_const directly here as that doesn't
1752 handle all cases and we might not be able to negate some
1753 constants. */
1758 }
1767 {
1771 }
1779 /* Perform BIT_NOT_EXPR on each element individually. */
1781 {
1782 tree elem;
1784 /* This can cope with stepped encodings because ~x == -1 - x. */
1785 tree_vector_builder elements;
1789 {
1795 }
1798 }
1820 {
1839 else
1844 {
1850 }
1853 }
1862 }
1865 }
1867 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1868 indicates which particular sizetype to create. */
1870 tree
1872 {
1874 }
1875 \f
1876 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1877 is a tree code. The type of the result is taken from the operands.
1878 Both must be equivalent integer types, ala int_binop_types_match_p.
1879 If the operands are constant, so is the result. */
1881 tree
1883 {
1892 /* Handle the special case of two poly_int constants faster. */
1894 {
1895 /* And some specific cases even faster than that. */
1897 {
1902 }
1904 {
1907 }
1909 {
1912 }
1914 /* Handle general case of two integer constants. For sizetype
1915 constant calculations we always want to know about overflow,
1916 even in the unsigned case. */
1920 }
1923 }
1925 /* Given two values, either both of sizetype or both of bitsizetype,
1926 compute the difference between the two values. Return the value
1927 in signed type corresponding to the type of the operands. */
1929 tree
1931 {
1933 tree ctype;
1938 /* If the type is already signed, just do the simple thing. */
1946 else
1949 /* If either operand is not a constant, do the conversions to the signed
1950 type and subtract. The hardware will do the right thing with any
1951 overflow in the subtraction. */
1957 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1958 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1959 overflow) and negate (which can't either). Special-case a result
1960 of zero while we're here. */
1966 else
1970 MINUS_EXPR,
1972 }
1973 \f
1974 /* A subroutine of fold_convert_const handling conversions of an
1975 INTEGER_CST to another integer type. */
1977 static tree
1979 {
1980 /* Given an integer constant, make new constant with new type,
1981 appropriately sign-extended or truncated. Use widest_int
1982 so that any extension is done according ARG1's type. */
1986 }
1988 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1989 to an integer type. */
1991 static tree
1993 {
1995 tree t;
1997 /* The following code implements the floating point to integer
1998 conversion rules required by the Java Language Specification,
1999 that IEEE NaNs are mapped to zero and values that overflow
2000 the target precision saturate, i.e. values greater than
2001 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2002 are mapped to INT_MIN. These semantics are allowed by the
2003 C and C++ standards that simply state that the behavior of
2004 FP-to-integer conversion is unspecified upon overflow. */
2006 wide_int val;
2007 REAL_VALUE_TYPE r;
2011 {
2018 }
2020 /* If R is NaN, return zero and show we have an overflow. */
2022 {
2025 }
2027 /* See if R is less than the lower bound or greater than the
2028 upper bound. */
2031 {
2035 {
2038 }
2039 }
2042 {
2045 {
2048 {
2051 }
2052 }
2053 }
2060 }
2062 /* A subroutine of fold_convert_const handling conversions of a
2063 FIXED_CST to an integer type. */
2065 static tree
2067 {
2068 tree t;
2070 scalar_mode mode;
2072 /* Right shift FIXED_CST to temp by fbit. */
2076 {
2078 HOST_BITS_PER_DOUBLE_INT,
2081 /* Left shift temp to temp_trunc by fbit. */
2083 HOST_BITS_PER_DOUBLE_INT,
2085 }
2086 else
2087 {
2090 }
2092 /* If FIXED_CST is negative, we need to round the value toward 0.
2093 By checking if the fractional bits are not zero to add 1 to temp. */
2099 /* Given a fixed-point constant, make new constant with new type,
2100 appropriately sign-extended or truncated. */
2108 }
2110 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2111 to another floating point type. */
2113 static tree
2115 {
2116 REAL_VALUE_TYPE value;
2117 tree t;
2119 /* Don't perform the operation if flag_signaling_nans is on
2120 and the operand is a signaling NaN. */
2128 /* If converting an infinity or NAN to a representation that doesn't
2129 have one, set the overflow bit so that we can produce some kind of
2130 error message at the appropriate point if necessary. It's not the
2131 most user-friendly message, but it's better than nothing. */
2138 /* Regular overflow, conversion produced an infinity in a mode that
2139 can't represent them. */
2144 else
2147 }
2149 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2150 to a floating point type. */
2152 static tree
2154 {
2155 REAL_VALUE_TYPE value;
2156 tree t;
2164 }
2166 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2167 to another fixed-point type. */
2169 static tree
2171 {
2172 FIXED_VALUE_TYPE value;
2173 tree t;
2180 /* Propagate overflow flags. */
2184 }
2186 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2187 to a fixed-point type. */
2189 static tree
2191 {
2192 FIXED_VALUE_TYPE value;
2193 tree t;
2195 double_int di;
2202 else
2210 /* Propagate overflow flags. */
2214 }
2216 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2217 to a fixed-point type. */
2219 static tree
2221 {
2222 FIXED_VALUE_TYPE value;
2223 tree t;
2231 /* Propagate overflow flags. */
2235 }
2237 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2238 type TYPE. If no simplification can be done return NULL_TREE. */
2240 static tree
2242 {
2247 /* We can't widen types, since the runtime value could overflow the
2248 original type before being extended to the new type. */
2259 {
2266 }
2268 {
2275 }
2277 {
2284 }
2286 {
2289 {
2292 /* We can't handle steps directly when extending, since the
2293 values need to wrap at the original precision first. */
2294 bool step_ok_p
2298 tree_vector_builder v;
2303 {
2309 }
2311 }
2312 }
2314 }
2316 /* Construct a vector of zero elements of vector type TYPE. */
2318 static tree
2320 {
2321 tree t;
2325 }
2327 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2329 bool
2331 {
2346 {
2361 }
2362 }
2364 /* Convert expression ARG to type TYPE. Used by the middle-end for
2365 simple conversions in preference to calling the front-end's convert. */
2367 tree
2369 {
2371 tree tem;
2382 {
2385 /* Handle conversions between pointers to different address spaces. */
2390 /* fall through */
2395 {
2399 }
2413 {
2417 }
2419 {
2423 }
2425 {
2429 }
2432 {
2450 }
2455 {
2459 }
2462 {
2476 }
2480 {
2489 integer_zero_node));
2491 {
2495 {
2501 }
2509 }
2513 }
2531 }
2532 fold_convert_exit:
2535 }
2536 \f
2537 /* Return false if expr can be assumed not to be an lvalue, true
2538 otherwise. */
2540 static bool
2542 {
2543 /* We only need to wrap lvalue tree codes. */
2545 {
2576 /* Assume the worst for front-end tree codes. */
2580 }
2583 }
2585 /* Return an expr equal to X but certainly not valid as an lvalue. */
2587 tree
2589 {
2590 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2591 us. */
2598 }
2600 /* When pedantic, return an expr equal to X but certainly not valid as a
2601 pedantic lvalue. Otherwise, return X. */
2603 static tree
2605 {
2607 }
2608 \f
2609 /* Given a tree comparison code, return the code that is the logical inverse.
2610 It is generally not safe to do this for floating-point comparisons, except
2611 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2612 ERROR_MARK in this case. */
2614 enum tree_code
2616 {
2622 {
2653 }
2654 }
2656 /* Similar, but return the comparison that results if the operands are
2657 swapped. This is safe for floating-point. */
2659 enum tree_code
2661 {
2663 {
2689 }
2690 }
2693 /* Convert a comparison tree code from an enum tree_code representation
2694 into a compcode bit-based encoding. This function is the inverse of
2695 compcode_to_comparison. */
2697 static enum comparison_code
2699 {
2701 {
2732 }
2733 }
2735 /* Convert a compcode bit-based encoding of a comparison operator back
2736 to GCC's enum tree_code representation. This function is the
2737 inverse of comparison_to_compcode. */
2739 static enum tree_code
2741 {
2743 {
2774 }
2775 }
2777 /* Return a tree for the comparison which is the combination of
2778 doing the AND or OR (depending on CODE) of the two operations LCODE
2779 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2780 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2781 if this makes the transformation invalid. */
2783 tree
2788 {
2795 {
2806 }
2809 {
2810 /* Eliminate unordered comparisons, as well as LTGT and ORD
2811 which are not used unless the mode has NaNs. */
2817 }
2819 {
2820 /* Check that the original operation and the optimized ones will trap
2821 under the same condition. */
2832 /* In a short-circuited boolean expression the LHS might be
2833 such that the RHS, if evaluated, will never trap. For
2834 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2835 if neither x nor y is NaN. (This is a mixed blessing: for
2836 example, the expression above will never trap, hence
2837 optimizing it to x < y would be invalid). */
2842 /* If the comparison was short-circuited, and only the RHS
2843 trapped, we may now generate a spurious trap. */
2848 /* If we changed the conditions that cause a trap, we lose. */
2851 }
2857 else
2858 {
2863 }
2864 }
2865 \f
2866 /* Return nonzero if two operands (typically of the same tree node)
2867 are necessarily equal. FLAGS modifies behavior as follows:
2869 If OEP_ONLY_CONST is set, only return nonzero for constants.
2870 This function tests whether the operands are indistinguishable;
2871 it does not test whether they are equal using C's == operation.
2872 The distinction is important for IEEE floating point, because
2873 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2874 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2876 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2877 even though it may hold multiple values during a function.
2878 This is because a GCC tree node guarantees that nothing else is
2879 executed between the evaluation of its "operands" (which may often
2880 be evaluated in arbitrary order). Hence if the operands themselves
2881 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2882 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2883 unset means assuming isochronic (or instantaneous) tree equivalence.
2884 Unless comparing arbitrary expression trees, such as from different
2885 statements, this flag can usually be left unset.
2887 If OEP_PURE_SAME is set, then pure functions with identical arguments
2888 are considered the same. It is used when the caller has other ways
2889 to ensure that global memory is unchanged in between.
2891 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2892 not values of expressions.
2894 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
2895 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
2897 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2898 any operand with side effect. This is unnecesarily conservative in the
2899 case we know that arg0 and arg1 are in disjoint code paths (such as in
2900 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2901 addresses with TREE_CONSTANT flag set so we know that &var == &var
2902 even if var is volatile. */
2904 int
2906 {
2907 /* When checking, verify at the outermost operand_equal_p call that
2908 if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
2909 hash value. */
2911 {
2913 {
2915 {
2922 }
2924 }
2925 else
2927 }
2929 /* If either is ERROR_MARK, they aren't equal. */
2935 /* Similar, if either does not have a type (like a released SSA name),
2936 they aren't equal. */
2940 /* We cannot consider pointers to different address space equal. */
2947 /* Check equality of integer constants before bailing out due to
2948 precision differences. */
2950 {
2951 /* Address of INTEGER_CST is not defined; check that we did not forget
2952 to drop the OEP_ADDRESS_OF flags. */
2955 }
2958 {
2959 /* If both types don't have the same signedness, then we can't consider
2960 them equal. We must check this before the STRIP_NOPS calls
2961 because they may change the signedness of the arguments. As pointers
2962 strictly don't have a signedness, require either two pointers or
2963 two non-pointers as well. */
2969 /* If both types don't have the same precision, then it is not safe
2970 to strip NOPs. */
2977 }
2978 #if 0
2979 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
2980 sanity check once the issue is solved. */
2981 else
2982 /* Addresses of conversions and SSA_NAMEs (and many other things)
2983 are not defined. Check that we did not forget to drop the
2984 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
2987 #endif
2989 /* In case both args are comparisons but with different comparison
2990 code, try to swap the comparison operands of one arg to produce
2991 a match and compare that variant. */
2995 {
3003 }
3006 {
3007 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
3009 ;
3011 {
3012 /* If we are interested in comparing addresses ignore
3013 MEM_REF wrappings of the base that can appear just for
3014 TBAA reasons. */
3028 }
3029 else
3031 }
3033 /* When not checking adddresses, this is needed for conversions and for
3034 COMPONENT_REF. Might as well play it safe and always test this. */
3041 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3042 We don't care about side effects in that case because the SAVE_EXPR
3043 takes care of that for us. In all other cases, two expressions are
3044 equal if they have no side effects. If we have two identical
3045 expressions with side effects that should be treated the same due
3046 to the only side effects being identical SAVE_EXPR's, that will
3047 be detected in the recursive calls below.
3048 If we are taking an invariant address of two identical objects
3049 they are necessarily equal as well. */
3056 /* Next handle constant cases, those for which we can return 1 even
3057 if ONLY_CONST is set. */
3060 {
3074 {
3075 /* If we do not distinguish between signed and unsigned zero,
3076 consider them equal. */
3079 }
3083 {
3098 }
3102 flags)
3104 flags));
3115 flags | OEP_ADDRESS_OF
3118 /* In GIMPLE empty constructors are allowed in initializers of
3119 aggregates. */
3123 }
3128 /* Define macros to test an operand from arg0 and arg1 for equality and a
3129 variant that allows null and views null as being different from any
3130 non-null value. In the latter case, if either is null, the both
3131 must be; otherwise, do the normal comparison. */
3132 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3133 TREE_OPERAND (arg1, N), flags)
3135 #define OP_SAME_WITH_NULL(N) \
3136 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3137 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3140 {
3142 /* Two conversions are equal only if signedness and modes match. */
3144 {
3145 CASE_CONVERT:
3153 }
3163 /* For commutative ops, allow the other order. */
3171 /* If either of the pointer (or reference) expressions we are
3172 dereferencing contain a side effect, these cannot be equal,
3173 but their addresses can be. */
3180 {
3190 /* Require the same offset. */
3196 /* Fallthru. */
3204 {
3205 /* Require equal access sizes */
3211 flags)))
3213 /* Verify that access happens in similar types. */
3216 /* Verify that accesses are TBAA compatible. */
3225 /* Verify that alignment is compatible. */
3229 }
3232 /* TARGET_MEM_REF require equal extra operands. */
3243 /* Compare the array index by value if it is constant first as we
3244 may have different types but same value here. */
3250 /* Compare low bound and element size as with OEP_ADDRESS_OF
3251 we have to account for the offset of the ref. */
3256 array_ref_low_bound
3260 array_ref_element_size
3262 flags))));
3265 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3266 may be NULL when we're called to compare MEM_EXPRs. */
3281 }
3285 {
3287 /* Be sure we pass right ADDRESS_OF flag. */
3305 /* The multiplcation operands are commutative. */
3306 /* FALLTHRU */
3314 /* Otherwise take into account this is a commutative operation. */
3327 /* BIT_INSERT_EXPR has an implict operand as the type precision
3328 of op1. Need to check to make sure they are the same. */
3334 /* FALLTHRU */
3359 }
3363 {
3367 /* If not both CALL_EXPRs are either internal or normal function
3368 functions, then they are not equal. */
3371 {
3372 /* If the CALL_EXPRs call different internal functions, then they
3373 are not equal. */
3376 }
3377 else
3378 {
3379 /* If the CALL_EXPRs call different functions, then they are not
3380 equal. */
3382 flags))
3384 }
3386 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3387 {
3391 else
3395 }
3397 /* Now see if all the arguments are the same. */
3398 {
3409 /* If we get here and both argument lists are exhausted
3410 then the CALL_EXPRs are equal. */
3412 }
3415 }
3418 /* Consider __builtin_sqrt equal to sqrt. */
3426 {
3427 /* In GIMPLE constructors are used only to build vectors from
3428 elements. Individual elements in the constructor must be
3429 indexed in increasing order and form an initial sequence.
3431 We make no effort to compare constructors in generic.
3432 (see sem_variable::equals in ipa-icf which can do so for
3433 constants). */
3438 /* Be sure that vectors constructed have the same representation.
3439 We only tested element precision and modes to match.
3440 Vectors may be BLKmode and thus also check that the number of
3441 parts match. */
3454 {
3459 /* In GIMPLE the indexes can be either NULL or matching i.
3460 Double check this so we won't get false
3461 positives for GENERIC. */
3469 }
3471 }
3474 {
3475 /* Compare the STATEMENT_LISTs. */
3481 {
3482 /* The lists don't have the same number of statements. */
3488 flags & (OEP_LEXICOGRAPHIC
3491 }
3492 }
3497 {
3508 }
3512 }
3514 #undef OP_SAME
3515 #undef OP_SAME_WITH_NULL
3516 }
3517 \f
3518 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
3519 with a different signedness or a narrower precision. */
3521 static bool
3523 {
3531 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3532 and see if the inner values are the same. This removes any
3533 signedness comparison, which doesn't matter here. */
3541 /* Discard a single widening conversion from ARG1 and see if the inner
3542 value is the same as ARG0. */
3551 }
3552 \f
3553 /* See if ARG is an expression that is either a comparison or is performing
3554 arithmetic on comparisons. The comparisons must only be comparing
3555 two different values, which will be stored in *CVAL1 and *CVAL2; if
3556 they are nonzero it means that some operands have already been found.
3557 No variables may be used anywhere else in the expression except in the
3558 comparisons.
3560 If this is true, return 1. Otherwise, return zero. */
3562 static int
3564 {
3568 /* We can handle some of the tcc_expression cases here. */
3577 {
3596 /* First see if we can handle the first operand, then the second. For
3597 the second operand, we know *CVAL1 can't be zero. It must be that
3598 one side of the comparison is each of the values; test for the
3599 case where this isn't true by failing if the two operands
3600 are the same. */
3609 ;
3613 ;
3614 else
3618 ;
3622 ;
3623 else
3630 }
3631 }
3632 \f
3633 /* ARG is a tree that is known to contain just arithmetic operations and
3634 comparisons. Evaluate the operations in the tree substituting NEW0 for
3635 any occurrence of OLD0 as an operand of a comparison and likewise for
3636 NEW1 and OLD1. */
3638 static tree
3641 {
3646 /* We can handle some of the tcc_expression cases here. */
3654 {
3669 {
3688 }
3689 /* Fall through - ??? */
3692 {
3696 /* We need to check both for exact equality and tree equality. The
3697 former will be true if the operand has a side-effect. In that
3698 case, we know the operand occurred exactly once. */
3711 }
3715 }
3716 }
3717 \f
3718 /* Return a tree for the case when the result of an expression is RESULT
3719 converted to TYPE and OMITTED was previously an operand of the expression
3720 but is now not needed (e.g., we folded OMITTED * 0).
3722 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3723 the conversion of RESULT to TYPE. */
3725 tree
3727 {
3730 /* If the resulting operand is an empty statement, just return the omitted
3731 statement casted to void. */
3741 }
3743 /* Return a tree for the case when the result of an expression is RESULT
3744 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3745 of the expression but are now not needed.
3747 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3748 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3749 evaluated before OMITTED2. Otherwise, if neither has side effects,
3750 just do the conversion of RESULT to TYPE. */
3752 tree
3755 {
3764 }
3766 \f
3767 /* Return a simplified tree node for the truth-negation of ARG. This
3768 never alters ARG itself. We assume that ARG is an operation that
3769 returns a truth value (0 or 1).
3771 FIXME: one would think we would fold the result, but it causes
3772 problems with the dominator optimizer. */
3774 static tree
3776 {
3781 /* If this is a comparison, we can simply invert it, except for
3782 floating-point non-equality comparisons, in which case we just
3783 enclose a TRUTH_NOT_EXPR around what we have. */
3786 {
3789 && flag_trapping_math
3803 }
3806 {
3825 /* Here we can invert either operand. We invert the first operand
3826 unless the second operand is a TRUTH_NOT_EXPR in which case our
3827 result is the XOR of the first operand with the inside of the
3828 negation of the second operand. */
3833 else
3856 {
3863 /* A COND_EXPR may have a throw as one operand, which
3864 then has void type. Just leave void operands
3865 as they are. */
3871 }
3883 CASE_CONVERT:
3887 /* fall through */
3909 }
3910 }
3912 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3913 assume that ARG is an operation that returns a truth value (0 or 1
3914 for scalars, 0 or -1 for vectors). Return the folded expression if
3915 folding is successful. Otherwise, return NULL_TREE. */
3917 static tree
3919 {
3922 ? BIT_NOT_EXPR
3925 }
3927 /* Return a simplified tree node for the truth-negation of ARG. This
3928 never alters ARG itself. We assume that ARG is an operation that
3929 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3931 tree
3933 {
3939 ? BIT_NOT_EXPR
3942 }
3943 \f
3944 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3945 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
3946 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
3947 is the original memory reference used to preserve the alias set of
3948 the access. */
3950 static tree
3954 {
3957 /* Attempt not to lose the access path if possible. */
3959 {
3961 machine_mode nmode;
3963 tree noffset;
3971 && !reversep
3972 && !nreversep
3974 {
3977 }
3978 }
3987 {
3994 }
4009 }
4011 /* Optimize a bit-field compare.
4013 There are two cases: First is a compare against a constant and the
4014 second is a comparison of two items where the fields are at the same
4015 bit position relative to the start of a chunk (byte, halfword, word)
4016 large enough to contain it. In these cases we can avoid the shift
4017 implicit in bitfield extractions.
4019 For constants, we emit a compare of the shifted constant with the
4020 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4021 compared. For two fields at the same position, we do the ANDs with the
4022 similar mask and compare the result of the ANDs.
4024 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4025 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4026 are the left and right operands of the comparison, respectively.
4028 If the optimization described above can be done, we return the resulting
4029 tree. Otherwise we return zero. */
4031 static tree
4034 {
4038 tree unsigned_type;
4041 scalar_int_mode nmode;
4046 tree mask;
4047 tree offset;
4049 /* Get all the information about the extractions being done. If the bit size
4050 is the same as the size of the underlying object, we aren't doing an
4051 extraction at all and so can do nothing. We also don't want to
4052 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4053 then will no longer be able to replace it. */
4068 else
4069 {
4070 /* If this is not a constant, we can only do something if bit positions,
4071 sizes, signedness and storage order are the same. */
4072 rinner
4085 }
4087 /* Honor the C++ memory model and mimic what RTL expansion does. */
4091 {
4095 }
4097 /* See if we can find a mode to refer to this field. We should be able to,
4098 but fail if we can't. */
4106 /* Set signed and unsigned types of the precision of this mode for the
4107 shifts below. */
4110 /* Compute the bit position and size for the new reference and our offset
4111 within it. If the new reference is the same size as the original, we
4112 won't optimize anything, so return zero. */
4122 /* Make the mask to be used against the extracted field. */
4129 {
4133 /* If not comparing with constant, just rework the comparison
4134 and return. */
4142 }
4144 /* Otherwise, we are handling the constant case. See if the constant is too
4145 big for the field. Warn and return a tree for 0 (false) if so. We do
4146 this not only for its own sake, but to avoid having to test for this
4147 error case below. If we didn't, we might generate wrong code.
4149 For unsigned fields, the constant shifted right by the field length should
4150 be all zero. For signed fields, the high-order bits should agree with
4151 the sign bit. */
4154 {
4156 {
4160 }
4161 }
4162 else
4163 {
4166 {
4170 }
4171 }
4176 /* Single-bit compares should always be against zero. */
4178 {
4181 }
4183 /* Make a new bitfield reference, shift the constant over the
4184 appropriate number of bits and mask it with the computed mask
4185 (in case this was a signed field). If we changed it, make a new one. */
4193 mask);
4198 }
4199 \f
4200 /* Subroutine for fold_truth_andor_1: decode a field reference.
4202 If EXP is a comparison reference, we return the innermost reference.
4204 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4205 set to the starting bit number.
4207 If the innermost field can be completely contained in a mode-sized
4208 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4210 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4211 otherwise it is not changed.
4213 *PUNSIGNEDP is set to the signedness of the field.
4215 *PREVERSEP is set to the storage order of the field.
4217 *PMASK is set to the mask used. This is either contained in a
4218 BIT_AND_EXPR or derived from the width of the field.
4220 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4222 Return 0 if this is not a component reference or is one that we can't
4223 do anything with. */
4225 static tree
4230 {
4235 tree unsigned_type;
4238 /* All the optimizations using this function assume integer fields.
4239 There are problems with FP fields since the type_for_size call
4240 below can fail for, e.g., XFmode. */
4244 /* We are interested in the bare arrangement of bits, so strip everything
4245 that doesn't affect the machine mode. However, record the type of the
4246 outermost expression if it may matter below. */
4253 {
4259 }
4270 /* Reject out-of-bound accesses (PR79731). */
4278 /* If the number of bits in the reference is the same as the bitsize of
4279 the outer type, then the outer type gives the signedness. Otherwise
4280 (in case of a small bitfield) the signedness is unchanged. */
4284 /* Compute the mask to access the bitfield. */
4293 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4301 }
4303 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4304 bit positions and MASK is SIGNED. */
4306 static int
4308 {
4312 /* If this function returns true when the type of the mask is
4313 UNSIGNED, then there will be errors. In particular see
4314 gcc.c-torture/execute/990326-1.c. There does not appear to be
4315 any documentation paper trail as to why this is so. But the pre
4316 wide-int worked with that restriction and it has been preserved
4317 here. */
4322 }
4324 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4325 represents the sign bit of EXP's type. If EXP represents a sign
4326 or zero extension, also test VAL against the unextended type.
4327 The return value is the (sub)expression whose sign bit is VAL,
4328 or NULL_TREE otherwise. */
4330 tree
4332 {
4334 tree t;
4336 /* Tree EXP must have an integral type. */
4341 /* Tree VAL must be an integer constant. */
4350 /* Handle extension from a narrower type. */
4356 }
4358 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4359 to be evaluated unconditionally. */
4361 static int
4363 {
4364 /* Strip any conversions that don't change the machine mode. */
4373 /* Don't regard global variables as simple. They may be
4374 allocated in ways unknown to the compiler (shared memory,
4375 #pragma weak, etc). */
4378 /* Weakrefs are not safe to be read, since they can be NULL.
4379 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4380 have DECL_WEAK flag set. */
4382 /* Loading a static variable is unduly expensive, but global
4383 registers aren't expensive. */
4385 }
4387 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4388 to be evaluated unconditionally.
4389 I addition to simple_operand_p, we assume that comparisons, conversions,
4390 and logic-not operations are simple, if their operands are simple, too. */
4392 static bool
4394 {
4414 }
4416 \f
4417 /* The following functions are subroutines to fold_range_test and allow it to
4418 try to change a logical combination of comparisons into a range test.
4420 For example, both
4421 X == 2 || X == 3 || X == 4 || X == 5
4422 and
4423 X >= 2 && X <= 5
4424 are converted to
4425 (unsigned) (X - 2) <= 3
4427 We describe each set of comparisons as being either inside or outside
4428 a range, using a variable named like IN_P, and then describe the
4429 range with a lower and upper bound. If one of the bounds is omitted,
4430 it represents either the highest or lowest value of the type.
4432 In the comments below, we represent a range by two numbers in brackets
4433 preceded by a "+" to designate being inside that range, or a "-" to
4434 designate being outside that range, so the condition can be inverted by
4435 flipping the prefix. An omitted bound is represented by a "-". For
4436 example, "- [-, 10]" means being outside the range starting at the lowest
4437 possible value and ending at 10, in other words, being greater than 10.
4438 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4439 always false.
4441 We set up things so that the missing bounds are handled in a consistent
4442 manner so neither a missing bound nor "true" and "false" need to be
4443 handled using a special case. */
4445 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4446 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4447 and UPPER1_P are nonzero if the respective argument is an upper bound
4448 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4449 must be specified for a comparison. ARG1 will be converted to ARG0's
4450 type if both are specified. */
4452 static tree
4455 {
4456 tree tem;
4460 /* If neither arg represents infinity, do the normal operation.
4461 Else, if not a comparison, return infinity. Else handle the special
4462 comparison rules. Note that most of the cases below won't occur, but
4463 are handled for consistency. */
4466 {
4471 }
4476 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4477 for neither. In real maths, we cannot assume open ended ranges are
4478 the same. But, this is computer arithmetic, where numbers are finite.
4479 We can therefore make the transformation of any unbounded range with
4480 the value Z, Z being greater than any representable number. This permits
4481 us to treat unbounded ranges as equal. */
4485 {
4506 }
4509 }
4510 \f
4511 /* Helper routine for make_range. Perform one step for it, return
4512 new expression if the loop should continue or NULL_TREE if it should
4513 stop. */
4515 tree
4519 {
4525 {
4527 /* We can only do something if the range is testing for zero. */
4536 /* We can only do something if the range is testing for zero
4537 and if the second operand is an integer constant. Note that
4538 saying something is "in" the range we make is done by
4539 complementing IN_P since it will set in the initial case of
4540 being not equal to zero; "out" is leaving it alone. */
4547 {
4568 }
4570 /* If this is an unsigned comparison, we also know that EXP is
4571 greater than or equal to zero. We base the range tests we make
4572 on that fact, so we record it here so we can parse existing
4573 range tests. We test arg0_type since often the return type
4574 of, e.g. EQ_EXPR, is boolean. */
4576 {
4580 NULL_TREE))
4585 /* If the high bound is missing, but we have a nonzero low
4586 bound, reverse the range so it goes from zero to the low bound
4587 minus 1. */
4589 {
4594 }
4595 }
4603 /* If flag_wrapv and ARG0_TYPE is signed, make sure
4604 low and high are non-NULL, then normalize will DTRT. */
4607 {
4612 }
4614 /* (-x) IN [a,b] -> x in [-b, -a] */
4626 /* ~ X -> -X - 1 */
4635 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4636 move a constant to the other side. */
4641 /* If EXP is signed, any overflow in the computation is undefined,
4642 so we don't worry about it so long as our computations on
4643 the bounds don't overflow. For unsigned, overflow is defined
4644 and this is exactly the right thing. */
4656 normalize:
4657 /* Check for an unsigned range which has wrapped around the maximum
4658 value thus making n_high < n_low, and normalize it. */
4660 {
4666 /* If the range is of the form +/- [ x+1, x ], we won't
4667 be able to normalize it. But then, it represents the
4668 whole range or the empty set, so make it
4669 +/- [ -, - ]. */
4673 else
4675 }
4676 else
4684 CASE_CONVERT:
4702 /* If we're converting arg0 from an unsigned type, to exp,
4703 a signed type, we will be doing the comparison as unsigned.
4704 The tests above have already verified that LOW and HIGH
4705 are both positive.
4707 So we have to ensure that we will handle large unsigned
4708 values the same way that the current signed bounds treat
4709 negative values. */
4712 {
4713 tree high_positive;
4714 tree equiv_type;
4715 /* For fixed-point modes, we need to pass the saturating flag
4716 as the 2nd parameter. */
4718 equiv_type
4721 else
4722 equiv_type
4725 /* A range without an upper bound is, naturally, unbounded.
4726 Since convert would have cropped a very large value, use
4727 the max value for the destination type. */
4728 high_positive
4735 high_positive),
4738 /* If the low bound is specified, "and" the range with the
4739 range for which the original unsigned value will be
4740 positive. */
4742 {
4745 integer_zero_node),
4746 high_positive))
4750 }
4751 else
4752 {
4753 /* Otherwise, "or" the range with the range of the input
4754 that will be interpreted as negative. */
4757 integer_zero_node),
4758 high_positive))
4762 }
4763 }
4772 }
4773 }
4775 /* Given EXP, a logical expression, set the range it is testing into
4776 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4777 actually being tested. *PLOW and *PHIGH will be made of the same
4778 type as the returned expression. If EXP is not a comparison, we
4779 will most likely not be returning a useful value and range. Set
4780 *STRICT_OVERFLOW_P to true if the return value is only valid
4781 because signed overflow is undefined; otherwise, do not change
4782 *STRICT_OVERFLOW_P. */
4784 tree
4787 {
4795 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4796 and see if we can refine the range. Some of the cases below may not
4797 happen, but it doesn't seem worth worrying about this. We "continue"
4798 the outer loop when we've changed something; otherwise we "break"
4799 the switch, which will "break" the while. */
4805 {
4811 {
4819 }
4828 }
4830 /* If EXP is a constant, we can evaluate whether this is true or false. */
4832 {
4839 }
4843 }
4845 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
4846 a bitwise check i.e. when
4847 LOW == 0xXX...X00...0
4848 HIGH == 0xXX...X11...1
4849 Return corresponding mask in MASK and stem in VALUE. */
4851 static bool
4854 {
4877 }
4878 \f
4879 /* Helper routine for build_range_check and match.pd. Return the type to
4880 perform the check or NULL if it shouldn't be optimized. */
4882 tree
4884 {
4885 /* First make sure that arithmetics in this type is valid, then make sure
4886 that it wraps around. */
4892 {
4895 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4896 for the type in question, as we rely on this here. */
4906 else
4908 }
4910 }
4912 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4913 type, TYPE, return an expression to test if EXP is in (or out of, depending
4914 on IN_P) the range. Return 0 if the test couldn't be created. */
4916 tree
4919 {
4922 /* Disable this optimization for function pointer expressions
4923 on targets that require function pointer canonicalization. */
4930 {
4936 }
4958 value);
4961 {
4963 {
4967 }
4969 }
4971 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4973 {
4977 {
4979 {
4982 etype
4984 else
4987 }
4990 }
4991 }
4993 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4994 This requires wrap-around arithmetics for the type of the expression. */
5014 }
5015 \f
5016 /* Return the predecessor of VAL in its type, handling the infinite case. */
5018 static tree
5020 {
5026 else
5029 }
5031 /* Return the successor of VAL in its type, handling the infinite case. */
5033 static tree
5035 {
5041 else
5044 }
5046 /* Given two ranges, see if we can merge them into one. Return 1 if we
5047 can, 0 if we can't. Set the output range into the specified parameters. */
5049 bool
5052 {
5056 tree tem;
5066 /* Make range 0 be the range that starts first, or ends last if they
5067 start at the same value. Swap them if it isn't. */
5070 || (lowequal
5073 {
5077 }
5079 /* Now flag two cases, whether the ranges are disjoint or whether the
5080 second range is totally subsumed in the first. Note that the tests
5081 below are simplified by the ones above. */
5087 /* We now have four cases, depending on whether we are including or
5088 excluding the two ranges. */
5090 {
5091 /* If they don't overlap, the result is false. If the second range
5092 is a subset it is the result. Otherwise, the range is from the start
5093 of the second to the end of the first. */
5098 else
5100 }
5103 {
5104 /* If they don't overlap, the result is the first range. If they are
5105 equal, the result is false. If the second range is a subset of the
5106 first, and the ranges begin at the same place, we go from just after
5107 the end of the second range to the end of the first. If the second
5108 range is not a subset of the first, or if it is a subset and both
5109 ranges end at the same place, the range starts at the start of the
5110 first range and ends just before the second range.
5111 Otherwise, we can't describe this as a single range. */
5117 {
5122 {
5123 /* We are in the weird situation where high0 > high1 but
5124 high1 has no successor. Punt. */
5126 }
5127 }
5129 {
5134 {
5135 /* low0 < low1 but low1 has no predecessor. Punt. */
5137 }
5138 }
5139 else
5141 }
5144 {
5145 /* If they don't overlap, the result is the second range. If the second
5146 is a subset of the first, the result is false. Otherwise,
5147 the range starts just after the first range and ends at the
5148 end of the second. */
5153 else
5154 {
5159 {
5160 /* high1 > high0 but high0 has no successor. Punt. */
5162 }
5163 }
5164 }
5166 else
5167 {
5168 /* The case where we are excluding both ranges. Here the complex case
5169 is if they don't overlap. In that case, the only time we have a
5170 range is if they are adjacent. If the second is a subset of the
5171 first, the result is the first. Otherwise, the range to exclude
5172 starts at the beginning of the first range and ends at the end of the
5173 second. */
5175 {
5180 else
5181 {
5182 /* Canonicalize - [min, x] into - [-, x]. */
5185 {
5188 GET_MODE_BITSIZE
5191 /* FALLTHROUGH */
5204 }
5206 /* Canonicalize - [x, max] into - [x, -]. */
5209 {
5212 GET_MODE_BITSIZE
5215 /* FALLTHROUGH */
5231 }
5233 /* The ranges might be also adjacent between the maximum and
5234 minimum values of the given type. For
5235 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5236 return + [x + 1, y - 1]. */
5238 {
5245 }
5246 else
5248 }
5249 }
5252 else
5254 }
5258 }
5259 \f
5261 /* Subroutine of fold, looking inside expressions of the form
5262 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5263 of the COND_EXPR. This function is being used also to optimize
5264 A op B ? C : A, by reversing the comparison first.
5266 Return a folded expression whose code is not a COND_EXPR
5267 anymore, or NULL_TREE if no folding opportunity is found. */
5269 static tree
5272 {
5277 tree tem;
5282 /* If we have A op 0 ? A : -A, consider applying the following
5283 transformations:
5285 A == 0? A : -A same as -A
5286 A != 0? A : -A same as A
5287 A >= 0? A : -A same as abs (A)
5288 A > 0? A : -A same as abs (A)
5289 A <= 0? A : -A same as -abs (A)
5290 A < 0? A : -A same as -abs (A)
5292 None of these transformations work for modes with signed
5293 zeros. If A is +/-0, the first two transformations will
5294 change the sign of the result (from +0 to -0, or vice
5295 versa). The last four will fix the sign of the result,
5296 even though the original expressions could be positive or
5297 negative, depending on the sign of A.
5299 Note that all these transformations are correct if A is
5300 NaN, since the two alternatives (A and -A) are also NaNs. */
5307 /* In the case that A is of the form X-Y, '-A' (arg2) may
5308 have already been folded to Y-X, check for that. */
5316 {
5328 /* Fall through. */
5339 /* FALLTHRU */
5349 }
5351 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5352 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5353 both transformations are correct when A is NaN: A != 0
5354 is then true, and A == 0 is false. */
5358 {
5363 }
5365 /* Try some transformations of A op B ? A : B.
5367 A == B? A : B same as B
5368 A != B? A : B same as A
5369 A >= B? A : B same as max (A, B)
5370 A > B? A : B same as max (B, A)
5371 A <= B? A : B same as min (A, B)
5372 A < B? A : B same as min (B, A)
5374 As above, these transformations don't work in the presence
5375 of signed zeros. For example, if A and B are zeros of
5376 opposite sign, the first two transformations will change
5377 the sign of the result. In the last four, the original
5378 expressions give different results for (A=+0, B=-0) and
5379 (A=-0, B=+0), but the transformed expressions do not.
5381 The first two transformations are correct if either A or B
5382 is a NaN. In the first transformation, the condition will
5383 be false, and B will indeed be chosen. In the case of the
5384 second transformation, the condition A != B will be true,
5385 and A will be chosen.
5387 The conversions to max() and min() are not correct if B is
5388 a number and A is not. The conditions in the original
5389 expressions will be false, so all four give B. The min()
5390 and max() versions would give a NaN instead. */
5393 /* Avoid these transformations if the COND_EXPR may be used
5394 as an lvalue in the C++ front-end. PR c++/19199. */
5395 && (in_gimple_form
5401 {
5407 {
5416 /* In C++ a ?: expression can be an lvalue, so put the
5417 operand which will be used if they are equal first
5418 so that we can convert this back to the
5419 corresponding COND_EXPR. */
5421 {
5429 }
5436 {
5444 }
5457 }
5458 }
5461 }
5464 \f
5465 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5466 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5467 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5468 false) >= 2)
5469 #endif
5471 /* EXP is some logical combination of boolean tests. See if we can
5472 merge it into some range test. Return the new tree if so. */
5474 static tree
5477 {
5493 /* If this is an OR operation, invert both sides; we will invert
5494 again at the end. */
5498 /* If both expressions are the same, if we can merge the ranges, and we
5499 can build the range test, return it or it inverted. If one of the
5500 ranges is always true or always false, consider it to be the same
5501 expression as the other. */
5509 {
5513 }
5515 /* On machines where the branch cost is expensive, if this is a
5516 short-circuited branch and the underlying object on both sides
5517 is the same, make a non-short-circuit operation. */
5519 && !flag_sanitize_coverage
5524 {
5525 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5526 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5527 which cases we can't do this. */
5535 {
5544 {
5547 WARN_STRICT_OVERFLOW_COMPARISON);
5551 }
5552 }
5553 }
5556 }
5557 \f
5558 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
5559 bit value. Arrange things so the extra bits will be set to zero if and
5560 only if C is signed-extended to its full width. If MASK is nonzero,
5561 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5563 static tree
5565 {
5568 tree temp;
5573 /* We work by getting just the sign bit into the low-order bit, then
5574 into the high-order bit, then sign-extend. We then XOR that value
5575 with C. */
5579 /* We must use a signed type in order to get an arithmetic right shift.
5580 However, we must also avoid introducing accidental overflows, so that
5581 a subsequent call to integer_zerop will work. Hence we must
5582 do the type conversion here. At this point, the constant is either
5583 zero or one, and the conversion to a signed type can never overflow.
5584 We could get an overflow if this conversion is done anywhere else. */
5593 /* If necessary, convert the type back to match the type of C. */
5598 }
5599 \f
5600 /* For an expression that has the form
5601 (A && B) || ~B
5602 or
5603 (A || B) && ~B,
5604 we can drop one of the inner expressions and simplify to
5605 A || ~B
5606 or
5607 A && ~B
5608 LOC is the location of the resulting expression. OP is the inner
5609 logical operation; the left-hand side in the examples above, while CMPOP
5610 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5611 removing a condition that guards another, as in
5612 (A != NULL && A->...) || A == NULL
5613 which we must not transform. If RHS_ONLY is true, only eliminate the
5614 right-most operand of the inner logical operation. */
5616 static tree
5619 {
5637 {
5640 {
5643 }
5644 }
5646 {
5649 {
5652 }
5653 }
5668 }
5670 /* Find ways of folding logical expressions of LHS and RHS:
5671 Try to merge two comparisons to the same innermost item.
5672 Look for range tests like "ch >= '0' && ch <= '9'".
5673 Look for combinations of simple terms on machines with expensive branches
5674 and evaluate the RHS unconditionally.
5676 For example, if we have p->a == 2 && p->b == 4 and we can make an
5677 object large enough to span both A and B, we can do this with a comparison
5678 against the object ANDed with the a mask.
5680 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5681 operations to do this with one comparison.
5683 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5684 function and the one above.
5686 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5687 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5689 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5690 two operands.
5692 We return the simplified tree or 0 if no optimization is possible. */
5694 static tree
5697 {
5698 /* If this is the "or" of two comparisons, we can do something if
5699 the comparisons are NE_EXPR. If this is the "and", we can do something
5700 if the comparisons are EQ_EXPR. I.e.,
5701 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5703 WANTED_CODE is this operation code. For single bit fields, we can
5704 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5705 comparison for one-bit fields. */
5726 /* Start by getting the comparison codes. Fail if anything is volatile.
5727 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5728 it were surrounded with a NE_EXPR. */
5737 {
5741 }
5744 {
5748 }
5759 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5762 {
5765 {
5770 }
5773 {
5779 }
5780 }
5785 /* If the RHS can be evaluated unconditionally and its operands are
5786 simple, it wins to evaluate the RHS unconditionally on machines
5787 with expensive branches. In this case, this isn't a comparison
5788 that can be merged. */
5795 {
5796 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5807 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5817 }
5819 /* See if the comparisons can be merged. Then get all the parameters for
5820 each side. */
5845 /* It must be true that the inner operation on the lhs of each
5846 comparison must be the same if we are to be able to do anything.
5847 Then see if we have constants. If not, the same must be true for
5848 the rhs's. */
5857 {
5860 }
5865 else
5868 /* If either comparison code is not correct for our logical operation,
5869 fail. However, we can convert a one-bit comparison against zero into
5870 the opposite comparison against that bit being set in the field. */
5874 {
5876 {
5877 /* Make the left operand unsigned, since we are only interested
5878 in the value of one bit. Otherwise we are doing the wrong
5879 thing below. */
5882 }
5883 else
5885 }
5887 /* This is analogous to the code for l_const above. */
5889 {
5891 {
5894 }
5895 else
5897 }
5899 /* See if we can find a mode that contains both fields being compared on
5900 the left. If we can't, fail. Otherwise, update all constants and masks
5901 to be relative to a field of that size. */
5915 {
5918 }
5926 {
5933 {
5937 }
5938 }
5940 {
5947 {
5951 }
5952 }
5954 /* If the right sides are not constant, do the same for it. Also,
5955 disallow this optimization if a size or signedness mismatch occurs
5956 between the left and right sides. */
5958 {
5961 /* Make sure the two fields on the right
5962 correspond to the left without being swapped. */
5979 {
5982 }
5991 /* Make a mask that corresponds to both fields being compared.
5992 Do this for both items being compared. If the operands are the
5993 same size and the bits being compared are in the same position
5994 then we can do this by masking both and comparing the masked
5995 results. */
6002 {
6016 }
6018 /* There is still another way we can do something: If both pairs of
6019 fields being compared are adjacent, we may be able to make a wider
6020 field containing them both.
6022 Note that we still must mask the lhs/rhs expressions. Furthermore,
6023 the mask must be shifted to account for the shift done by
6024 make_bit_field_ref. */
6033 {
6034 tree type;
6050 /* Convert to the smaller type before masking out unwanted bits. */
6053 {
6055 {
6059 }
6061 {
6065 }
6066 }
6075 }
6078 }
6080 /* Handle the case of comparisons with constants. If there is something in
6081 common between the masks, those bits of the constants must be the same.
6082 If not, the condition is always false. Test for this to avoid generating
6083 incorrect code below. */
6088 {
6090 {
6093 }
6094 else
6095 {
6098 }
6099 }
6104 /* Construct the expression we will return. First get the component
6105 reference we will make. Unless the mask is all ones the width of
6106 that field, perform the mask operation. Then compare with the
6107 merged constant. */
6118 }
6119 \f
6120 /* T is an integer expression that is being multiplied, divided, or taken a
6121 modulus (CODE says which and what kind of divide or modulus) by a
6122 constant C. See if we can eliminate that operation by folding it with
6123 other operations already in T. WIDE_TYPE, if non-null, is a type that
6124 should be used for the computation if wider than our type.
6126 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6127 (X * 2) + (Y * 4). We must, however, be assured that either the original
6128 expression would not overflow or that overflow is undefined for the type
6129 in the language in question.
6131 If we return a non-null expression, it is an equivalent form of the
6132 original computation, but need not be in the original type.
6134 We set *STRICT_OVERFLOW_P to true if the return values depends on
6135 signed overflow being undefined. Otherwise we do not change
6136 *STRICT_OVERFLOW_P. */
6138 static tree
6141 {
6142 /* To avoid exponential search depth, refuse to allow recursion past
6143 three levels. Beyond that (1) it's highly unlikely that we'll find
6144 something interesting and (2) we've probably processed it before
6145 when we built the inner expression. */
6148 tree ret;
6153 depth++;
6155 depth--;
6158 }
6160 static tree
6163 {
6175 /* Don't deal with constants of zero here; they confuse the code below. */
6185 /* Note that we need not handle conditional operations here since fold
6186 already handles those cases. So just do arithmetic here. */
6188 {
6190 /* For a constant, we can always simplify if we are a multiply
6191 or (for divide and modulus) if it is a multiple of our constant. */
6195 {
6198 /* If the multiplication overflowed, we lost information on it.
6199 See PR68142 and PR69845. */
6203 }
6207 /* If op0 is an expression ... */
6213 /* ... and has wrapping overflow, and its type is smaller
6214 than ctype, then we cannot pass through as widening. */
6219 /* ... or this is a truncation (t is narrower than op0),
6220 then we cannot pass through this narrowing. */
6223 /* ... or signedness changes for division or modulus,
6224 then we cannot pass through this conversion. */
6228 /* ... or has undefined overflow while the converted to
6229 type has not, we cannot do the operation in the inner type
6230 as that would introduce undefined overflow. */
6236 /* Pass the constant down and see if we can make a simplification. If
6237 we can, replace this expression with the inner simplification for
6238 possible later conversion to our or some other type. */
6249 /* If widening the type changes it from signed to unsigned, then we
6250 must avoid building ABS_EXPR itself as unsigned. */
6252 {
6256 {
6259 }
6261 }
6262 /* If the constant is negative, we cannot simplify this. */
6265 /* FALLTHROUGH */
6267 /* For division and modulus, type can't be unsigned, as e.g.
6268 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6269 For signed types, even with wrapping overflow, this is fine. */
6278 /* If widening the type changes the signedness, then we can't perform
6279 this optimization as that changes the result. */
6283 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6289 {
6296 }
6300 /* If the second operand is constant, this is a multiplication
6301 or floor division, by a power of two, so we can treat it that
6302 way unless the multiplier or divisor overflows. Signed
6303 left-shift overflow is implementation-defined rather than
6304 undefined in C90, so do not convert signed left shift into
6305 multiplication. */
6308 /* const_binop may not detect overflow correctly,
6309 so check for it explicitly here. */
6318 ctype,
6320 t1),
6325 /* See if we can eliminate the operation on both sides. If we can, we
6326 can return a new PLUS or MINUS. If we can't, the only remaining
6327 cases where we can do anything are if the second operand is a
6328 constant. */
6335 /* If not multiplication, we can only do this if both operands
6336 are divisible by c. */
6339 {
6344 }
6346 /* If this was a subtraction, negate OP1 and set it to be an addition.
6347 This simplifies the logic below. */
6349 {
6351 /* If OP1 was not easily negatable, the constant may be OP0. */
6353 {
6356 }
6357 }
6362 /* If either OP1 or C are negative, this optimization is not safe for
6363 some of the division and remainder types while for others we need
6364 to change the code. */
6366 {
6374 }
6376 /* If it's a multiply or a division/modulus operation of a multiple
6377 of our constant, do the operation and verify it doesn't overflow. */
6381 {
6384 /* We allow the constant to overflow with wrapping semantics. */
6388 }
6389 else
6392 /* If we have an unsigned type, we cannot widen the operation since it
6393 will change the result if the original computation overflowed. */
6397 /* The last case is if we are a multiply. In that case, we can
6398 apply the distributive law to commute the multiply and addition
6399 if the multiplication of the constants doesn't overflow
6400 and overflow is defined. With undefined overflow
6401 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
6407 op1);
6412 /* We have a special case here if we are doing something like
6413 (C * 8) % 4 since we know that's zero. */
6416 /* If the multiplication can overflow we cannot optimize this. */
6421 {
6424 }
6426 /* ... fall through ... */
6430 /* If we can extract our operation from the LHS, do so and return a
6431 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6432 do something only if the second operand is a constant. */
6448 /* If these are the same operation types, we can associate them
6449 assuming no overflow. */
6451 {
6466 }
6468 /* If these operations "cancel" each other, we have the main
6469 optimizations of this pass, which occur when either constant is a
6470 multiple of the other, in which case we replace this with either an
6471 operation or CODE or TCODE.
6473 If we have an unsigned type, we cannot do this since it will change
6474 the result if the original computation overflowed. */
6481 {
6484 {
6491 }
6494 {
6501 }
6502 }
6507 }
6510 }
6511 \f
6512 /* Return a node which has the indicated constant VALUE (either 0 or
6513 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6514 and is of the indicated TYPE. */
6516 tree
6518 {
6527 else
6529 }
6532 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6533 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6534 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6535 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6536 COND is the first argument to CODE; otherwise (as in the example
6537 given here), it is the second argument. TYPE is the type of the
6538 original expression. Return NULL_TREE if no simplification is
6539 possible. */
6541 static tree
6546 {
6556 {
6560 /* If this operand throws an expression, then it does not make
6561 sense to try to perform a logical or arithmetic operation
6562 involving it. */
6567 }
6570 {
6575 }
6576 else
6577 /* Detect the case of mixing vector and scalar types - bail out. */
6583 /* This transformation is only worthwhile if we don't have to wrap ARG
6584 in a SAVE_EXPR and the operation can be simplified without recursing
6585 on at least one of the branches once its pushed inside the COND_EXPR. */
6594 {
6598 else
6600 }
6602 {
6606 else
6608 }
6610 /* Check that we have simplified at least one of the branches. */
6615 }
6617 \f
6618 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6620 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6621 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6622 ADDEND is the same as X.
6624 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6625 and finite. The problematic cases are when X is zero, and its mode
6626 has signed zeros. In the case of rounding towards -infinity,
6627 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6628 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6630 bool
6632 {
6636 /* Don't allow the fold with -fsignaling-nans. */
6640 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6644 /* In a vector or complex, we would need to check the sign of all zeros. */
6648 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6652 /* The mode has signed zeros, and we have to honor their sign.
6653 In this situation, there is only one case we can return true for.
6654 X - 0 is the same as X unless rounding towards -infinity is
6655 supported. */
6657 }
6659 /* Subroutine of match.pd that optimizes comparisons of a division by
6660 a nonzero integer constant against an integer constant, i.e.
6661 X/C1 op C2.
6663 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6664 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
6666 enum tree_code
6669 {
6674 /* We have to do this the hard way to detect unsigned overflow.
6675 prod = int_const_binop (MULT_EXPR, c1, c2); */
6681 {
6685 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6688 }
6690 {
6693 {
6712 }
6713 }
6714 else
6715 {
6716 /* A negative divisor reverses the relational operators. */
6721 {
6740 }
6741 }
6754 }
6757 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6758 equality/inequality test, then return a simplified form of the test
6759 using a sign testing. Otherwise return NULL. TYPE is the desired
6760 result type. */
6762 static tree
6765 tree result_type)
6766 {
6767 /* If this is testing a single bit, we can optimize the test. */
6771 {
6772 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6773 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6777 /* This is only a win if casting to a signed type is cheap,
6778 i.e. when arg00's type is not a partial mode. */
6780 {
6783 result_type,
6786 }
6787 }
6790 }
6792 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6793 equality/inequality test, then return a simplified form of
6794 the test using shifts and logical operations. Otherwise return
6795 NULL. TYPE is the desired result type. */
6797 tree
6800 {
6801 /* If this is testing a single bit, we can optimize the test. */
6805 {
6814 /* First, see if we can fold the single bit test into a sign-bit
6815 test. */
6817 result_type);
6821 /* Otherwise we have (A & C) != 0 where C is a single bit,
6822 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6823 Similarly for (A & C) == 0. */
6825 /* If INNER is a right shift of a constant and it plus BITNUM does
6826 not overflow, adjust BITNUM and INNER. */
6832 {
6835 }
6837 /* If we are going to be able to omit the AND below, we must do our
6838 operations as unsigned. If we must use the AND, we have a choice.
6839 Normally unsigned is faster, but for some machines signed is. */
6857 /* Put the AND last so it can combine with more things. */
6860 /* Make sure to return the proper type. */
6864 }
6866 }
6868 /* Test whether it is preferable two swap two operands, ARG0 and
6869 ARG1, for example because ARG0 is an integer constant and ARG1
6870 isn't. */
6872 bool
6874 {
6888 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6889 for commutative and comparison operators. Ensuring a canonical
6890 form allows the optimizers to find additional redundancies without
6891 having to explicitly check for both orderings. */
6897 /* Put SSA_NAMEs last. */
6903 /* Put variables last. */
6910 }
6913 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6914 means A >= Y && A != MAX, but in this case we know that
6915 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6917 static tree
6919 {
6926 else
6935 {
6938 }
6940 {
6943 }
6944 else
6951 {
6952 /* Convert the pointer types into integer before taking the difference. */
6956 }
6957 else
6964 }
6966 /* Fold a sum or difference of at least one multiplication.
6967 Returns the folded tree or NULL if no simplification could be made. */
6969 static tree
6972 {
6976 /* (A * C) +- (B * C) -> (A+-B) * C.
6977 (A * C) +- A -> A * (C+-1).
6978 We are most concerned about the case where C is a constant,
6979 but other combinations show up during loop reduction. Since
6980 it is not difficult, try all four possibilities. */
6983 {
6986 }
6988 {
6991 }
6992 else
6993 {
6994 /* We cannot generate constant 1 for fract. */
6999 }
7001 {
7004 }
7006 {
7008 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7009 the purpose of this canonicalization. */
7013 {
7016 }
7017 else
7019 }
7020 else
7021 {
7022 /* We cannot generate constant 1 for fract. */
7027 }
7030 /* Prefer factoring a common non-constant. */
7040 /* No identical multiplicands; see if we can find a common
7041 power-of-two factor in non-power-of-two multiplies. This
7042 can help in multi-dimensional array access. */
7045 {
7048 tree maybe_same;
7052 /* Move min of absolute values to int11. */
7054 {
7059 }
7060 else
7064 /* The remainder should not be a constant, otherwise we
7065 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7066 increased the number of multiplications necessary. */
7068 {
7076 }
7077 }
7084 /* We are neither factoring zero nor minus one. */
7092 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7093 same may be minus one and thus the multiplication may overflow. Perform
7094 the sum operation in an unsigned type. */
7099 /* If the sum evaluated to a constant that is not -INF the multiplication
7100 cannot overflow. */
7107 /* Do not resort to unsigned multiplication because
7108 we lose the no-overflow property of the expression. */
7110 }
7112 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7113 specified by EXPR into the buffer PTR of length LEN bytes.
7114 Return the number of bytes placed in the buffer, or zero
7115 upon failure. */
7117 static int
7119 {
7131 /* Dry run. */
7137 {
7139 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7140 number of bytes. */
7144 {
7151 else
7153 }
7154 else
7158 }
7160 }
7163 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7164 specified by EXPR into the buffer PTR of length LEN bytes.
7165 Return the number of bytes placed in the buffer, or zero
7166 upon failure. */
7168 static int
7170 {
7174 FIXED_VALUE_TYPE value;
7189 }
7192 /* Subroutine of native_encode_expr. Encode the REAL_CST
7193 specified by EXPR into the buffer PTR of length LEN bytes.
7194 Return the number of bytes placed in the buffer, or zero
7195 upon failure. */
7197 static int
7199 {
7205 /* There are always 32 bits in each long, no matter the size of
7206 the hosts long. We handle floating point representations with
7207 up to 192 bits. */
7216 /* Dry run. */
7225 {
7230 {
7237 else
7239 }
7240 else
7241 {
7244 {
7245 /* Reverse bytes within each long, or within the entire float
7246 if it's smaller than a long (for HFmode). */
7249 }
7250 }
7255 }
7257 }
7259 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7260 specified by EXPR into the buffer PTR of length LEN bytes.
7261 Return the number of bytes placed in the buffer, or zero
7262 upon failure. */
7264 static int
7266 {
7268 tree part;
7282 }
7285 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7286 specified by EXPR into the buffer PTR of length LEN bytes.
7287 Return the number of bytes placed in the buffer, or zero
7288 upon failure. */
7290 static int
7292 {
7303 {
7305 {
7308 }
7319 }
7321 }
7324 /* Subroutine of native_encode_expr. Encode the STRING_CST
7325 specified by EXPR into the buffer PTR of length LEN bytes.
7326 Return the number of bytes placed in the buffer, or zero
7327 upon failure. */
7329 static int
7331 {
7334 /* Wide-char strings are encoded in target byte-order so native
7335 encoding them is trivial. */
7350 {
7353 {
7356 }
7359 }
7360 else
7363 }
7366 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7367 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7368 buffer PTR of length LEN bytes. If PTR is NULL, don't actually store
7369 anything, just do a dry run. If OFF is not -1 then start
7370 the encoding at byte offset OFF and encode at most LEN bytes.
7371 Return the number of bytes placed in the buffer, or zero upon failure. */
7373 int
7375 {
7376 /* We don't support starting at negative offset and -1 is special. */
7381 {
7402 }
7403 }
7406 /* Subroutine of native_interpret_expr. Interpret the contents of
7407 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7408 If the buffer cannot be interpreted, return NULL_TREE. */
7410 static tree
7412 {
7422 }
7425 /* Subroutine of native_interpret_expr. Interpret the contents of
7426 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7427 If the buffer cannot be interpreted, return NULL_TREE. */
7429 static tree
7431 {
7434 double_int result;
7435 FIXED_VALUE_TYPE fixed_value;
7445 }
7448 /* Subroutine of native_interpret_expr. Interpret the contents of
7449 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7450 If the buffer cannot be interpreted, return NULL_TREE. */
7452 static tree
7454 {
7458 /* There are always 32 bits in each long, no matter the size of
7459 the hosts long. We handle floating point representations with
7460 up to 192 bits. */
7461 REAL_VALUE_TYPE r;
7471 {
7472 /* Both OFFSET and BYTE index within a long;
7473 bitpos indexes the whole float. */
7476 {
7483 else
7485 }
7486 else
7487 {
7490 {
7491 /* Reverse bytes within each long, or within the entire float
7492 if it's smaller than a long (for HFmode). */
7495 }
7496 }
7500 }
7504 }
7507 /* Subroutine of native_interpret_expr. Interpret the contents of
7508 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7509 If the buffer cannot be interpreted, return NULL_TREE. */
7511 static tree
7513 {
7528 }
7531 /* Subroutine of native_interpret_expr. Interpret the contents of
7532 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7533 If the buffer cannot be interpreted, return NULL_TREE. */
7535 static tree
7537 {
7550 {
7555 }
7557 }
7560 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7561 the buffer PTR of length LEN as a constant of type TYPE. For
7562 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7563 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7564 return NULL_TREE. */
7566 tree
7568 {
7570 {
7592 }
7593 }
7595 /* Returns true if we can interpret the contents of a native encoding
7596 as TYPE. */
7598 static bool
7600 {
7602 {
7615 }
7616 }
7619 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7620 TYPE at compile-time. If we're unable to perform the conversion
7621 return NULL_TREE. */
7623 static tree
7625 {
7626 /* We support up to 512-bit values (for V8DFmode). */
7630 /* Check that the host and target are sane. */
7639 }
7641 /* Build an expression for the address of T. Folds away INDIRECT_REF
7642 to avoid confusing the gimplify process. */
7644 tree
7646 {
7647 /* The size of the object is not relevant when talking about its address. */
7652 {
7657 }
7667 {
7672 }
7673 else
7677 }
7679 /* Build an expression for the address of T. */
7681 tree
7683 {
7687 }
7689 /* Fold a unary expression of code CODE and type TYPE with operand
7690 OP0. Return the folded expression if folding is successful.
7691 Otherwise, return NULL_TREE. */
7693 tree
7695 {
7696 tree tem;
7697 tree arg0;
7705 {
7708 {
7709 /* Don't use STRIP_NOPS, because signedness of argument type
7710 matters. */
7712 }
7713 else
7714 {
7715 /* Strip any conversions that don't change the mode. This
7716 is safe for every expression, except for a comparison
7717 expression because its signedness is derived from its
7718 operands.
7720 Note that this is done as an internal manipulation within
7721 the constant folder, in order to find the simplest
7722 representation of the arguments so that their form can be
7723 studied. In any cases, the appropriate type conversions
7724 should be put back in the tree that will get out of the
7725 constant folder. */
7727 }
7730 {
7733 {
7737 }
7738 }
7739 }
7746 {
7753 {
7767 /* If this was a conversion, and all we did was to move into
7768 inside the COND_EXPR, bring it back out. But leave it if
7769 it is a conversion from integer to integer and the
7770 result precision is no wider than a word since such a
7771 conversion is cheap and may be optimized away by combine,
7772 while it couldn't if it were outside the COND_EXPR. Then return
7773 so we don't get into an infinite recursion loop taking the
7774 conversion out and then back in. */
7786 && (INTEGRAL_TYPE_P
7799 }
7800 }
7803 {
7809 CASE_CONVERT:
7813 {
7814 /* If we have (type) (a CMP b) and type is an integral type, return
7815 new expression involving the new type. Canonicalize
7816 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7817 non-integral type.
7818 Do not fold the result as that would not simplify further, also
7819 folding again results in recursions. */
7829 }
7831 /* Handle (T *)&A.B.C for A being of type T and B and C
7832 living at offset zero. This occurs frequently in
7833 C++ upcasting and then accessing the base. */
7837 {
7839 tree offset;
7840 machine_mode mode;
7842 tree base
7846 /* If the reference was to a (constant) zero offset, we can use
7847 the address of the base if it has the same base type
7848 as the result type and the pointer type is unqualified. */
7856 }
7860 /* Detect assigning a bitfield. */
7862 && DECL_BIT_FIELD
7864 {
7865 /* Don't leave an assignment inside a conversion
7866 unless assigning a bitfield. */
7868 /* First do the assignment, then return converted constant. */
7873 }
7875 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7876 constants (if x has signed type, the sign bit cannot be set
7877 in c). This folds extension into the BIT_AND_EXPR.
7878 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7879 very likely don't have maximal range for their precision and this
7880 transformation effectively doesn't preserve non-maximal ranges. */
7884 {
7895 <= HOST_BITS_PER_WIDE_INT
7897 {
7901 cst &= HOST_WIDE_INT_M1U
7905 && !flag_syntax_only
7908 {
7912 }
7913 }
7915 {
7920 }
7921 }
7923 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
7924 cast (T1)X will fold away. We assume that this happens when X itself
7925 is a cast. */
7929 {
7933 return fold_build_pointer_plus_loc
7935 }
7937 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7938 of the same precision, and X is an integer type not narrower than
7939 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7945 {
7951 }
7953 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7954 type of X and Y (integer types only). */
7959 {
7960 /* Be careful not to introduce new overflows. */
7961 tree mult_type;
7964 else
7968 {
7975 }
7976 }
7982 {
7989 }
8000 /* Convert fabs((double)float) into (double)fabsf(float). */
8003 {
8009 targ0));
8010 }
8014 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8033 /* Note that the operand of this must be an int
8034 and its values must be 0 or 1.
8035 ("true" is a fixed value perhaps depending on the language,
8036 but we don't handle values other than 1 correctly yet.) */
8043 /* Fold *&X to X if X is an lvalue. */
8045 {
8052 }
8058 }
8061 /* If the operation was a conversion do _not_ mark a resulting constant
8062 with TREE_OVERFLOW if the original constant was not. These conversions
8063 have implementation defined behavior and retaining the TREE_OVERFLOW
8064 flag here would confuse later passes such as VRP. */
8065 tree
8068 {
8077 }
8079 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
8080 operands OP0 and OP1. LOC is the location of the resulting expression.
8081 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
8082 Return the folded expression if folding is successful. Otherwise,
8083 return NULL_TREE. */
8084 static tree
8087 {
8088 tree tem;
8090 /* We only do these simplifications if we are optimizing. */
8094 /* Check for things like (A || B) && (A || C). We can convert this
8095 to A || (B && C). Note that either operator can be any of the four
8096 truth and/or operations and the transformation will still be
8097 valid. Also note that we only care about order for the
8098 ANDIF and ORIF operators. If B contains side effects, this
8099 might change the truth-value of A. */
8106 {
8126 /* This case if tricky because we must either have commutative
8127 operators or else A10 must not have side-effects. */
8133 a01);
8134 }
8136 /* See if we can build a range comparison. */
8142 {
8146 }
8150 {
8154 }
8156 /* Check for the possibility of merging component references. If our
8157 lhs is another similar operation, try to merge its rhs with our
8158 rhs. Then try to merge our lhs and rhs. */
8168 && !flag_sanitize_coverage
8173 {
8180 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8181 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8182 We don't want to pack more than two leafs to a non-IF AND/OR
8183 expression.
8184 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8185 equal to IF-CODE, then we don't want to add right-hand operand.
8186 If the inner right-hand side of left-hand operand has
8187 side-effects, or isn't simple, then we can't add to it,
8188 as otherwise we might destroy if-sequence. */
8191 /* Needed for sequence points to handle trappings, and
8192 side-effects. */
8194 {
8196 arg1);
8198 tem);
8199 }
8200 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8201 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8204 /* Needed for sequence points to handle trappings, and
8205 side-effects. */
8207 {
8212 }
8213 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8214 into (A OR B).
8215 For sequence point consistancy, we need to check for trapping,
8216 and side-effects. */
8220 }
8223 }
8225 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8226 by changing CODE to reduce the magnitude of constants involved in
8227 ARG0 of the comparison.
8228 Returns a canonicalized comparison tree if a simplification was
8229 possible, otherwise returns NULL_TREE.
8230 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8231 valid if signed overflow is undefined. */
8233 static tree
8237 {
8242 /* Match A +- CST code arg1. We can change this only if overflow
8243 is undefined. */
8246 /* In principle pointers also have undefined overflow behavior,
8247 but that causes problems elsewhere. */
8254 /* Identify the constant in arg0 and its sign. */
8258 /* Overflowed constants and zero will cause problems. */
8263 /* See if we can reduce the magnitude of the constant in
8264 arg0 by changing the comparison code. */
8265 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8269 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8273 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8277 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8281 else
8285 /* Now build the constant reduced in magnitude. But not if that
8286 would produce one outside of its types range. */
8302 }
8304 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8305 overflow further. Try to decrease the magnitude of constants involved
8306 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8307 and put sole constants at the second argument position.
8308 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8310 static tree
8313 {
8314 tree t;
8319 /* Try canonicalization by simplifying arg0. */
8324 {
8328 }
8330 /* Try canonicalization by simplifying arg1 using the swapped
8331 comparison. */
8339 }
8341 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8342 space. This is used to avoid issuing overflow warnings for
8343 expressions like &p->x which can not wrap. */
8345 static bool
8347 {
8354 poly_wide_int wi_offset;
8360 else
8365 precision);
8380 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8381 array. */
8390 }
8392 /* Return a positive integer when the symbol DECL is known to have
8393 a nonzero address, zero when it's known not to (e.g., it's a weak
8394 symbol), and a negative integer when the symbol is not yet in the
8395 symbol table and so whether or not its address is zero is unknown.
8396 For function local objects always return positive integer. */
8397 static int
8399 {
8404 /* Function local objects are never NULL. */
8412 }
8414 /* Subroutine of fold_binary. This routine performs all of the
8415 transformations that are common to the equality/inequality
8416 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8417 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8418 fold_binary should call fold_binary. Fold a comparison with
8419 tree code CODE and type TYPE with operands OP0 and OP1. Return
8420 the folded comparison or NULL_TREE. */
8422 static tree
8425 {
8435 /* For comparisons of pointers we can decompose it to a compile time
8436 comparison of the base objects and the offsets into the object.
8437 This requires at least one operand being an ADDR_EXPR or a
8438 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8444 {
8447 machine_mode mode;
8451 /* Get base and offset for the access. Strip ADDR_EXPR for
8452 get_inner_reference, but put it back by stripping INDIRECT_REF
8453 off the base object if possible. indirect_baseN will be true
8454 if baseN is not an address but refers to the object itself. */
8457 {
8458 base0
8464 else
8466 }
8468 {
8472 {
8473 base0
8479 else
8481 }
8484 else
8488 {
8495 }
8496 }
8500 {
8501 base1
8507 else
8509 }
8511 {
8515 {
8516 base1
8522 else
8524 }
8527 else
8531 {
8538 }
8539 }
8541 /* If we have equivalent bases we might be able to simplify. */
8545 {
8546 /* We can fold this expression to a constant if the non-constant
8547 offset parts are equal. */
8551 && (equality_code
8552 || (indirect_base0
8555 {
8561 "occur when comparing P +- C1 with "
8563 WARN_STRICT_OVERFLOW_CONDITIONAL);
8566 {
8604 }
8605 }
8606 /* We can simplify the comparison to a comparison of the variable
8607 offset parts if the constant offset parts are equal.
8608 Be careful to use signed sizetype here because otherwise we
8609 mess with array offsets in the wrong way. This is possible
8610 because pointer arithmetic is restricted to retain within an
8611 object and overflow on pointer differences is undefined as of
8612 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8614 && (equality_code
8615 || (indirect_base0
8618 {
8619 /* By converting to signed sizetype we cover middle-end pointer
8620 arithmetic which operates on unsigned pointer types of size
8621 type size and ARRAY_REF offsets which are properly sign or
8622 zero extended from their type in case it is narrower than
8623 sizetype. */
8626 else
8630 else
8637 "occur when comparing P +- C1 with "
8639 WARN_STRICT_OVERFLOW_COMPARISON);
8642 }
8643 }
8644 /* For equal offsets we can simplify to a comparison of the
8645 base addresses. */
8647 && (indirect_base0
8649 && (indirect_base1
8654 {
8660 }
8661 /* Comparison between an ordinary (non-weak) symbol and a null
8662 pointer can be eliminated since such symbols must have a non
8663 null address. In C, relational expressions between pointers
8664 to objects and null pointers are undefined. The results
8665 below follow the C++ rules with the additional property that
8666 every object pointer compares greater than a null pointer.
8667 */
8670 /* Avoid folding references to struct members at offset 0 to
8671 prevent tests like '&ptr->firstmember == 0' from getting
8672 eliminated. When ptr is null, although the -> expression
8673 is strictly speaking invalid, GCC retains it as a matter
8674 of QoI. See PR c/44555. */
8677 && indirect_base0
8678 /* The caller guarantees that when one of the arguments is
8679 constant (i.e., null in this case) it is second. */
8681 {
8683 {
8694 }
8695 }
8696 }
8698 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8699 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8700 the resulting offset is smaller in absolute value than the
8701 original one and has the same sign. */
8710 {
8715 tree cst;
8717 "occur when combining constants around "
8720 /* Put the constant on the side where it doesn't overflow and is
8721 of lower absolute value and of same sign than before. */
8728 {
8731 variable1,
8735 }
8743 {
8749 variable2);
8750 }
8751 }
8757 /* If we are comparing an expression that just has comparisons
8758 of two integer values, arithmetic expressions of those comparisons,
8759 and constants, we can simplify it. There are only three cases
8760 to check: the two values can either be equal, the first can be
8761 greater, or the second can be greater. Fold the expression for
8762 those three values. Since each value must be 0 or 1, we have
8763 eight possibilities, each of which corresponds to the constant 0
8764 or 1 or one of the six possible comparisons.
8766 This handles common cases like (a > b) == 0 but also handles
8767 expressions like ((x > y) - (y > x)) > 0, which supposedly
8768 occur in macroized code. */
8771 {
8775 /* Don't handle degenerate cases here; they should already
8776 have been handled anyway. */
8785 {
8789 /* We can't just pass T to eval_subst in case cval1 or cval2
8790 was the same as ARG1. */
8792 tree high_result
8796 arg1);
8797 tree equal_result
8801 arg1);
8802 tree low_result
8806 arg1);
8808 /* All three of these results should be 0 or 1. Confirm they are.
8809 Then use those values to select the proper code to use. */
8814 {
8815 /* Make a 3-bit mask with the high-order bit being the
8816 value for `>', the next for '=', and the low for '<'. */
8820 {
8822 /* Always false. */
8843 /* Always true. */
8845 }
8848 }
8849 }
8850 }
8853 }
8856 /* Subroutine of fold_binary. Optimize complex multiplications of the
8857 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
8858 argument EXPR represents the expression "z" of type TYPE. */
8860 static tree
8862 {
8867 {
8870 }
8872 {
8875 }
8876 else
8877 {
8881 }
8890 }
8893 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
8894 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
8895 true if successful. */
8897 static bool
8899 {
8904 {
8907 }
8909 {
8915 else
8917 }
8918 else
8924 }
8926 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
8927 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
8928 NULL_TREE otherwise. */
8930 static tree
8932 {
8953 {
8954 HOST_WIDE_INT index;
8960 }
8963 {
8969 }
8970 else
8972 }
8974 /* Try to fold a pointer difference of type TYPE two address expressions of
8975 array references AREF0 and AREF1 using location LOC. Return a
8976 simplified expression for the difference or NULL_TREE. */
8978 static tree
8982 {
8987 /* If the bases are array references as well, recurse. If the bases
8988 are pointer indirections compute the difference of the pointers.
8989 If the bases are equal, we are set. */
8992 && (base_offset
8994 use_pointer_diff)))
8997 && (base_offset
8998 = use_pointer_diff
9008 {
9014 base_offset,
9017 }
9019 }
9021 /* If the real or vector real constant CST of type TYPE has an exact
9022 inverse, return it, else return NULL. */
9024 tree
9026 {
9027 REAL_VALUE_TYPE r;
9028 tree unit_type;
9029 machine_mode mode;
9032 {
9042 {
9046 tree_vector_builder elts;
9051 {
9056 }
9059 }
9063 }
9064 }
9066 /* Mask out the tz least significant bits of X of type TYPE where
9067 tz is the number of trailing zeroes in Y. */
9068 static wide_int
9070 {
9075 }
9077 /* Return true when T is an address and is known to be nonzero.
9078 For floating point we further ensure that T is not denormal.
9079 Similar logic is present in nonzero_address in rtlanal.h.
9081 If the return value is based on the assumption that signed overflow
9082 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
9083 change *STRICT_OVERFLOW_P. */
9085 static bool
9087 {
9091 /* Doing something useful for floating point would need more work. */
9097 {
9100 strict_overflow_p);
9106 strict_overflow_p);
9114 }
9117 {
9120 strict_overflow_p);
9128 strict_overflow_p);
9143 strict_overflow_p);
9147 strict_overflow_p);
9150 {
9162 }
9166 }
9168 }
9170 /* Return true when T is an address and is known to be nonzero.
9171 Handle warnings about undefined signed overflow. */
9173 bool
9175 {
9182 "determining that expression is always "
9184 WARN_STRICT_OVERFLOW_MISC);
9186 }
9188 /* Return true if T is known not to be equal to an integer W. */
9190 bool
9192 {
9194 value_range_type rtype;
9196 {
9205 {
9210 }
9215 /* If T has some known zero bits and W has any of those bits set,
9216 then T is known not to be equal to W. */
9224 }
9225 }
9227 /* Fold a binary expression of code CODE and type TYPE with operands
9228 OP0 and OP1. LOC is the location of the resulting expression.
9229 Return the folded expression if folding is successful. Otherwise,
9230 return NULL_TREE. */
9232 tree
9235 {
9250 /* Strip any conversions that don't change the mode. This is
9251 safe for every expression, except for a comparison expression
9252 because its signedness is derived from its operands. So, in
9253 the latter case, only strip conversions that don't change the
9254 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9255 preserved.
9257 Note that this is done as an internal manipulation within the
9258 constant folder, in order to find the simplest representation
9259 of the arguments so that their form can be studied. In any
9260 cases, the appropriate type conversions should be put back in
9261 the tree that will get out of the constant folder. */
9264 {
9267 }
9268 else
9269 {
9272 }
9274 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9275 constant but we can't do arithmetic on them. */
9277 {
9280 {
9284 }
9285 }
9287 /* If this is a commutative operation, and ARG0 is a constant, move it
9288 to ARG1 to reduce the number of tests below. */
9293 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9294 to ARG1 to reduce the number of tests below. */
9303 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9305 First check for cases where an arithmetic operation is applied to a
9306 compound, conditional, or comparison operation. Push the arithmetic
9307 operation inside the compound or conditional to see if any folding
9308 can then be done. Convert comparison to conditional for this purpose.
9309 The also optimizes non-constant cases that used to be done in
9310 expand_expr.
9312 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9313 one of the operands is a comparison and the other is a comparison, a
9314 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9315 code below would make the expression more complex. Change it to a
9316 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9317 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9330 {
9334 boolean_type_node,
9342 }
9346 {
9348 {
9353 tem);
9354 }
9356 {
9361 tem);
9362 }
9367 {
9373 }
9378 {
9384 }
9385 }
9388 {
9390 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9393 {
9399 }
9401 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9404 {
9405 tree base;
9406 poly_int64 coffset;
9415 }
9420 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9426 arg1),
9428 arg0)));
9434 {
9435 /* X + (X / CST) * -CST is X % CST. */
9440 {
9449 cst0));
9450 }
9451 }
9453 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9454 one. Make sure the type is not saturating and has the signedness of
9455 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9456 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9463 {
9467 }
9470 {
9471 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9472 (plus (plus (mult) (mult)) (foo)) so that we can
9473 take advantage of the factoring cases below. */
9482 {
9488 else
9501 parg0),
9503 marg)),
9507 return
9513 parg1)));
9514 }
9515 }
9516 else
9517 {
9518 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9519 to __complex__ ( x, y ). This is not the same for SNaNs or
9520 if signed zeros are involved. */
9524 {
9531 {
9535 {
9541 }
9543 {
9549 }
9550 }
9551 }
9553 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9554 We associate floats only if the user has specified
9555 -fassociative-math. */
9559 {
9564 {
9565 tree tree0;
9568 }
9569 }
9570 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9571 We associate floats only if the user has specified
9572 -fassociative-math. */
9576 {
9581 {
9582 tree tree0;
9585 }
9586 }
9587 }
9589 bit_rotate:
9590 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9591 is a rotate of A by C1 bits. */
9592 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9593 is a rotate of A by B bits.
9594 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
9595 though in this case CODE must be | and not + or ^, otherwise
9596 it doesn't return A when B is 0. */
9597 {
9599 tree rtype;
9608 /* Only create rotates in complete modes. Other cases are not
9609 expanded properly. */
9612 {
9625 {
9630 }
9635 {
9638 code0 == LSHIFT_EXPR
9641 }
9643 {
9653 {
9657 orig_tree01);
9659 }
9660 }
9664 {
9675 {
9679 orig_tree01);
9681 }
9682 }
9683 }
9684 }
9686 associate:
9687 /* In most languages, can't associate operations on floats through
9688 parentheses. Rather than remember where the parentheses were, we
9689 don't associate floats at all, unless the user has specified
9690 -fassociative-math.
9691 And, we need to make sure type is not saturating. */
9695 {
9701 /* Split both trees into variables, constants, and literals. Then
9702 associate each group together, the constants with literals,
9703 then the result with variables. This increases the chances of
9704 literals being recombined later and of generating relocatable
9705 expressions for the sum of a constant and literal. */
9713 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9717 /* With undefined overflow prefer doing association in a type
9718 which wraps on overflow, if that is one of the operand types. */
9721 {
9729 }
9731 /* With undefined overflow we can only associate constants with one
9732 variable, and constants whose association doesn't overflow. */
9735 {
9737 {
9738 /* ??? If split_tree would handle NEGATE_EXPR we could
9739 simply reject these cases and the allowed cases would
9740 be the var0/minus_var1 ones. */
9746 {
9749 }
9756 {
9759 }
9765 /* The only case we can still associate with two variables
9766 is if they cancel out. */
9770 }
9776 }
9778 /* Only do something if we found more than two objects. Otherwise,
9779 nothing has changed and we risk infinite recursion. */
9787 {
9799 {
9803 }
9805 {
9809 }
9811 /* Preserve the MINUS_EXPR if the negative part of the literal is
9812 greater than the positive part. Otherwise, the multiplicative
9813 folding code (i.e extract_muldiv) may be fooled in case
9814 unsigned constants are subtracted, like in the following
9815 example: ((X*2 + 4) - 8U)/2. */
9817 {
9821 /* But avoid ending up with only negated parts. */
9823 {
9827 }
9828 else
9829 {
9833 }
9834 }
9836 /* Don't introduce overflows through reassociation. */
9841 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
9848 /* Eliminate minus_con0. */
9850 {
9857 else
9860 }
9862 /* Eliminate minus_var0. */
9864 {
9868 else
9871 }
9873 return
9876 }
9877 }
9883 /* Fold &a[i] - &a[j] to i-j. */
9888 {
9892 code
9896 }
9898 /* Further transformations are not for pointers. */
9902 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9905 /* If arg0 is e.g. unsigned int and type is int, then this could
9906 introduce UB, because if A is INT_MIN at runtime, the original
9907 expression can be well defined while the latter is not.
9908 See PR83269. */
9917 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
9918 __complex__ ( x, -y ). This is not the same for SNaNs or if
9919 signed zeros are involved. */
9923 {
9930 {
9934 {
9936 arg1r ? arg1r
9941 }
9943 {
9947 arg1i ? arg1i
9950 }
9951 }
9952 }
9954 /* A - B -> A + (-B) if B is easily negatable. */
9958 /* Avoid this transformation if B is a positive REAL_CST. */
9966 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
9967 one. Make sure the type is not saturating and has the signedness of
9968 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9969 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9976 {
9980 }
9986 {
9987 /* Transform x * -C into -x * C if x is easily negatable. */
10002 {
10005 "occur when simplifying "
10007 WARN_STRICT_OVERFLOW_MISC);
10009 }
10011 /* Optimize z * conj(z) for integer complex numbers. */
10018 }
10019 else
10020 {
10021 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10022 This is not the same for NaNs or if signed zeros are
10023 involved. */
10029 {
10032 return
10038 return
10043 }
10045 /* Optimize z * conj(z) for floating point complex numbers.
10046 Guarded by flag_unsafe_math_optimizations as non-finite
10047 imaginary components don't produce scalar results. */
10056 }
10060 /* Canonicalize (X & C1) | C2. */
10064 {
10069 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10077 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10079 {
10082 }
10084 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10085 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10086 mode which allows further optimizations. */
10091 {
10096 {
10099 }
10100 }
10103 {
10108 }
10109 }
10111 /* See if this can be simplified into a rotate first. If that
10112 is unsuccessful continue in the association code. */
10116 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10124 /* See if this can be simplified into a rotate first. If that
10125 is unsuccessful continue in the association code. */
10129 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10134 {
10135 tree tem2;
10142 }
10143 /* Fold ~X & 1 as (X & 1) == 0. */
10147 {
10148 tree tem2;
10155 }
10156 /* Fold !X & 1 as X == 0. */
10159 {
10163 }
10165 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
10166 multiple of 1 << CST. */
10168 {
10175 }
10177 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
10178 bits from CST2. */
10182 {
10184 wide_int masked
10191 {
10192 /* Avoid the transform if arg1 is a mask of some
10193 mode which allows further optimizations. */
10200 }
10201 }
10203 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
10204 ((A & N) + B) & M -> (A + B) & M
10205 Similarly if (N & M) == 0,
10206 ((A | N) + B) & M -> (A + B) & M
10207 and for - instead of + (or unary - instead of +)
10208 and/or ^ instead of |.
10209 If B is constant and (B & M) == 0, fold into A & M. */
10211 {
10220 {
10223 wide_int cst0;
10225 /* Now we know that arg0 is (C + D) or (C - D) or
10226 -C and arg1 (M) is == (1LL << cst) - 1.
10227 Store C into PMOP[0] and D into PMOP[1]. */
10231 {
10234 }
10241 {
10250 {
10253 }
10256 /* If C or D is of the form (A & N) where
10257 (N & M) == M, or of the form (A | N) or
10258 (A ^ N) where (N & M) == 0, replace it with A. */
10262 /* If C or D is a N where (N & M) == 0, it can be
10263 omitted (assumed 0). */
10271 }
10273 /* Only build anything new if we optimized one or both arguments
10274 above. */
10278 {
10281 {
10282 /* Perform the operations in a type that has defined
10283 overflow behavior. */
10289 }
10294 {
10302 else
10304 }
10307 else
10310 /* TEM is now the new binary +, - or unary - replacement. */
10314 }
10315 }
10316 }
10318 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10321 {
10326 return
10328 }
10333 /* Don't touch a floating-point divide by zero unless the mode
10334 of the constant can represent infinity. */
10340 /* (-A) / (-B) -> A / B */
10352 /* Fall through */
10355 /* Simplify A / (B << N) where A and B are positive and B is
10356 a power of 2, to A >> (N + log2(B)). */
10361 {
10364 {
10372 WARN_STRICT_OVERFLOW_MISC);
10378 }
10379 }
10381 /* Fall through */
10389 /* Convert -A / -B to A / B when the type is signed and overflow is
10390 undefined. */
10394 {
10397 "when distributing negation across "
10399 WARN_STRICT_OVERFLOW_MISC);
10404 }
10408 {
10411 "when distributing negation across "
10413 WARN_STRICT_OVERFLOW_MISC);
10418 }
10420 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
10421 operation, EXACT_DIV_EXPR.
10423 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
10424 At one time others generated faster code, it's not clear if they do
10425 after the last round to changes to the DIV code in expmed.c. */
10436 {
10440 WARN_STRICT_OVERFLOW_MISC);
10442 }
10454 {
10458 WARN_STRICT_OVERFLOW_MISC);
10460 }
10468 /* Since negative shift count is not well-defined,
10469 don't try to compute it in the compiler. */
10475 /* If we have a rotate of a bit operation with the rotate count and
10476 the second operand of the bit operation both constant,
10477 permute the two operations. */
10483 {
10491 }
10493 /* Two consecutive rotates adding up to the some integer
10494 multiple of the precision of the type can be ignored. */
10510 /* Note that the operands of this must be ints
10511 and their values must be 0 or 1.
10512 ("true" is a fixed value perhaps depending on the language.) */
10513 /* If first arg is constant zero, return it. */
10516 /* FALLTHRU */
10518 /* If either arg is constant true, drop it. */
10522 /* Preserve sequence points. */
10525 /* If second arg is constant zero, result is zero, but first arg
10526 must be evaluated. */
10529 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
10530 case will be handled here. */
10534 /* !X && X is always false. */
10538 /* X && !X is always false. */
10543 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
10544 means A >= Y && A != MAX, but in this case we know that
10545 A < X <= MAX. */
10549 {
10557 }
10566 /* Note that the operands of this must be ints
10567 and their values must be 0 or true.
10568 ("true" is a fixed value perhaps depending on the language.) */
10569 /* If first arg is constant true, return it. */
10572 /* FALLTHRU */
10574 /* If either arg is constant zero, drop it. */
10578 /* Preserve sequence points. */
10581 /* If second arg is constant true, result is true, but we must
10582 evaluate first arg. */
10585 /* Likewise for first arg, but note this only occurs here for
10586 TRUTH_OR_EXPR. */
10590 /* !X || X is always true. */
10594 /* X || !X is always true. */
10599 /* (X && !Y) || (!X && Y) is X ^ Y */
10602 {
10619 }
10628 /* If the second arg is constant zero, drop it. */
10631 /* If the second arg is constant true, this is a logical inversion. */
10633 {
10636 }
10637 /* Identical arguments cancel to zero. */
10641 /* !X ^ X is always true. */
10646 /* X ^ !X is always true. */
10662 /* bool_var != 1 becomes !bool_var. */
10669 /* bool_var == 0 becomes !bool_var. */
10676 /* !exp != 0 becomes !exp */
10681 /* If this is an EQ or NE comparison with zero and ARG0 is
10682 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
10683 two operations, but the latter can be done in one less insn
10684 on machines that have only two-operand insns or on which a
10685 constant cannot be the first operand. */
10688 {
10693 {
10700 arg1);
10701 }
10704 {
10711 arg1);
10712 }
10713 }
10715 /* If this is an NE or EQ comparison of zero against the result of a
10716 signed MOD operation whose second operand is a power of 2, make
10717 the MOD operation unsigned since it is simpler and equivalent. */
10725 {
10735 }
10737 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
10738 C1 is a valid shift constant, and C2 is a power of two, i.e.
10739 a single bit. */
10743 == INTEGER_CST
10746 {
10751 /* Check for a valid shift count. */
10753 {
10757 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
10758 can be rewritten as (X & (C2 << C1)) != 0. */
10760 {
10765 }
10766 /* Otherwise, for signed (arithmetic) shifts,
10767 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
10768 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
10772 /* Otherwise, of unsigned (logical) shifts,
10773 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
10774 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
10775 else
10779 arg000);
10780 }
10781 }
10783 /* If this is a comparison of a field, we may be able to simplify it. */
10786 /* Handle the constant case even without -O
10787 to make sure the warnings are given. */
10789 {
10793 }
10795 /* Optimize comparisons of strlen vs zero to a compare of the
10796 first character of the string vs zero. To wit,
10797 strlen(ptr) == 0 => *ptr == 0
10798 strlen(ptr) != 0 => *ptr != 0
10799 Other cases should reduce to one of these two (or a constant)
10800 due to the return value of strlen being unsigned. */
10803 {
10811 {
10816 }
10817 }
10819 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
10820 of X. Similarly fold (X >> C) == 0 into X >= 0. */
10824 {
10829 {
10831 {
10834 }
10837 }
10838 }
10840 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
10841 (X & C) == 0 when C is a single bit. */
10846 {
10853 arg1));
10854 }
10856 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
10857 constant C is a power of two, i.e. a single bit. */
10864 {
10868 }
10870 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
10871 when is C is a power of two, i.e. a single bit. */
10878 {
10884 }
10888 {
10891 }
10893 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
10896 {
10904 {
10910 }
10912 {
10918 }
10920 {
10926 }
10928 {
10934 }
10935 }
10939 {
10946 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
10947 operand_equal_p guarantees no side-effects so we don't need
10948 to use omit_one_operand on Z. */
10952 arg10));
10956 arg11));
10960 arg10));
10964 arg11));
10966 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
10969 {
10975 }
10976 }
10978 /* Attempt to simplify equality/inequality comparisons of complex
10979 values. Only lower the comparison if the result is known or
10980 can be simplified to a single scalar comparison. */
10985 {
10990 {
10993 }
10994 else
10995 {
10998 }
11001 {
11004 }
11005 else
11006 {
11009 }
11013 {
11015 {
11020 }
11021 else
11022 {
11027 }
11028 }
11032 {
11034 {
11039 }
11040 else
11041 {
11046 }
11047 }
11048 }
11060 /* Transform comparisons of the form X +- C CMP X. */
11065 {
11070 /* (X - c) > X becomes false. */
11076 /* Likewise (X + c) < X becomes false. */
11082 /* Convert (X - c) <= X to true. */
11089 /* Convert (X + c) >= X to true. */
11095 }
11097 /* If we are comparing an ABS_EXPR with a constant, we can
11098 convert all the cases into explicit comparisons, but they may
11099 well not be faster than doing the ABS and one comparison.
11100 But ABS (X) <= C is a range comparison, which becomes a subtraction
11101 and a comparison, and is probably faster. */
11115 /* Convert ABS_EXPR<x> >= 0 to true. */
11122 {
11125 "when simplifying comparison of "
11127 WARN_STRICT_OVERFLOW_CONDITIONAL);
11130 arg0);
11131 }
11133 /* Convert ABS_EXPR<x> < 0 to false. */
11138 {
11141 "when simplifying comparison of "
11143 WARN_STRICT_OVERFLOW_CONDITIONAL);
11146 arg0);
11147 }
11149 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
11150 and similarly for >= into !=. */
11160 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
11161 otherwise Y might be >= # of bits in X's type and thus e.g.
11162 (unsigned char) (1 << Y) for Y 15 might be 0.
11163 If the cast is widening, then 1 << Y should have unsigned type,
11164 otherwise if Y is number of bits in the signed shift type minus 1,
11165 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
11166 31 might be 0xffffffff80000000. */
11177 {
11183 }
11195 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
11196 {
11208 }
11213 /* When pedantic, a compound expression can be neither an lvalue
11214 nor an integer constant expression. */
11217 /* Don't let (0, 0) be null pointer constant. */
11223 /* An ASSERT_EXPR should never be passed to fold_binary. */
11229 }
11231 /* Used by contains_label_[p1]. */
11233 struct contains_label_data
11234 {
11237 };
11239 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
11240 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
11241 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
11243 static tree
11245 {
11248 {
11259 {
11267 }
11276 }
11277 }
11279 /* Return whether the sub-tree ST contains a label which is accessible from
11280 outside the sub-tree. */
11282 static bool
11284 {
11288 }
11290 /* Fold a ternary expression of code CODE and type TYPE with operands
11291 OP0, OP1, and OP2. Return the folded expression if folding is
11292 successful. Otherwise, return NULL_TREE. */
11294 tree
11297 {
11298 tree tem;
11305 /* If this is a commutative operation, and OP0 is a constant, move it
11306 to OP1 to reduce the number of tests below. */
11315 /* Strip any conversions that don't change the mode. This is safe
11316 for every expression, except for a comparison expression because
11317 its signedness is derived from its operands. So, in the latter
11318 case, only strip conversions that don't change the signedness.
11320 Note that this is done as an internal manipulation within the
11321 constant folder, in order to find the simplest representation of
11322 the arguments so that their form can be studied. In any cases,
11323 the appropriate type conversions should be put back in the tree
11324 that will get out of the constant folder. */
11326 {
11329 }
11332 {
11335 }
11338 {
11341 }
11344 {
11348 {
11354 }
11359 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
11360 so all simple results must be passed through pedantic_non_lvalue. */
11362 {
11365 /* Only optimize constant conditions when the selected branch
11366 has the same type as the COND_EXPR. This avoids optimizing
11367 away "c ? x : throw", where the throw has a void type.
11368 Avoid throwing away that operand which contains label. */
11375 }
11377 {
11384 {
11387 {
11395 }
11400 }
11401 }
11403 /* If we have A op B ? A : C, we may be able to convert this to a
11404 simpler expression, depending on the operation and the values
11405 of B and C. Signed zeros prevent all of these transformations,
11406 for reasons given above each one.
11408 Also try swapping the arguments and inverting the conditional. */
11412 {
11416 }
11421 {
11425 {
11429 }
11430 }
11432 /* If the second operand is simpler than the third, swap them
11433 since that produces better jump optimization results. */
11436 {
11438 /* See if this can be inverted. If it can't, possibly because
11439 it was a floating-point inequality comparison, don't do
11440 anything. */
11444 }
11446 /* Convert A ? 1 : 0 to simply A. */
11451 /* If we try to convert OP0 to our type, the
11452 call to fold will try to move the conversion inside
11453 a COND, which will recurse. In that case, the COND_EXPR
11454 is probably the best choice, so leave it alone. */
11458 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
11459 over COND_EXPR in cases such as floating point comparisons. */
11468 arg0)));
11470 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
11475 {
11476 /* sign_bit_p looks through both zero and sign extensions,
11477 but for this optimization only sign extensions are
11478 usable. */
11481 {
11484 {
11487 }
11489 }
11490 /* sign_bit_p only checks ARG1 bits within A's precision.
11491 If <sign bit of A> has wider type than A, bits outside
11492 of A's precision in <sign bit of A> need to be checked.
11493 If they are all 0, this optimization needs to be done
11494 in unsigned A's type, if they are all 1 in signed A's type,
11495 otherwise this can't be done. */
11501 {
11503 tree tem_type;
11516 {
11519 }
11521 {
11524 }
11525 else
11527 }
11530 return
11536 arg1)));
11537 }
11539 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
11540 already handled above. */
11545 {
11555 op1);
11556 }
11558 /* A & N ? N : 0 is simply A & N if N is a power of two. This
11559 is probably obsolete because the first operand should be a
11560 truth value (that's why we have the two cases above), but let's
11561 leave it in until we can confirm this for all front-ends. */
11573 /* Disable the transformations below for vectors, since
11574 fold_binary_op_with_conditional_arg may undo them immediately,
11575 yielding an infinite loop. */
11579 /* Convert A ? B : 0 into A && B if A and B are truth values. */
11588 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
11593 {
11595 /* Only perform transformation if ARG0 is easily inverted. */
11599 ? BIT_IOR_EXPR
11602 op1);
11603 }
11605 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
11610 {
11612 /* Only perform transformation if ARG0 is easily inverted. */
11618 op2);
11619 }
11621 /* Convert A ? 1 : B into A || B if A and B are truth values. */
11633 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
11634 of fold_ternary on them. */
11644 {
11655 {
11660 {
11662 {
11667 }
11673 }
11674 }
11675 }
11677 /* On constants we can use native encode/interpret to constant
11678 fold (nearly) all BIT_FIELD_REFs. */
11684 {
11687 /* Limit us to a reasonable amount of work. To relax the
11688 other limitations we need bit-shifting of the buffer
11689 and rounding up the size. */
11693 {
11695 unsigned HOST_WIDE_INT len
11700 {
11705 }
11706 }
11707 }
11712 /* For integers we can decompose the FMA if possible. */
11724 {
11725 /* Build a vector of integers from the tree mask. */
11726 vec_perm_builder builder;
11730 /* Create a vec_perm_indices for the integer vector. */
11735 /* Check for cases that fold to OP0 or OP1 in their original
11736 element order. */
11743 {
11747 {
11750 }
11751 }
11757 {
11761 }
11765 /* Generate a canonical form of the selector. */
11767 {
11768 /* Some targets are deficient and fail to expand a single
11769 argument permutation while still allowing an equivalent
11770 2-argument version. */
11774 else
11775 {
11779 else
11780 /* Not directly supported with either encoding,
11781 so use the preferred form. */
11783 }
11785 }
11789 }
11793 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
11796 {
11802 wide_int tem2
11806 }
11811 {
11813 unsigned HOST_WIDE_INT elsize
11816 {
11822 {
11828 }
11829 }
11830 }
11836 }
11838 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
11839 of an array (or vector). */
11841 tree
11843 {
11848 {
11851 {
11852 /* Static constructors for variably sized objects makes no sense. */
11856 }
11857 }
11868 offset_int max_index;
11873 {
11874 /* Array constructor might explicitly set index, or specify a range,
11875 or leave index NULL meaning that it is next index after previous
11876 one. */
11878 {
11881 else
11882 {
11886 }
11887 }
11888 else
11889 {
11895 }
11897 /* Do we have match? */
11901 }
11903 }
11905 /* Perform constant folding and related simplification of EXPR.
11906 The related simplifications include x*1 => x, x*0 => 0, etc.,
11907 and application of the associative law.
11908 NOP_EXPR conversions may be removed freely (as long as we
11909 are careful not to change the type of the overall expression).
11910 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
11911 but we can constant-fold them if they have constant operands. */
11913 #ifdef ENABLE_FOLD_CHECKING
11914 # define fold(x) fold_1 (x)
11916 static
11917 #endif
11918 tree
11920 {
11924 tree tem;
11927 /* Return right away if a constant. */
11931 /* CALL_EXPR-like objects with variable numbers of operands are
11932 treated specially. */
11934 {
11936 {
11939 }
11941 }
11944 {
11949 {
11967 }
11968 }
11971 {
11973 {
11980 {
11985 }
11988 }
11990 /* Return a VECTOR_CST if possible. */
11992 {
11998 tree val;
12004 }
12012 }
12014 #ifdef ENABLE_FOLD_CHECKING
12015 #undef fold
12022 /* When --enable-checking=fold, compute a digest of expr before
12023 and after actual fold call to see if fold did not accidentally
12024 change original expr. */
12026 tree
12028 {
12029 tree ret;
12049 }
12051 void
12053 {
12064 }
12066 static void
12068 {
12070 }
12072 static void
12075 {
12081 recursive_label:
12091 {
12092 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
12097 }
12105 {
12106 /* Allow these fields to be modified. */
12107 tree tmp;
12116 {
12119 }
12120 }
12131 {
12134 {
12150 }
12154 {
12167 }
12184 {
12190 }
12193 {
12195 {
12198 }
12200 }
12211 {
12214 }
12224 }
12225 }
12227 /* Helper function for outputting the checksum of a tree T. When
12228 debugging with gdb, you can "define mynext" to be "next" followed
12229 by "call debug_fold_checksum (op0)", then just trace down till the
12230 outputs differ. */
12232 DEBUG_FUNCTION void
12234 {
12249 }
12251 #endif
12253 /* Fold a unary tree expression with code CODE of type TYPE with an
12254 operand OP0. LOC is the location of the resulting expression.
12255 Return a folded expression if successful. Otherwise, return a tree
12256 expression with code CODE of type TYPE with an operand OP0. */
12258 tree
12261 {
12262 tree tem;
12263 #ifdef ENABLE_FOLD_CHECKING
12272 #endif
12278 #ifdef ENABLE_FOLD_CHECKING
12285 #endif
12287 }
12289 /* Fold a binary tree expression with code CODE of type TYPE with
12290 operands OP0 and OP1. LOC is the location of the resulting
12291 expression. Return a folded expression if successful. Otherwise,
12292 return a tree expression with code CODE of type TYPE with operands
12293 OP0 and OP1. */
12295 tree
12298 MEM_STAT_DECL)
12299 {
12300 tree tem;
12301 #ifdef ENABLE_FOLD_CHECKING
12318 #endif
12324 #ifdef ENABLE_FOLD_CHECKING
12339 #endif
12341 }
12343 /* Fold a ternary tree expression with code CODE of type TYPE with
12344 operands OP0, OP1, and OP2. Return a folded expression if
12345 successful. Otherwise, return a tree expression with code CODE of
12346 type TYPE with operands OP0, OP1, and OP2. */
12348 tree
12351 {
12352 tree tem;
12353 #ifdef ENABLE_FOLD_CHECKING
12377 #endif
12384 #ifdef ENABLE_FOLD_CHECKING
12407 #endif
12409 }
12411 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
12412 arguments in ARGARRAY, and a null static chain.
12413 Return a folded expression if successful. Otherwise, return a CALL_EXPR
12414 of type TYPE from the given operands as constructed by build_call_array. */
12416 tree
12419 {
12420 tree tem;
12421 #ifdef ENABLE_FOLD_CHECKING
12440 #endif
12446 #ifdef ENABLE_FOLD_CHECKING
12462 #endif
12464 }
12466 /* Perform constant folding and related simplification of initializer
12467 expression EXPR. These behave identically to "fold_buildN" but ignore
12468 potential run-time traps and exceptions that fold must preserve. */
12470 #define START_FOLD_INIT \
12471 int saved_signaling_nans = flag_signaling_nans;\
12472 int saved_trapping_math = flag_trapping_math;\
12473 int saved_rounding_math = flag_rounding_math;\
12474 int saved_trapv = flag_trapv;\
12475 int saved_folding_initializer = folding_initializer;\
12476 flag_signaling_nans = 0;\
12477 flag_trapping_math = 0;\
12478 flag_rounding_math = 0;\
12479 flag_trapv = 0;\
12480 folding_initializer = 1;
12482 #define END_FOLD_INIT \
12483 flag_signaling_nans = saved_signaling_nans;\
12484 flag_trapping_math = saved_trapping_math;\
12485 flag_rounding_math = saved_rounding_math;\
12486 flag_trapv = saved_trapv;\
12487 folding_initializer = saved_folding_initializer;
12489 tree
12492 {
12493 tree result;
12494 START_FOLD_INIT;
12498 END_FOLD_INIT;
12500 }
12502 tree
12505 {
12506 tree result;
12507 START_FOLD_INIT;
12511 END_FOLD_INIT;
12513 }
12515 tree
12518 {
12519 tree result;
12520 START_FOLD_INIT;
12524 END_FOLD_INIT;
12526 }
12528 #undef START_FOLD_INIT
12529 #undef END_FOLD_INIT
12531 /* Determine if first argument is a multiple of second argument. Return 0 if
12532 it is not, or we cannot easily determined it to be.
12534 An example of the sort of thing we care about (at this point; this routine
12535 could surely be made more general, and expanded to do what the *_DIV_EXPR's
12536 fold cases do now) is discovering that
12538 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12540 is a multiple of
12542 SAVE_EXPR (J * 8)
12544 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
12546 This code also handles discovering that
12548 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12550 is a multiple of 8 so we don't have to worry about dealing with a
12551 possible remainder.
12553 Note that we *look* inside a SAVE_EXPR only to determine how it was
12554 calculated; it is not safe for fold to do much of anything else with the
12555 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
12556 at run time. For example, the latter example above *cannot* be implemented
12557 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
12558 evaluation time of the original SAVE_EXPR is not necessarily the same at
12559 the time the new expression is evaluated. The only optimization of this
12560 sort that would be valid is changing
12562 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
12564 divided by 8 to
12566 SAVE_EXPR (I) * SAVE_EXPR (J)
12568 (where the same SAVE_EXPR (J) is used in the original and the
12569 transformed version). */
12571 int
12573 {
12584 {
12586 /* Bitwise and provides a power of two multiple. If the mask is
12587 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
12595 {
12601 {
12604 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
12606 {
12610 {
12613 }
12614 }
12616 }
12617 }
12622 /* It is impossible to prove if op0 - op1 is multiple of bottom
12623 precisely, so be conservative here checking if both op0 and op1
12624 are multiple of bottom. Note we check the second operand first
12625 since it's usually simpler. */
12630 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
12631 as op0 - 3 if the expression has unsigned type. For example,
12632 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
12642 {
12644 /* const_binop may not detect overflow correctly,
12645 so check for it explicitly here. */
12653 }
12657 /* Can't handle conversions from non-integral or wider integral type. */
12663 /* fall through */
12680 SIGNED);
12686 {
12689 /* Check for special cases to see if top is defined as multiple
12690 of bottom:
12692 top = (X & ~(bottom - 1) ; bottom is power of 2
12694 or
12696 Y = X % bottom
12697 top = X - Y. */
12716 }
12718 /* fall through */
12726 }
12727 }
12729 #define tree_expr_nonnegative_warnv_p(X, Y) \
12732 #define RECURSE(X) \
12733 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
12735 /* Return true if CODE or TYPE is known to be non-negative. */
12737 static bool
12739 {
12742 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
12743 have a signed:1 type (where the value is -1 and 0). */
12746 }
12748 /* Return true if (CODE OP0) is known to be non-negative. If the return
12749 value is based on the assumption that signed overflow is undefined,
12750 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12751 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12753 bool
12756 {
12761 {
12763 /* We can't return 1 if flag_wrapv is set because
12764 ABS_EXPR<INT_MIN> = INT_MIN. */
12768 {
12771 }
12779 CASE_CONVERT:
12780 {
12785 {
12789 {
12793 }
12794 }
12796 {
12802 }
12803 }
12808 }
12810 /* We don't know sign of `t', so be conservative and return false. */
12812 }
12814 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
12815 value is based on the assumption that signed overflow is undefined,
12816 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12817 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12819 bool
12823 {
12828 {
12834 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
12835 both unsigned and at least 2 bits shorter than the result. */
12839 {
12844 {
12848 }
12849 }
12854 {
12855 /* x * x is always non-negative for floating point x
12856 or without overflow. */
12859 {
12864 }
12865 }
12867 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
12868 both unsigned and their total bits is shorter than the result. */
12872 {
12891 {
12901 }
12902 }
12929 }
12931 /* We don't know sign of `t', so be conservative and return false. */
12933 }
12935 /* Return true if T is known to be non-negative. If the return
12936 value is based on the assumption that signed overflow is undefined,
12937 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12938 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12940 bool
12942 {
12947 {
12961 /* Limit the depth of recursion to avoid quadratic behavior.
12962 This is expected to catch almost all occurrences in practice.
12963 If this code misses important cases that unbounded recursion
12964 would not, passes that need this information could be revised
12965 to provide it through dataflow propagation. */
12973 }
12974 }
12976 /* Return true if T is known to be non-negative. If the return
12977 value is based on the assumption that signed overflow is undefined,
12978 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12979 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12981 bool
12984 {
12986 {
12987 CASE_CFN_ACOS:
12988 CASE_CFN_ACOSH:
12989 CASE_CFN_CABS:
12990 CASE_CFN_COSH:
12991 CASE_CFN_ERFC:
12992 CASE_CFN_EXP:
12993 CASE_CFN_EXP10:
12994 CASE_CFN_EXP2:
12995 CASE_CFN_FABS:
12996 CASE_CFN_FDIM:
12997 CASE_CFN_HYPOT:
12998 CASE_CFN_POW10:
12999 CASE_CFN_FFS:
13000 CASE_CFN_PARITY:
13001 CASE_CFN_POPCOUNT:
13002 CASE_CFN_CLZ:
13003 CASE_CFN_CLRSB:
13006 /* Always true. */
13009 CASE_CFN_SQRT:
13010 CASE_CFN_SQRT_FN:
13011 /* sqrt(-0.0) is -0.0. */
13016 CASE_CFN_ASINH:
13017 CASE_CFN_ATAN:
13018 CASE_CFN_ATANH:
13019 CASE_CFN_CBRT:
13020 CASE_CFN_CEIL:
13021 CASE_CFN_CEIL_FN:
13022 CASE_CFN_ERF:
13023 CASE_CFN_EXPM1:
13024 CASE_CFN_FLOOR:
13025 CASE_CFN_FLOOR_FN:
13026 CASE_CFN_FMOD:
13027 CASE_CFN_FREXP:
13028 CASE_CFN_ICEIL:
13029 CASE_CFN_IFLOOR:
13030 CASE_CFN_IRINT:
13031 CASE_CFN_IROUND:
13032 CASE_CFN_LCEIL:
13033 CASE_CFN_LDEXP:
13034 CASE_CFN_LFLOOR:
13035 CASE_CFN_LLCEIL:
13036 CASE_CFN_LLFLOOR:
13037 CASE_CFN_LLRINT:
13038 CASE_CFN_LLROUND:
13039 CASE_CFN_LRINT:
13040 CASE_CFN_LROUND:
13041 CASE_CFN_MODF:
13042 CASE_CFN_NEARBYINT:
13043 CASE_CFN_NEARBYINT_FN:
13044 CASE_CFN_RINT:
13045 CASE_CFN_RINT_FN:
13046 CASE_CFN_ROUND:
13047 CASE_CFN_ROUND_FN:
13048 CASE_CFN_SCALB:
13049 CASE_CFN_SCALBLN:
13050 CASE_CFN_SCALBN:
13051 CASE_CFN_SIGNBIT:
13052 CASE_CFN_SIGNIFICAND:
13053 CASE_CFN_SINH:
13054 CASE_CFN_TANH:
13055 CASE_CFN_TRUNC:
13056 CASE_CFN_TRUNC_FN:
13057 /* True if the 1st argument is nonnegative. */
13060 CASE_CFN_FMAX:
13061 CASE_CFN_FMAX_FN:
13062 /* True if the 1st OR 2nd arguments are nonnegative. */
13065 CASE_CFN_FMIN:
13066 CASE_CFN_FMIN_FN:
13067 /* True if the 1st AND 2nd arguments are nonnegative. */
13070 CASE_CFN_COPYSIGN:
13071 CASE_CFN_COPYSIGN_FN:
13072 /* True if the 2nd argument is nonnegative. */
13075 CASE_CFN_POWI:
13076 /* True if the 1st argument is nonnegative or the second
13077 argument is an even integer. */
13083 CASE_CFN_POW:
13084 /* True if the 1st argument is nonnegative or the second
13085 argument is an even integer valued real. */
13087 {
13088 REAL_VALUE_TYPE c;
13089 HOST_WIDE_INT n;
13094 {
13095 REAL_VALUE_TYPE cint;
13099 }
13100 }
13105 }
13107 }
13109 /* Return true if T is known to be non-negative. If the return
13110 value is based on the assumption that signed overflow is undefined,
13111 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13112 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13114 static bool
13116 {
13122 {
13124 {
13128 /* If the initializer is non-void, then it's a normal expression
13129 that will be assigned to the slot. */
13133 /* Otherwise, the initializer sets the slot in some way. One common
13134 way is an assignment statement at the end of the initializer. */
13136 {
13144 else
13146 }
13152 }
13155 {
13161 arg0,
13162 arg1,
13164 }
13177 }
13178 }
13180 #undef RECURSE
13181 #undef tree_expr_nonnegative_warnv_p
13183 /* Return true if T is known to be non-negative. If the return
13184 value is based on the assumption that signed overflow is undefined,
13185 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13186 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13188 bool
13190 {
13197 {
13219 }
13222 {
13248 }
13249 }
13251 /* Return true if `t' is known to be non-negative. Handle warnings
13252 about undefined signed overflow. */
13254 bool
13256 {
13263 "determining that expression is always "
13265 WARN_STRICT_OVERFLOW_MISC);
13267 }
13270 /* Return true when (CODE OP0) is an address and is known to be nonzero.
13271 For floating point we further ensure that T is not denormal.
13272 Similar logic is present in nonzero_address in rtlanal.h.
13274 If the return value is based on the assumption that signed overflow
13275 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13276 change *STRICT_OVERFLOW_P. */
13278 bool
13281 {
13283 {
13286 strict_overflow_p);
13289 {
13295 strict_overflow_p));
13296 }
13301 strict_overflow_p);
13305 }
13308 }
13310 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
13311 For floating point we further ensure that T is not denormal.
13312 Similar logic is present in nonzero_address in rtlanal.h.
13314 If the return value is based on the assumption that signed overflow
13315 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13316 change *STRICT_OVERFLOW_P. */
13318 bool
13320 tree type,
13321 tree op0,
13323 {
13326 {
13330 {
13331 /* With the presence of negative values it is hard
13332 to say something. */
13339 /* One of operands must be positive and the other non-negative. */
13340 /* We don't set *STRICT_OVERFLOW_P here: even if this value
13341 overflows, on a twos-complement machine the sum of two
13342 nonnegative numbers can never be zero. */
13344 strict_overflow_p)
13346 strict_overflow_p));
13347 }
13352 {
13354 strict_overflow_p)
13356 strict_overflow_p))
13357 {
13360 }
13361 }
13370 {
13373 }
13380 {
13384 /* When both operands are nonzero, then MAX must be too. */
13386 strict_overflow_p))
13389 /* MAX where operand 0 is positive is positive. */
13391 strict_overflow_p);
13392 }
13393 /* MAX where operand 1 is positive is positive. */
13398 {
13402 }
13407 strict_overflow_p)
13409 strict_overflow_p));
13413 }
13416 }
13418 /* Return true when T is an address and is known to be nonzero.
13419 For floating point we further ensure that T is not denormal.
13420 Similar logic is present in nonzero_address in rtlanal.h.
13422 If the return value is based on the assumption that signed overflow
13423 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13424 change *STRICT_OVERFLOW_P. */
13426 bool
13428 {
13431 {
13436 {
13448 /* For objects in symbol table check if we know they are non-zero.
13449 Don't do anything for variables and functions before symtab is built;
13450 it is quite possible that they will be declared weak later. */
13455 /* Constants are never weak. */
13460 }
13468 {
13472 }
13482 }
13484 }
13486 #define integer_valued_real_p(X) \
13489 #define RECURSE(X) \
13490 ((integer_valued_real_p) (X, depth + 1))
13492 /* Return true if the floating point result of (CODE OP0) has an
13493 integer value. We also allow +Inf, -Inf and NaN to be considered
13494 integer values. Return false for signaling NaN.
13496 DEPTH is the current nesting depth of the query. */
13498 bool
13500 {
13502 {
13509 CASE_CONVERT:
13510 {
13517 }
13521 }
13523 }
13525 /* Return true if the floating point result of (CODE OP0 OP1) has an
13526 integer value. We also allow +Inf, -Inf and NaN to be considered
13527 integer values. Return false for signaling NaN.
13529 DEPTH is the current nesting depth of the query. */
13531 bool
13533 {
13535 {
13545 }
13547 }
13549 /* Return true if the floating point result of calling FNDECL with arguments
13550 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
13551 considered integer values. Return false for signaling NaN. If FNDECL
13552 takes fewer than 2 arguments, the remaining ARGn are null.
13554 DEPTH is the current nesting depth of the query. */
13556 bool
13558 {
13560 {
13561 CASE_CFN_CEIL:
13562 CASE_CFN_CEIL_FN:
13563 CASE_CFN_FLOOR:
13564 CASE_CFN_FLOOR_FN:
13565 CASE_CFN_NEARBYINT:
13566 CASE_CFN_NEARBYINT_FN:
13567 CASE_CFN_RINT:
13568 CASE_CFN_RINT_FN:
13569 CASE_CFN_ROUND:
13570 CASE_CFN_ROUND_FN:
13571 CASE_CFN_TRUNC:
13572 CASE_CFN_TRUNC_FN:
13575 CASE_CFN_FMIN:
13576 CASE_CFN_FMIN_FN:
13577 CASE_CFN_FMAX:
13578 CASE_CFN_FMAX_FN:
13583 }
13585 }
13587 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
13588 has an integer value. We also allow +Inf, -Inf and NaN to be
13589 considered integer values. Return false for signaling NaN.
13591 DEPTH is the current nesting depth of the query. */
13593 bool
13595 {
13597 {
13605 /* Limit the depth of recursion to avoid quadratic behavior.
13606 This is expected to catch almost all occurrences in practice.
13607 If this code misses important cases that unbounded recursion
13608 would not, passes that need this information could be revised
13609 to provide it through dataflow propagation. */
13613 depth));
13617 }
13619 }
13621 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
13622 has an integer value. We also allow +Inf, -Inf and NaN to be
13623 considered integer values. Return false for signaling NaN.
13625 DEPTH is the current nesting depth of the query. */
13627 static bool
13629 {
13631 {
13642 }
13644 }
13646 #undef RECURSE
13647 #undef integer_valued_real_p
13649 /* Return true if the floating point expression T has an integer value.
13650 We also allow +Inf, -Inf and NaN to be considered integer values.
13651 Return false for signaling NaN.
13653 DEPTH is the current nesting depth of the query. */
13655 bool
13657 {
13663 {
13679 }
13682 {
13688 {
13697 }
13701 }
13702 }
13704 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
13705 attempt to fold the expression to a constant without modifying TYPE,
13706 OP0 or OP1.
13708 If the expression could be simplified to a constant, then return
13709 the constant. If the expression would not be simplified to a
13710 constant, then return NULL_TREE. */
13712 tree
13714 {
13717 }
13719 /* Given the components of a unary expression CODE, TYPE and OP0,
13720 attempt to fold the expression to a constant without modifying
13721 TYPE or OP0.
13723 If the expression could be simplified to a constant, then return
13724 the constant. If the expression would not be simplified to a
13725 constant, then return NULL_TREE. */
13727 tree
13729 {
13732 }
13734 /* If EXP represents referencing an element in a constant string
13735 (either via pointer arithmetic or array indexing), return the
13736 tree representing the value accessed, otherwise return NULL. */
13738 tree
13740 {
13744 {
13746 tree index;
13747 tree string;
13752 else
13753 {
13757 /* Optimize the special-case of a zero lower bound.
13759 We convert the low_bound to sizetype to avoid some problems
13760 with constant folding. (E.g. suppose the lower bound is 1,
13761 and its mode is QI. Without the conversion,l (ARRAY
13762 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
13763 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
13769 }
13771 scalar_int_mode char_mode;
13783 }
13785 }
13787 /* Return the tree for neg (ARG0) when ARG0 is known to be either
13788 an integer constant, real, or fixed-point constant.
13790 TYPE is the type of the result. */
13792 static tree
13794 {
13798 {
13804 {
13805 FIXED_VALUE_TYPE f;
13810 /* Propagate overflow flags. */
13814 }
13818 {
13825 }
13828 }
13831 }
13833 /* Return the tree for abs (ARG0) when ARG0 is known to be either
13834 an integer constant or real constant.
13836 TYPE is the type of the result. */
13838 tree
13840 {
13844 {
13846 {
13847 /* If the value is unsigned or non-negative, then the absolute value
13848 is the same as the ordinary value. */
13852 /* If the value is negative, then the absolute value is
13853 its negation. */
13854 else
13855 {
13860 }
13861 }
13867 else
13873 }
13876 }
13878 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
13879 constant. TYPE is the type of the result. */
13881 static tree
13883 {
13887 }
13889 /* Given CODE, a relational operator, the target type, TYPE and two
13890 constant operands OP0 and OP1, return the result of the
13891 relational operation. If the result is not a compile time
13892 constant, then return NULL_TREE. */
13894 static tree
13896 {
13899 /* From here on, the only cases we handle are when the result is
13900 known to be a constant. */
13903 {
13907 /* Handle the cases where either operand is a NaN. */
13909 {
13911 {
13939 }
13942 }
13945 }
13948 {
13952 }
13954 /* Handle equality/inequality of complex constants. */
13956 {
13967 else
13969 }
13972 {
13974 {
13975 /* Have vector comparison with scalar boolean result. */
13983 {
13991 }
13993 }
13994 tree_vector_builder elts;
13999 {
14012 }
14015 }
14017 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
14019 To compute GT, swap the arguments and do LT.
14020 To compute GE, do LT and invert the result.
14021 To compute LE, swap the arguments, do LT and invert the result.
14022 To compute NE, do EQ and invert the result.
14024 Therefore, the code below must handle only EQ and LT. */
14027 {
14030 }
14032 /* Note that it is safe to invert for real values here because we
14033 have already handled the one case that it matters. */
14037 {
14040 }
14042 /* Compute a result for LT or EQ if args permit;
14043 Otherwise return T. */
14045 {
14048 else
14050 }
14051 else
14057 }
14059 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
14060 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
14061 itself. */
14063 tree
14065 {
14066 /* If the expression does not have side effects then we don't have to wrap
14067 it with a cleanup point expression. */
14071 /* If the expression is a return, check to see if the expression inside the
14072 return has no side effects or the right hand side of the modify expression
14073 inside the return. If either don't have side effects set we don't need to
14074 wrap the expression in a cleanup point expression. Note we don't check the
14075 left hand side of the modify because it should always be a return decl. */
14077 {
14084 }
14087 }
14089 /* Given a pointer value OP0 and a type TYPE, return a simplified version
14090 of an indirection through OP0, or NULL_TREE if no simplification is
14091 possible. */
14093 tree
14095 {
14097 tree subtype;
14098 poly_uint64 const_op01;
14107 {
14111 /* *&CONST_DECL -> to the value of the const decl. */
14114 /* *&p => p; make sure to handle *&"str"[cst] here. */
14116 {
14120 else
14122 }
14123 /* *(foo *)&fooarray => fooarray[0] */
14126 && (!in_gimple_form
14128 {
14138 }
14139 /* *(foo *)&complexfoo => __real__ complexfoo */
14143 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14146 {
14150 index);
14151 }
14152 }
14156 {
14162 {
14163 tree op00type;
14167 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
14170 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
14171 but we want to treat offsets with MSB set as negative.
14172 For the code below negative offsets are invalid and
14173 TYPE_SIZE of the element is something unsigned, so
14174 check whether op01 fits into poly_int64, which implies
14175 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
14176 then just use poly_uint64 because we want to treat the
14177 value as unsigned. */
14179 {
14181 poly_uint64 max_offset
14185 {
14190 }
14191 }
14192 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
14195 {
14197 const_op01))
14199 }
14200 /* ((foo *)&fooarray)[1] => fooarray[1] */
14203 {
14210 offset_int remainder;
14213 {
14218 }
14219 }
14220 }
14221 }
14223 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
14226 && (!in_gimple_form
14228 {
14229 tree type_domain;
14239 NULL_TREE);
14240 }
14243 }
14245 /* Builds an expression for an indirection through T, simplifying some
14246 cases. */
14248 tree
14250 {
14258 }
14260 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14262 tree
14264 {
14269 else
14271 }
14273 /* Strip non-trapping, non-side-effecting tree nodes from an expression
14274 whose result is ignored. The type of the returned tree need not be
14275 the same as the original expression. */
14277 tree
14279 {
14285 {
14296 else
14302 {
14318 }
14323 }
14324 }
14326 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
14328 tree
14330 {
14336 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14337 have to do anything. Only do this when we are not given a const,
14338 because in that case, this check is more expensive than just
14339 doing it. */
14341 {
14346 }
14348 /* If divisor is a power of two, simplify this to bit manipulation. */
14350 {
14352 {
14366 }
14367 else
14368 {
14369 tree t;
14375 }
14376 }
14377 else
14378 {
14383 }
14386 }
14388 /* Likewise, but round down. */
14390 tree
14392 {
14399 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14400 have to do anything. Only do this when we are not given a const,
14401 because in that case, this check is more expensive than just
14402 doing it. */
14404 {
14409 }
14411 /* If divisor is a power of two, simplify this to bit manipulation. */
14413 {
14414 tree t;
14418 }
14419 else
14420 {
14425 }
14428 }
14430 /* Returns the pointer to the base of the object addressed by EXP and
14431 extracts the information about the offset of the access, storing it
14432 to PBITPOS and POFFSET. */
14434 static tree
14437 {
14438 tree core;
14439 machine_mode mode;
14441 poly_int64 bitsize;
14445 {
14450 }
14452 {
14458 {
14459 poly_offset_int tem
14465 }
14466 }
14467 else
14468 {
14472 }
14475 }
14477 /* Returns true if addresses of E1 and E2 differ by a constant, false
14478 otherwise. If they do, E1 - E2 is stored in *DIFF. */
14480 bool
14482 {
14497 {
14507 }
14509 {
14510 /* If only one of the offsets is non-constant, the difference cannot
14511 be a constant. */
14513 }
14514 else
14519 }
14521 /* Return OFF converted to a pointer offset type suitable as offset for
14522 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
14523 tree
14525 {
14527 }
14529 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14530 tree
14532 {
14535 }
14537 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14538 tree
14540 {
14543 }
14545 /* Return a char pointer for a C string if it is a string constant
14546 or sum of string constant and integer constant. We only support
14547 string constants properly terminated with '\0' character.
14548 If STRLEN is a valid pointer, length (including terminating character)
14549 of returned string is stored to the argument. */
14553 {
14554 tree offset_node;
14565 {
14568 else
14570 }
14575 /* Support only properly null-terminated strings. */
14584 }
14586 #if CHECKING_P
14590 /* Helper functions for writing tests of folding trees. */
14592 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
14594 static void
14596 tree constant)
14597 {
14599 }
14601 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
14602 wrapping WRAPPED_EXPR. */
14604 static void
14606 tree wrapped_expr)
14607 {
14612 }
14614 /* Verify that various arithmetic binary operations are folded
14615 correctly. */
14617 static void
14619 {
14625 /* Addition. */
14626 /* 1 <-- (0 + 1) */
14628 one);
14630 one);
14632 /* (nonlvalue)x <-- (x + 0) */
14634 x);
14636 /* Subtraction. */
14637 /* 0 <-- (x - x) */
14639 zero);
14641 x);
14643 /* Multiplication. */
14644 /* 0 <-- (x * 0) */
14646 zero);
14648 /* (nonlvalue)x <-- (x * 1) */
14650 x);
14651 }
14653 /* Verify that various binary operations on vectors are folded
14654 correctly. */
14656 static void
14658 {
14664 /* Verify equality tests that return a scalar boolean result. */
14670 }
14672 /* Verify folding of VEC_DUPLICATE_EXPRs. */
14674 static void
14676 {
14679 /* This will be 1 if VEC_MODE isn't a vector mode. */
14686 }
14688 /* Run all of the selftests within this file. */
14690 void
14692 {
14696 }