| blob | dc277440aa9a5c354ea79b3a02e46a49c72ea4bd |
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. */
3304 /* The multiplcation operands are commutative. */
3305 /* FALLTHRU */
3313 /* Otherwise take into account this is a commutative operation. */
3326 /* BIT_INSERT_EXPR has an implict operand as the type precision
3327 of op1. Need to check to make sure they are the same. */
3333 /* FALLTHRU */
3358 }
3362 {
3366 /* If not both CALL_EXPRs are either internal or normal function
3367 functions, then they are not equal. */
3370 {
3371 /* If the CALL_EXPRs call different internal functions, then they
3372 are not equal. */
3375 }
3376 else
3377 {
3378 /* If the CALL_EXPRs call different functions, then they are not
3379 equal. */
3381 flags))
3383 }
3385 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3386 {
3390 else
3394 }
3396 /* Now see if all the arguments are the same. */
3397 {
3408 /* If we get here and both argument lists are exhausted
3409 then the CALL_EXPRs are equal. */
3411 }
3414 }
3417 /* Consider __builtin_sqrt equal to sqrt. */
3425 {
3426 /* In GIMPLE constructors are used only to build vectors from
3427 elements. Individual elements in the constructor must be
3428 indexed in increasing order and form an initial sequence.
3430 We make no effort to compare constructors in generic.
3431 (see sem_variable::equals in ipa-icf which can do so for
3432 constants). */
3437 /* Be sure that vectors constructed have the same representation.
3438 We only tested element precision and modes to match.
3439 Vectors may be BLKmode and thus also check that the number of
3440 parts match. */
3453 {
3458 /* In GIMPLE the indexes can be either NULL or matching i.
3459 Double check this so we won't get false
3460 positives for GENERIC. */
3468 }
3470 }
3473 {
3474 /* Compare the STATEMENT_LISTs. */
3480 {
3481 /* The lists don't have the same number of statements. */
3487 flags & (OEP_LEXICOGRAPHIC
3490 }
3491 }
3496 {
3507 }
3511 }
3513 #undef OP_SAME
3514 #undef OP_SAME_WITH_NULL
3515 }
3516 \f
3517 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
3518 with a different signedness or a narrower precision. */
3520 static bool
3522 {
3530 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3531 and see if the inner values are the same. This removes any
3532 signedness comparison, which doesn't matter here. */
3540 /* Discard a single widening conversion from ARG1 and see if the inner
3541 value is the same as ARG0. */
3550 }
3551 \f
3552 /* See if ARG is an expression that is either a comparison or is performing
3553 arithmetic on comparisons. The comparisons must only be comparing
3554 two different values, which will be stored in *CVAL1 and *CVAL2; if
3555 they are nonzero it means that some operands have already been found.
3556 No variables may be used anywhere else in the expression except in the
3557 comparisons.
3559 If this is true, return 1. Otherwise, return zero. */
3561 static int
3563 {
3567 /* We can handle some of the tcc_expression cases here. */
3576 {
3595 /* First see if we can handle the first operand, then the second. For
3596 the second operand, we know *CVAL1 can't be zero. It must be that
3597 one side of the comparison is each of the values; test for the
3598 case where this isn't true by failing if the two operands
3599 are the same. */
3608 ;
3612 ;
3613 else
3617 ;
3621 ;
3622 else
3629 }
3630 }
3631 \f
3632 /* ARG is a tree that is known to contain just arithmetic operations and
3633 comparisons. Evaluate the operations in the tree substituting NEW0 for
3634 any occurrence of OLD0 as an operand of a comparison and likewise for
3635 NEW1 and OLD1. */
3637 static tree
3640 {
3645 /* We can handle some of the tcc_expression cases here. */
3653 {
3668 {
3687 }
3688 /* Fall through - ??? */
3691 {
3695 /* We need to check both for exact equality and tree equality. The
3696 former will be true if the operand has a side-effect. In that
3697 case, we know the operand occurred exactly once. */
3710 }
3714 }
3715 }
3716 \f
3717 /* Return a tree for the case when the result of an expression is RESULT
3718 converted to TYPE and OMITTED was previously an operand of the expression
3719 but is now not needed (e.g., we folded OMITTED * 0).
3721 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3722 the conversion of RESULT to TYPE. */
3724 tree
3726 {
3729 /* If the resulting operand is an empty statement, just return the omitted
3730 statement casted to void. */
3740 }
3742 /* Return a tree for the case when the result of an expression is RESULT
3743 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3744 of the expression but are now not needed.
3746 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3747 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3748 evaluated before OMITTED2. Otherwise, if neither has side effects,
3749 just do the conversion of RESULT to TYPE. */
3751 tree
3754 {
3763 }
3765 \f
3766 /* Return a simplified tree node for the truth-negation of ARG. This
3767 never alters ARG itself. We assume that ARG is an operation that
3768 returns a truth value (0 or 1).
3770 FIXME: one would think we would fold the result, but it causes
3771 problems with the dominator optimizer. */
3773 static tree
3775 {
3780 /* If this is a comparison, we can simply invert it, except for
3781 floating-point non-equality comparisons, in which case we just
3782 enclose a TRUTH_NOT_EXPR around what we have. */
3785 {
3788 && flag_trapping_math
3802 }
3805 {
3824 /* Here we can invert either operand. We invert the first operand
3825 unless the second operand is a TRUTH_NOT_EXPR in which case our
3826 result is the XOR of the first operand with the inside of the
3827 negation of the second operand. */
3832 else
3855 {
3862 /* A COND_EXPR may have a throw as one operand, which
3863 then has void type. Just leave void operands
3864 as they are. */
3870 }
3882 CASE_CONVERT:
3886 /* fall through */
3908 }
3909 }
3911 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3912 assume that ARG is an operation that returns a truth value (0 or 1
3913 for scalars, 0 or -1 for vectors). Return the folded expression if
3914 folding is successful. Otherwise, return NULL_TREE. */
3916 static tree
3918 {
3921 ? BIT_NOT_EXPR
3924 }
3926 /* Return a simplified tree node for the truth-negation of ARG. This
3927 never alters ARG itself. We assume that ARG is an operation that
3928 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3930 tree
3932 {
3938 ? BIT_NOT_EXPR
3941 }
3942 \f
3943 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3944 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
3945 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
3946 is the original memory reference used to preserve the alias set of
3947 the access. */
3949 static tree
3953 {
3956 /* Attempt not to lose the access path if possible. */
3958 {
3960 machine_mode nmode;
3962 tree noffset;
3970 && !reversep
3971 && !nreversep
3973 {
3976 }
3977 }
3986 {
3993 }
4008 }
4010 /* Optimize a bit-field compare.
4012 There are two cases: First is a compare against a constant and the
4013 second is a comparison of two items where the fields are at the same
4014 bit position relative to the start of a chunk (byte, halfword, word)
4015 large enough to contain it. In these cases we can avoid the shift
4016 implicit in bitfield extractions.
4018 For constants, we emit a compare of the shifted constant with the
4019 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4020 compared. For two fields at the same position, we do the ANDs with the
4021 similar mask and compare the result of the ANDs.
4023 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4024 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4025 are the left and right operands of the comparison, respectively.
4027 If the optimization described above can be done, we return the resulting
4028 tree. Otherwise we return zero. */
4030 static tree
4033 {
4037 tree unsigned_type;
4040 scalar_int_mode nmode;
4045 tree mask;
4046 tree offset;
4048 /* Get all the information about the extractions being done. If the bit size
4049 is the same as the size of the underlying object, we aren't doing an
4050 extraction at all and so can do nothing. We also don't want to
4051 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4052 then will no longer be able to replace it. */
4067 else
4068 {
4069 /* If this is not a constant, we can only do something if bit positions,
4070 sizes, signedness and storage order are the same. */
4071 rinner
4084 }
4086 /* Honor the C++ memory model and mimic what RTL expansion does. */
4090 {
4094 }
4096 /* See if we can find a mode to refer to this field. We should be able to,
4097 but fail if we can't. */
4105 /* Set signed and unsigned types of the precision of this mode for the
4106 shifts below. */
4109 /* Compute the bit position and size for the new reference and our offset
4110 within it. If the new reference is the same size as the original, we
4111 won't optimize anything, so return zero. */
4121 /* Make the mask to be used against the extracted field. */
4128 {
4132 /* If not comparing with constant, just rework the comparison
4133 and return. */
4141 }
4143 /* Otherwise, we are handling the constant case. See if the constant is too
4144 big for the field. Warn and return a tree for 0 (false) if so. We do
4145 this not only for its own sake, but to avoid having to test for this
4146 error case below. If we didn't, we might generate wrong code.
4148 For unsigned fields, the constant shifted right by the field length should
4149 be all zero. For signed fields, the high-order bits should agree with
4150 the sign bit. */
4153 {
4155 {
4159 }
4160 }
4161 else
4162 {
4165 {
4169 }
4170 }
4175 /* Single-bit compares should always be against zero. */
4177 {
4180 }
4182 /* Make a new bitfield reference, shift the constant over the
4183 appropriate number of bits and mask it with the computed mask
4184 (in case this was a signed field). If we changed it, make a new one. */
4192 mask);
4197 }
4198 \f
4199 /* Subroutine for fold_truth_andor_1: decode a field reference.
4201 If EXP is a comparison reference, we return the innermost reference.
4203 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4204 set to the starting bit number.
4206 If the innermost field can be completely contained in a mode-sized
4207 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4209 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4210 otherwise it is not changed.
4212 *PUNSIGNEDP is set to the signedness of the field.
4214 *PREVERSEP is set to the storage order of the field.
4216 *PMASK is set to the mask used. This is either contained in a
4217 BIT_AND_EXPR or derived from the width of the field.
4219 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4221 Return 0 if this is not a component reference or is one that we can't
4222 do anything with. */
4224 static tree
4229 {
4234 tree unsigned_type;
4237 /* All the optimizations using this function assume integer fields.
4238 There are problems with FP fields since the type_for_size call
4239 below can fail for, e.g., XFmode. */
4243 /* We are interested in the bare arrangement of bits, so strip everything
4244 that doesn't affect the machine mode. However, record the type of the
4245 outermost expression if it may matter below. */
4252 {
4258 }
4269 /* Reject out-of-bound accesses (PR79731). */
4277 /* If the number of bits in the reference is the same as the bitsize of
4278 the outer type, then the outer type gives the signedness. Otherwise
4279 (in case of a small bitfield) the signedness is unchanged. */
4283 /* Compute the mask to access the bitfield. */
4292 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4300 }
4302 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4303 bit positions and MASK is SIGNED. */
4305 static int
4307 {
4311 /* If this function returns true when the type of the mask is
4312 UNSIGNED, then there will be errors. In particular see
4313 gcc.c-torture/execute/990326-1.c. There does not appear to be
4314 any documentation paper trail as to why this is so. But the pre
4315 wide-int worked with that restriction and it has been preserved
4316 here. */
4321 }
4323 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4324 represents the sign bit of EXP's type. If EXP represents a sign
4325 or zero extension, also test VAL against the unextended type.
4326 The return value is the (sub)expression whose sign bit is VAL,
4327 or NULL_TREE otherwise. */
4329 tree
4331 {
4333 tree t;
4335 /* Tree EXP must have an integral type. */
4340 /* Tree VAL must be an integer constant. */
4349 /* Handle extension from a narrower type. */
4355 }
4357 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4358 to be evaluated unconditionally. */
4360 static int
4362 {
4363 /* Strip any conversions that don't change the machine mode. */
4372 /* Don't regard global variables as simple. They may be
4373 allocated in ways unknown to the compiler (shared memory,
4374 #pragma weak, etc). */
4377 /* Weakrefs are not safe to be read, since they can be NULL.
4378 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4379 have DECL_WEAK flag set. */
4381 /* Loading a static variable is unduly expensive, but global
4382 registers aren't expensive. */
4384 }
4386 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4387 to be evaluated unconditionally.
4388 I addition to simple_operand_p, we assume that comparisons, conversions,
4389 and logic-not operations are simple, if their operands are simple, too. */
4391 static bool
4393 {
4413 }
4415 \f
4416 /* The following functions are subroutines to fold_range_test and allow it to
4417 try to change a logical combination of comparisons into a range test.
4419 For example, both
4420 X == 2 || X == 3 || X == 4 || X == 5
4421 and
4422 X >= 2 && X <= 5
4423 are converted to
4424 (unsigned) (X - 2) <= 3
4426 We describe each set of comparisons as being either inside or outside
4427 a range, using a variable named like IN_P, and then describe the
4428 range with a lower and upper bound. If one of the bounds is omitted,
4429 it represents either the highest or lowest value of the type.
4431 In the comments below, we represent a range by two numbers in brackets
4432 preceded by a "+" to designate being inside that range, or a "-" to
4433 designate being outside that range, so the condition can be inverted by
4434 flipping the prefix. An omitted bound is represented by a "-". For
4435 example, "- [-, 10]" means being outside the range starting at the lowest
4436 possible value and ending at 10, in other words, being greater than 10.
4437 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4438 always false.
4440 We set up things so that the missing bounds are handled in a consistent
4441 manner so neither a missing bound nor "true" and "false" need to be
4442 handled using a special case. */
4444 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4445 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4446 and UPPER1_P are nonzero if the respective argument is an upper bound
4447 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4448 must be specified for a comparison. ARG1 will be converted to ARG0's
4449 type if both are specified. */
4451 static tree
4454 {
4455 tree tem;
4459 /* If neither arg represents infinity, do the normal operation.
4460 Else, if not a comparison, return infinity. Else handle the special
4461 comparison rules. Note that most of the cases below won't occur, but
4462 are handled for consistency. */
4465 {
4470 }
4475 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4476 for neither. In real maths, we cannot assume open ended ranges are
4477 the same. But, this is computer arithmetic, where numbers are finite.
4478 We can therefore make the transformation of any unbounded range with
4479 the value Z, Z being greater than any representable number. This permits
4480 us to treat unbounded ranges as equal. */
4484 {
4505 }
4508 }
4509 \f
4510 /* Helper routine for make_range. Perform one step for it, return
4511 new expression if the loop should continue or NULL_TREE if it should
4512 stop. */
4514 tree
4518 {
4524 {
4526 /* We can only do something if the range is testing for zero. */
4535 /* We can only do something if the range is testing for zero
4536 and if the second operand is an integer constant. Note that
4537 saying something is "in" the range we make is done by
4538 complementing IN_P since it will set in the initial case of
4539 being not equal to zero; "out" is leaving it alone. */
4546 {
4567 }
4569 /* If this is an unsigned comparison, we also know that EXP is
4570 greater than or equal to zero. We base the range tests we make
4571 on that fact, so we record it here so we can parse existing
4572 range tests. We test arg0_type since often the return type
4573 of, e.g. EQ_EXPR, is boolean. */
4575 {
4579 NULL_TREE))
4584 /* If the high bound is missing, but we have a nonzero low
4585 bound, reverse the range so it goes from zero to the low bound
4586 minus 1. */
4588 {
4593 }
4594 }
4602 /* If flag_wrapv and ARG0_TYPE is signed, make sure
4603 low and high are non-NULL, then normalize will DTRT. */
4606 {
4611 }
4613 /* (-x) IN [a,b] -> x in [-b, -a] */
4625 /* ~ X -> -X - 1 */
4634 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4635 move a constant to the other side. */
4640 /* If EXP is signed, any overflow in the computation is undefined,
4641 so we don't worry about it so long as our computations on
4642 the bounds don't overflow. For unsigned, overflow is defined
4643 and this is exactly the right thing. */
4655 normalize:
4656 /* Check for an unsigned range which has wrapped around the maximum
4657 value thus making n_high < n_low, and normalize it. */
4659 {
4665 /* If the range is of the form +/- [ x+1, x ], we won't
4666 be able to normalize it. But then, it represents the
4667 whole range or the empty set, so make it
4668 +/- [ -, - ]. */
4672 else
4674 }
4675 else
4683 CASE_CONVERT:
4701 /* If we're converting arg0 from an unsigned type, to exp,
4702 a signed type, we will be doing the comparison as unsigned.
4703 The tests above have already verified that LOW and HIGH
4704 are both positive.
4706 So we have to ensure that we will handle large unsigned
4707 values the same way that the current signed bounds treat
4708 negative values. */
4711 {
4712 tree high_positive;
4713 tree equiv_type;
4714 /* For fixed-point modes, we need to pass the saturating flag
4715 as the 2nd parameter. */
4717 equiv_type
4720 else
4721 equiv_type
4724 /* A range without an upper bound is, naturally, unbounded.
4725 Since convert would have cropped a very large value, use
4726 the max value for the destination type. */
4727 high_positive
4734 high_positive),
4737 /* If the low bound is specified, "and" the range with the
4738 range for which the original unsigned value will be
4739 positive. */
4741 {
4744 integer_zero_node),
4745 high_positive))
4749 }
4750 else
4751 {
4752 /* Otherwise, "or" the range with the range of the input
4753 that will be interpreted as negative. */
4756 integer_zero_node),
4757 high_positive))
4761 }
4762 }
4771 }
4772 }
4774 /* Given EXP, a logical expression, set the range it is testing into
4775 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4776 actually being tested. *PLOW and *PHIGH will be made of the same
4777 type as the returned expression. If EXP is not a comparison, we
4778 will most likely not be returning a useful value and range. Set
4779 *STRICT_OVERFLOW_P to true if the return value is only valid
4780 because signed overflow is undefined; otherwise, do not change
4781 *STRICT_OVERFLOW_P. */
4783 tree
4786 {
4794 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4795 and see if we can refine the range. Some of the cases below may not
4796 happen, but it doesn't seem worth worrying about this. We "continue"
4797 the outer loop when we've changed something; otherwise we "break"
4798 the switch, which will "break" the while. */
4804 {
4810 {
4818 }
4827 }
4829 /* If EXP is a constant, we can evaluate whether this is true or false. */
4831 {
4838 }
4842 }
4844 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
4845 a bitwise check i.e. when
4846 LOW == 0xXX...X00...0
4847 HIGH == 0xXX...X11...1
4848 Return corresponding mask in MASK and stem in VALUE. */
4850 static bool
4853 {
4876 }
4877 \f
4878 /* Helper routine for build_range_check and match.pd. Return the type to
4879 perform the check or NULL if it shouldn't be optimized. */
4881 tree
4883 {
4884 /* First make sure that arithmetics in this type is valid, then make sure
4885 that it wraps around. */
4891 {
4894 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4895 for the type in question, as we rely on this here. */
4905 else
4907 }
4909 }
4911 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4912 type, TYPE, return an expression to test if EXP is in (or out of, depending
4913 on IN_P) the range. Return 0 if the test couldn't be created. */
4915 tree
4918 {
4921 /* Disable this optimization for function pointer expressions
4922 on targets that require function pointer canonicalization. */
4929 {
4935 }
4957 value);
4960 {
4962 {
4966 }
4968 }
4970 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4972 {
4976 {
4978 {
4981 etype
4983 else
4986 }
4989 }
4990 }
4992 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4993 This requires wrap-around arithmetics for the type of the expression. */
5013 }
5014 \f
5015 /* Return the predecessor of VAL in its type, handling the infinite case. */
5017 static tree
5019 {
5025 else
5028 }
5030 /* Return the successor of VAL in its type, handling the infinite case. */
5032 static tree
5034 {
5040 else
5043 }
5045 /* Given two ranges, see if we can merge them into one. Return 1 if we
5046 can, 0 if we can't. Set the output range into the specified parameters. */
5048 bool
5051 {
5055 tree tem;
5065 /* Make range 0 be the range that starts first, or ends last if they
5066 start at the same value. Swap them if it isn't. */
5069 || (lowequal
5072 {
5076 }
5078 /* Now flag two cases, whether the ranges are disjoint or whether the
5079 second range is totally subsumed in the first. Note that the tests
5080 below are simplified by the ones above. */
5086 /* We now have four cases, depending on whether we are including or
5087 excluding the two ranges. */
5089 {
5090 /* If they don't overlap, the result is false. If the second range
5091 is a subset it is the result. Otherwise, the range is from the start
5092 of the second to the end of the first. */
5097 else
5099 }
5102 {
5103 /* If they don't overlap, the result is the first range. If they are
5104 equal, the result is false. If the second range is a subset of the
5105 first, and the ranges begin at the same place, we go from just after
5106 the end of the second range to the end of the first. If the second
5107 range is not a subset of the first, or if it is a subset and both
5108 ranges end at the same place, the range starts at the start of the
5109 first range and ends just before the second range.
5110 Otherwise, we can't describe this as a single range. */
5116 {
5121 {
5122 /* We are in the weird situation where high0 > high1 but
5123 high1 has no successor. Punt. */
5125 }
5126 }
5128 {
5133 {
5134 /* low0 < low1 but low1 has no predecessor. Punt. */
5136 }
5137 }
5138 else
5140 }
5143 {
5144 /* If they don't overlap, the result is the second range. If the second
5145 is a subset of the first, the result is false. Otherwise,
5146 the range starts just after the first range and ends at the
5147 end of the second. */
5152 else
5153 {
5158 {
5159 /* high1 > high0 but high0 has no successor. Punt. */
5161 }
5162 }
5163 }
5165 else
5166 {
5167 /* The case where we are excluding both ranges. Here the complex case
5168 is if they don't overlap. In that case, the only time we have a
5169 range is if they are adjacent. If the second is a subset of the
5170 first, the result is the first. Otherwise, the range to exclude
5171 starts at the beginning of the first range and ends at the end of the
5172 second. */
5174 {
5179 else
5180 {
5181 /* Canonicalize - [min, x] into - [-, x]. */
5184 {
5187 GET_MODE_BITSIZE
5190 /* FALLTHROUGH */
5203 }
5205 /* Canonicalize - [x, max] into - [x, -]. */
5208 {
5211 GET_MODE_BITSIZE
5214 /* FALLTHROUGH */
5230 }
5232 /* The ranges might be also adjacent between the maximum and
5233 minimum values of the given type. For
5234 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5235 return + [x + 1, y - 1]. */
5237 {
5244 }
5245 else
5247 }
5248 }
5251 else
5253 }
5257 }
5258 \f
5260 /* Subroutine of fold, looking inside expressions of the form
5261 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5262 of the COND_EXPR. This function is being used also to optimize
5263 A op B ? C : A, by reversing the comparison first.
5265 Return a folded expression whose code is not a COND_EXPR
5266 anymore, or NULL_TREE if no folding opportunity is found. */
5268 static tree
5271 {
5276 tree tem;
5281 /* If we have A op 0 ? A : -A, consider applying the following
5282 transformations:
5284 A == 0? A : -A same as -A
5285 A != 0? A : -A same as A
5286 A >= 0? A : -A same as abs (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)
5291 None of these transformations work for modes with signed
5292 zeros. If A is +/-0, the first two transformations will
5293 change the sign of the result (from +0 to -0, or vice
5294 versa). The last four will fix the sign of the result,
5295 even though the original expressions could be positive or
5296 negative, depending on the sign of A.
5298 Note that all these transformations are correct if A is
5299 NaN, since the two alternatives (A and -A) are also NaNs. */
5306 /* In the case that A is of the form X-Y, '-A' (arg2) may
5307 have already been folded to Y-X, check for that. */
5315 {
5327 /* Fall through. */
5338 /* FALLTHRU */
5348 }
5350 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5351 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5352 both transformations are correct when A is NaN: A != 0
5353 is then true, and A == 0 is false. */
5357 {
5362 }
5364 /* Try some transformations of A op B ? A : B.
5366 A == B? A : B same as B
5367 A != B? A : B same as A
5368 A >= B? A : B same as max (A, B)
5369 A > B? A : B same as max (B, A)
5370 A <= B? A : B same as min (A, B)
5371 A < B? A : B same as min (B, A)
5373 As above, these transformations don't work in the presence
5374 of signed zeros. For example, if A and B are zeros of
5375 opposite sign, the first two transformations will change
5376 the sign of the result. In the last four, the original
5377 expressions give different results for (A=+0, B=-0) and
5378 (A=-0, B=+0), but the transformed expressions do not.
5380 The first two transformations are correct if either A or B
5381 is a NaN. In the first transformation, the condition will
5382 be false, and B will indeed be chosen. In the case of the
5383 second transformation, the condition A != B will be true,
5384 and A will be chosen.
5386 The conversions to max() and min() are not correct if B is
5387 a number and A is not. The conditions in the original
5388 expressions will be false, so all four give B. The min()
5389 and max() versions would give a NaN instead. */
5392 /* Avoid these transformations if the COND_EXPR may be used
5393 as an lvalue in the C++ front-end. PR c++/19199. */
5394 && (in_gimple_form
5400 {
5406 {
5415 /* In C++ a ?: expression can be an lvalue, so put the
5416 operand which will be used if they are equal first
5417 so that we can convert this back to the
5418 corresponding COND_EXPR. */
5420 {
5428 }
5435 {
5443 }
5456 }
5457 }
5460 }
5463 \f
5464 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5465 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5466 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5467 false) >= 2)
5468 #endif
5470 /* EXP is some logical combination of boolean tests. See if we can
5471 merge it into some range test. Return the new tree if so. */
5473 static tree
5476 {
5492 /* If this is an OR operation, invert both sides; we will invert
5493 again at the end. */
5497 /* If both expressions are the same, if we can merge the ranges, and we
5498 can build the range test, return it or it inverted. If one of the
5499 ranges is always true or always false, consider it to be the same
5500 expression as the other. */
5508 {
5512 }
5514 /* On machines where the branch cost is expensive, if this is a
5515 short-circuited branch and the underlying object on both sides
5516 is the same, make a non-short-circuit operation. */
5518 && !flag_sanitize_coverage
5523 {
5524 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5525 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5526 which cases we can't do this. */
5534 {
5543 {
5546 WARN_STRICT_OVERFLOW_COMPARISON);
5550 }
5551 }
5552 }
5555 }
5556 \f
5557 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
5558 bit value. Arrange things so the extra bits will be set to zero if and
5559 only if C is signed-extended to its full width. If MASK is nonzero,
5560 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5562 static tree
5564 {
5567 tree temp;
5572 /* We work by getting just the sign bit into the low-order bit, then
5573 into the high-order bit, then sign-extend. We then XOR that value
5574 with C. */
5578 /* We must use a signed type in order to get an arithmetic right shift.
5579 However, we must also avoid introducing accidental overflows, so that
5580 a subsequent call to integer_zerop will work. Hence we must
5581 do the type conversion here. At this point, the constant is either
5582 zero or one, and the conversion to a signed type can never overflow.
5583 We could get an overflow if this conversion is done anywhere else. */
5592 /* If necessary, convert the type back to match the type of C. */
5597 }
5598 \f
5599 /* For an expression that has the form
5600 (A && B) || ~B
5601 or
5602 (A || B) && ~B,
5603 we can drop one of the inner expressions and simplify to
5604 A || ~B
5605 or
5606 A && ~B
5607 LOC is the location of the resulting expression. OP is the inner
5608 logical operation; the left-hand side in the examples above, while CMPOP
5609 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5610 removing a condition that guards another, as in
5611 (A != NULL && A->...) || A == NULL
5612 which we must not transform. If RHS_ONLY is true, only eliminate the
5613 right-most operand of the inner logical operation. */
5615 static tree
5618 {
5636 {
5639 {
5642 }
5643 }
5645 {
5648 {
5651 }
5652 }
5667 }
5669 /* Find ways of folding logical expressions of LHS and RHS:
5670 Try to merge two comparisons to the same innermost item.
5671 Look for range tests like "ch >= '0' && ch <= '9'".
5672 Look for combinations of simple terms on machines with expensive branches
5673 and evaluate the RHS unconditionally.
5675 For example, if we have p->a == 2 && p->b == 4 and we can make an
5676 object large enough to span both A and B, we can do this with a comparison
5677 against the object ANDed with the a mask.
5679 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5680 operations to do this with one comparison.
5682 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5683 function and the one above.
5685 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5686 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5688 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5689 two operands.
5691 We return the simplified tree or 0 if no optimization is possible. */
5693 static tree
5696 {
5697 /* If this is the "or" of two comparisons, we can do something if
5698 the comparisons are NE_EXPR. If this is the "and", we can do something
5699 if the comparisons are EQ_EXPR. I.e.,
5700 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5702 WANTED_CODE is this operation code. For single bit fields, we can
5703 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5704 comparison for one-bit fields. */
5725 /* Start by getting the comparison codes. Fail if anything is volatile.
5726 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5727 it were surrounded with a NE_EXPR. */
5736 {
5740 }
5743 {
5747 }
5758 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5761 {
5764 {
5769 }
5772 {
5778 }
5779 }
5784 /* If the RHS can be evaluated unconditionally and its operands are
5785 simple, it wins to evaluate the RHS unconditionally on machines
5786 with expensive branches. In this case, this isn't a comparison
5787 that can be merged. */
5794 {
5795 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5806 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5816 }
5818 /* See if the comparisons can be merged. Then get all the parameters for
5819 each side. */
5844 /* It must be true that the inner operation on the lhs of each
5845 comparison must be the same if we are to be able to do anything.
5846 Then see if we have constants. If not, the same must be true for
5847 the rhs's. */
5856 {
5859 }
5864 else
5867 /* If either comparison code is not correct for our logical operation,
5868 fail. However, we can convert a one-bit comparison against zero into
5869 the opposite comparison against that bit being set in the field. */
5873 {
5875 {
5876 /* Make the left operand unsigned, since we are only interested
5877 in the value of one bit. Otherwise we are doing the wrong
5878 thing below. */
5881 }
5882 else
5884 }
5886 /* This is analogous to the code for l_const above. */
5888 {
5890 {
5893 }
5894 else
5896 }
5898 /* See if we can find a mode that contains both fields being compared on
5899 the left. If we can't, fail. Otherwise, update all constants and masks
5900 to be relative to a field of that size. */
5914 {
5917 }
5925 {
5932 {
5936 }
5937 }
5939 {
5946 {
5950 }
5951 }
5953 /* If the right sides are not constant, do the same for it. Also,
5954 disallow this optimization if a size or signedness mismatch occurs
5955 between the left and right sides. */
5957 {
5960 /* Make sure the two fields on the right
5961 correspond to the left without being swapped. */
5978 {
5981 }
5990 /* Make a mask that corresponds to both fields being compared.
5991 Do this for both items being compared. If the operands are the
5992 same size and the bits being compared are in the same position
5993 then we can do this by masking both and comparing the masked
5994 results. */
6001 {
6015 }
6017 /* There is still another way we can do something: If both pairs of
6018 fields being compared are adjacent, we may be able to make a wider
6019 field containing them both.
6021 Note that we still must mask the lhs/rhs expressions. Furthermore,
6022 the mask must be shifted to account for the shift done by
6023 make_bit_field_ref. */
6032 {
6033 tree type;
6049 /* Convert to the smaller type before masking out unwanted bits. */
6052 {
6054 {
6058 }
6060 {
6064 }
6065 }
6074 }
6077 }
6079 /* Handle the case of comparisons with constants. If there is something in
6080 common between the masks, those bits of the constants must be the same.
6081 If not, the condition is always false. Test for this to avoid generating
6082 incorrect code below. */
6087 {
6089 {
6092 }
6093 else
6094 {
6097 }
6098 }
6103 /* Construct the expression we will return. First get the component
6104 reference we will make. Unless the mask is all ones the width of
6105 that field, perform the mask operation. Then compare with the
6106 merged constant. */
6117 }
6118 \f
6119 /* T is an integer expression that is being multiplied, divided, or taken a
6120 modulus (CODE says which and what kind of divide or modulus) by a
6121 constant C. See if we can eliminate that operation by folding it with
6122 other operations already in T. WIDE_TYPE, if non-null, is a type that
6123 should be used for the computation if wider than our type.
6125 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6126 (X * 2) + (Y * 4). We must, however, be assured that either the original
6127 expression would not overflow or that overflow is undefined for the type
6128 in the language in question.
6130 If we return a non-null expression, it is an equivalent form of the
6131 original computation, but need not be in the original type.
6133 We set *STRICT_OVERFLOW_P to true if the return values depends on
6134 signed overflow being undefined. Otherwise we do not change
6135 *STRICT_OVERFLOW_P. */
6137 static tree
6140 {
6141 /* To avoid exponential search depth, refuse to allow recursion past
6142 three levels. Beyond that (1) it's highly unlikely that we'll find
6143 something interesting and (2) we've probably processed it before
6144 when we built the inner expression. */
6147 tree ret;
6152 depth++;
6154 depth--;
6157 }
6159 static tree
6162 {
6174 /* Don't deal with constants of zero here; they confuse the code below. */
6184 /* Note that we need not handle conditional operations here since fold
6185 already handles those cases. So just do arithmetic here. */
6187 {
6189 /* For a constant, we can always simplify if we are a multiply
6190 or (for divide and modulus) if it is a multiple of our constant. */
6194 {
6197 /* If the multiplication overflowed, we lost information on it.
6198 See PR68142 and PR69845. */
6202 }
6206 /* If op0 is an expression ... */
6212 /* ... and has wrapping overflow, and its type is smaller
6213 than ctype, then we cannot pass through as widening. */
6218 /* ... or this is a truncation (t is narrower than op0),
6219 then we cannot pass through this narrowing. */
6222 /* ... or signedness changes for division or modulus,
6223 then we cannot pass through this conversion. */
6227 /* ... or has undefined overflow while the converted to
6228 type has not, we cannot do the operation in the inner type
6229 as that would introduce undefined overflow. */
6235 /* Pass the constant down and see if we can make a simplification. If
6236 we can, replace this expression with the inner simplification for
6237 possible later conversion to our or some other type. */
6248 /* If widening the type changes it from signed to unsigned, then we
6249 must avoid building ABS_EXPR itself as unsigned. */
6251 {
6255 {
6258 }
6260 }
6261 /* If the constant is negative, we cannot simplify this. */
6264 /* FALLTHROUGH */
6266 /* For division and modulus, type can't be unsigned, as e.g.
6267 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6268 For signed types, even with wrapping overflow, this is fine. */
6277 /* If widening the type changes the signedness, then we can't perform
6278 this optimization as that changes the result. */
6282 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6288 {
6295 }
6299 /* If the second operand is constant, this is a multiplication
6300 or floor division, by a power of two, so we can treat it that
6301 way unless the multiplier or divisor overflows. Signed
6302 left-shift overflow is implementation-defined rather than
6303 undefined in C90, so do not convert signed left shift into
6304 multiplication. */
6307 /* const_binop may not detect overflow correctly,
6308 so check for it explicitly here. */
6317 ctype,
6319 t1),
6324 /* See if we can eliminate the operation on both sides. If we can, we
6325 can return a new PLUS or MINUS. If we can't, the only remaining
6326 cases where we can do anything are if the second operand is a
6327 constant. */
6334 /* If not multiplication, we can only do this if both operands
6335 are divisible by c. */
6338 {
6343 }
6345 /* If this was a subtraction, negate OP1 and set it to be an addition.
6346 This simplifies the logic below. */
6348 {
6350 /* If OP1 was not easily negatable, the constant may be OP0. */
6352 {
6355 }
6356 }
6361 /* If either OP1 or C are negative, this optimization is not safe for
6362 some of the division and remainder types while for others we need
6363 to change the code. */
6365 {
6373 }
6375 /* If it's a multiply or a division/modulus operation of a multiple
6376 of our constant, do the operation and verify it doesn't overflow. */
6380 {
6383 /* We allow the constant to overflow with wrapping semantics. */
6387 }
6388 else
6391 /* If we have an unsigned type, we cannot widen the operation since it
6392 will change the result if the original computation overflowed. */
6396 /* The last case is if we are a multiply. In that case, we can
6397 apply the distributive law to commute the multiply and addition
6398 if the multiplication of the constants doesn't overflow
6399 and overflow is defined. With undefined overflow
6400 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
6406 op1);
6411 /* We have a special case here if we are doing something like
6412 (C * 8) % 4 since we know that's zero. */
6415 /* If the multiplication can overflow we cannot optimize this. */
6420 {
6423 }
6425 /* ... fall through ... */
6429 /* If we can extract our operation from the LHS, do so and return a
6430 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6431 do something only if the second operand is a constant. */
6447 /* If these are the same operation types, we can associate them
6448 assuming no overflow. */
6450 {
6465 }
6467 /* If these operations "cancel" each other, we have the main
6468 optimizations of this pass, which occur when either constant is a
6469 multiple of the other, in which case we replace this with either an
6470 operation or CODE or TCODE.
6472 If we have an unsigned type, we cannot do this since it will change
6473 the result if the original computation overflowed. */
6480 {
6483 {
6490 }
6493 {
6500 }
6501 }
6506 }
6509 }
6510 \f
6511 /* Return a node which has the indicated constant VALUE (either 0 or
6512 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6513 and is of the indicated TYPE. */
6515 tree
6517 {
6526 else
6528 }
6531 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6532 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6533 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6534 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6535 COND is the first argument to CODE; otherwise (as in the example
6536 given here), it is the second argument. TYPE is the type of the
6537 original expression. Return NULL_TREE if no simplification is
6538 possible. */
6540 static tree
6545 {
6555 {
6559 /* If this operand throws an expression, then it does not make
6560 sense to try to perform a logical or arithmetic operation
6561 involving it. */
6566 }
6569 {
6574 }
6575 else
6576 /* Detect the case of mixing vector and scalar types - bail out. */
6582 /* This transformation is only worthwhile if we don't have to wrap ARG
6583 in a SAVE_EXPR and the operation can be simplified without recursing
6584 on at least one of the branches once its pushed inside the COND_EXPR. */
6593 {
6597 else
6599 }
6601 {
6605 else
6607 }
6609 /* Check that we have simplified at least one of the branches. */
6614 }
6616 \f
6617 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6619 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6620 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6621 ADDEND is the same as X.
6623 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6624 and finite. The problematic cases are when X is zero, and its mode
6625 has signed zeros. In the case of rounding towards -infinity,
6626 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6627 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6629 bool
6631 {
6635 /* Don't allow the fold with -fsignaling-nans. */
6639 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6643 /* In a vector or complex, we would need to check the sign of all zeros. */
6647 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6651 /* The mode has signed zeros, and we have to honor their sign.
6652 In this situation, there is only one case we can return true for.
6653 X - 0 is the same as X unless rounding towards -infinity is
6654 supported. */
6656 }
6658 /* Subroutine of match.pd that optimizes comparisons of a division by
6659 a nonzero integer constant against an integer constant, i.e.
6660 X/C1 op C2.
6662 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6663 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
6665 enum tree_code
6668 {
6673 /* We have to do this the hard way to detect unsigned overflow.
6674 prod = int_const_binop (MULT_EXPR, c1, c2); */
6680 {
6684 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6687 }
6689 {
6692 {
6711 }
6712 }
6713 else
6714 {
6715 /* A negative divisor reverses the relational operators. */
6720 {
6739 }
6740 }
6753 }
6756 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6757 equality/inequality test, then return a simplified form of the test
6758 using a sign testing. Otherwise return NULL. TYPE is the desired
6759 result type. */
6761 static tree
6764 tree result_type)
6765 {
6766 /* If this is testing a single bit, we can optimize the test. */
6770 {
6771 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6772 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6776 /* This is only a win if casting to a signed type is cheap,
6777 i.e. when arg00's type is not a partial mode. */
6779 {
6782 result_type,
6785 }
6786 }
6789 }
6791 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6792 equality/inequality test, then return a simplified form of
6793 the test using shifts and logical operations. Otherwise return
6794 NULL. TYPE is the desired result type. */
6796 tree
6799 {
6800 /* If this is testing a single bit, we can optimize the test. */
6804 {
6813 /* First, see if we can fold the single bit test into a sign-bit
6814 test. */
6816 result_type);
6820 /* Otherwise we have (A & C) != 0 where C is a single bit,
6821 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6822 Similarly for (A & C) == 0. */
6824 /* If INNER is a right shift of a constant and it plus BITNUM does
6825 not overflow, adjust BITNUM and INNER. */
6831 {
6834 }
6836 /* If we are going to be able to omit the AND below, we must do our
6837 operations as unsigned. If we must use the AND, we have a choice.
6838 Normally unsigned is faster, but for some machines signed is. */
6856 /* Put the AND last so it can combine with more things. */
6859 /* Make sure to return the proper type. */
6863 }
6865 }
6867 /* Test whether it is preferable two swap two operands, ARG0 and
6868 ARG1, for example because ARG0 is an integer constant and ARG1
6869 isn't. */
6871 bool
6873 {
6887 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6888 for commutative and comparison operators. Ensuring a canonical
6889 form allows the optimizers to find additional redundancies without
6890 having to explicitly check for both orderings. */
6896 /* Put SSA_NAMEs last. */
6902 /* Put variables last. */
6909 }
6912 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6913 means A >= Y && A != MAX, but in this case we know that
6914 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6916 static tree
6918 {
6925 else
6934 {
6937 }
6939 {
6942 }
6943 else
6950 {
6951 /* Convert the pointer types into integer before taking the difference. */
6955 }
6956 else
6963 }
6965 /* Fold a sum or difference of at least one multiplication.
6966 Returns the folded tree or NULL if no simplification could be made. */
6968 static tree
6971 {
6975 /* (A * C) +- (B * C) -> (A+-B) * C.
6976 (A * C) +- A -> A * (C+-1).
6977 We are most concerned about the case where C is a constant,
6978 but other combinations show up during loop reduction. Since
6979 it is not difficult, try all four possibilities. */
6982 {
6985 }
6987 {
6990 }
6991 else
6992 {
6993 /* We cannot generate constant 1 for fract. */
6998 }
7000 {
7003 }
7005 {
7007 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7008 the purpose of this canonicalization. */
7012 {
7015 }
7016 else
7018 }
7019 else
7020 {
7021 /* We cannot generate constant 1 for fract. */
7026 }
7029 /* Prefer factoring a common non-constant. */
7039 /* No identical multiplicands; see if we can find a common
7040 power-of-two factor in non-power-of-two multiplies. This
7041 can help in multi-dimensional array access. */
7044 {
7047 tree maybe_same;
7051 /* Move min of absolute values to int11. */
7053 {
7058 }
7059 else
7063 /* The remainder should not be a constant, otherwise we
7064 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7065 increased the number of multiplications necessary. */
7067 {
7075 }
7076 }
7083 /* We are neither factoring zero nor minus one. */
7091 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7092 same may be minus one and thus the multiplication may overflow. Perform
7093 the sum operation in an unsigned type. */
7098 /* If the sum evaluated to a constant that is not -INF the multiplication
7099 cannot overflow. */
7106 /* Do not resort to unsigned multiplication because
7107 we lose the no-overflow property of the expression. */
7109 }
7111 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7112 specified by EXPR into the buffer PTR of length LEN bytes.
7113 Return the number of bytes placed in the buffer, or zero
7114 upon failure. */
7116 static int
7118 {
7130 /* Dry run. */
7136 {
7138 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7139 number of bytes. */
7143 {
7150 else
7152 }
7153 else
7157 }
7159 }
7162 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7163 specified by EXPR into the buffer PTR of length LEN bytes.
7164 Return the number of bytes placed in the buffer, or zero
7165 upon failure. */
7167 static int
7169 {
7173 FIXED_VALUE_TYPE value;
7188 }
7191 /* Subroutine of native_encode_expr. Encode the REAL_CST
7192 specified by EXPR into the buffer PTR of length LEN bytes.
7193 Return the number of bytes placed in the buffer, or zero
7194 upon failure. */
7196 static int
7198 {
7204 /* There are always 32 bits in each long, no matter the size of
7205 the hosts long. We handle floating point representations with
7206 up to 192 bits. */
7215 /* Dry run. */
7224 {
7229 {
7236 else
7238 }
7239 else
7240 {
7243 {
7244 /* Reverse bytes within each long, or within the entire float
7245 if it's smaller than a long (for HFmode). */
7248 }
7249 }
7254 }
7256 }
7258 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7259 specified by EXPR into the buffer PTR of length LEN bytes.
7260 Return the number of bytes placed in the buffer, or zero
7261 upon failure. */
7263 static int
7265 {
7267 tree part;
7281 }
7284 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7285 specified by EXPR into the buffer PTR of length LEN bytes.
7286 Return the number of bytes placed in the buffer, or zero
7287 upon failure. */
7289 static int
7291 {
7302 {
7304 {
7307 }
7318 }
7320 }
7323 /* Subroutine of native_encode_expr. Encode the STRING_CST
7324 specified by EXPR into the buffer PTR of length LEN bytes.
7325 Return the number of bytes placed in the buffer, or zero
7326 upon failure. */
7328 static int
7330 {
7333 /* Wide-char strings are encoded in target byte-order so native
7334 encoding them is trivial. */
7349 {
7352 {
7355 }
7358 }
7359 else
7362 }
7365 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7366 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7367 buffer PTR of length LEN bytes. If PTR is NULL, don't actually store
7368 anything, just do a dry run. If OFF is not -1 then start
7369 the encoding at byte offset OFF and encode at most LEN bytes.
7370 Return the number of bytes placed in the buffer, or zero upon failure. */
7372 int
7374 {
7375 /* We don't support starting at negative offset and -1 is special. */
7380 {
7401 }
7402 }
7405 /* Subroutine of native_interpret_expr. Interpret the contents of
7406 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7407 If the buffer cannot be interpreted, return NULL_TREE. */
7409 static tree
7411 {
7421 }
7424 /* Subroutine of native_interpret_expr. Interpret the contents of
7425 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7426 If the buffer cannot be interpreted, return NULL_TREE. */
7428 static tree
7430 {
7433 double_int result;
7434 FIXED_VALUE_TYPE fixed_value;
7444 }
7447 /* Subroutine of native_interpret_expr. Interpret the contents of
7448 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7449 If the buffer cannot be interpreted, return NULL_TREE. */
7451 static tree
7453 {
7457 /* There are always 32 bits in each long, no matter the size of
7458 the hosts long. We handle floating point representations with
7459 up to 192 bits. */
7460 REAL_VALUE_TYPE r;
7470 {
7471 /* Both OFFSET and BYTE index within a long;
7472 bitpos indexes the whole float. */
7475 {
7482 else
7484 }
7485 else
7486 {
7489 {
7490 /* Reverse bytes within each long, or within the entire float
7491 if it's smaller than a long (for HFmode). */
7494 }
7495 }
7499 }
7503 }
7506 /* Subroutine of native_interpret_expr. Interpret the contents of
7507 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7508 If the buffer cannot be interpreted, return NULL_TREE. */
7510 static tree
7512 {
7527 }
7530 /* Subroutine of native_interpret_expr. Interpret the contents of
7531 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7532 If the buffer cannot be interpreted, return NULL_TREE. */
7534 static tree
7536 {
7549 {
7554 }
7556 }
7559 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7560 the buffer PTR of length LEN as a constant of type TYPE. For
7561 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7562 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7563 return NULL_TREE. */
7565 tree
7567 {
7569 {
7591 }
7592 }
7594 /* Returns true if we can interpret the contents of a native encoding
7595 as TYPE. */
7597 static bool
7599 {
7601 {
7614 }
7615 }
7618 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7619 TYPE at compile-time. If we're unable to perform the conversion
7620 return NULL_TREE. */
7622 static tree
7624 {
7625 /* We support up to 512-bit values (for V8DFmode). */
7629 /* Check that the host and target are sane. */
7638 }
7640 /* Build an expression for the address of T. Folds away INDIRECT_REF
7641 to avoid confusing the gimplify process. */
7643 tree
7645 {
7646 /* The size of the object is not relevant when talking about its address. */
7651 {
7656 }
7666 {
7671 }
7672 else
7676 }
7678 /* Build an expression for the address of T. */
7680 tree
7682 {
7686 }
7688 /* Fold a unary expression of code CODE and type TYPE with operand
7689 OP0. Return the folded expression if folding is successful.
7690 Otherwise, return NULL_TREE. */
7692 tree
7694 {
7695 tree tem;
7696 tree arg0;
7704 {
7707 {
7708 /* Don't use STRIP_NOPS, because signedness of argument type
7709 matters. */
7711 }
7712 else
7713 {
7714 /* Strip any conversions that don't change the mode. This
7715 is safe for every expression, except for a comparison
7716 expression because its signedness is derived from its
7717 operands.
7719 Note that this is done as an internal manipulation within
7720 the constant folder, in order to find the simplest
7721 representation of the arguments so that their form can be
7722 studied. In any cases, the appropriate type conversions
7723 should be put back in the tree that will get out of the
7724 constant folder. */
7726 }
7729 {
7732 {
7736 }
7737 }
7738 }
7745 {
7752 {
7766 /* If this was a conversion, and all we did was to move into
7767 inside the COND_EXPR, bring it back out. But leave it if
7768 it is a conversion from integer to integer and the
7769 result precision is no wider than a word since such a
7770 conversion is cheap and may be optimized away by combine,
7771 while it couldn't if it were outside the COND_EXPR. Then return
7772 so we don't get into an infinite recursion loop taking the
7773 conversion out and then back in. */
7785 && (INTEGRAL_TYPE_P
7798 }
7799 }
7802 {
7808 CASE_CONVERT:
7812 {
7813 /* If we have (type) (a CMP b) and type is an integral type, return
7814 new expression involving the new type. Canonicalize
7815 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7816 non-integral type.
7817 Do not fold the result as that would not simplify further, also
7818 folding again results in recursions. */
7828 }
7830 /* Handle (T *)&A.B.C for A being of type T and B and C
7831 living at offset zero. This occurs frequently in
7832 C++ upcasting and then accessing the base. */
7836 {
7838 tree offset;
7839 machine_mode mode;
7841 tree base
7845 /* If the reference was to a (constant) zero offset, we can use
7846 the address of the base if it has the same base type
7847 as the result type and the pointer type is unqualified. */
7855 }
7859 /* Detect assigning a bitfield. */
7861 && DECL_BIT_FIELD
7863 {
7864 /* Don't leave an assignment inside a conversion
7865 unless assigning a bitfield. */
7867 /* First do the assignment, then return converted constant. */
7872 }
7874 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7875 constants (if x has signed type, the sign bit cannot be set
7876 in c). This folds extension into the BIT_AND_EXPR.
7877 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7878 very likely don't have maximal range for their precision and this
7879 transformation effectively doesn't preserve non-maximal ranges. */
7883 {
7894 <= HOST_BITS_PER_WIDE_INT
7896 {
7900 cst &= HOST_WIDE_INT_M1U
7904 && !flag_syntax_only
7907 {
7911 }
7912 }
7914 {
7919 }
7920 }
7922 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
7923 cast (T1)X will fold away. We assume that this happens when X itself
7924 is a cast. */
7928 {
7932 return fold_build_pointer_plus_loc
7934 }
7936 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7937 of the same precision, and X is an integer type not narrower than
7938 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7944 {
7950 }
7952 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7953 type of X and Y (integer types only). */
7958 {
7959 /* Be careful not to introduce new overflows. */
7960 tree mult_type;
7963 else
7967 {
7974 }
7975 }
7981 {
7988 }
7999 /* Convert fabs((double)float) into (double)fabsf(float). */
8002 {
8008 targ0));
8009 }
8013 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8032 /* Note that the operand of this must be an int
8033 and its values must be 0 or 1.
8034 ("true" is a fixed value perhaps depending on the language,
8035 but we don't handle values other than 1 correctly yet.) */
8042 /* Fold *&X to X if X is an lvalue. */
8044 {
8051 }
8057 }
8060 /* If the operation was a conversion do _not_ mark a resulting constant
8061 with TREE_OVERFLOW if the original constant was not. These conversions
8062 have implementation defined behavior and retaining the TREE_OVERFLOW
8063 flag here would confuse later passes such as VRP. */
8064 tree
8067 {
8076 }
8078 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
8079 operands OP0 and OP1. LOC is the location of the resulting expression.
8080 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
8081 Return the folded expression if folding is successful. Otherwise,
8082 return NULL_TREE. */
8083 static tree
8086 {
8087 tree tem;
8089 /* We only do these simplifications if we are optimizing. */
8093 /* Check for things like (A || B) && (A || C). We can convert this
8094 to A || (B && C). Note that either operator can be any of the four
8095 truth and/or operations and the transformation will still be
8096 valid. Also note that we only care about order for the
8097 ANDIF and ORIF operators. If B contains side effects, this
8098 might change the truth-value of A. */
8105 {
8125 /* This case if tricky because we must either have commutative
8126 operators or else A10 must not have side-effects. */
8132 a01);
8133 }
8135 /* See if we can build a range comparison. */
8141 {
8145 }
8149 {
8153 }
8155 /* Check for the possibility of merging component references. If our
8156 lhs is another similar operation, try to merge its rhs with our
8157 rhs. Then try to merge our lhs and rhs. */
8167 && !flag_sanitize_coverage
8172 {
8179 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8180 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8181 We don't want to pack more than two leafs to a non-IF AND/OR
8182 expression.
8183 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8184 equal to IF-CODE, then we don't want to add right-hand operand.
8185 If the inner right-hand side of left-hand operand has
8186 side-effects, or isn't simple, then we can't add to it,
8187 as otherwise we might destroy if-sequence. */
8190 /* Needed for sequence points to handle trappings, and
8191 side-effects. */
8193 {
8195 arg1);
8197 tem);
8198 }
8199 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8200 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8203 /* Needed for sequence points to handle trappings, and
8204 side-effects. */
8206 {
8211 }
8212 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8213 into (A OR B).
8214 For sequence point consistancy, we need to check for trapping,
8215 and side-effects. */
8219 }
8222 }
8224 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8225 by changing CODE to reduce the magnitude of constants involved in
8226 ARG0 of the comparison.
8227 Returns a canonicalized comparison tree if a simplification was
8228 possible, otherwise returns NULL_TREE.
8229 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8230 valid if signed overflow is undefined. */
8232 static tree
8236 {
8241 /* Match A +- CST code arg1. We can change this only if overflow
8242 is undefined. */
8245 /* In principle pointers also have undefined overflow behavior,
8246 but that causes problems elsewhere. */
8253 /* Identify the constant in arg0 and its sign. */
8257 /* Overflowed constants and zero will cause problems. */
8262 /* See if we can reduce the magnitude of the constant in
8263 arg0 by changing the comparison code. */
8264 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8268 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8272 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8276 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8280 else
8284 /* Now build the constant reduced in magnitude. But not if that
8285 would produce one outside of its types range. */
8301 }
8303 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8304 overflow further. Try to decrease the magnitude of constants involved
8305 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8306 and put sole constants at the second argument position.
8307 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8309 static tree
8312 {
8313 tree t;
8318 /* Try canonicalization by simplifying arg0. */
8323 {
8327 }
8329 /* Try canonicalization by simplifying arg1 using the swapped
8330 comparison. */
8338 }
8340 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8341 space. This is used to avoid issuing overflow warnings for
8342 expressions like &p->x which can not wrap. */
8344 static bool
8346 {
8353 poly_wide_int wi_offset;
8359 else
8364 precision);
8379 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8380 array. */
8389 }
8391 /* Return a positive integer when the symbol DECL is known to have
8392 a nonzero address, zero when it's known not to (e.g., it's a weak
8393 symbol), and a negative integer when the symbol is not yet in the
8394 symbol table and so whether or not its address is zero is unknown.
8395 For function local objects always return positive integer. */
8396 static int
8398 {
8403 /* Function local objects are never NULL. */
8411 }
8413 /* Subroutine of fold_binary. This routine performs all of the
8414 transformations that are common to the equality/inequality
8415 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8416 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8417 fold_binary should call fold_binary. Fold a comparison with
8418 tree code CODE and type TYPE with operands OP0 and OP1. Return
8419 the folded comparison or NULL_TREE. */
8421 static tree
8424 {
8434 /* For comparisons of pointers we can decompose it to a compile time
8435 comparison of the base objects and the offsets into the object.
8436 This requires at least one operand being an ADDR_EXPR or a
8437 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8443 {
8446 machine_mode mode;
8450 /* Get base and offset for the access. Strip ADDR_EXPR for
8451 get_inner_reference, but put it back by stripping INDIRECT_REF
8452 off the base object if possible. indirect_baseN will be true
8453 if baseN is not an address but refers to the object itself. */
8456 {
8457 base0
8463 else
8465 }
8467 {
8471 {
8472 base0
8478 else
8480 }
8483 else
8487 {
8494 }
8495 }
8499 {
8500 base1
8506 else
8508 }
8510 {
8514 {
8515 base1
8521 else
8523 }
8526 else
8530 {
8537 }
8538 }
8540 /* If we have equivalent bases we might be able to simplify. */
8544 {
8545 /* We can fold this expression to a constant if the non-constant
8546 offset parts are equal. */
8550 && (equality_code
8551 || (indirect_base0
8554 {
8560 "occur when comparing P +- C1 with "
8562 WARN_STRICT_OVERFLOW_CONDITIONAL);
8565 {
8603 }
8604 }
8605 /* We can simplify the comparison to a comparison of the variable
8606 offset parts if the constant offset parts are equal.
8607 Be careful to use signed sizetype here because otherwise we
8608 mess with array offsets in the wrong way. This is possible
8609 because pointer arithmetic is restricted to retain within an
8610 object and overflow on pointer differences is undefined as of
8611 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8613 && (equality_code
8614 || (indirect_base0
8617 {
8618 /* By converting to signed sizetype we cover middle-end pointer
8619 arithmetic which operates on unsigned pointer types of size
8620 type size and ARRAY_REF offsets which are properly sign or
8621 zero extended from their type in case it is narrower than
8622 sizetype. */
8625 else
8629 else
8636 "occur when comparing P +- C1 with "
8638 WARN_STRICT_OVERFLOW_COMPARISON);
8641 }
8642 }
8643 /* For equal offsets we can simplify to a comparison of the
8644 base addresses. */
8646 && (indirect_base0
8648 && (indirect_base1
8653 {
8659 }
8660 /* Comparison between an ordinary (non-weak) symbol and a null
8661 pointer can be eliminated since such symbols must have a non
8662 null address. In C, relational expressions between pointers
8663 to objects and null pointers are undefined. The results
8664 below follow the C++ rules with the additional property that
8665 every object pointer compares greater than a null pointer.
8666 */
8669 /* Avoid folding references to struct members at offset 0 to
8670 prevent tests like '&ptr->firstmember == 0' from getting
8671 eliminated. When ptr is null, although the -> expression
8672 is strictly speaking invalid, GCC retains it as a matter
8673 of QoI. See PR c/44555. */
8676 && indirect_base0
8677 /* The caller guarantees that when one of the arguments is
8678 constant (i.e., null in this case) it is second. */
8680 {
8682 {
8693 }
8694 }
8695 }
8697 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8698 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8699 the resulting offset is smaller in absolute value than the
8700 original one and has the same sign. */
8709 {
8714 tree cst;
8716 "occur when combining constants around "
8719 /* Put the constant on the side where it doesn't overflow and is
8720 of lower absolute value and of same sign than before. */
8727 {
8730 variable1,
8734 }
8742 {
8748 variable2);
8749 }
8750 }
8756 /* If we are comparing an expression that just has comparisons
8757 of two integer values, arithmetic expressions of those comparisons,
8758 and constants, we can simplify it. There are only three cases
8759 to check: the two values can either be equal, the first can be
8760 greater, or the second can be greater. Fold the expression for
8761 those three values. Since each value must be 0 or 1, we have
8762 eight possibilities, each of which corresponds to the constant 0
8763 or 1 or one of the six possible comparisons.
8765 This handles common cases like (a > b) == 0 but also handles
8766 expressions like ((x > y) - (y > x)) > 0, which supposedly
8767 occur in macroized code. */
8770 {
8774 /* Don't handle degenerate cases here; they should already
8775 have been handled anyway. */
8784 {
8788 /* We can't just pass T to eval_subst in case cval1 or cval2
8789 was the same as ARG1. */
8791 tree high_result
8795 arg1);
8796 tree equal_result
8800 arg1);
8801 tree low_result
8805 arg1);
8807 /* All three of these results should be 0 or 1. Confirm they are.
8808 Then use those values to select the proper code to use. */
8813 {
8814 /* Make a 3-bit mask with the high-order bit being the
8815 value for `>', the next for '=', and the low for '<'. */
8819 {
8821 /* Always false. */
8842 /* Always true. */
8844 }
8847 }
8848 }
8849 }
8852 }
8855 /* Subroutine of fold_binary. Optimize complex multiplications of the
8856 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
8857 argument EXPR represents the expression "z" of type TYPE. */
8859 static tree
8861 {
8866 {
8869 }
8871 {
8874 }
8875 else
8876 {
8880 }
8889 }
8892 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
8893 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
8894 true if successful. */
8896 static bool
8898 {
8903 {
8906 }
8908 {
8914 else
8916 }
8917 else
8923 }
8925 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
8926 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
8927 NULL_TREE otherwise. */
8929 static tree
8931 {
8952 {
8953 HOST_WIDE_INT index;
8959 }
8962 {
8968 }
8969 else
8971 }
8973 /* Try to fold a pointer difference of type TYPE two address expressions of
8974 array references AREF0 and AREF1 using location LOC. Return a
8975 simplified expression for the difference or NULL_TREE. */
8977 static tree
8981 {
8986 /* If the bases are array references as well, recurse. If the bases
8987 are pointer indirections compute the difference of the pointers.
8988 If the bases are equal, we are set. */
8991 && (base_offset
8993 use_pointer_diff)))
8996 && (base_offset
8997 = use_pointer_diff
9007 {
9013 base_offset,
9016 }
9018 }
9020 /* If the real or vector real constant CST of type TYPE has an exact
9021 inverse, return it, else return NULL. */
9023 tree
9025 {
9026 REAL_VALUE_TYPE r;
9027 tree unit_type;
9028 machine_mode mode;
9031 {
9041 {
9045 tree_vector_builder elts;
9050 {
9055 }
9058 }
9062 }
9063 }
9065 /* Mask out the tz least significant bits of X of type TYPE where
9066 tz is the number of trailing zeroes in Y. */
9067 static wide_int
9069 {
9074 }
9076 /* Return true when T is an address and is known to be nonzero.
9077 For floating point we further ensure that T is not denormal.
9078 Similar logic is present in nonzero_address in rtlanal.h.
9080 If the return value is based on the assumption that signed overflow
9081 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
9082 change *STRICT_OVERFLOW_P. */
9084 static bool
9086 {
9090 /* Doing something useful for floating point would need more work. */
9096 {
9099 strict_overflow_p);
9105 strict_overflow_p);
9113 }
9116 {
9119 strict_overflow_p);
9127 strict_overflow_p);
9142 strict_overflow_p);
9146 strict_overflow_p);
9149 {
9161 }
9165 }
9167 }
9169 /* Return true when T is an address and is known to be nonzero.
9170 Handle warnings about undefined signed overflow. */
9172 bool
9174 {
9181 "determining that expression is always "
9183 WARN_STRICT_OVERFLOW_MISC);
9185 }
9187 /* Return true if T is known not to be equal to an integer W. */
9189 bool
9191 {
9193 value_range_type rtype;
9195 {
9204 {
9209 }
9214 /* If T has some known zero bits and W has any of those bits set,
9215 then T is known not to be equal to W. */
9223 }
9224 }
9226 /* Fold a binary expression of code CODE and type TYPE with operands
9227 OP0 and OP1. LOC is the location of the resulting expression.
9228 Return the folded expression if folding is successful. Otherwise,
9229 return NULL_TREE. */
9231 tree
9234 {
9249 /* Strip any conversions that don't change the mode. This is
9250 safe for every expression, except for a comparison expression
9251 because its signedness is derived from its operands. So, in
9252 the latter case, only strip conversions that don't change the
9253 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9254 preserved.
9256 Note that this is done as an internal manipulation within the
9257 constant folder, in order to find the simplest representation
9258 of the arguments so that their form can be studied. In any
9259 cases, the appropriate type conversions should be put back in
9260 the tree that will get out of the constant folder. */
9263 {
9266 }
9267 else
9268 {
9271 }
9273 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9274 constant but we can't do arithmetic on them. */
9276 {
9279 {
9283 }
9284 }
9286 /* If this is a commutative operation, and ARG0 is a constant, move it
9287 to ARG1 to reduce the number of tests below. */
9292 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9293 to ARG1 to reduce the number of tests below. */
9302 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9304 First check for cases where an arithmetic operation is applied to a
9305 compound, conditional, or comparison operation. Push the arithmetic
9306 operation inside the compound or conditional to see if any folding
9307 can then be done. Convert comparison to conditional for this purpose.
9308 The also optimizes non-constant cases that used to be done in
9309 expand_expr.
9311 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9312 one of the operands is a comparison and the other is a comparison, a
9313 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9314 code below would make the expression more complex. Change it to a
9315 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9316 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9329 {
9333 boolean_type_node,
9341 }
9345 {
9347 {
9352 tem);
9353 }
9355 {
9360 tem);
9361 }
9366 {
9372 }
9377 {
9383 }
9384 }
9387 {
9389 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9392 {
9398 }
9400 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9403 {
9404 tree base;
9405 poly_int64 coffset;
9414 }
9419 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9425 arg1),
9427 arg0)));
9433 {
9434 /* X + (X / CST) * -CST is X % CST. */
9439 {
9448 cst0));
9449 }
9450 }
9452 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9453 one. Make sure the type is not saturating and has the signedness of
9454 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9455 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9462 {
9466 }
9469 {
9470 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9471 (plus (plus (mult) (mult)) (foo)) so that we can
9472 take advantage of the factoring cases below. */
9481 {
9487 else
9500 parg0),
9502 marg)),
9506 return
9512 parg1)));
9513 }
9514 }
9515 else
9516 {
9517 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9518 to __complex__ ( x, y ). This is not the same for SNaNs or
9519 if signed zeros are involved. */
9523 {
9530 {
9534 {
9540 }
9542 {
9548 }
9549 }
9550 }
9552 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9553 We associate floats only if the user has specified
9554 -fassociative-math. */
9558 {
9563 {
9564 tree tree0;
9567 }
9568 }
9569 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9570 We associate floats only if the user has specified
9571 -fassociative-math. */
9575 {
9580 {
9581 tree tree0;
9584 }
9585 }
9586 }
9588 bit_rotate:
9589 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9590 is a rotate of A by C1 bits. */
9591 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9592 is a rotate of A by B bits.
9593 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
9594 though in this case CODE must be | and not + or ^, otherwise
9595 it doesn't return A when B is 0. */
9596 {
9598 tree rtype;
9607 /* Only create rotates in complete modes. Other cases are not
9608 expanded properly. */
9611 {
9624 {
9629 }
9634 {
9637 code0 == LSHIFT_EXPR
9640 }
9642 {
9652 {
9656 orig_tree01);
9658 }
9659 }
9663 {
9674 {
9678 orig_tree01);
9680 }
9681 }
9682 }
9683 }
9685 associate:
9686 /* In most languages, can't associate operations on floats through
9687 parentheses. Rather than remember where the parentheses were, we
9688 don't associate floats at all, unless the user has specified
9689 -fassociative-math.
9690 And, we need to make sure type is not saturating. */
9694 {
9700 /* Split both trees into variables, constants, and literals. Then
9701 associate each group together, the constants with literals,
9702 then the result with variables. This increases the chances of
9703 literals being recombined later and of generating relocatable
9704 expressions for the sum of a constant and literal. */
9712 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9716 /* With undefined overflow prefer doing association in a type
9717 which wraps on overflow, if that is one of the operand types. */
9720 {
9728 }
9730 /* With undefined overflow we can only associate constants with one
9731 variable, and constants whose association doesn't overflow. */
9734 {
9736 {
9737 /* ??? If split_tree would handle NEGATE_EXPR we could
9738 simply reject these cases and the allowed cases would
9739 be the var0/minus_var1 ones. */
9745 {
9748 }
9755 {
9758 }
9764 /* The only case we can still associate with two variables
9765 is if they cancel out. */
9769 }
9775 }
9777 /* Only do something if we found more than two objects. Otherwise,
9778 nothing has changed and we risk infinite recursion. */
9786 {
9798 {
9802 }
9804 {
9808 }
9810 /* Preserve the MINUS_EXPR if the negative part of the literal is
9811 greater than the positive part. Otherwise, the multiplicative
9812 folding code (i.e extract_muldiv) may be fooled in case
9813 unsigned constants are subtracted, like in the following
9814 example: ((X*2 + 4) - 8U)/2. */
9816 {
9820 /* But avoid ending up with only negated parts. */
9822 {
9826 }
9827 else
9828 {
9832 }
9833 }
9835 /* Don't introduce overflows through reassociation. */
9840 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
9847 /* Eliminate minus_con0. */
9849 {
9856 else
9859 }
9861 /* Eliminate minus_var0. */
9863 {
9867 else
9870 }
9872 return
9875 }
9876 }
9882 /* Fold &a[i] - &a[j] to i-j. */
9887 {
9891 code
9895 }
9897 /* Further transformations are not for pointers. */
9901 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9904 /* If arg0 is e.g. unsigned int and type is int, then this could
9905 introduce UB, because if A is INT_MIN at runtime, the original
9906 expression can be well defined while the latter is not.
9907 See PR83269. */
9916 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
9917 __complex__ ( x, -y ). This is not the same for SNaNs or if
9918 signed zeros are involved. */
9922 {
9929 {
9933 {
9935 arg1r ? arg1r
9940 }
9942 {
9946 arg1i ? arg1i
9949 }
9950 }
9951 }
9953 /* A - B -> A + (-B) if B is easily negatable. */
9957 /* Avoid this transformation if B is a positive REAL_CST. */
9965 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
9966 one. Make sure the type is not saturating and has the signedness of
9967 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9968 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9975 {
9979 }
9985 {
9986 /* Transform x * -C into -x * C if x is easily negatable. */
10001 {
10004 "occur when simplifying "
10006 WARN_STRICT_OVERFLOW_MISC);
10008 }
10010 /* Optimize z * conj(z) for integer complex numbers. */
10017 }
10018 else
10019 {
10020 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10021 This is not the same for NaNs or if signed zeros are
10022 involved. */
10028 {
10031 return
10037 return
10042 }
10044 /* Optimize z * conj(z) for floating point complex numbers.
10045 Guarded by flag_unsafe_math_optimizations as non-finite
10046 imaginary components don't produce scalar results. */
10055 }
10059 /* Canonicalize (X & C1) | C2. */
10063 {
10068 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10076 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10078 {
10081 }
10083 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10084 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10085 mode which allows further optimizations. */
10090 {
10095 {
10098 }
10099 }
10102 {
10107 }
10108 }
10110 /* See if this can be simplified into a rotate first. If that
10111 is unsuccessful continue in the association code. */
10115 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10123 /* See if this can be simplified into a rotate first. If that
10124 is unsuccessful continue in the association code. */
10128 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10133 {
10134 tree tem2;
10141 }
10142 /* Fold ~X & 1 as (X & 1) == 0. */
10146 {
10147 tree tem2;
10154 }
10155 /* Fold !X & 1 as X == 0. */
10158 {
10162 }
10164 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
10165 multiple of 1 << CST. */
10167 {
10174 }
10176 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
10177 bits from CST2. */
10181 {
10183 wide_int masked
10190 {
10191 /* Avoid the transform if arg1 is a mask of some
10192 mode which allows further optimizations. */
10199 }
10200 }
10202 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
10203 ((A & N) + B) & M -> (A + B) & M
10204 Similarly if (N & M) == 0,
10205 ((A | N) + B) & M -> (A + B) & M
10206 and for - instead of + (or unary - instead of +)
10207 and/or ^ instead of |.
10208 If B is constant and (B & M) == 0, fold into A & M. */
10210 {
10219 {
10222 wide_int cst0;
10224 /* Now we know that arg0 is (C + D) or (C - D) or
10225 -C and arg1 (M) is == (1LL << cst) - 1.
10226 Store C into PMOP[0] and D into PMOP[1]. */
10230 {
10233 }
10240 {
10249 {
10252 }
10255 /* If C or D is of the form (A & N) where
10256 (N & M) == M, or of the form (A | N) or
10257 (A ^ N) where (N & M) == 0, replace it with A. */
10261 /* If C or D is a N where (N & M) == 0, it can be
10262 omitted (assumed 0). */
10270 }
10272 /* Only build anything new if we optimized one or both arguments
10273 above. */
10277 {
10280 {
10281 /* Perform the operations in a type that has defined
10282 overflow behavior. */
10288 }
10293 {
10301 else
10303 }
10306 else
10309 /* TEM is now the new binary +, - or unary - replacement. */
10313 }
10314 }
10315 }
10317 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10320 {
10325 return
10327 }
10332 /* Don't touch a floating-point divide by zero unless the mode
10333 of the constant can represent infinity. */
10339 /* (-A) / (-B) -> A / B */
10351 /* Fall through */
10354 /* Simplify A / (B << N) where A and B are positive and B is
10355 a power of 2, to A >> (N + log2(B)). */
10360 {
10363 {
10371 WARN_STRICT_OVERFLOW_MISC);
10377 }
10378 }
10380 /* Fall through */
10388 /* Convert -A / -B to A / B when the type is signed and overflow is
10389 undefined. */
10393 {
10396 "when distributing negation across "
10398 WARN_STRICT_OVERFLOW_MISC);
10403 }
10407 {
10410 "when distributing negation across "
10412 WARN_STRICT_OVERFLOW_MISC);
10417 }
10419 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
10420 operation, EXACT_DIV_EXPR.
10422 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
10423 At one time others generated faster code, it's not clear if they do
10424 after the last round to changes to the DIV code in expmed.c. */
10435 {
10439 WARN_STRICT_OVERFLOW_MISC);
10441 }
10453 {
10457 WARN_STRICT_OVERFLOW_MISC);
10459 }
10467 /* Since negative shift count is not well-defined,
10468 don't try to compute it in the compiler. */
10474 /* If we have a rotate of a bit operation with the rotate count and
10475 the second operand of the bit operation both constant,
10476 permute the two operations. */
10482 {
10490 }
10492 /* Two consecutive rotates adding up to the some integer
10493 multiple of the precision of the type can be ignored. */
10509 /* Note that the operands of this must be ints
10510 and their values must be 0 or 1.
10511 ("true" is a fixed value perhaps depending on the language.) */
10512 /* If first arg is constant zero, return it. */
10515 /* FALLTHRU */
10517 /* If either arg is constant true, drop it. */
10521 /* Preserve sequence points. */
10524 /* If second arg is constant zero, result is zero, but first arg
10525 must be evaluated. */
10528 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
10529 case will be handled here. */
10533 /* !X && X is always false. */
10537 /* X && !X is always false. */
10542 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
10543 means A >= Y && A != MAX, but in this case we know that
10544 A < X <= MAX. */
10548 {
10556 }
10565 /* Note that the operands of this must be ints
10566 and their values must be 0 or true.
10567 ("true" is a fixed value perhaps depending on the language.) */
10568 /* If first arg is constant true, return it. */
10571 /* FALLTHRU */
10573 /* If either arg is constant zero, drop it. */
10577 /* Preserve sequence points. */
10580 /* If second arg is constant true, result is true, but we must
10581 evaluate first arg. */
10584 /* Likewise for first arg, but note this only occurs here for
10585 TRUTH_OR_EXPR. */
10589 /* !X || X is always true. */
10593 /* X || !X is always true. */
10598 /* (X && !Y) || (!X && Y) is X ^ Y */
10601 {
10618 }
10627 /* If the second arg is constant zero, drop it. */
10630 /* If the second arg is constant true, this is a logical inversion. */
10632 {
10635 }
10636 /* Identical arguments cancel to zero. */
10640 /* !X ^ X is always true. */
10645 /* X ^ !X is always true. */
10661 /* bool_var != 1 becomes !bool_var. */
10668 /* bool_var == 0 becomes !bool_var. */
10675 /* !exp != 0 becomes !exp */
10680 /* If this is an EQ or NE comparison with zero and ARG0 is
10681 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
10682 two operations, but the latter can be done in one less insn
10683 on machines that have only two-operand insns or on which a
10684 constant cannot be the first operand. */
10687 {
10692 {
10699 arg1);
10700 }
10703 {
10710 arg1);
10711 }
10712 }
10714 /* If this is an NE or EQ comparison of zero against the result of a
10715 signed MOD operation whose second operand is a power of 2, make
10716 the MOD operation unsigned since it is simpler and equivalent. */
10724 {
10734 }
10736 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
10737 C1 is a valid shift constant, and C2 is a power of two, i.e.
10738 a single bit. */
10742 == INTEGER_CST
10745 {
10750 /* Check for a valid shift count. */
10752 {
10756 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
10757 can be rewritten as (X & (C2 << C1)) != 0. */
10759 {
10764 }
10765 /* Otherwise, for signed (arithmetic) shifts,
10766 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
10767 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
10771 /* Otherwise, of unsigned (logical) shifts,
10772 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
10773 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
10774 else
10778 arg000);
10779 }
10780 }
10782 /* If this is a comparison of a field, we may be able to simplify it. */
10785 /* Handle the constant case even without -O
10786 to make sure the warnings are given. */
10788 {
10792 }
10794 /* Optimize comparisons of strlen vs zero to a compare of the
10795 first character of the string vs zero. To wit,
10796 strlen(ptr) == 0 => *ptr == 0
10797 strlen(ptr) != 0 => *ptr != 0
10798 Other cases should reduce to one of these two (or a constant)
10799 due to the return value of strlen being unsigned. */
10802 {
10810 {
10815 }
10816 }
10818 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
10819 of X. Similarly fold (X >> C) == 0 into X >= 0. */
10823 {
10828 {
10830 {
10833 }
10836 }
10837 }
10839 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
10840 (X & C) == 0 when C is a single bit. */
10845 {
10852 arg1));
10853 }
10855 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
10856 constant C is a power of two, i.e. a single bit. */
10863 {
10867 }
10869 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
10870 when is C is a power of two, i.e. a single bit. */
10877 {
10883 }
10887 {
10890 }
10892 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
10895 {
10903 {
10909 }
10911 {
10917 }
10919 {
10925 }
10927 {
10933 }
10934 }
10938 {
10945 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
10946 operand_equal_p guarantees no side-effects so we don't need
10947 to use omit_one_operand on Z. */
10951 arg10));
10955 arg11));
10959 arg10));
10963 arg11));
10965 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
10968 {
10974 }
10975 }
10977 /* Attempt to simplify equality/inequality comparisons of complex
10978 values. Only lower the comparison if the result is known or
10979 can be simplified to a single scalar comparison. */
10984 {
10989 {
10992 }
10993 else
10994 {
10997 }
11000 {
11003 }
11004 else
11005 {
11008 }
11012 {
11014 {
11019 }
11020 else
11021 {
11026 }
11027 }
11031 {
11033 {
11038 }
11039 else
11040 {
11045 }
11046 }
11047 }
11059 /* Transform comparisons of the form X +- C CMP X. */
11064 {
11069 /* (X - c) > X becomes false. */
11075 /* Likewise (X + c) < X becomes false. */
11081 /* Convert (X - c) <= X to true. */
11088 /* Convert (X + c) >= X to true. */
11094 }
11096 /* If we are comparing an ABS_EXPR with a constant, we can
11097 convert all the cases into explicit comparisons, but they may
11098 well not be faster than doing the ABS and one comparison.
11099 But ABS (X) <= C is a range comparison, which becomes a subtraction
11100 and a comparison, and is probably faster. */
11114 /* Convert ABS_EXPR<x> >= 0 to true. */
11121 {
11124 "when simplifying comparison of "
11126 WARN_STRICT_OVERFLOW_CONDITIONAL);
11129 arg0);
11130 }
11132 /* Convert ABS_EXPR<x> < 0 to false. */
11137 {
11140 "when simplifying comparison of "
11142 WARN_STRICT_OVERFLOW_CONDITIONAL);
11145 arg0);
11146 }
11148 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
11149 and similarly for >= into !=. */
11159 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
11160 otherwise Y might be >= # of bits in X's type and thus e.g.
11161 (unsigned char) (1 << Y) for Y 15 might be 0.
11162 If the cast is widening, then 1 << Y should have unsigned type,
11163 otherwise if Y is number of bits in the signed shift type minus 1,
11164 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
11165 31 might be 0xffffffff80000000. */
11176 {
11182 }
11194 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
11195 {
11207 }
11212 /* When pedantic, a compound expression can be neither an lvalue
11213 nor an integer constant expression. */
11216 /* Don't let (0, 0) be null pointer constant. */
11222 /* An ASSERT_EXPR should never be passed to fold_binary. */
11228 }
11230 /* Used by contains_label_[p1]. */
11232 struct contains_label_data
11233 {
11236 };
11238 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
11239 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
11240 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
11242 static tree
11244 {
11247 {
11258 {
11266 }
11275 }
11276 }
11278 /* Return whether the sub-tree ST contains a label which is accessible from
11279 outside the sub-tree. */
11281 static bool
11283 {
11287 }
11289 /* Fold a ternary expression of code CODE and type TYPE with operands
11290 OP0, OP1, and OP2. Return the folded expression if folding is
11291 successful. Otherwise, return NULL_TREE. */
11293 tree
11296 {
11297 tree tem;
11304 /* If this is a commutative operation, and OP0 is a constant, move it
11305 to OP1 to reduce the number of tests below. */
11314 /* Strip any conversions that don't change the mode. This is safe
11315 for every expression, except for a comparison expression because
11316 its signedness is derived from its operands. So, in the latter
11317 case, only strip conversions that don't change the signedness.
11319 Note that this is done as an internal manipulation within the
11320 constant folder, in order to find the simplest representation of
11321 the arguments so that their form can be studied. In any cases,
11322 the appropriate type conversions should be put back in the tree
11323 that will get out of the constant folder. */
11325 {
11328 }
11331 {
11334 }
11337 {
11340 }
11343 {
11347 {
11353 }
11358 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
11359 so all simple results must be passed through pedantic_non_lvalue. */
11361 {
11364 /* Only optimize constant conditions when the selected branch
11365 has the same type as the COND_EXPR. This avoids optimizing
11366 away "c ? x : throw", where the throw has a void type.
11367 Avoid throwing away that operand which contains label. */
11374 }
11376 {
11383 {
11386 {
11394 }
11399 }
11400 }
11402 /* If we have A op B ? A : C, we may be able to convert this to a
11403 simpler expression, depending on the operation and the values
11404 of B and C. Signed zeros prevent all of these transformations,
11405 for reasons given above each one.
11407 Also try swapping the arguments and inverting the conditional. */
11411 {
11415 }
11420 {
11424 {
11428 }
11429 }
11431 /* If the second operand is simpler than the third, swap them
11432 since that produces better jump optimization results. */
11435 {
11437 /* See if this can be inverted. If it can't, possibly because
11438 it was a floating-point inequality comparison, don't do
11439 anything. */
11443 }
11445 /* Convert A ? 1 : 0 to simply A. */
11450 /* If we try to convert OP0 to our type, the
11451 call to fold will try to move the conversion inside
11452 a COND, which will recurse. In that case, the COND_EXPR
11453 is probably the best choice, so leave it alone. */
11457 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
11458 over COND_EXPR in cases such as floating point comparisons. */
11467 arg0)));
11469 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
11474 {
11475 /* sign_bit_p looks through both zero and sign extensions,
11476 but for this optimization only sign extensions are
11477 usable. */
11480 {
11483 {
11486 }
11488 }
11489 /* sign_bit_p only checks ARG1 bits within A's precision.
11490 If <sign bit of A> has wider type than A, bits outside
11491 of A's precision in <sign bit of A> need to be checked.
11492 If they are all 0, this optimization needs to be done
11493 in unsigned A's type, if they are all 1 in signed A's type,
11494 otherwise this can't be done. */
11500 {
11502 tree tem_type;
11515 {
11518 }
11520 {
11523 }
11524 else
11526 }
11529 return
11535 arg1)));
11536 }
11538 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
11539 already handled above. */
11544 {
11554 op1);
11555 }
11557 /* A & N ? N : 0 is simply A & N if N is a power of two. This
11558 is probably obsolete because the first operand should be a
11559 truth value (that's why we have the two cases above), but let's
11560 leave it in until we can confirm this for all front-ends. */
11572 /* Disable the transformations below for vectors, since
11573 fold_binary_op_with_conditional_arg may undo them immediately,
11574 yielding an infinite loop. */
11578 /* Convert A ? B : 0 into A && B if A and B are truth values. */
11587 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
11592 {
11594 /* Only perform transformation if ARG0 is easily inverted. */
11598 ? BIT_IOR_EXPR
11601 op1);
11602 }
11604 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
11609 {
11611 /* Only perform transformation if ARG0 is easily inverted. */
11617 op2);
11618 }
11620 /* Convert A ? 1 : B into A || B if A and B are truth values. */
11632 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
11633 of fold_ternary on them. */
11643 {
11654 {
11659 {
11661 {
11666 }
11672 }
11673 }
11674 }
11676 /* On constants we can use native encode/interpret to constant
11677 fold (nearly) all BIT_FIELD_REFs. */
11683 {
11686 /* Limit us to a reasonable amount of work. To relax the
11687 other limitations we need bit-shifting of the buffer
11688 and rounding up the size. */
11692 {
11694 unsigned HOST_WIDE_INT len
11699 {
11704 }
11705 }
11706 }
11712 {
11713 /* Build a vector of integers from the tree mask. */
11714 vec_perm_builder builder;
11718 /* Create a vec_perm_indices for the integer vector. */
11723 /* Check for cases that fold to OP0 or OP1 in their original
11724 element order. */
11731 {
11735 {
11738 }
11739 }
11745 {
11749 }
11753 /* Generate a canonical form of the selector. */
11755 {
11756 /* Some targets are deficient and fail to expand a single
11757 argument permutation while still allowing an equivalent
11758 2-argument version. */
11762 else
11763 {
11767 else
11768 /* Not directly supported with either encoding,
11769 so use the preferred form. */
11771 }
11773 }
11777 }
11781 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
11784 {
11790 wide_int tem2
11794 }
11799 {
11801 unsigned HOST_WIDE_INT elsize
11804 {
11810 {
11816 }
11817 }
11818 }
11824 }
11826 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
11827 of an array (or vector). */
11829 tree
11831 {
11836 {
11839 {
11840 /* Static constructors for variably sized objects makes no sense. */
11844 }
11845 }
11856 offset_int max_index;
11861 {
11862 /* Array constructor might explicitly set index, or specify a range,
11863 or leave index NULL meaning that it is next index after previous
11864 one. */
11866 {
11869 else
11870 {
11874 }
11875 }
11876 else
11877 {
11883 }
11885 /* Do we have match? */
11889 }
11891 }
11893 /* Perform constant folding and related simplification of EXPR.
11894 The related simplifications include x*1 => x, x*0 => 0, etc.,
11895 and application of the associative law.
11896 NOP_EXPR conversions may be removed freely (as long as we
11897 are careful not to change the type of the overall expression).
11898 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
11899 but we can constant-fold them if they have constant operands. */
11901 #ifdef ENABLE_FOLD_CHECKING
11902 # define fold(x) fold_1 (x)
11904 static
11905 #endif
11906 tree
11908 {
11912 tree tem;
11915 /* Return right away if a constant. */
11919 /* CALL_EXPR-like objects with variable numbers of operands are
11920 treated specially. */
11922 {
11924 {
11927 }
11929 }
11932 {
11937 {
11955 }
11956 }
11959 {
11961 {
11968 {
11973 }
11976 }
11978 /* Return a VECTOR_CST if possible. */
11980 {
11986 tree val;
11992 }
12000 }
12002 #ifdef ENABLE_FOLD_CHECKING
12003 #undef fold
12010 /* When --enable-checking=fold, compute a digest of expr before
12011 and after actual fold call to see if fold did not accidentally
12012 change original expr. */
12014 tree
12016 {
12017 tree ret;
12037 }
12039 void
12041 {
12052 }
12054 static void
12056 {
12058 }
12060 static void
12063 {
12069 recursive_label:
12079 {
12080 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
12085 }
12093 {
12094 /* Allow these fields to be modified. */
12095 tree tmp;
12104 {
12107 }
12108 }
12119 {
12122 {
12138 }
12142 {
12155 }
12172 {
12178 }
12181 {
12183 {
12186 }
12188 }
12199 {
12202 }
12212 }
12213 }
12215 /* Helper function for outputting the checksum of a tree T. When
12216 debugging with gdb, you can "define mynext" to be "next" followed
12217 by "call debug_fold_checksum (op0)", then just trace down till the
12218 outputs differ. */
12220 DEBUG_FUNCTION void
12222 {
12237 }
12239 #endif
12241 /* Fold a unary tree expression with code CODE of type TYPE with an
12242 operand OP0. LOC is the location of the resulting expression.
12243 Return a folded expression if successful. Otherwise, return a tree
12244 expression with code CODE of type TYPE with an operand OP0. */
12246 tree
12249 {
12250 tree tem;
12251 #ifdef ENABLE_FOLD_CHECKING
12260 #endif
12266 #ifdef ENABLE_FOLD_CHECKING
12273 #endif
12275 }
12277 /* Fold a binary tree expression with code CODE of type TYPE with
12278 operands OP0 and OP1. LOC is the location of the resulting
12279 expression. Return a folded expression if successful. Otherwise,
12280 return a tree expression with code CODE of type TYPE with operands
12281 OP0 and OP1. */
12283 tree
12286 MEM_STAT_DECL)
12287 {
12288 tree tem;
12289 #ifdef ENABLE_FOLD_CHECKING
12306 #endif
12312 #ifdef ENABLE_FOLD_CHECKING
12327 #endif
12329 }
12331 /* Fold a ternary tree expression with code CODE of type TYPE with
12332 operands OP0, OP1, and OP2. Return a folded expression if
12333 successful. Otherwise, return a tree expression with code CODE of
12334 type TYPE with operands OP0, OP1, and OP2. */
12336 tree
12339 {
12340 tree tem;
12341 #ifdef ENABLE_FOLD_CHECKING
12365 #endif
12372 #ifdef ENABLE_FOLD_CHECKING
12395 #endif
12397 }
12399 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
12400 arguments in ARGARRAY, and a null static chain.
12401 Return a folded expression if successful. Otherwise, return a CALL_EXPR
12402 of type TYPE from the given operands as constructed by build_call_array. */
12404 tree
12407 {
12408 tree tem;
12409 #ifdef ENABLE_FOLD_CHECKING
12428 #endif
12434 #ifdef ENABLE_FOLD_CHECKING
12450 #endif
12452 }
12454 /* Perform constant folding and related simplification of initializer
12455 expression EXPR. These behave identically to "fold_buildN" but ignore
12456 potential run-time traps and exceptions that fold must preserve. */
12458 #define START_FOLD_INIT \
12459 int saved_signaling_nans = flag_signaling_nans;\
12460 int saved_trapping_math = flag_trapping_math;\
12461 int saved_rounding_math = flag_rounding_math;\
12462 int saved_trapv = flag_trapv;\
12463 int saved_folding_initializer = folding_initializer;\
12464 flag_signaling_nans = 0;\
12465 flag_trapping_math = 0;\
12466 flag_rounding_math = 0;\
12467 flag_trapv = 0;\
12468 folding_initializer = 1;
12470 #define END_FOLD_INIT \
12471 flag_signaling_nans = saved_signaling_nans;\
12472 flag_trapping_math = saved_trapping_math;\
12473 flag_rounding_math = saved_rounding_math;\
12474 flag_trapv = saved_trapv;\
12475 folding_initializer = saved_folding_initializer;
12477 tree
12480 {
12481 tree result;
12482 START_FOLD_INIT;
12486 END_FOLD_INIT;
12488 }
12490 tree
12493 {
12494 tree result;
12495 START_FOLD_INIT;
12499 END_FOLD_INIT;
12501 }
12503 tree
12506 {
12507 tree result;
12508 START_FOLD_INIT;
12512 END_FOLD_INIT;
12514 }
12516 #undef START_FOLD_INIT
12517 #undef END_FOLD_INIT
12519 /* Determine if first argument is a multiple of second argument. Return 0 if
12520 it is not, or we cannot easily determined it to be.
12522 An example of the sort of thing we care about (at this point; this routine
12523 could surely be made more general, and expanded to do what the *_DIV_EXPR's
12524 fold cases do now) is discovering that
12526 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12528 is a multiple of
12530 SAVE_EXPR (J * 8)
12532 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
12534 This code also handles discovering that
12536 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12538 is a multiple of 8 so we don't have to worry about dealing with a
12539 possible remainder.
12541 Note that we *look* inside a SAVE_EXPR only to determine how it was
12542 calculated; it is not safe for fold to do much of anything else with the
12543 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
12544 at run time. For example, the latter example above *cannot* be implemented
12545 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
12546 evaluation time of the original SAVE_EXPR is not necessarily the same at
12547 the time the new expression is evaluated. The only optimization of this
12548 sort that would be valid is changing
12550 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
12552 divided by 8 to
12554 SAVE_EXPR (I) * SAVE_EXPR (J)
12556 (where the same SAVE_EXPR (J) is used in the original and the
12557 transformed version). */
12559 int
12561 {
12572 {
12574 /* Bitwise and provides a power of two multiple. If the mask is
12575 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
12583 {
12589 {
12592 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
12594 {
12598 {
12601 }
12602 }
12604 }
12605 }
12610 /* It is impossible to prove if op0 - op1 is multiple of bottom
12611 precisely, so be conservative here checking if both op0 and op1
12612 are multiple of bottom. Note we check the second operand first
12613 since it's usually simpler. */
12618 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
12619 as op0 - 3 if the expression has unsigned type. For example,
12620 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
12630 {
12632 /* const_binop may not detect overflow correctly,
12633 so check for it explicitly here. */
12641 }
12645 /* Can't handle conversions from non-integral or wider integral type. */
12651 /* fall through */
12668 SIGNED);
12674 {
12677 /* Check for special cases to see if top is defined as multiple
12678 of bottom:
12680 top = (X & ~(bottom - 1) ; bottom is power of 2
12682 or
12684 Y = X % bottom
12685 top = X - Y. */
12704 }
12706 /* fall through */
12714 }
12715 }
12717 #define tree_expr_nonnegative_warnv_p(X, Y) \
12720 #define RECURSE(X) \
12721 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
12723 /* Return true if CODE or TYPE is known to be non-negative. */
12725 static bool
12727 {
12730 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
12731 have a signed:1 type (where the value is -1 and 0). */
12734 }
12736 /* Return true if (CODE OP0) is known to be non-negative. If the return
12737 value is based on the assumption that signed overflow is undefined,
12738 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12739 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12741 bool
12744 {
12749 {
12751 /* We can't return 1 if flag_wrapv is set because
12752 ABS_EXPR<INT_MIN> = INT_MIN. */
12756 {
12759 }
12767 CASE_CONVERT:
12768 {
12773 {
12777 {
12781 }
12782 }
12784 {
12790 }
12791 }
12796 }
12798 /* We don't know sign of `t', so be conservative and return false. */
12800 }
12802 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
12803 value is based on the assumption that signed overflow is undefined,
12804 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12805 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12807 bool
12811 {
12816 {
12822 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
12823 both unsigned and at least 2 bits shorter than the result. */
12827 {
12832 {
12836 }
12837 }
12842 {
12843 /* x * x is always non-negative for floating point x
12844 or without overflow. */
12847 {
12852 }
12853 }
12855 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
12856 both unsigned and their total bits is shorter than the result. */
12860 {
12879 {
12889 }
12890 }
12917 }
12919 /* We don't know sign of `t', so be conservative and return false. */
12921 }
12923 /* Return true if T is known to be non-negative. If the return
12924 value is based on the assumption that signed overflow is undefined,
12925 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12926 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12928 bool
12930 {
12935 {
12949 /* Limit the depth of recursion to avoid quadratic behavior.
12950 This is expected to catch almost all occurrences in practice.
12951 If this code misses important cases that unbounded recursion
12952 would not, passes that need this information could be revised
12953 to provide it through dataflow propagation. */
12961 }
12962 }
12964 /* Return true if T is known to be non-negative. If the return
12965 value is based on the assumption that signed overflow is undefined,
12966 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12967 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12969 bool
12972 {
12974 {
12975 CASE_CFN_ACOS:
12976 CASE_CFN_ACOSH:
12977 CASE_CFN_CABS:
12978 CASE_CFN_COSH:
12979 CASE_CFN_ERFC:
12980 CASE_CFN_EXP:
12981 CASE_CFN_EXP10:
12982 CASE_CFN_EXP2:
12983 CASE_CFN_FABS:
12984 CASE_CFN_FDIM:
12985 CASE_CFN_HYPOT:
12986 CASE_CFN_POW10:
12987 CASE_CFN_FFS:
12988 CASE_CFN_PARITY:
12989 CASE_CFN_POPCOUNT:
12990 CASE_CFN_CLZ:
12991 CASE_CFN_CLRSB:
12994 /* Always true. */
12997 CASE_CFN_SQRT:
12998 CASE_CFN_SQRT_FN:
12999 /* sqrt(-0.0) is -0.0. */
13004 CASE_CFN_ASINH:
13005 CASE_CFN_ATAN:
13006 CASE_CFN_ATANH:
13007 CASE_CFN_CBRT:
13008 CASE_CFN_CEIL:
13009 CASE_CFN_CEIL_FN:
13010 CASE_CFN_ERF:
13011 CASE_CFN_EXPM1:
13012 CASE_CFN_FLOOR:
13013 CASE_CFN_FLOOR_FN:
13014 CASE_CFN_FMOD:
13015 CASE_CFN_FREXP:
13016 CASE_CFN_ICEIL:
13017 CASE_CFN_IFLOOR:
13018 CASE_CFN_IRINT:
13019 CASE_CFN_IROUND:
13020 CASE_CFN_LCEIL:
13021 CASE_CFN_LDEXP:
13022 CASE_CFN_LFLOOR:
13023 CASE_CFN_LLCEIL:
13024 CASE_CFN_LLFLOOR:
13025 CASE_CFN_LLRINT:
13026 CASE_CFN_LLROUND:
13027 CASE_CFN_LRINT:
13028 CASE_CFN_LROUND:
13029 CASE_CFN_MODF:
13030 CASE_CFN_NEARBYINT:
13031 CASE_CFN_NEARBYINT_FN:
13032 CASE_CFN_RINT:
13033 CASE_CFN_RINT_FN:
13034 CASE_CFN_ROUND:
13035 CASE_CFN_ROUND_FN:
13036 CASE_CFN_SCALB:
13037 CASE_CFN_SCALBLN:
13038 CASE_CFN_SCALBN:
13039 CASE_CFN_SIGNBIT:
13040 CASE_CFN_SIGNIFICAND:
13041 CASE_CFN_SINH:
13042 CASE_CFN_TANH:
13043 CASE_CFN_TRUNC:
13044 CASE_CFN_TRUNC_FN:
13045 /* True if the 1st argument is nonnegative. */
13048 CASE_CFN_FMAX:
13049 CASE_CFN_FMAX_FN:
13050 /* True if the 1st OR 2nd arguments are nonnegative. */
13053 CASE_CFN_FMIN:
13054 CASE_CFN_FMIN_FN:
13055 /* True if the 1st AND 2nd arguments are nonnegative. */
13058 CASE_CFN_COPYSIGN:
13059 CASE_CFN_COPYSIGN_FN:
13060 /* True if the 2nd argument is nonnegative. */
13063 CASE_CFN_POWI:
13064 /* True if the 1st argument is nonnegative or the second
13065 argument is an even integer. */
13071 CASE_CFN_POW:
13072 /* True if the 1st argument is nonnegative or the second
13073 argument is an even integer valued real. */
13075 {
13076 REAL_VALUE_TYPE c;
13077 HOST_WIDE_INT n;
13082 {
13083 REAL_VALUE_TYPE cint;
13087 }
13088 }
13093 }
13095 }
13097 /* Return true if T is known to be non-negative. If the return
13098 value is based on the assumption that signed overflow is undefined,
13099 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13100 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13102 static bool
13104 {
13110 {
13112 {
13116 /* If the initializer is non-void, then it's a normal expression
13117 that will be assigned to the slot. */
13121 /* Otherwise, the initializer sets the slot in some way. One common
13122 way is an assignment statement at the end of the initializer. */
13124 {
13132 else
13134 }
13140 }
13143 {
13149 arg0,
13150 arg1,
13152 }
13165 }
13166 }
13168 #undef RECURSE
13169 #undef tree_expr_nonnegative_warnv_p
13171 /* Return true if T is known to be non-negative. If the return
13172 value is based on the assumption that signed overflow is undefined,
13173 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13174 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13176 bool
13178 {
13185 {
13207 }
13210 {
13236 }
13237 }
13239 /* Return true if `t' is known to be non-negative. Handle warnings
13240 about undefined signed overflow. */
13242 bool
13244 {
13251 "determining that expression is always "
13253 WARN_STRICT_OVERFLOW_MISC);
13255 }
13258 /* Return true when (CODE OP0) is an address and is known to be nonzero.
13259 For floating point we further ensure that T is not denormal.
13260 Similar logic is present in nonzero_address in rtlanal.h.
13262 If the return value is based on the assumption that signed overflow
13263 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13264 change *STRICT_OVERFLOW_P. */
13266 bool
13269 {
13271 {
13274 strict_overflow_p);
13277 {
13283 strict_overflow_p));
13284 }
13289 strict_overflow_p);
13293 }
13296 }
13298 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
13299 For floating point we further ensure that T is not denormal.
13300 Similar logic is present in nonzero_address in rtlanal.h.
13302 If the return value is based on the assumption that signed overflow
13303 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13304 change *STRICT_OVERFLOW_P. */
13306 bool
13308 tree type,
13309 tree op0,
13311 {
13314 {
13318 {
13319 /* With the presence of negative values it is hard
13320 to say something. */
13327 /* One of operands must be positive and the other non-negative. */
13328 /* We don't set *STRICT_OVERFLOW_P here: even if this value
13329 overflows, on a twos-complement machine the sum of two
13330 nonnegative numbers can never be zero. */
13332 strict_overflow_p)
13334 strict_overflow_p));
13335 }
13340 {
13342 strict_overflow_p)
13344 strict_overflow_p))
13345 {
13348 }
13349 }
13358 {
13361 }
13368 {
13372 /* When both operands are nonzero, then MAX must be too. */
13374 strict_overflow_p))
13377 /* MAX where operand 0 is positive is positive. */
13379 strict_overflow_p);
13380 }
13381 /* MAX where operand 1 is positive is positive. */
13386 {
13390 }
13395 strict_overflow_p)
13397 strict_overflow_p));
13401 }
13404 }
13406 /* Return true when T is an address and is known to be nonzero.
13407 For floating point we further ensure that T is not denormal.
13408 Similar logic is present in nonzero_address in rtlanal.h.
13410 If the return value is based on the assumption that signed overflow
13411 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13412 change *STRICT_OVERFLOW_P. */
13414 bool
13416 {
13419 {
13424 {
13436 /* For objects in symbol table check if we know they are non-zero.
13437 Don't do anything for variables and functions before symtab is built;
13438 it is quite possible that they will be declared weak later. */
13443 /* Constants are never weak. */
13448 }
13456 {
13460 }
13470 }
13472 }
13474 #define integer_valued_real_p(X) \
13477 #define RECURSE(X) \
13478 ((integer_valued_real_p) (X, depth + 1))
13480 /* Return true if the floating point result of (CODE OP0) has an
13481 integer value. We also allow +Inf, -Inf and NaN to be considered
13482 integer values. Return false for signaling NaN.
13484 DEPTH is the current nesting depth of the query. */
13486 bool
13488 {
13490 {
13497 CASE_CONVERT:
13498 {
13505 }
13509 }
13511 }
13513 /* Return true if the floating point result of (CODE OP0 OP1) has an
13514 integer value. We also allow +Inf, -Inf and NaN to be considered
13515 integer values. Return false for signaling NaN.
13517 DEPTH is the current nesting depth of the query. */
13519 bool
13521 {
13523 {
13533 }
13535 }
13537 /* Return true if the floating point result of calling FNDECL with arguments
13538 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
13539 considered integer values. Return false for signaling NaN. If FNDECL
13540 takes fewer than 2 arguments, the remaining ARGn are null.
13542 DEPTH is the current nesting depth of the query. */
13544 bool
13546 {
13548 {
13549 CASE_CFN_CEIL:
13550 CASE_CFN_CEIL_FN:
13551 CASE_CFN_FLOOR:
13552 CASE_CFN_FLOOR_FN:
13553 CASE_CFN_NEARBYINT:
13554 CASE_CFN_NEARBYINT_FN:
13555 CASE_CFN_RINT:
13556 CASE_CFN_RINT_FN:
13557 CASE_CFN_ROUND:
13558 CASE_CFN_ROUND_FN:
13559 CASE_CFN_TRUNC:
13560 CASE_CFN_TRUNC_FN:
13563 CASE_CFN_FMIN:
13564 CASE_CFN_FMIN_FN:
13565 CASE_CFN_FMAX:
13566 CASE_CFN_FMAX_FN:
13571 }
13573 }
13575 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
13576 has an integer value. We also allow +Inf, -Inf and NaN to be
13577 considered integer values. Return false for signaling NaN.
13579 DEPTH is the current nesting depth of the query. */
13581 bool
13583 {
13585 {
13593 /* Limit the depth of recursion to avoid quadratic behavior.
13594 This is expected to catch almost all occurrences in practice.
13595 If this code misses important cases that unbounded recursion
13596 would not, passes that need this information could be revised
13597 to provide it through dataflow propagation. */
13601 depth));
13605 }
13607 }
13609 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
13610 has an integer value. We also allow +Inf, -Inf and NaN to be
13611 considered integer values. Return false for signaling NaN.
13613 DEPTH is the current nesting depth of the query. */
13615 static bool
13617 {
13619 {
13630 }
13632 }
13634 #undef RECURSE
13635 #undef integer_valued_real_p
13637 /* Return true if the floating point expression T has an integer value.
13638 We also allow +Inf, -Inf and NaN to be considered integer values.
13639 Return false for signaling NaN.
13641 DEPTH is the current nesting depth of the query. */
13643 bool
13645 {
13651 {
13667 }
13670 {
13676 {
13685 }
13689 }
13690 }
13692 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
13693 attempt to fold the expression to a constant without modifying TYPE,
13694 OP0 or OP1.
13696 If the expression could be simplified to a constant, then return
13697 the constant. If the expression would not be simplified to a
13698 constant, then return NULL_TREE. */
13700 tree
13702 {
13705 }
13707 /* Given the components of a unary expression CODE, TYPE and OP0,
13708 attempt to fold the expression to a constant without modifying
13709 TYPE or OP0.
13711 If the expression could be simplified to a constant, then return
13712 the constant. If the expression would not be simplified to a
13713 constant, then return NULL_TREE. */
13715 tree
13717 {
13720 }
13722 /* If EXP represents referencing an element in a constant string
13723 (either via pointer arithmetic or array indexing), return the
13724 tree representing the value accessed, otherwise return NULL. */
13726 tree
13728 {
13732 {
13734 tree index;
13735 tree string;
13740 else
13741 {
13745 /* Optimize the special-case of a zero lower bound.
13747 We convert the low_bound to sizetype to avoid some problems
13748 with constant folding. (E.g. suppose the lower bound is 1,
13749 and its mode is QI. Without the conversion,l (ARRAY
13750 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
13751 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
13757 }
13759 scalar_int_mode char_mode;
13771 }
13773 }
13775 /* Return the tree for neg (ARG0) when ARG0 is known to be either
13776 an integer constant, real, or fixed-point constant.
13778 TYPE is the type of the result. */
13780 static tree
13782 {
13786 {
13792 {
13793 FIXED_VALUE_TYPE f;
13798 /* Propagate overflow flags. */
13802 }
13806 {
13813 }
13816 }
13819 }
13821 /* Return the tree for abs (ARG0) when ARG0 is known to be either
13822 an integer constant or real constant.
13824 TYPE is the type of the result. */
13826 tree
13828 {
13832 {
13834 {
13835 /* If the value is unsigned or non-negative, then the absolute value
13836 is the same as the ordinary value. */
13840 /* If the value is negative, then the absolute value is
13841 its negation. */
13842 else
13843 {
13848 }
13849 }
13855 else
13861 }
13864 }
13866 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
13867 constant. TYPE is the type of the result. */
13869 static tree
13871 {
13875 }
13877 /* Given CODE, a relational operator, the target type, TYPE and two
13878 constant operands OP0 and OP1, return the result of the
13879 relational operation. If the result is not a compile time
13880 constant, then return NULL_TREE. */
13882 static tree
13884 {
13887 /* From here on, the only cases we handle are when the result is
13888 known to be a constant. */
13891 {
13895 /* Handle the cases where either operand is a NaN. */
13897 {
13899 {
13927 }
13930 }
13933 }
13936 {
13940 }
13942 /* Handle equality/inequality of complex constants. */
13944 {
13955 else
13957 }
13960 {
13962 {
13963 /* Have vector comparison with scalar boolean result. */
13971 {
13979 }
13981 }
13982 tree_vector_builder elts;
13987 {
14000 }
14003 }
14005 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
14007 To compute GT, swap the arguments and do LT.
14008 To compute GE, do LT and invert the result.
14009 To compute LE, swap the arguments, do LT and invert the result.
14010 To compute NE, do EQ and invert the result.
14012 Therefore, the code below must handle only EQ and LT. */
14015 {
14018 }
14020 /* Note that it is safe to invert for real values here because we
14021 have already handled the one case that it matters. */
14025 {
14028 }
14030 /* Compute a result for LT or EQ if args permit;
14031 Otherwise return T. */
14033 {
14036 else
14038 }
14039 else
14045 }
14047 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
14048 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
14049 itself. */
14051 tree
14053 {
14054 /* If the expression does not have side effects then we don't have to wrap
14055 it with a cleanup point expression. */
14059 /* If the expression is a return, check to see if the expression inside the
14060 return has no side effects or the right hand side of the modify expression
14061 inside the return. If either don't have side effects set we don't need to
14062 wrap the expression in a cleanup point expression. Note we don't check the
14063 left hand side of the modify because it should always be a return decl. */
14065 {
14072 }
14075 }
14077 /* Given a pointer value OP0 and a type TYPE, return a simplified version
14078 of an indirection through OP0, or NULL_TREE if no simplification is
14079 possible. */
14081 tree
14083 {
14085 tree subtype;
14086 poly_uint64 const_op01;
14095 {
14099 /* *&CONST_DECL -> to the value of the const decl. */
14102 /* *&p => p; make sure to handle *&"str"[cst] here. */
14104 {
14108 else
14110 }
14111 /* *(foo *)&fooarray => fooarray[0] */
14114 && (!in_gimple_form
14116 {
14126 }
14127 /* *(foo *)&complexfoo => __real__ complexfoo */
14131 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14134 {
14138 index);
14139 }
14140 }
14144 {
14150 {
14151 tree op00type;
14155 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
14158 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
14159 but we want to treat offsets with MSB set as negative.
14160 For the code below negative offsets are invalid and
14161 TYPE_SIZE of the element is something unsigned, so
14162 check whether op01 fits into poly_int64, which implies
14163 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
14164 then just use poly_uint64 because we want to treat the
14165 value as unsigned. */
14167 {
14169 poly_uint64 max_offset
14173 {
14178 }
14179 }
14180 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
14183 {
14185 const_op01))
14187 }
14188 /* ((foo *)&fooarray)[1] => fooarray[1] */
14191 {
14198 offset_int remainder;
14201 {
14206 }
14207 }
14208 }
14209 }
14211 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
14214 && (!in_gimple_form
14216 {
14217 tree type_domain;
14227 NULL_TREE);
14228 }
14231 }
14233 /* Builds an expression for an indirection through T, simplifying some
14234 cases. */
14236 tree
14238 {
14246 }
14248 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14250 tree
14252 {
14257 else
14259 }
14261 /* Strip non-trapping, non-side-effecting tree nodes from an expression
14262 whose result is ignored. The type of the returned tree need not be
14263 the same as the original expression. */
14265 tree
14267 {
14273 {
14284 else
14290 {
14306 }
14311 }
14312 }
14314 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
14316 tree
14318 {
14324 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14325 have to do anything. Only do this when we are not given a const,
14326 because in that case, this check is more expensive than just
14327 doing it. */
14329 {
14334 }
14336 /* If divisor is a power of two, simplify this to bit manipulation. */
14338 {
14340 {
14354 }
14355 else
14356 {
14357 tree t;
14363 }
14364 }
14365 else
14366 {
14371 }
14374 }
14376 /* Likewise, but round down. */
14378 tree
14380 {
14387 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14388 have to do anything. Only do this when we are not given a const,
14389 because in that case, this check is more expensive than just
14390 doing it. */
14392 {
14397 }
14399 /* If divisor is a power of two, simplify this to bit manipulation. */
14401 {
14402 tree t;
14406 }
14407 else
14408 {
14413 }
14416 }
14418 /* Returns the pointer to the base of the object addressed by EXP and
14419 extracts the information about the offset of the access, storing it
14420 to PBITPOS and POFFSET. */
14422 static tree
14425 {
14426 tree core;
14427 machine_mode mode;
14429 poly_int64 bitsize;
14433 {
14438 }
14440 {
14446 {
14447 poly_offset_int tem
14453 }
14454 }
14455 else
14456 {
14460 }
14463 }
14465 /* Returns true if addresses of E1 and E2 differ by a constant, false
14466 otherwise. If they do, E1 - E2 is stored in *DIFF. */
14468 bool
14470 {
14485 {
14495 }
14497 {
14498 /* If only one of the offsets is non-constant, the difference cannot
14499 be a constant. */
14501 }
14502 else
14507 }
14509 /* Return OFF converted to a pointer offset type suitable as offset for
14510 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
14511 tree
14513 {
14515 }
14517 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14518 tree
14520 {
14523 }
14525 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14526 tree
14528 {
14531 }
14533 /* Return a char pointer for a C string if it is a string constant
14534 or sum of string constant and integer constant. We only support
14535 string constants properly terminated with '\0' character.
14536 If STRLEN is a valid pointer, length (including terminating character)
14537 of returned string is stored to the argument. */
14541 {
14542 tree offset_node;
14553 {
14556 else
14558 }
14563 /* Support only properly null-terminated strings. */
14572 }
14574 #if CHECKING_P
14578 /* Helper functions for writing tests of folding trees. */
14580 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
14582 static void
14584 tree constant)
14585 {
14587 }
14589 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
14590 wrapping WRAPPED_EXPR. */
14592 static void
14594 tree wrapped_expr)
14595 {
14600 }
14602 /* Verify that various arithmetic binary operations are folded
14603 correctly. */
14605 static void
14607 {
14613 /* Addition. */
14614 /* 1 <-- (0 + 1) */
14616 one);
14618 one);
14620 /* (nonlvalue)x <-- (x + 0) */
14622 x);
14624 /* Subtraction. */
14625 /* 0 <-- (x - x) */
14627 zero);
14629 x);
14631 /* Multiplication. */
14632 /* 0 <-- (x * 0) */
14634 zero);
14636 /* (nonlvalue)x <-- (x * 1) */
14638 x);
14639 }
14641 /* Verify that various binary operations on vectors are folded
14642 correctly. */
14644 static void
14646 {
14652 /* Verify equality tests that return a scalar boolean result. */
14658 }
14660 /* Verify folding of VEC_DUPLICATE_EXPRs. */
14662 static void
14664 {
14667 /* This will be 1 if VEC_MODE isn't a vector mode. */
14674 }
14676 /* Run all of the selftests within this file. */
14678 void
14680 {
14684 }