| blob | af67feb5fbc7c8cad8d1b694c07dd549d0c0fa3d |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2018 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /*@@ This file should be rewritten to use an arbitrary precision
21 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
22 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
23 @@ The routines that translate from the ap rep should
24 @@ warn if precision et. al. is lost.
25 @@ This would also make life easier when this technology is used
26 @@ for cross-compilers. */
28 /* The entry points in this file are fold, size_int_wide and size_binop.
30 fold takes a tree as argument and returns a simplified tree.
32 size_binop takes a tree code for an arithmetic operation
33 and two operands that are trees, and produces a tree for the
34 result, assuming the type comes from `sizetype'.
36 size_int takes an integer value, and creates a tree constant
37 with type from `sizetype'.
39 Note: Since the folders get called on non-gimple code as well as
40 gimple code, we need to handle GIMPLE tuples as well as their
41 corresponding tree equivalents. */
87 /* Nonzero if we are folding constants inside an initializer; zero
88 otherwise. */
91 /* The following constants represent a bit based encoding of GCC's
92 comparison operators. This encoding simplifies transformations
93 on relational comparison operators, such as AND and OR. */
111 };
144 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
145 Otherwise, return LOC. */
147 static location_t
149 {
152 }
154 /* Similar to protected_set_expr_location, but never modify x in place,
155 if location can and needs to be set, unshare it. */
159 {
165 {
168 }
170 }
171 \f
172 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
173 division and returns the quotient. Otherwise returns
174 NULL_TREE. */
176 tree
178 {
179 widest_int quo;
186 }
187 \f
188 /* This is nonzero if we should defer warnings about undefined
189 overflow. This facility exists because these warnings are a
190 special case. The code to estimate loop iterations does not want
191 to issue any warnings, since it works with expressions which do not
192 occur in user code. Various bits of cleanup code call fold(), but
193 only use the result if it has certain characteristics (e.g., is a
194 constant); that code only wants to issue a warning if the result is
195 used. */
199 /* If a warning about undefined overflow is deferred, this is the
200 warning. Note that this may cause us to turn two warnings into
201 one, but that is fine since it is sufficient to only give one
202 warning per expression. */
206 /* If a warning about undefined overflow is deferred, this is the
207 level at which the warning should be emitted. */
211 /* Start deferring overflow warnings. We could use a stack here to
212 permit nested calls, but at present it is not necessary. */
214 void
216 {
218 }
220 /* Stop deferring overflow warnings. If there is a pending warning,
221 and ISSUE is true, then issue the warning if appropriate. STMT is
222 the statement with which the warning should be associated (used for
223 location information); STMT may be NULL. CODE is the level of the
224 warning--a warn_strict_overflow_code value. This function will use
225 the smaller of CODE and the deferred code when deciding whether to
226 issue the warning. CODE may be zero to mean to always use the
227 deferred code. */
229 void
231 {
233 location_t locus;
238 {
244 }
255 /* Use the smallest code level when deciding to issue the
256 warning. */
265 else
268 }
270 /* Stop deferring overflow warnings, ignoring any deferred
271 warnings. */
273 void
275 {
277 }
279 /* Whether we are deferring overflow warnings. */
281 bool
283 {
285 }
287 /* This is called when we fold something based on the fact that signed
288 overflow is undefined. */
290 void
292 {
294 {
297 {
300 }
301 }
304 }
305 \f
306 /* Return true if the built-in mathematical function specified by CODE
307 is odd, i.e. -f(x) == f(-x). */
309 bool
311 {
313 {
314 CASE_CFN_ASIN:
315 CASE_CFN_ASINH:
316 CASE_CFN_ATAN:
317 CASE_CFN_ATANH:
318 CASE_CFN_CASIN:
319 CASE_CFN_CASINH:
320 CASE_CFN_CATAN:
321 CASE_CFN_CATANH:
322 CASE_CFN_CBRT:
323 CASE_CFN_CPROJ:
324 CASE_CFN_CSIN:
325 CASE_CFN_CSINH:
326 CASE_CFN_CTAN:
327 CASE_CFN_CTANH:
328 CASE_CFN_ERF:
329 CASE_CFN_LLROUND:
330 CASE_CFN_LROUND:
331 CASE_CFN_ROUND:
332 CASE_CFN_SIN:
333 CASE_CFN_SINH:
334 CASE_CFN_TAN:
335 CASE_CFN_TANH:
336 CASE_CFN_TRUNC:
339 CASE_CFN_LLRINT:
340 CASE_CFN_LRINT:
341 CASE_CFN_NEARBYINT:
342 CASE_CFN_RINT:
347 }
349 }
351 /* Check whether we may negate an integer constant T without causing
352 overflow. */
354 bool
356 {
357 tree type;
366 }
368 /* Determine whether an expression T can be cheaply negated using
369 the function negate_expr without introducing undefined overflow. */
371 static bool
373 {
374 tree type;
383 {
388 /* Check that -CST will not overflow type. */
401 /* We want to canonicalize to positive real constants. Pretend
402 that only negative ones can be easily negated. */
410 {
414 /* Steps don't prevent negation. */
421 }
436 /* -(A + B) -> (-B) - A. */
439 /* -(A + B) -> (-A) - B. */
443 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
452 /* INT_MIN/n * n doesn't overflow while negating one operand it does
453 if n is a (negative) power of two. */
464 /* Fall through. */
477 /* In general we can't negate A in A / B, because if A is INT_MIN and
478 B is not 1 we change the sign of the result. */
482 /* In general we can't negate B in A / B, because if A is INT_MIN and
483 B is 1, we may turn this into INT_MIN / -1 which is undefined
484 and actually traps on some architectures. */
493 /* Negate -((double)float) as (double)(-float). */
495 {
499 }
503 /* Negate -f(x) as f(-x). */
509 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
511 {
515 }
520 }
522 }
524 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
525 simplification is possible.
526 If negate_expr_p would return true for T, NULL_TREE will never be
527 returned. */
529 static tree
531 {
533 tree tem;
536 {
537 /* Convert - (~A) to A + 1. */
561 {
566 }
570 {
571 tree_vector_builder elts;
575 {
580 }
583 }
606 {
607 /* -(A + B) -> (-B) - A. */
609 {
613 }
615 /* -(A + B) -> (-A) - B. */
617 {
621 }
622 }
626 /* - (A - B) -> B - A */
637 /* Fall through. */
641 {
650 }
658 /* In general we can't negate A in A / B, because if A is INT_MIN and
659 B is not 1 we change the sign of the result. */
665 /* In general we can't negate B in A / B, because if A is INT_MIN and
666 B is 1, we may turn this into INT_MIN / -1 which is undefined
667 and actually traps on some architectures. */
679 /* Convert -((double)float) into (double)(-float). */
681 {
685 }
689 /* Negate -f(x) as f(-x). */
692 {
698 }
702 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
704 {
707 {
714 }
715 }
720 }
723 }
725 /* A wrapper for fold_negate_expr_1. */
727 static tree
729 {
736 }
738 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
739 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
740 return NULL_TREE. */
742 static tree
744 {
746 location_t loc;
759 }
760 \f
761 /* Split a tree IN into a constant, literal and variable parts that could be
762 combined with CODE to make IN. "constant" means an expression with
763 TREE_CONSTANT but that isn't an actual constant. CODE must be a
764 commutative arithmetic operation. Store the constant part into *CONP,
765 the literal in *LITP and return the variable part. If a part isn't
766 present, set it to null. If the tree does not decompose in this way,
767 return the entire tree as the variable part and the other parts as null.
769 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
770 case, we negate an operand that was subtracted. Except if it is a
771 literal for which we use *MINUS_LITP instead.
773 If NEGATE_P is true, we are negating all of IN, again except a literal
774 for which we use *MINUS_LITP instead. If a variable part is of pointer
775 type, it is negated after converting to TYPE. This prevents us from
776 generating illegal MINUS pointer expression. LOC is the location of
777 the converted variable part.
779 If IN is itself a literal or constant, return it as appropriate.
781 Note that we do not guarantee that any of the three values will be the
782 same type as IN, but they will have the same signedness and mode. */
784 static tree
788 {
796 /* Strip any conversions that don't change the machine mode or signedness. */
805 /* We can associate addition and subtraction together (even
806 though the C standard doesn't say so) for integers because
807 the value is not affected. For reals, the value might be
808 affected, so we can't. */
814 {
820 /* First see if either of the operands is a literal, then a constant. */
833 /* If we haven't dealt with either operand, this is not a case we can
834 decompose. Otherwise, VAR is either of the ones remaining, if any. */
839 else
842 /* Now do any needed negations. */
849 }
854 {
855 /* -1 - X is folded to ~X, undo that here. Do _not_ do this
856 when IN is constant. */
859 }
860 else
864 {
877 }
887 }
889 /* Re-associate trees split by the above function. T1 and T2 are
890 either expressions to associate or null. Return the new
891 expression, if any. LOC is the location of the new expression. If
892 we build an operation, do it in TYPE and with CODE. */
894 static tree
896 {
898 {
901 }
905 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
906 try to fold this since we will have infinite recursion. But do
907 deal with any NEGATE_EXPRs. */
911 {
913 {
926 }
928 {
931 }
935 }
939 }
940 \f
941 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
942 for use in int_const_binop, size_binop and size_diffop. */
944 static bool
946 {
953 {
962 }
967 }
969 /* Subroutine of int_const_binop_1 that handles two INTEGER_CSTs. */
971 static tree
974 {
975 wide_int res;
976 tree t;
985 {
1001 {
1005 else
1007 }
1010 /* It's unclear from the C standard whether shifts can overflow.
1011 The following code ignores overflow; perhaps a C standard
1012 interpretation ruling is needed. */
1014 else
1021 {
1025 else
1027 }
1031 else
1110 }
1118 }
1120 /* Combine two integer constants PARG1 and PARG2 under operation CODE
1121 to produce a new constant. Return NULL_TREE if we don't know how
1122 to evaluate CODE at compile-time. */
1124 static tree
1127 {
1134 {
1135 poly_wide_int res;
1140 {
1158 else
1165 else
1178 }
1183 }
1186 }
1188 tree
1190 {
1192 }
1194 /* Return true if binary operation OP distributes over addition in operand
1195 OPNO, with the other operand being held constant. OPNO counts from 1. */
1197 static bool
1199 {
1201 {
1212 }
1213 }
1215 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1216 constant. We assume ARG1 and ARG2 have the same data type, or at least
1217 are the same kind of constant and the same machine mode. Return zero if
1218 combining the constants is not allowed in the current operating mode. */
1220 static tree
1222 {
1223 /* Sanity check for the recursive cases. */
1231 {
1237 }
1240 {
1241 machine_mode mode;
1242 REAL_VALUE_TYPE d1;
1243 REAL_VALUE_TYPE d2;
1244 REAL_VALUE_TYPE value;
1245 REAL_VALUE_TYPE result;
1249 /* The following codes are handled by real_arithmetic. */
1251 {
1262 }
1270 /* Don't perform operation if we honor signaling NaNs and
1271 either operand is a signaling NaN. */
1277 /* Don't perform operation if it would raise a division
1278 by zero exception. */
1284 /* If either operand is a NaN, just return it. Otherwise, set up
1285 for floating-point trap; we return an overflow. */
1287 {
1288 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1289 is off. */
1293 }
1295 {
1296 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1297 is off. */
1301 }
1306 /* Don't constant fold this floating point operation if
1307 the result has overflowed and flag_trapping_math. */
1315 /* Don't constant fold this floating point operation if the
1316 result may dependent upon the run-time rounding mode and
1317 flag_rounding_math is set, or if GCC's software emulation
1318 is unable to accurately represent the result. */
1328 }
1331 {
1332 FIXED_VALUE_TYPE f1;
1333 FIXED_VALUE_TYPE f2;
1334 FIXED_VALUE_TYPE result;
1339 /* The following codes are handled by fixed_arithmetic. */
1341 {
1353 {
1360 }
1365 }
1372 /* Propagate overflow flags. */
1376 }
1379 {
1388 {
1399 mpc_mul);
1413 mpc_div);
1414 /* Fallthru. */
1420 {
1421 /* Keep this algorithm in sync with
1422 tree-complex.c:expand_complex_div_straight().
1424 Expand complex division to scalars, straightforward algorithm.
1425 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1426 t = br*br + bi*bi
1427 */
1428 tree magsquared
1432 tree t1
1436 tree t2
1443 }
1444 else
1445 {
1446 /* Keep this algorithm in sync with
1447 tree-complex.c:expand_complex_div_wide().
1449 Expand complex division to scalars, modified algorithm to minimize
1450 overflow with wide input ranges. */
1456 {
1457 /* In the TRUE branch, we compute
1458 ratio = br/bi;
1459 div = (br * ratio) + bi;
1460 tr = (ar * ratio) + ai;
1461 ti = (ai * ratio) - ar;
1462 tr = tr / div;
1463 ti = ti / div; */
1474 }
1475 else
1476 {
1477 /* In the FALSE branch, we compute
1478 ratio = d/c;
1479 divisor = (d * ratio) + c;
1480 tr = (b * ratio) + a;
1481 ti = b - (a * ratio);
1482 tr = tr / div;
1483 ti = ti / div; */
1495 }
1496 }
1501 }
1505 }
1511 {
1516 /* We can operate directly on the encoding if:
1518 a3 - a2 == a2 - a1 && b3 - b2 == b2 - b1
1519 implies
1520 (a3 op b3) - (a2 op b2) == (a2 op b2) - (a1 op b1)
1522 Addition and subtraction are the supported operators
1523 for which this is true. */
1526 /* We can operate directly on stepped encodings if:
1528 a3 - a2 == a2 - a1
1529 implies:
1530 (a3 op c) - (a2 op c) == (a2 op c) - (a1 op c)
1532 which is true if (x -> x op c) distributes over addition. */
1534 else
1535 /* Similarly in reverse. */
1537 tree_vector_builder elts;
1542 {
1548 /* It is possible that const_binop cannot handle the given
1549 code and return NULL_TREE */
1553 }
1556 }
1558 /* Shifts allow a scalar offset for a vector. */
1561 {
1564 tree_vector_builder elts;
1569 {
1574 /* It is possible that const_binop cannot handle the given
1575 code and return NULL_TREE. */
1579 }
1582 }
1584 }
1586 /* Overload that adds a TYPE parameter to be able to dispatch
1587 to fold_relational_const. */
1589 tree
1591 {
1595 /* ??? Until we make the const_binop worker take the type of the
1596 result as argument put those cases that need it here. */
1598 {
1615 {
1620 }
1625 {
1641 {
1651 }
1654 }
1660 {
1683 {
1696 }
1699 }
1702 }
1707 /* Make sure type and arg0 have the same saturating flag. */
1712 }
1714 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1715 Return zero if computing the constants is not possible. */
1717 tree
1719 {
1720 /* Don't perform the operation, other than NEGATE and ABS, if
1721 flag_signaling_nans is on and the operand is a signaling NaN. */
1730 {
1731 CASE_CONVERT:
1738 /* If the source address is 0, and the source address space
1739 cannot have a valid object at 0, fold to dest type null. */
1750 {
1751 /* Can't call fold_negate_const directly here as that doesn't
1752 handle all cases and we might not be able to negate some
1753 constants. */
1758 }
1767 {
1771 }
1779 /* Perform BIT_NOT_EXPR on each element individually. */
1781 {
1782 tree elem;
1784 /* This can cope with stepped encodings because ~x == -1 - x. */
1785 tree_vector_builder elements;
1789 {
1795 }
1798 }
1820 {
1839 else
1844 {
1850 }
1853 }
1862 }
1865 }
1867 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1868 indicates which particular sizetype to create. */
1870 tree
1872 {
1874 }
1875 \f
1876 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1877 is a tree code. The type of the result is taken from the operands.
1878 Both must be equivalent integer types, ala int_binop_types_match_p.
1879 If the operands are constant, so is the result. */
1881 tree
1883 {
1892 /* Handle the special case of two poly_int constants faster. */
1894 {
1895 /* And some specific cases even faster than that. */
1897 {
1902 }
1904 {
1907 }
1909 {
1912 }
1914 /* Handle general case of two integer constants. For sizetype
1915 constant calculations we always want to know about overflow,
1916 even in the unsigned case. */
1920 }
1923 }
1925 /* Given two values, either both of sizetype or both of bitsizetype,
1926 compute the difference between the two values. Return the value
1927 in signed type corresponding to the type of the operands. */
1929 tree
1931 {
1933 tree ctype;
1938 /* If the type is already signed, just do the simple thing. */
1946 else
1949 /* If either operand is not a constant, do the conversions to the signed
1950 type and subtract. The hardware will do the right thing with any
1951 overflow in the subtraction. */
1957 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1958 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1959 overflow) and negate (which can't either). Special-case a result
1960 of zero while we're here. */
1966 else
1970 MINUS_EXPR,
1972 }
1973 \f
1974 /* A subroutine of fold_convert_const handling conversions of an
1975 INTEGER_CST to another integer type. */
1977 static tree
1979 {
1980 /* Given an integer constant, make new constant with new type,
1981 appropriately sign-extended or truncated. Use widest_int
1982 so that any extension is done according ARG1's type. */
1986 }
1988 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1989 to an integer type. */
1991 static tree
1993 {
1995 tree t;
1997 /* The following code implements the floating point to integer
1998 conversion rules required by the Java Language Specification,
1999 that IEEE NaNs are mapped to zero and values that overflow
2000 the target precision saturate, i.e. values greater than
2001 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2002 are mapped to INT_MIN. These semantics are allowed by the
2003 C and C++ standards that simply state that the behavior of
2004 FP-to-integer conversion is unspecified upon overflow. */
2006 wide_int val;
2007 REAL_VALUE_TYPE r;
2011 {
2018 }
2020 /* If R is NaN, return zero and show we have an overflow. */
2022 {
2025 }
2027 /* See if R is less than the lower bound or greater than the
2028 upper bound. */
2031 {
2035 {
2038 }
2039 }
2042 {
2045 {
2048 {
2051 }
2052 }
2053 }
2060 }
2062 /* A subroutine of fold_convert_const handling conversions of a
2063 FIXED_CST to an integer type. */
2065 static tree
2067 {
2068 tree t;
2070 scalar_mode mode;
2072 /* Right shift FIXED_CST to temp by fbit. */
2076 {
2078 HOST_BITS_PER_DOUBLE_INT,
2081 /* Left shift temp to temp_trunc by fbit. */
2083 HOST_BITS_PER_DOUBLE_INT,
2085 }
2086 else
2087 {
2090 }
2092 /* If FIXED_CST is negative, we need to round the value toward 0.
2093 By checking if the fractional bits are not zero to add 1 to temp. */
2099 /* Given a fixed-point constant, make new constant with new type,
2100 appropriately sign-extended or truncated. */
2108 }
2110 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2111 to another floating point type. */
2113 static tree
2115 {
2116 REAL_VALUE_TYPE value;
2117 tree t;
2119 /* Don't perform the operation if flag_signaling_nans is on
2120 and the operand is a signaling NaN. */
2128 /* If converting an infinity or NAN to a representation that doesn't
2129 have one, set the overflow bit so that we can produce some kind of
2130 error message at the appropriate point if necessary. It's not the
2131 most user-friendly message, but it's better than nothing. */
2138 /* Regular overflow, conversion produced an infinity in a mode that
2139 can't represent them. */
2144 else
2147 }
2149 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2150 to a floating point type. */
2152 static tree
2154 {
2155 REAL_VALUE_TYPE value;
2156 tree t;
2164 }
2166 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2167 to another fixed-point type. */
2169 static tree
2171 {
2172 FIXED_VALUE_TYPE value;
2173 tree t;
2180 /* Propagate overflow flags. */
2184 }
2186 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2187 to a fixed-point type. */
2189 static tree
2191 {
2192 FIXED_VALUE_TYPE value;
2193 tree t;
2195 double_int di;
2202 else
2210 /* Propagate overflow flags. */
2214 }
2216 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2217 to a fixed-point type. */
2219 static tree
2221 {
2222 FIXED_VALUE_TYPE value;
2223 tree t;
2231 /* Propagate overflow flags. */
2235 }
2237 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2238 type TYPE. If no simplification can be done return NULL_TREE. */
2240 static tree
2242 {
2247 /* We can't widen types, since the runtime value could overflow the
2248 original type before being extended to the new type. */
2259 {
2266 }
2268 {
2275 }
2277 {
2284 }
2286 {
2289 {
2292 /* We can't handle steps directly when extending, since the
2293 values need to wrap at the original precision first. */
2294 bool step_ok_p
2298 tree_vector_builder v;
2303 {
2309 }
2311 }
2312 }
2314 }
2316 /* Construct a vector of zero elements of vector type TYPE. */
2318 static tree
2320 {
2321 tree t;
2325 }
2327 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2329 bool
2331 {
2346 {
2361 }
2362 }
2364 /* Convert expression ARG to type TYPE. Used by the middle-end for
2365 simple conversions in preference to calling the front-end's convert. */
2367 tree
2369 {
2371 tree tem;
2382 {
2385 /* Handle conversions between pointers to different address spaces. */
2390 /* fall through */
2395 {
2399 }
2413 {
2417 }
2419 {
2423 }
2425 {
2429 }
2432 {
2450 }
2455 {
2459 }
2462 {
2476 }
2480 {
2489 integer_zero_node));
2491 {
2495 {
2501 }
2509 }
2513 }
2531 }
2532 fold_convert_exit:
2535 }
2536 \f
2537 /* Return false if expr can be assumed not to be an lvalue, true
2538 otherwise. */
2540 static bool
2542 {
2543 /* We only need to wrap lvalue tree codes. */
2545 {
2576 /* Assume the worst for front-end tree codes. */
2580 }
2583 }
2585 /* Return an expr equal to X but certainly not valid as an lvalue. */
2587 tree
2589 {
2590 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2591 us. */
2598 }
2600 /* When pedantic, return an expr equal to X but certainly not valid as a
2601 pedantic lvalue. Otherwise, return X. */
2603 static tree
2605 {
2607 }
2608 \f
2609 /* Given a tree comparison code, return the code that is the logical inverse.
2610 It is generally not safe to do this for floating-point comparisons, except
2611 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2612 ERROR_MARK in this case. */
2614 enum tree_code
2616 {
2622 {
2653 }
2654 }
2656 /* Similar, but return the comparison that results if the operands are
2657 swapped. This is safe for floating-point. */
2659 enum tree_code
2661 {
2663 {
2689 }
2690 }
2693 /* Convert a comparison tree code from an enum tree_code representation
2694 into a compcode bit-based encoding. This function is the inverse of
2695 compcode_to_comparison. */
2697 static enum comparison_code
2699 {
2701 {
2732 }
2733 }
2735 /* Convert a compcode bit-based encoding of a comparison operator back
2736 to GCC's enum tree_code representation. This function is the
2737 inverse of comparison_to_compcode. */
2739 static enum tree_code
2741 {
2743 {
2774 }
2775 }
2777 /* Return a tree for the comparison which is the combination of
2778 doing the AND or OR (depending on CODE) of the two operations LCODE
2779 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2780 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2781 if this makes the transformation invalid. */
2783 tree
2788 {
2795 {
2806 }
2809 {
2810 /* Eliminate unordered comparisons, as well as LTGT and ORD
2811 which are not used unless the mode has NaNs. */
2817 }
2819 {
2820 /* Check that the original operation and the optimized ones will trap
2821 under the same condition. */
2832 /* In a short-circuited boolean expression the LHS might be
2833 such that the RHS, if evaluated, will never trap. For
2834 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2835 if neither x nor y is NaN. (This is a mixed blessing: for
2836 example, the expression above will never trap, hence
2837 optimizing it to x < y would be invalid). */
2842 /* If the comparison was short-circuited, and only the RHS
2843 trapped, we may now generate a spurious trap. */
2848 /* If we changed the conditions that cause a trap, we lose. */
2851 }
2857 else
2858 {
2863 }
2864 }
2865 \f
2866 /* Return nonzero if two operands (typically of the same tree node)
2867 are necessarily equal. FLAGS modifies behavior as follows:
2869 If OEP_ONLY_CONST is set, only return nonzero for constants.
2870 This function tests whether the operands are indistinguishable;
2871 it does not test whether they are equal using C's == operation.
2872 The distinction is important for IEEE floating point, because
2873 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2874 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2876 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2877 even though it may hold multiple values during a function.
2878 This is because a GCC tree node guarantees that nothing else is
2879 executed between the evaluation of its "operands" (which may often
2880 be evaluated in arbitrary order). Hence if the operands themselves
2881 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2882 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2883 unset means assuming isochronic (or instantaneous) tree equivalence.
2884 Unless comparing arbitrary expression trees, such as from different
2885 statements, this flag can usually be left unset.
2887 If OEP_PURE_SAME is set, then pure functions with identical arguments
2888 are considered the same. It is used when the caller has other ways
2889 to ensure that global memory is unchanged in between.
2891 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2892 not values of expressions.
2894 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
2895 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
2897 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2898 any operand with side effect. This is unnecesarily conservative in the
2899 case we know that arg0 and arg1 are in disjoint code paths (such as in
2900 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2901 addresses with TREE_CONSTANT flag set so we know that &var == &var
2902 even if var is volatile. */
2904 int
2906 {
2907 /* When checking, verify at the outermost operand_equal_p call that
2908 if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
2909 hash value. */
2911 {
2913 {
2915 {
2922 }
2924 }
2925 else
2927 }
2929 /* If either is ERROR_MARK, they aren't equal. */
2935 /* Similar, if either does not have a type (like a released SSA name),
2936 they aren't equal. */
2940 /* We cannot consider pointers to different address space equal. */
2947 /* Check equality of integer constants before bailing out due to
2948 precision differences. */
2950 {
2951 /* Address of INTEGER_CST is not defined; check that we did not forget
2952 to drop the OEP_ADDRESS_OF flags. */
2955 }
2958 {
2959 /* If both types don't have the same signedness, then we can't consider
2960 them equal. We must check this before the STRIP_NOPS calls
2961 because they may change the signedness of the arguments. As pointers
2962 strictly don't have a signedness, require either two pointers or
2963 two non-pointers as well. */
2969 /* If both types don't have the same precision, then it is not safe
2970 to strip NOPs. */
2977 }
2978 #if 0
2979 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
2980 sanity check once the issue is solved. */
2981 else
2982 /* Addresses of conversions and SSA_NAMEs (and many other things)
2983 are not defined. Check that we did not forget to drop the
2984 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
2987 #endif
2989 /* In case both args are comparisons but with different comparison
2990 code, try to swap the comparison operands of one arg to produce
2991 a match and compare that variant. */
2995 {
3003 }
3006 {
3007 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
3009 ;
3011 {
3012 /* If we are interested in comparing addresses ignore
3013 MEM_REF wrappings of the base that can appear just for
3014 TBAA reasons. */
3028 }
3029 else
3031 }
3033 /* When not checking adddresses, this is needed for conversions and for
3034 COMPONENT_REF. Might as well play it safe and always test this. */
3041 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3042 We don't care about side effects in that case because the SAVE_EXPR
3043 takes care of that for us. In all other cases, two expressions are
3044 equal if they have no side effects. If we have two identical
3045 expressions with side effects that should be treated the same due
3046 to the only side effects being identical SAVE_EXPR's, that will
3047 be detected in the recursive calls below.
3048 If we are taking an invariant address of two identical objects
3049 they are necessarily equal as well. */
3056 /* Next handle constant cases, those for which we can return 1 even
3057 if ONLY_CONST is set. */
3060 {
3074 {
3075 /* If we do not distinguish between signed and unsigned zero,
3076 consider them equal. */
3079 }
3083 {
3098 }
3102 flags)
3104 flags));
3115 flags | OEP_ADDRESS_OF
3118 /* In GIMPLE empty constructors are allowed in initializers of
3119 aggregates. */
3123 }
3128 /* Define macros to test an operand from arg0 and arg1 for equality and a
3129 variant that allows null and views null as being different from any
3130 non-null value. In the latter case, if either is null, the both
3131 must be; otherwise, do the normal comparison. */
3132 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3133 TREE_OPERAND (arg1, N), flags)
3135 #define OP_SAME_WITH_NULL(N) \
3136 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3137 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3140 {
3142 /* Two conversions are equal only if signedness and modes match. */
3144 {
3145 CASE_CONVERT:
3153 }
3163 /* For commutative ops, allow the other order. */
3171 /* If either of the pointer (or reference) expressions we are
3172 dereferencing contain a side effect, these cannot be equal,
3173 but their addresses can be. */
3180 {
3190 /* Require the same offset. */
3196 /* Fallthru. */
3204 {
3205 /* Require equal access sizes */
3211 flags)))
3213 /* Verify that access happens in similar types. */
3216 /* Verify that accesses are TBAA compatible. */
3225 /* Verify that alignment is compatible. */
3229 }
3232 /* TARGET_MEM_REF require equal extra operands. */
3243 /* Compare the array index by value if it is constant first as we
3244 may have different types but same value here. */
3250 /* Compare low bound and element size as with OEP_ADDRESS_OF
3251 we have to account for the offset of the ref. */
3256 array_ref_low_bound
3260 array_ref_element_size
3262 flags))));
3265 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3266 may be NULL when we're called to compare MEM_EXPRs. */
3281 }
3285 {
3287 /* Be sure we pass right ADDRESS_OF flag. */
3305 /* The multiplcation operands are commutative. */
3306 /* FALLTHRU */
3314 /* Otherwise take into account this is a commutative operation. */
3327 /* BIT_INSERT_EXPR has an implict operand as the type precision
3328 of op1. Need to check to make sure they are the same. */
3334 /* FALLTHRU */
3359 }
3363 {
3367 /* If not both CALL_EXPRs are either internal or normal function
3368 functions, then they are not equal. */
3371 {
3372 /* If the CALL_EXPRs call different internal functions, then they
3373 are not equal. */
3376 }
3377 else
3378 {
3379 /* If the CALL_EXPRs call different functions, then they are not
3380 equal. */
3382 flags))
3384 }
3386 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3387 {
3391 else
3395 }
3397 /* Now see if all the arguments are the same. */
3398 {
3409 /* If we get here and both argument lists are exhausted
3410 then the CALL_EXPRs are equal. */
3412 }
3415 }
3418 /* Consider __builtin_sqrt equal to sqrt. */
3426 {
3427 /* In GIMPLE constructors are used only to build vectors from
3428 elements. Individual elements in the constructor must be
3429 indexed in increasing order and form an initial sequence.
3431 We make no effort to compare constructors in generic.
3432 (see sem_variable::equals in ipa-icf which can do so for
3433 constants). */
3438 /* Be sure that vectors constructed have the same representation.
3439 We only tested element precision and modes to match.
3440 Vectors may be BLKmode and thus also check that the number of
3441 parts match. */
3454 {
3459 /* In GIMPLE the indexes can be either NULL or matching i.
3460 Double check this so we won't get false
3461 positives for GENERIC. */
3469 }
3471 }
3474 {
3475 /* Compare the STATEMENT_LISTs. */
3481 {
3482 /* The lists don't have the same number of statements. */
3488 flags & (OEP_LEXICOGRAPHIC
3491 }
3492 }
3497 {
3508 }
3512 }
3514 #undef OP_SAME
3515 #undef OP_SAME_WITH_NULL
3516 }
3517 \f
3518 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
3519 with a different signedness or a narrower precision. */
3521 static bool
3523 {
3531 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3532 and see if the inner values are the same. This removes any
3533 signedness comparison, which doesn't matter here. */
3541 /* Discard a single widening conversion from ARG1 and see if the inner
3542 value is the same as ARG0. */
3551 }
3552 \f
3553 /* See if ARG is an expression that is either a comparison or is performing
3554 arithmetic on comparisons. The comparisons must only be comparing
3555 two different values, which will be stored in *CVAL1 and *CVAL2; if
3556 they are nonzero it means that some operands have already been found.
3557 No variables may be used anywhere else in the expression except in the
3558 comparisons.
3560 If this is true, return 1. Otherwise, return zero. */
3562 static int
3564 {
3568 /* We can handle some of the tcc_expression cases here. */
3577 {
3596 /* First see if we can handle the first operand, then the second. For
3597 the second operand, we know *CVAL1 can't be zero. It must be that
3598 one side of the comparison is each of the values; test for the
3599 case where this isn't true by failing if the two operands
3600 are the same. */
3609 ;
3613 ;
3614 else
3618 ;
3622 ;
3623 else
3630 }
3631 }
3632 \f
3633 /* ARG is a tree that is known to contain just arithmetic operations and
3634 comparisons. Evaluate the operations in the tree substituting NEW0 for
3635 any occurrence of OLD0 as an operand of a comparison and likewise for
3636 NEW1 and OLD1. */
3638 static tree
3641 {
3646 /* We can handle some of the tcc_expression cases here. */
3654 {
3669 {
3688 }
3689 /* Fall through - ??? */
3692 {
3696 /* We need to check both for exact equality and tree equality. The
3697 former will be true if the operand has a side-effect. In that
3698 case, we know the operand occurred exactly once. */
3711 }
3715 }
3716 }
3717 \f
3718 /* Return a tree for the case when the result of an expression is RESULT
3719 converted to TYPE and OMITTED was previously an operand of the expression
3720 but is now not needed (e.g., we folded OMITTED * 0).
3722 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3723 the conversion of RESULT to TYPE. */
3725 tree
3727 {
3730 /* If the resulting operand is an empty statement, just return the omitted
3731 statement casted to void. */
3741 }
3743 /* Return a tree for the case when the result of an expression is RESULT
3744 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3745 of the expression but are now not needed.
3747 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3748 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3749 evaluated before OMITTED2. Otherwise, if neither has side effects,
3750 just do the conversion of RESULT to TYPE. */
3752 tree
3755 {
3764 }
3766 \f
3767 /* Return a simplified tree node for the truth-negation of ARG. This
3768 never alters ARG itself. We assume that ARG is an operation that
3769 returns a truth value (0 or 1).
3771 FIXME: one would think we would fold the result, but it causes
3772 problems with the dominator optimizer. */
3774 static tree
3776 {
3781 /* If this is a comparison, we can simply invert it, except for
3782 floating-point non-equality comparisons, in which case we just
3783 enclose a TRUTH_NOT_EXPR around what we have. */
3786 {
3789 && flag_trapping_math
3803 }
3806 {
3825 /* Here we can invert either operand. We invert the first operand
3826 unless the second operand is a TRUTH_NOT_EXPR in which case our
3827 result is the XOR of the first operand with the inside of the
3828 negation of the second operand. */
3833 else
3856 {
3863 /* A COND_EXPR may have a throw as one operand, which
3864 then has void type. Just leave void operands
3865 as they are. */
3871 }
3883 CASE_CONVERT:
3887 /* fall through */
3909 }
3910 }
3912 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3913 assume that ARG is an operation that returns a truth value (0 or 1
3914 for scalars, 0 or -1 for vectors). Return the folded expression if
3915 folding is successful. Otherwise, return NULL_TREE. */
3917 static tree
3919 {
3922 ? BIT_NOT_EXPR
3925 }
3927 /* Return a simplified tree node for the truth-negation of ARG. This
3928 never alters ARG itself. We assume that ARG is an operation that
3929 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3931 tree
3933 {
3939 ? BIT_NOT_EXPR
3942 }
3943 \f
3944 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3945 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
3946 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
3947 is the original memory reference used to preserve the alias set of
3948 the access. */
3950 static tree
3954 {
3957 /* Attempt not to lose the access path if possible. */
3959 {
3961 machine_mode nmode;
3963 tree noffset;
3971 && !reversep
3972 && !nreversep
3974 {
3977 }
3978 }
3987 {
3994 }
4009 }
4011 /* Optimize a bit-field compare.
4013 There are two cases: First is a compare against a constant and the
4014 second is a comparison of two items where the fields are at the same
4015 bit position relative to the start of a chunk (byte, halfword, word)
4016 large enough to contain it. In these cases we can avoid the shift
4017 implicit in bitfield extractions.
4019 For constants, we emit a compare of the shifted constant with the
4020 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4021 compared. For two fields at the same position, we do the ANDs with the
4022 similar mask and compare the result of the ANDs.
4024 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4025 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4026 are the left and right operands of the comparison, respectively.
4028 If the optimization described above can be done, we return the resulting
4029 tree. Otherwise we return zero. */
4031 static tree
4034 {
4038 tree unsigned_type;
4041 scalar_int_mode nmode;
4046 tree mask;
4047 tree offset;
4049 /* Get all the information about the extractions being done. If the bit size
4050 is the same as the size of the underlying object, we aren't doing an
4051 extraction at all and so can do nothing. We also don't want to
4052 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4053 then will no longer be able to replace it. */
4068 else
4069 {
4070 /* If this is not a constant, we can only do something if bit positions,
4071 sizes, signedness and storage order are the same. */
4072 rinner
4085 }
4087 /* Honor the C++ memory model and mimic what RTL expansion does. */
4091 {
4095 }
4097 /* See if we can find a mode to refer to this field. We should be able to,
4098 but fail if we can't. */
4106 /* Set signed and unsigned types of the precision of this mode for the
4107 shifts below. */
4110 /* Compute the bit position and size for the new reference and our offset
4111 within it. If the new reference is the same size as the original, we
4112 won't optimize anything, so return zero. */
4122 /* Make the mask to be used against the extracted field. */
4129 {
4133 /* If not comparing with constant, just rework the comparison
4134 and return. */
4142 }
4144 /* Otherwise, we are handling the constant case. See if the constant is too
4145 big for the field. Warn and return a tree for 0 (false) if so. We do
4146 this not only for its own sake, but to avoid having to test for this
4147 error case below. If we didn't, we might generate wrong code.
4149 For unsigned fields, the constant shifted right by the field length should
4150 be all zero. For signed fields, the high-order bits should agree with
4151 the sign bit. */
4154 {
4156 {
4160 }
4161 }
4162 else
4163 {
4166 {
4170 }
4171 }
4176 /* Single-bit compares should always be against zero. */
4178 {
4181 }
4183 /* Make a new bitfield reference, shift the constant over the
4184 appropriate number of bits and mask it with the computed mask
4185 (in case this was a signed field). If we changed it, make a new one. */
4193 mask);
4198 }
4199 \f
4200 /* Subroutine for fold_truth_andor_1: decode a field reference.
4202 If EXP is a comparison reference, we return the innermost reference.
4204 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4205 set to the starting bit number.
4207 If the innermost field can be completely contained in a mode-sized
4208 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4210 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4211 otherwise it is not changed.
4213 *PUNSIGNEDP is set to the signedness of the field.
4215 *PREVERSEP is set to the storage order of the field.
4217 *PMASK is set to the mask used. This is either contained in a
4218 BIT_AND_EXPR or derived from the width of the field.
4220 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4222 Return 0 if this is not a component reference or is one that we can't
4223 do anything with. */
4225 static tree
4230 {
4235 tree unsigned_type;
4238 /* All the optimizations using this function assume integer fields.
4239 There are problems with FP fields since the type_for_size call
4240 below can fail for, e.g., XFmode. */
4244 /* We are interested in the bare arrangement of bits, so strip everything
4245 that doesn't affect the machine mode. However, record the type of the
4246 outermost expression if it may matter below. */
4253 {
4259 }
4270 /* Reject out-of-bound accesses (PR79731). */
4278 /* If the number of bits in the reference is the same as the bitsize of
4279 the outer type, then the outer type gives the signedness. Otherwise
4280 (in case of a small bitfield) the signedness is unchanged. */
4284 /* Compute the mask to access the bitfield. */
4293 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4301 }
4303 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4304 bit positions and MASK is SIGNED. */
4306 static int
4308 {
4312 /* If this function returns true when the type of the mask is
4313 UNSIGNED, then there will be errors. In particular see
4314 gcc.c-torture/execute/990326-1.c. There does not appear to be
4315 any documentation paper trail as to why this is so. But the pre
4316 wide-int worked with that restriction and it has been preserved
4317 here. */
4322 }
4324 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4325 represents the sign bit of EXP's type. If EXP represents a sign
4326 or zero extension, also test VAL against the unextended type.
4327 The return value is the (sub)expression whose sign bit is VAL,
4328 or NULL_TREE otherwise. */
4330 tree
4332 {
4334 tree t;
4336 /* Tree EXP must have an integral type. */
4341 /* Tree VAL must be an integer constant. */
4350 /* Handle extension from a narrower type. */
4356 }
4358 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4359 to be evaluated unconditionally. */
4361 static int
4363 {
4364 /* Strip any conversions that don't change the machine mode. */
4373 /* Don't regard global variables as simple. They may be
4374 allocated in ways unknown to the compiler (shared memory,
4375 #pragma weak, etc). */
4378 /* Weakrefs are not safe to be read, since they can be NULL.
4379 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4380 have DECL_WEAK flag set. */
4382 /* Loading a static variable is unduly expensive, but global
4383 registers aren't expensive. */
4385 }
4387 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4388 to be evaluated unconditionally.
4389 I addition to simple_operand_p, we assume that comparisons, conversions,
4390 and logic-not operations are simple, if their operands are simple, too. */
4392 static bool
4394 {
4414 }
4416 \f
4417 /* The following functions are subroutines to fold_range_test and allow it to
4418 try to change a logical combination of comparisons into a range test.
4420 For example, both
4421 X == 2 || X == 3 || X == 4 || X == 5
4422 and
4423 X >= 2 && X <= 5
4424 are converted to
4425 (unsigned) (X - 2) <= 3
4427 We describe each set of comparisons as being either inside or outside
4428 a range, using a variable named like IN_P, and then describe the
4429 range with a lower and upper bound. If one of the bounds is omitted,
4430 it represents either the highest or lowest value of the type.
4432 In the comments below, we represent a range by two numbers in brackets
4433 preceded by a "+" to designate being inside that range, or a "-" to
4434 designate being outside that range, so the condition can be inverted by
4435 flipping the prefix. An omitted bound is represented by a "-". For
4436 example, "- [-, 10]" means being outside the range starting at the lowest
4437 possible value and ending at 10, in other words, being greater than 10.
4438 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4439 always false.
4441 We set up things so that the missing bounds are handled in a consistent
4442 manner so neither a missing bound nor "true" and "false" need to be
4443 handled using a special case. */
4445 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4446 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4447 and UPPER1_P are nonzero if the respective argument is an upper bound
4448 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4449 must be specified for a comparison. ARG1 will be converted to ARG0's
4450 type if both are specified. */
4452 static tree
4455 {
4456 tree tem;
4460 /* If neither arg represents infinity, do the normal operation.
4461 Else, if not a comparison, return infinity. Else handle the special
4462 comparison rules. Note that most of the cases below won't occur, but
4463 are handled for consistency. */
4466 {
4471 }
4476 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4477 for neither. In real maths, we cannot assume open ended ranges are
4478 the same. But, this is computer arithmetic, where numbers are finite.
4479 We can therefore make the transformation of any unbounded range with
4480 the value Z, Z being greater than any representable number. This permits
4481 us to treat unbounded ranges as equal. */
4485 {
4506 }
4509 }
4510 \f
4511 /* Helper routine for make_range. Perform one step for it, return
4512 new expression if the loop should continue or NULL_TREE if it should
4513 stop. */
4515 tree
4519 {
4525 {
4527 /* We can only do something if the range is testing for zero. */
4536 /* We can only do something if the range is testing for zero
4537 and if the second operand is an integer constant. Note that
4538 saying something is "in" the range we make is done by
4539 complementing IN_P since it will set in the initial case of
4540 being not equal to zero; "out" is leaving it alone. */
4547 {
4568 }
4570 /* If this is an unsigned comparison, we also know that EXP is
4571 greater than or equal to zero. We base the range tests we make
4572 on that fact, so we record it here so we can parse existing
4573 range tests. We test arg0_type since often the return type
4574 of, e.g. EQ_EXPR, is boolean. */
4576 {
4580 NULL_TREE))
4585 /* If the high bound is missing, but we have a nonzero low
4586 bound, reverse the range so it goes from zero to the low bound
4587 minus 1. */
4589 {
4594 }
4595 }
4603 /* If flag_wrapv and ARG0_TYPE is signed, make sure
4604 low and high are non-NULL, then normalize will DTRT. */
4607 {
4612 }
4614 /* (-x) IN [a,b] -> x in [-b, -a] */
4626 /* ~ X -> -X - 1 */
4635 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4636 move a constant to the other side. */
4641 /* If EXP is signed, any overflow in the computation is undefined,
4642 so we don't worry about it so long as our computations on
4643 the bounds don't overflow. For unsigned, overflow is defined
4644 and this is exactly the right thing. */
4656 normalize:
4657 /* Check for an unsigned range which has wrapped around the maximum
4658 value thus making n_high < n_low, and normalize it. */
4660 {
4666 /* If the range is of the form +/- [ x+1, x ], we won't
4667 be able to normalize it. But then, it represents the
4668 whole range or the empty set, so make it
4669 +/- [ -, - ]. */
4673 else
4675 }
4676 else
4684 CASE_CONVERT:
4702 /* If we're converting arg0 from an unsigned type, to exp,
4703 a signed type, we will be doing the comparison as unsigned.
4704 The tests above have already verified that LOW and HIGH
4705 are both positive.
4707 So we have to ensure that we will handle large unsigned
4708 values the same way that the current signed bounds treat
4709 negative values. */
4712 {
4713 tree high_positive;
4714 tree equiv_type;
4715 /* For fixed-point modes, we need to pass the saturating flag
4716 as the 2nd parameter. */
4718 equiv_type
4721 else
4722 equiv_type
4725 /* A range without an upper bound is, naturally, unbounded.
4726 Since convert would have cropped a very large value, use
4727 the max value for the destination type. */
4728 high_positive
4735 high_positive),
4738 /* If the low bound is specified, "and" the range with the
4739 range for which the original unsigned value will be
4740 positive. */
4742 {
4745 integer_zero_node),
4746 high_positive))
4750 }
4751 else
4752 {
4753 /* Otherwise, "or" the range with the range of the input
4754 that will be interpreted as negative. */
4757 integer_zero_node),
4758 high_positive))
4762 }
4763 }
4772 }
4773 }
4775 /* Given EXP, a logical expression, set the range it is testing into
4776 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4777 actually being tested. *PLOW and *PHIGH will be made of the same
4778 type as the returned expression. If EXP is not a comparison, we
4779 will most likely not be returning a useful value and range. Set
4780 *STRICT_OVERFLOW_P to true if the return value is only valid
4781 because signed overflow is undefined; otherwise, do not change
4782 *STRICT_OVERFLOW_P. */
4784 tree
4787 {
4795 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4796 and see if we can refine the range. Some of the cases below may not
4797 happen, but it doesn't seem worth worrying about this. We "continue"
4798 the outer loop when we've changed something; otherwise we "break"
4799 the switch, which will "break" the while. */
4805 {
4811 {
4819 }
4828 }
4830 /* If EXP is a constant, we can evaluate whether this is true or false. */
4832 {
4839 }
4843 }
4845 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
4846 a bitwise check i.e. when
4847 LOW == 0xXX...X00...0
4848 HIGH == 0xXX...X11...1
4849 Return corresponding mask in MASK and stem in VALUE. */
4851 static bool
4854 {
4877 }
4878 \f
4879 /* Helper routine for build_range_check and match.pd. Return the type to
4880 perform the check or NULL if it shouldn't be optimized. */
4882 tree
4884 {
4885 /* First make sure that arithmetics in this type is valid, then make sure
4886 that it wraps around. */
4892 {
4895 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4896 for the type in question, as we rely on this here. */
4906 else
4908 }
4910 }
4912 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4913 type, TYPE, return an expression to test if EXP is in (or out of, depending
4914 on IN_P) the range. Return 0 if the test couldn't be created. */
4916 tree
4919 {
4922 /* Disable this optimization for function pointer expressions
4923 on targets that require function pointer canonicalization. */
4930 {
4936 }
4958 value);
4961 {
4963 {
4967 }
4969 }
4971 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4973 {
4977 {
4979 {
4982 etype
4984 else
4987 }
4990 }
4991 }
4993 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4994 This requires wrap-around arithmetics for the type of the expression. */
5014 }
5015 \f
5016 /* Return the predecessor of VAL in its type, handling the infinite case. */
5018 static tree
5020 {
5026 else
5029 }
5031 /* Return the successor of VAL in its type, handling the infinite case. */
5033 static tree
5035 {
5041 else
5044 }
5046 /* Given two ranges, see if we can merge them into one. Return 1 if we
5047 can, 0 if we can't. Set the output range into the specified parameters. */
5049 bool
5052 {
5056 tree tem;
5066 /* Make range 0 be the range that starts first, or ends last if they
5067 start at the same value. Swap them if it isn't. */
5070 || (lowequal
5073 {
5077 }
5079 /* Now flag two cases, whether the ranges are disjoint or whether the
5080 second range is totally subsumed in the first. Note that the tests
5081 below are simplified by the ones above. */
5087 /* We now have four cases, depending on whether we are including or
5088 excluding the two ranges. */
5090 {
5091 /* If they don't overlap, the result is false. If the second range
5092 is a subset it is the result. Otherwise, the range is from the start
5093 of the second to the end of the first. */
5098 else
5100 }
5103 {
5104 /* If they don't overlap, the result is the first range. If they are
5105 equal, the result is false. If the second range is a subset of the
5106 first, and the ranges begin at the same place, we go from just after
5107 the end of the second range to the end of the first. If the second
5108 range is not a subset of the first, or if it is a subset and both
5109 ranges end at the same place, the range starts at the start of the
5110 first range and ends just before the second range.
5111 Otherwise, we can't describe this as a single range. */
5117 {
5122 {
5123 /* We are in the weird situation where high0 > high1 but
5124 high1 has no successor. Punt. */
5126 }
5127 }
5129 {
5134 {
5135 /* low0 < low1 but low1 has no predecessor. Punt. */
5137 }
5138 }
5139 else
5141 }
5144 {
5145 /* If they don't overlap, the result is the second range. If the second
5146 is a subset of the first, the result is false. Otherwise,
5147 the range starts just after the first range and ends at the
5148 end of the second. */
5153 else
5154 {
5159 {
5160 /* high1 > high0 but high0 has no successor. Punt. */
5162 }
5163 }
5164 }
5166 else
5167 {
5168 /* The case where we are excluding both ranges. Here the complex case
5169 is if they don't overlap. In that case, the only time we have a
5170 range is if they are adjacent. If the second is a subset of the
5171 first, the result is the first. Otherwise, the range to exclude
5172 starts at the beginning of the first range and ends at the end of the
5173 second. */
5175 {
5180 else
5181 {
5182 /* Canonicalize - [min, x] into - [-, x]. */
5185 {
5188 GET_MODE_BITSIZE
5191 /* FALLTHROUGH */
5204 }
5206 /* Canonicalize - [x, max] into - [x, -]. */
5209 {
5212 GET_MODE_BITSIZE
5215 /* FALLTHROUGH */
5231 }
5233 /* The ranges might be also adjacent between the maximum and
5234 minimum values of the given type. For
5235 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5236 return + [x + 1, y - 1]. */
5238 {
5245 }
5246 else
5248 }
5249 }
5252 else
5254 }
5258 }
5259 \f
5261 /* Subroutine of fold, looking inside expressions of the form
5262 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5263 of the COND_EXPR. This function is being used also to optimize
5264 A op B ? C : A, by reversing the comparison first.
5266 Return a folded expression whose code is not a COND_EXPR
5267 anymore, or NULL_TREE if no folding opportunity is found. */
5269 static tree
5272 {
5277 tree tem;
5282 /* If we have A op 0 ? A : -A, consider applying the following
5283 transformations:
5285 A == 0? A : -A same as -A
5286 A != 0? A : -A same as A
5287 A >= 0? A : -A same as abs (A)
5288 A > 0? A : -A same as abs (A)
5289 A <= 0? A : -A same as -abs (A)
5290 A < 0? A : -A same as -abs (A)
5292 None of these transformations work for modes with signed
5293 zeros. If A is +/-0, the first two transformations will
5294 change the sign of the result (from +0 to -0, or vice
5295 versa). The last four will fix the sign of the result,
5296 even though the original expressions could be positive or
5297 negative, depending on the sign of A.
5299 Note that all these transformations are correct if A is
5300 NaN, since the two alternatives (A and -A) are also NaNs. */
5307 /* In the case that A is of the form X-Y, '-A' (arg2) may
5308 have already been folded to Y-X, check for that. */
5316 {
5328 /* Fall through. */
5339 /* FALLTHRU */
5349 }
5351 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5352 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5353 both transformations are correct when A is NaN: A != 0
5354 is then true, and A == 0 is false. */
5358 {
5363 }
5365 /* Try some transformations of A op B ? A : B.
5367 A == B? A : B same as B
5368 A != B? A : B same as A
5369 A >= B? A : B same as max (A, B)
5370 A > B? A : B same as max (B, A)
5371 A <= B? A : B same as min (A, B)
5372 A < B? A : B same as min (B, A)
5374 As above, these transformations don't work in the presence
5375 of signed zeros. For example, if A and B are zeros of
5376 opposite sign, the first two transformations will change
5377 the sign of the result. In the last four, the original
5378 expressions give different results for (A=+0, B=-0) and
5379 (A=-0, B=+0), but the transformed expressions do not.
5381 The first two transformations are correct if either A or B
5382 is a NaN. In the first transformation, the condition will
5383 be false, and B will indeed be chosen. In the case of the
5384 second transformation, the condition A != B will be true,
5385 and A will be chosen.
5387 The conversions to max() and min() are not correct if B is
5388 a number and A is not. The conditions in the original
5389 expressions will be false, so all four give B. The min()
5390 and max() versions would give a NaN instead. */
5393 /* Avoid these transformations if the COND_EXPR may be used
5394 as an lvalue in the C++ front-end. PR c++/19199. */
5395 && (in_gimple_form
5401 {
5407 {
5416 /* In C++ a ?: expression can be an lvalue, so put the
5417 operand which will be used if they are equal first
5418 so that we can convert this back to the
5419 corresponding COND_EXPR. */
5421 {
5429 }
5436 {
5444 }
5457 }
5458 }
5461 }
5464 \f
5465 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5466 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5467 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5468 false) >= 2)
5469 #endif
5471 /* EXP is some logical combination of boolean tests. See if we can
5472 merge it into some range test. Return the new tree if so. */
5474 static tree
5477 {
5493 /* If this is an OR operation, invert both sides; we will invert
5494 again at the end. */
5498 /* If both expressions are the same, if we can merge the ranges, and we
5499 can build the range test, return it or it inverted. If one of the
5500 ranges is always true or always false, consider it to be the same
5501 expression as the other. */
5509 {
5513 }
5515 /* On machines where the branch cost is expensive, if this is a
5516 short-circuited branch and the underlying object on both sides
5517 is the same, make a non-short-circuit operation. */
5520 logical_op_non_short_circuit
5523 && !flag_sanitize_coverage
5527 {
5528 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5529 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5530 which cases we can't do this. */
5538 {
5547 {
5550 WARN_STRICT_OVERFLOW_COMPARISON);
5554 }
5555 }
5556 }
5559 }
5560 \f
5561 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
5562 bit value. Arrange things so the extra bits will be set to zero if and
5563 only if C is signed-extended to its full width. If MASK is nonzero,
5564 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5566 static tree
5568 {
5571 tree temp;
5576 /* We work by getting just the sign bit into the low-order bit, then
5577 into the high-order bit, then sign-extend. We then XOR that value
5578 with C. */
5582 /* We must use a signed type in order to get an arithmetic right shift.
5583 However, we must also avoid introducing accidental overflows, so that
5584 a subsequent call to integer_zerop will work. Hence we must
5585 do the type conversion here. At this point, the constant is either
5586 zero or one, and the conversion to a signed type can never overflow.
5587 We could get an overflow if this conversion is done anywhere else. */
5596 /* If necessary, convert the type back to match the type of C. */
5601 }
5602 \f
5603 /* For an expression that has the form
5604 (A && B) || ~B
5605 or
5606 (A || B) && ~B,
5607 we can drop one of the inner expressions and simplify to
5608 A || ~B
5609 or
5610 A && ~B
5611 LOC is the location of the resulting expression. OP is the inner
5612 logical operation; the left-hand side in the examples above, while CMPOP
5613 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5614 removing a condition that guards another, as in
5615 (A != NULL && A->...) || A == NULL
5616 which we must not transform. If RHS_ONLY is true, only eliminate the
5617 right-most operand of the inner logical operation. */
5619 static tree
5622 {
5640 {
5643 {
5646 }
5647 }
5649 {
5652 {
5655 }
5656 }
5671 }
5673 /* Find ways of folding logical expressions of LHS and RHS:
5674 Try to merge two comparisons to the same innermost item.
5675 Look for range tests like "ch >= '0' && ch <= '9'".
5676 Look for combinations of simple terms on machines with expensive branches
5677 and evaluate the RHS unconditionally.
5679 For example, if we have p->a == 2 && p->b == 4 and we can make an
5680 object large enough to span both A and B, we can do this with a comparison
5681 against the object ANDed with the a mask.
5683 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5684 operations to do this with one comparison.
5686 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5687 function and the one above.
5689 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5690 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5692 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5693 two operands.
5695 We return the simplified tree or 0 if no optimization is possible. */
5697 static tree
5700 {
5701 /* If this is the "or" of two comparisons, we can do something if
5702 the comparisons are NE_EXPR. If this is the "and", we can do something
5703 if the comparisons are EQ_EXPR. I.e.,
5704 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5706 WANTED_CODE is this operation code. For single bit fields, we can
5707 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5708 comparison for one-bit fields. */
5729 /* Start by getting the comparison codes. Fail if anything is volatile.
5730 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5731 it were surrounded with a NE_EXPR. */
5740 {
5744 }
5747 {
5751 }
5762 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5765 {
5768 {
5773 }
5776 {
5782 }
5783 }
5788 /* If the RHS can be evaluated unconditionally and its operands are
5789 simple, it wins to evaluate the RHS unconditionally on machines
5790 with expensive branches. In this case, this isn't a comparison
5791 that can be merged. */
5798 {
5799 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5810 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5820 }
5822 /* See if the comparisons can be merged. Then get all the parameters for
5823 each side. */
5848 /* It must be true that the inner operation on the lhs of each
5849 comparison must be the same if we are to be able to do anything.
5850 Then see if we have constants. If not, the same must be true for
5851 the rhs's. */
5860 {
5863 }
5868 else
5871 /* If either comparison code is not correct for our logical operation,
5872 fail. However, we can convert a one-bit comparison against zero into
5873 the opposite comparison against that bit being set in the field. */
5877 {
5879 {
5880 /* Make the left operand unsigned, since we are only interested
5881 in the value of one bit. Otherwise we are doing the wrong
5882 thing below. */
5885 }
5886 else
5888 }
5890 /* This is analogous to the code for l_const above. */
5892 {
5894 {
5897 }
5898 else
5900 }
5902 /* See if we can find a mode that contains both fields being compared on
5903 the left. If we can't, fail. Otherwise, update all constants and masks
5904 to be relative to a field of that size. */
5918 {
5921 }
5929 {
5936 {
5940 }
5941 }
5943 {
5950 {
5954 }
5955 }
5957 /* If the right sides are not constant, do the same for it. Also,
5958 disallow this optimization if a size, signedness or storage order
5959 mismatch occurs between the left and right sides. */
5961 {
5965 /* Make sure the two fields on the right
5966 correspond to the left without being swapped. */
5983 {
5986 }
5995 /* Make a mask that corresponds to both fields being compared.
5996 Do this for both items being compared. If the operands are the
5997 same size and the bits being compared are in the same position
5998 then we can do this by masking both and comparing the masked
5999 results. */
6006 {
6020 }
6022 /* There is still another way we can do something: If both pairs of
6023 fields being compared are adjacent, we may be able to make a wider
6024 field containing them both.
6026 Note that we still must mask the lhs/rhs expressions. Furthermore,
6027 the mask must be shifted to account for the shift done by
6028 make_bit_field_ref. */
6037 {
6038 tree type;
6054 /* Convert to the smaller type before masking out unwanted bits. */
6057 {
6059 {
6063 }
6065 {
6069 }
6070 }
6079 }
6082 }
6084 /* Handle the case of comparisons with constants. If there is something in
6085 common between the masks, those bits of the constants must be the same.
6086 If not, the condition is always false. Test for this to avoid generating
6087 incorrect code below. */
6092 {
6094 {
6097 }
6098 else
6099 {
6102 }
6103 }
6108 /* Construct the expression we will return. First get the component
6109 reference we will make. Unless the mask is all ones the width of
6110 that field, perform the mask operation. Then compare with the
6111 merged constant. */
6122 }
6123 \f
6124 /* T is an integer expression that is being multiplied, divided, or taken a
6125 modulus (CODE says which and what kind of divide or modulus) by a
6126 constant C. See if we can eliminate that operation by folding it with
6127 other operations already in T. WIDE_TYPE, if non-null, is a type that
6128 should be used for the computation if wider than our type.
6130 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6131 (X * 2) + (Y * 4). We must, however, be assured that either the original
6132 expression would not overflow or that overflow is undefined for the type
6133 in the language in question.
6135 If we return a non-null expression, it is an equivalent form of the
6136 original computation, but need not be in the original type.
6138 We set *STRICT_OVERFLOW_P to true if the return values depends on
6139 signed overflow being undefined. Otherwise we do not change
6140 *STRICT_OVERFLOW_P. */
6142 static tree
6145 {
6146 /* To avoid exponential search depth, refuse to allow recursion past
6147 three levels. Beyond that (1) it's highly unlikely that we'll find
6148 something interesting and (2) we've probably processed it before
6149 when we built the inner expression. */
6152 tree ret;
6157 depth++;
6159 depth--;
6162 }
6164 static tree
6167 {
6179 /* Don't deal with constants of zero here; they confuse the code below. */
6189 /* Note that we need not handle conditional operations here since fold
6190 already handles those cases. So just do arithmetic here. */
6192 {
6194 /* For a constant, we can always simplify if we are a multiply
6195 or (for divide and modulus) if it is a multiple of our constant. */
6199 {
6202 /* If the multiplication overflowed, we lost information on it.
6203 See PR68142 and PR69845. */
6207 }
6211 /* If op0 is an expression ... */
6217 /* ... and has wrapping overflow, and its type is smaller
6218 than ctype, then we cannot pass through as widening. */
6223 /* ... or this is a truncation (t is narrower than op0),
6224 then we cannot pass through this narrowing. */
6227 /* ... or signedness changes for division or modulus,
6228 then we cannot pass through this conversion. */
6232 /* ... or has undefined overflow while the converted to
6233 type has not, we cannot do the operation in the inner type
6234 as that would introduce undefined overflow. */
6240 /* Pass the constant down and see if we can make a simplification. If
6241 we can, replace this expression with the inner simplification for
6242 possible later conversion to our or some other type. */
6253 /* If widening the type changes it from signed to unsigned, then we
6254 must avoid building ABS_EXPR itself as unsigned. */
6256 {
6260 {
6263 }
6265 }
6266 /* If the constant is negative, we cannot simplify this. */
6269 /* FALLTHROUGH */
6271 /* For division and modulus, type can't be unsigned, as e.g.
6272 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6273 For signed types, even with wrapping overflow, this is fine. */
6282 /* If widening the type changes the signedness, then we can't perform
6283 this optimization as that changes the result. */
6287 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6293 {
6300 }
6304 /* If the second operand is constant, this is a multiplication
6305 or floor division, by a power of two, so we can treat it that
6306 way unless the multiplier or divisor overflows. Signed
6307 left-shift overflow is implementation-defined rather than
6308 undefined in C90, so do not convert signed left shift into
6309 multiplication. */
6312 /* const_binop may not detect overflow correctly,
6313 so check for it explicitly here. */
6322 ctype,
6324 t1),
6329 /* See if we can eliminate the operation on both sides. If we can, we
6330 can return a new PLUS or MINUS. If we can't, the only remaining
6331 cases where we can do anything are if the second operand is a
6332 constant. */
6339 /* If not multiplication, we can only do this if both operands
6340 are divisible by c. */
6343 {
6348 }
6350 /* If this was a subtraction, negate OP1 and set it to be an addition.
6351 This simplifies the logic below. */
6353 {
6355 /* If OP1 was not easily negatable, the constant may be OP0. */
6357 {
6360 }
6361 }
6366 /* If either OP1 or C are negative, this optimization is not safe for
6367 some of the division and remainder types while for others we need
6368 to change the code. */
6370 {
6378 }
6380 /* If it's a multiply or a division/modulus operation of a multiple
6381 of our constant, do the operation and verify it doesn't overflow. */
6385 {
6388 /* We allow the constant to overflow with wrapping semantics. */
6392 }
6393 else
6396 /* If we have an unsigned type, we cannot widen the operation since it
6397 will change the result if the original computation overflowed. */
6401 /* The last case is if we are a multiply. In that case, we can
6402 apply the distributive law to commute the multiply and addition
6403 if the multiplication of the constants doesn't overflow
6404 and overflow is defined. With undefined overflow
6405 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
6411 op1);
6416 /* We have a special case here if we are doing something like
6417 (C * 8) % 4 since we know that's zero. */
6420 /* If the multiplication can overflow we cannot optimize this. */
6425 {
6428 }
6430 /* ... fall through ... */
6434 /* If we can extract our operation from the LHS, do so and return a
6435 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6436 do something only if the second operand is a constant. */
6452 /* If these are the same operation types, we can associate them
6453 assuming no overflow. */
6455 {
6470 }
6472 /* If these operations "cancel" each other, we have the main
6473 optimizations of this pass, which occur when either constant is a
6474 multiple of the other, in which case we replace this with either an
6475 operation or CODE or TCODE.
6477 If we have an unsigned type, we cannot do this since it will change
6478 the result if the original computation overflowed. */
6485 {
6488 {
6495 }
6498 {
6505 }
6506 }
6511 }
6514 }
6515 \f
6516 /* Return a node which has the indicated constant VALUE (either 0 or
6517 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6518 and is of the indicated TYPE. */
6520 tree
6522 {
6531 else
6533 }
6536 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6537 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6538 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6539 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6540 COND is the first argument to CODE; otherwise (as in the example
6541 given here), it is the second argument. TYPE is the type of the
6542 original expression. Return NULL_TREE if no simplification is
6543 possible. */
6545 static tree
6550 {
6560 {
6564 /* If this operand throws an expression, then it does not make
6565 sense to try to perform a logical or arithmetic operation
6566 involving it. */
6571 }
6574 {
6579 }
6580 else
6581 /* Detect the case of mixing vector and scalar types - bail out. */
6587 /* This transformation is only worthwhile if we don't have to wrap ARG
6588 in a SAVE_EXPR and the operation can be simplified without recursing
6589 on at least one of the branches once its pushed inside the COND_EXPR. */
6598 {
6602 else
6604 }
6606 {
6610 else
6612 }
6614 /* Check that we have simplified at least one of the branches. */
6619 }
6621 \f
6622 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6624 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6625 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6626 ADDEND is the same as X.
6628 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6629 and finite. The problematic cases are when X is zero, and its mode
6630 has signed zeros. In the case of rounding towards -infinity,
6631 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6632 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6634 bool
6636 {
6640 /* Don't allow the fold with -fsignaling-nans. */
6644 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6648 /* In a vector or complex, we would need to check the sign of all zeros. */
6652 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6656 /* The mode has signed zeros, and we have to honor their sign.
6657 In this situation, there is only one case we can return true for.
6658 X - 0 is the same as X unless rounding towards -infinity is
6659 supported. */
6661 }
6663 /* Subroutine of match.pd that optimizes comparisons of a division by
6664 a nonzero integer constant against an integer constant, i.e.
6665 X/C1 op C2.
6667 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6668 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
6670 enum tree_code
6673 {
6678 /* We have to do this the hard way to detect unsigned overflow.
6679 prod = int_const_binop (MULT_EXPR, c1, c2); */
6685 {
6689 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6692 }
6694 {
6697 {
6716 }
6717 }
6718 else
6719 {
6720 /* A negative divisor reverses the relational operators. */
6725 {
6744 }
6745 }
6758 }
6761 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6762 equality/inequality test, then return a simplified form of the test
6763 using a sign testing. Otherwise return NULL. TYPE is the desired
6764 result type. */
6766 static tree
6769 tree result_type)
6770 {
6771 /* If this is testing a single bit, we can optimize the test. */
6775 {
6776 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6777 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6781 /* This is only a win if casting to a signed type is cheap,
6782 i.e. when arg00's type is not a partial mode. */
6784 {
6787 result_type,
6790 }
6791 }
6794 }
6796 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6797 equality/inequality test, then return a simplified form of
6798 the test using shifts and logical operations. Otherwise return
6799 NULL. TYPE is the desired result type. */
6801 tree
6804 {
6805 /* If this is testing a single bit, we can optimize the test. */
6809 {
6818 /* First, see if we can fold the single bit test into a sign-bit
6819 test. */
6821 result_type);
6825 /* Otherwise we have (A & C) != 0 where C is a single bit,
6826 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6827 Similarly for (A & C) == 0. */
6829 /* If INNER is a right shift of a constant and it plus BITNUM does
6830 not overflow, adjust BITNUM and INNER. */
6836 {
6839 }
6841 /* If we are going to be able to omit the AND below, we must do our
6842 operations as unsigned. If we must use the AND, we have a choice.
6843 Normally unsigned is faster, but for some machines signed is. */
6861 /* Put the AND last so it can combine with more things. */
6864 /* Make sure to return the proper type. */
6868 }
6870 }
6872 /* Test whether it is preferable two swap two operands, ARG0 and
6873 ARG1, for example because ARG0 is an integer constant and ARG1
6874 isn't. */
6876 bool
6878 {
6892 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6893 for commutative and comparison operators. Ensuring a canonical
6894 form allows the optimizers to find additional redundancies without
6895 having to explicitly check for both orderings. */
6901 /* Put SSA_NAMEs last. */
6907 /* Put variables last. */
6914 }
6917 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6918 means A >= Y && A != MAX, but in this case we know that
6919 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6921 static tree
6923 {
6930 else
6939 {
6942 }
6944 {
6947 }
6948 else
6955 {
6956 /* Convert the pointer types into integer before taking the difference. */
6960 }
6961 else
6968 }
6970 /* Fold a sum or difference of at least one multiplication.
6971 Returns the folded tree or NULL if no simplification could be made. */
6973 static tree
6976 {
6980 /* (A * C) +- (B * C) -> (A+-B) * C.
6981 (A * C) +- A -> A * (C+-1).
6982 We are most concerned about the case where C is a constant,
6983 but other combinations show up during loop reduction. Since
6984 it is not difficult, try all four possibilities. */
6987 {
6990 }
6992 {
6995 }
6996 else
6997 {
6998 /* We cannot generate constant 1 for fract. */
7003 }
7005 {
7008 }
7010 {
7012 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7013 the purpose of this canonicalization. */
7017 {
7020 }
7021 else
7023 }
7024 else
7025 {
7026 /* We cannot generate constant 1 for fract. */
7031 }
7034 /* Prefer factoring a common non-constant. */
7044 /* No identical multiplicands; see if we can find a common
7045 power-of-two factor in non-power-of-two multiplies. This
7046 can help in multi-dimensional array access. */
7049 {
7052 tree maybe_same;
7056 /* Move min of absolute values to int11. */
7058 {
7063 }
7064 else
7068 /* The remainder should not be a constant, otherwise we
7069 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7070 increased the number of multiplications necessary. */
7072 {
7080 }
7081 }
7088 /* We are neither factoring zero nor minus one. */
7096 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7097 same may be minus one and thus the multiplication may overflow. Perform
7098 the sum operation in an unsigned type. */
7103 /* If the sum evaluated to a constant that is not -INF the multiplication
7104 cannot overflow. */
7111 /* Do not resort to unsigned multiplication because
7112 we lose the no-overflow property of the expression. */
7114 }
7116 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7117 specified by EXPR into the buffer PTR of length LEN bytes.
7118 Return the number of bytes placed in the buffer, or zero
7119 upon failure. */
7121 static int
7123 {
7135 /* Dry run. */
7141 {
7143 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7144 number of bytes. */
7148 {
7155 else
7157 }
7158 else
7162 }
7164 }
7167 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7168 specified by EXPR into the buffer PTR of length LEN bytes.
7169 Return the number of bytes placed in the buffer, or zero
7170 upon failure. */
7172 static int
7174 {
7178 FIXED_VALUE_TYPE value;
7193 }
7196 /* Subroutine of native_encode_expr. Encode the REAL_CST
7197 specified by EXPR into the buffer PTR of length LEN bytes.
7198 Return the number of bytes placed in the buffer, or zero
7199 upon failure. */
7201 static int
7203 {
7209 /* There are always 32 bits in each long, no matter the size of
7210 the hosts long. We handle floating point representations with
7211 up to 192 bits. */
7220 /* Dry run. */
7229 {
7234 {
7241 else
7243 }
7244 else
7245 {
7248 {
7249 /* Reverse bytes within each long, or within the entire float
7250 if it's smaller than a long (for HFmode). */
7253 }
7254 }
7259 }
7261 }
7263 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7264 specified by EXPR into the buffer PTR of length LEN bytes.
7265 Return the number of bytes placed in the buffer, or zero
7266 upon failure. */
7268 static int
7270 {
7272 tree part;
7286 }
7289 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7290 specified by EXPR into the buffer PTR of length LEN bytes.
7291 Return the number of bytes placed in the buffer, or zero
7292 upon failure. */
7294 static int
7296 {
7307 {
7309 {
7312 }
7323 }
7325 }
7328 /* Subroutine of native_encode_expr. Encode the STRING_CST
7329 specified by EXPR into the buffer PTR of length LEN bytes.
7330 Return the number of bytes placed in the buffer, or zero
7331 upon failure. */
7333 static int
7335 {
7338 /* Wide-char strings are encoded in target byte-order so native
7339 encoding them is trivial. */
7354 {
7357 {
7360 }
7363 }
7364 else
7367 }
7370 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7371 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7372 buffer PTR of length LEN bytes. If PTR is NULL, don't actually store
7373 anything, just do a dry run. If OFF is not -1 then start
7374 the encoding at byte offset OFF and encode at most LEN bytes.
7375 Return the number of bytes placed in the buffer, or zero upon failure. */
7377 int
7379 {
7380 /* We don't support starting at negative offset and -1 is special. */
7385 {
7406 }
7407 }
7410 /* Subroutine of native_interpret_expr. Interpret the contents of
7411 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7412 If the buffer cannot be interpreted, return NULL_TREE. */
7414 static tree
7416 {
7426 }
7429 /* Subroutine of native_interpret_expr. Interpret the contents of
7430 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7431 If the buffer cannot be interpreted, return NULL_TREE. */
7433 static tree
7435 {
7438 double_int result;
7439 FIXED_VALUE_TYPE fixed_value;
7449 }
7452 /* Subroutine of native_interpret_expr. Interpret the contents of
7453 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7454 If the buffer cannot be interpreted, return NULL_TREE. */
7456 static tree
7458 {
7462 /* There are always 32 bits in each long, no matter the size of
7463 the hosts long. We handle floating point representations with
7464 up to 192 bits. */
7465 REAL_VALUE_TYPE r;
7475 {
7476 /* Both OFFSET and BYTE index within a long;
7477 bitpos indexes the whole float. */
7480 {
7487 else
7489 }
7490 else
7491 {
7494 {
7495 /* Reverse bytes within each long, or within the entire float
7496 if it's smaller than a long (for HFmode). */
7499 }
7500 }
7504 }
7508 }
7511 /* Subroutine of native_interpret_expr. Interpret the contents of
7512 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7513 If the buffer cannot be interpreted, return NULL_TREE. */
7515 static tree
7517 {
7532 }
7535 /* Subroutine of native_interpret_expr. Interpret the contents of
7536 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7537 If the buffer cannot be interpreted, return NULL_TREE. */
7539 static tree
7541 {
7554 {
7559 }
7561 }
7564 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7565 the buffer PTR of length LEN as a constant of type TYPE. For
7566 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7567 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7568 return NULL_TREE. */
7570 tree
7572 {
7574 {
7596 }
7597 }
7599 /* Returns true if we can interpret the contents of a native encoding
7600 as TYPE. */
7602 static bool
7604 {
7606 {
7619 }
7620 }
7623 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7624 TYPE at compile-time. If we're unable to perform the conversion
7625 return NULL_TREE. */
7627 static tree
7629 {
7630 /* We support up to 512-bit values (for V8DFmode). */
7634 /* Check that the host and target are sane. */
7643 }
7645 /* Build an expression for the address of T. Folds away INDIRECT_REF
7646 to avoid confusing the gimplify process. */
7648 tree
7650 {
7651 /* The size of the object is not relevant when talking about its address. */
7656 {
7661 }
7671 {
7676 }
7677 else
7681 }
7683 /* Build an expression for the address of T. */
7685 tree
7687 {
7691 }
7693 /* Fold a unary expression of code CODE and type TYPE with operand
7694 OP0. Return the folded expression if folding is successful.
7695 Otherwise, return NULL_TREE. */
7697 tree
7699 {
7700 tree tem;
7701 tree arg0;
7709 {
7712 {
7713 /* Don't use STRIP_NOPS, because signedness of argument type
7714 matters. */
7716 }
7717 else
7718 {
7719 /* Strip any conversions that don't change the mode. This
7720 is safe for every expression, except for a comparison
7721 expression because its signedness is derived from its
7722 operands.
7724 Note that this is done as an internal manipulation within
7725 the constant folder, in order to find the simplest
7726 representation of the arguments so that their form can be
7727 studied. In any cases, the appropriate type conversions
7728 should be put back in the tree that will get out of the
7729 constant folder. */
7731 }
7734 {
7737 {
7741 }
7742 }
7743 }
7750 {
7757 {
7771 /* If this was a conversion, and all we did was to move into
7772 inside the COND_EXPR, bring it back out. But leave it if
7773 it is a conversion from integer to integer and the
7774 result precision is no wider than a word since such a
7775 conversion is cheap and may be optimized away by combine,
7776 while it couldn't if it were outside the COND_EXPR. Then return
7777 so we don't get into an infinite recursion loop taking the
7778 conversion out and then back in. */
7790 && (INTEGRAL_TYPE_P
7803 }
7804 }
7807 {
7813 CASE_CONVERT:
7817 {
7818 /* If we have (type) (a CMP b) and type is an integral type, return
7819 new expression involving the new type. Canonicalize
7820 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7821 non-integral type.
7822 Do not fold the result as that would not simplify further, also
7823 folding again results in recursions. */
7833 }
7835 /* Handle (T *)&A.B.C for A being of type T and B and C
7836 living at offset zero. This occurs frequently in
7837 C++ upcasting and then accessing the base. */
7841 {
7843 tree offset;
7844 machine_mode mode;
7846 tree base
7850 /* If the reference was to a (constant) zero offset, we can use
7851 the address of the base if it has the same base type
7852 as the result type and the pointer type is unqualified. */
7860 }
7864 /* Detect assigning a bitfield. */
7866 && DECL_BIT_FIELD
7868 {
7869 /* Don't leave an assignment inside a conversion
7870 unless assigning a bitfield. */
7872 /* First do the assignment, then return converted constant. */
7877 }
7879 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7880 constants (if x has signed type, the sign bit cannot be set
7881 in c). This folds extension into the BIT_AND_EXPR.
7882 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7883 very likely don't have maximal range for their precision and this
7884 transformation effectively doesn't preserve non-maximal ranges. */
7888 {
7899 <= HOST_BITS_PER_WIDE_INT
7901 {
7905 cst &= HOST_WIDE_INT_M1U
7909 && !flag_syntax_only
7912 {
7916 }
7917 }
7919 {
7924 }
7925 }
7927 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
7928 cast (T1)X will fold away. We assume that this happens when X itself
7929 is a cast. */
7933 {
7937 return fold_build_pointer_plus_loc
7939 }
7941 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7942 of the same precision, and X is an integer type not narrower than
7943 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7949 {
7955 }
7957 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7958 type of X and Y (integer types only). */
7963 {
7964 /* Be careful not to introduce new overflows. */
7965 tree mult_type;
7968 else
7972 {
7979 }
7980 }
7986 {
7993 }
8004 /* Convert fabs((double)float) into (double)fabsf(float). */
8007 {
8013 targ0));
8014 }
8018 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8037 /* Note that the operand of this must be an int
8038 and its values must be 0 or 1.
8039 ("true" is a fixed value perhaps depending on the language,
8040 but we don't handle values other than 1 correctly yet.) */
8047 /* Fold *&X to X if X is an lvalue. */
8049 {
8056 }
8062 }
8065 /* If the operation was a conversion do _not_ mark a resulting constant
8066 with TREE_OVERFLOW if the original constant was not. These conversions
8067 have implementation defined behavior and retaining the TREE_OVERFLOW
8068 flag here would confuse later passes such as VRP. */
8069 tree
8072 {
8081 }
8083 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
8084 operands OP0 and OP1. LOC is the location of the resulting expression.
8085 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
8086 Return the folded expression if folding is successful. Otherwise,
8087 return NULL_TREE. */
8088 static tree
8091 {
8092 tree tem;
8094 /* We only do these simplifications if we are optimizing. */
8098 /* Check for things like (A || B) && (A || C). We can convert this
8099 to A || (B && C). Note that either operator can be any of the four
8100 truth and/or operations and the transformation will still be
8101 valid. Also note that we only care about order for the
8102 ANDIF and ORIF operators. If B contains side effects, this
8103 might change the truth-value of A. */
8110 {
8130 /* This case if tricky because we must either have commutative
8131 operators or else A10 must not have side-effects. */
8137 a01);
8138 }
8140 /* See if we can build a range comparison. */
8146 {
8150 }
8154 {
8158 }
8160 /* Check for the possibility of merging component references. If our
8161 lhs is another similar operation, try to merge its rhs with our
8162 rhs. Then try to merge our lhs and rhs. */
8173 logical_op_non_short_circuit
8176 && !flag_sanitize_coverage
8181 {
8188 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8189 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8190 We don't want to pack more than two leafs to a non-IF AND/OR
8191 expression.
8192 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8193 equal to IF-CODE, then we don't want to add right-hand operand.
8194 If the inner right-hand side of left-hand operand has
8195 side-effects, or isn't simple, then we can't add to it,
8196 as otherwise we might destroy if-sequence. */
8199 /* Needed for sequence points to handle trappings, and
8200 side-effects. */
8202 {
8204 arg1);
8206 tem);
8207 }
8208 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8209 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8212 /* Needed for sequence points to handle trappings, and
8213 side-effects. */
8215 {
8220 }
8221 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8222 into (A OR B).
8223 For sequence point consistancy, we need to check for trapping,
8224 and side-effects. */
8228 }
8231 }
8233 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8234 by changing CODE to reduce the magnitude of constants involved in
8235 ARG0 of the comparison.
8236 Returns a canonicalized comparison tree if a simplification was
8237 possible, otherwise returns NULL_TREE.
8238 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8239 valid if signed overflow is undefined. */
8241 static tree
8245 {
8250 /* Match A +- CST code arg1. We can change this only if overflow
8251 is undefined. */
8254 /* In principle pointers also have undefined overflow behavior,
8255 but that causes problems elsewhere. */
8262 /* Identify the constant in arg0 and its sign. */
8266 /* Overflowed constants and zero will cause problems. */
8271 /* See if we can reduce the magnitude of the constant in
8272 arg0 by changing the comparison code. */
8273 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8277 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8281 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8285 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8289 else
8293 /* Now build the constant reduced in magnitude. But not if that
8294 would produce one outside of its types range. */
8310 }
8312 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8313 overflow further. Try to decrease the magnitude of constants involved
8314 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8315 and put sole constants at the second argument position.
8316 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8318 static tree
8321 {
8322 tree t;
8327 /* Try canonicalization by simplifying arg0. */
8332 {
8336 }
8338 /* Try canonicalization by simplifying arg1 using the swapped
8339 comparison. */
8347 }
8349 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8350 space. This is used to avoid issuing overflow warnings for
8351 expressions like &p->x which can not wrap. */
8353 static bool
8355 {
8362 poly_wide_int wi_offset;
8368 else
8373 precision);
8388 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8389 array. */
8398 }
8400 /* Return a positive integer when the symbol DECL is known to have
8401 a nonzero address, zero when it's known not to (e.g., it's a weak
8402 symbol), and a negative integer when the symbol is not yet in the
8403 symbol table and so whether or not its address is zero is unknown.
8404 For function local objects always return positive integer. */
8405 static int
8407 {
8412 /* Function local objects are never NULL. */
8420 }
8422 /* Subroutine of fold_binary. This routine performs all of the
8423 transformations that are common to the equality/inequality
8424 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8425 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8426 fold_binary should call fold_binary. Fold a comparison with
8427 tree code CODE and type TYPE with operands OP0 and OP1. Return
8428 the folded comparison or NULL_TREE. */
8430 static tree
8433 {
8443 /* For comparisons of pointers we can decompose it to a compile time
8444 comparison of the base objects and the offsets into the object.
8445 This requires at least one operand being an ADDR_EXPR or a
8446 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8452 {
8455 machine_mode mode;
8459 /* Get base and offset for the access. Strip ADDR_EXPR for
8460 get_inner_reference, but put it back by stripping INDIRECT_REF
8461 off the base object if possible. indirect_baseN will be true
8462 if baseN is not an address but refers to the object itself. */
8465 {
8466 base0
8472 else
8474 }
8476 {
8480 {
8481 base0
8487 else
8489 }
8492 else
8496 {
8503 }
8504 }
8508 {
8509 base1
8515 else
8517 }
8519 {
8523 {
8524 base1
8530 else
8532 }
8535 else
8539 {
8546 }
8547 }
8549 /* If we have equivalent bases we might be able to simplify. */
8553 {
8554 /* We can fold this expression to a constant if the non-constant
8555 offset parts are equal. */
8559 && (equality_code
8560 || (indirect_base0
8563 {
8569 "occur when comparing P +- C1 with "
8571 WARN_STRICT_OVERFLOW_CONDITIONAL);
8574 {
8612 }
8613 }
8614 /* We can simplify the comparison to a comparison of the variable
8615 offset parts if the constant offset parts are equal.
8616 Be careful to use signed sizetype here because otherwise we
8617 mess with array offsets in the wrong way. This is possible
8618 because pointer arithmetic is restricted to retain within an
8619 object and overflow on pointer differences is undefined as of
8620 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8622 && (equality_code
8623 || (indirect_base0
8626 {
8627 /* By converting to signed sizetype we cover middle-end pointer
8628 arithmetic which operates on unsigned pointer types of size
8629 type size and ARRAY_REF offsets which are properly sign or
8630 zero extended from their type in case it is narrower than
8631 sizetype. */
8634 else
8638 else
8645 "occur when comparing P +- C1 with "
8647 WARN_STRICT_OVERFLOW_COMPARISON);
8650 }
8651 }
8652 /* For equal offsets we can simplify to a comparison of the
8653 base addresses. */
8655 && (indirect_base0
8657 && (indirect_base1
8662 {
8668 }
8669 /* Comparison between an ordinary (non-weak) symbol and a null
8670 pointer can be eliminated since such symbols must have a non
8671 null address. In C, relational expressions between pointers
8672 to objects and null pointers are undefined. The results
8673 below follow the C++ rules with the additional property that
8674 every object pointer compares greater than a null pointer.
8675 */
8678 /* Avoid folding references to struct members at offset 0 to
8679 prevent tests like '&ptr->firstmember == 0' from getting
8680 eliminated. When ptr is null, although the -> expression
8681 is strictly speaking invalid, GCC retains it as a matter
8682 of QoI. See PR c/44555. */
8685 && indirect_base0
8686 /* The caller guarantees that when one of the arguments is
8687 constant (i.e., null in this case) it is second. */
8689 {
8691 {
8702 }
8703 }
8704 }
8706 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8707 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8708 the resulting offset is smaller in absolute value than the
8709 original one and has the same sign. */
8718 {
8723 tree cst;
8725 "occur when combining constants around "
8728 /* Put the constant on the side where it doesn't overflow and is
8729 of lower absolute value and of same sign than before. */
8736 {
8739 variable1,
8743 }
8751 {
8757 variable2);
8758 }
8759 }
8765 /* If we are comparing an expression that just has comparisons
8766 of two integer values, arithmetic expressions of those comparisons,
8767 and constants, we can simplify it. There are only three cases
8768 to check: the two values can either be equal, the first can be
8769 greater, or the second can be greater. Fold the expression for
8770 those three values. Since each value must be 0 or 1, we have
8771 eight possibilities, each of which corresponds to the constant 0
8772 or 1 or one of the six possible comparisons.
8774 This handles common cases like (a > b) == 0 but also handles
8775 expressions like ((x > y) - (y > x)) > 0, which supposedly
8776 occur in macroized code. */
8779 {
8783 /* Don't handle degenerate cases here; they should already
8784 have been handled anyway. */
8793 {
8797 /* We can't just pass T to eval_subst in case cval1 or cval2
8798 was the same as ARG1. */
8800 tree high_result
8804 arg1);
8805 tree equal_result
8809 arg1);
8810 tree low_result
8814 arg1);
8816 /* All three of these results should be 0 or 1. Confirm they are.
8817 Then use those values to select the proper code to use. */
8822 {
8823 /* Make a 3-bit mask with the high-order bit being the
8824 value for `>', the next for '=', and the low for '<'. */
8828 {
8830 /* Always false. */
8851 /* Always true. */
8853 }
8856 }
8857 }
8858 }
8861 }
8864 /* Subroutine of fold_binary. Optimize complex multiplications of the
8865 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
8866 argument EXPR represents the expression "z" of type TYPE. */
8868 static tree
8870 {
8875 {
8878 }
8880 {
8883 }
8884 else
8885 {
8889 }
8898 }
8901 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
8902 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
8903 true if successful. */
8905 static bool
8907 {
8912 {
8915 }
8917 {
8923 else
8925 }
8926 else
8932 }
8934 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
8935 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
8936 NULL_TREE otherwise. */
8938 static tree
8940 {
8961 {
8962 HOST_WIDE_INT index;
8968 }
8971 {
8977 }
8978 else
8980 }
8982 /* Try to fold a pointer difference of type TYPE two address expressions of
8983 array references AREF0 and AREF1 using location LOC. Return a
8984 simplified expression for the difference or NULL_TREE. */
8986 static tree
8990 {
8995 /* If the bases are array references as well, recurse. If the bases
8996 are pointer indirections compute the difference of the pointers.
8997 If the bases are equal, we are set. */
9000 && (base_offset
9002 use_pointer_diff)))
9005 && (base_offset
9006 = use_pointer_diff
9016 {
9022 base_offset,
9025 }
9027 }
9029 /* If the real or vector real constant CST of type TYPE has an exact
9030 inverse, return it, else return NULL. */
9032 tree
9034 {
9035 REAL_VALUE_TYPE r;
9036 tree unit_type;
9037 machine_mode mode;
9040 {
9050 {
9054 tree_vector_builder elts;
9059 {
9064 }
9067 }
9071 }
9072 }
9074 /* Mask out the tz least significant bits of X of type TYPE where
9075 tz is the number of trailing zeroes in Y. */
9076 static wide_int
9078 {
9083 }
9085 /* Return true when T is an address and is known to be nonzero.
9086 For floating point we further ensure that T is not denormal.
9087 Similar logic is present in nonzero_address in rtlanal.h.
9089 If the return value is based on the assumption that signed overflow
9090 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
9091 change *STRICT_OVERFLOW_P. */
9093 static bool
9095 {
9099 /* Doing something useful for floating point would need more work. */
9105 {
9108 strict_overflow_p);
9114 strict_overflow_p);
9122 }
9125 {
9128 strict_overflow_p);
9136 strict_overflow_p);
9151 strict_overflow_p);
9155 strict_overflow_p);
9158 {
9170 }
9174 }
9176 }
9178 /* Return true when T is an address and is known to be nonzero.
9179 Handle warnings about undefined signed overflow. */
9181 bool
9183 {
9190 "determining that expression is always "
9192 WARN_STRICT_OVERFLOW_MISC);
9194 }
9196 /* Return true if T is known not to be equal to an integer W. */
9198 bool
9200 {
9202 value_range_type rtype;
9204 {
9213 {
9218 }
9223 /* If T has some known zero bits and W has any of those bits set,
9224 then T is known not to be equal to W. */
9232 }
9233 }
9235 /* Fold a binary expression of code CODE and type TYPE with operands
9236 OP0 and OP1. LOC is the location of the resulting expression.
9237 Return the folded expression if folding is successful. Otherwise,
9238 return NULL_TREE. */
9240 tree
9243 {
9258 /* Strip any conversions that don't change the mode. This is
9259 safe for every expression, except for a comparison expression
9260 because its signedness is derived from its operands. So, in
9261 the latter case, only strip conversions that don't change the
9262 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9263 preserved.
9265 Note that this is done as an internal manipulation within the
9266 constant folder, in order to find the simplest representation
9267 of the arguments so that their form can be studied. In any
9268 cases, the appropriate type conversions should be put back in
9269 the tree that will get out of the constant folder. */
9272 {
9275 }
9276 else
9277 {
9280 }
9282 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9283 constant but we can't do arithmetic on them. */
9285 {
9288 {
9292 }
9293 }
9295 /* If this is a commutative operation, and ARG0 is a constant, move it
9296 to ARG1 to reduce the number of tests below. */
9301 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9302 to ARG1 to reduce the number of tests below. */
9311 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9313 First check for cases where an arithmetic operation is applied to a
9314 compound, conditional, or comparison operation. Push the arithmetic
9315 operation inside the compound or conditional to see if any folding
9316 can then be done. Convert comparison to conditional for this purpose.
9317 The also optimizes non-constant cases that used to be done in
9318 expand_expr.
9320 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9321 one of the operands is a comparison and the other is a comparison, a
9322 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9323 code below would make the expression more complex. Change it to a
9324 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9325 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9338 {
9342 boolean_type_node,
9350 }
9354 {
9356 {
9361 tem);
9362 }
9364 {
9369 tem);
9370 }
9375 {
9381 }
9386 {
9392 }
9393 }
9396 {
9398 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9401 {
9407 }
9409 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9412 {
9413 tree base;
9414 poly_int64 coffset;
9423 }
9428 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9434 arg1),
9436 arg0)));
9442 {
9443 /* X + (X / CST) * -CST is X % CST. */
9448 {
9457 cst0));
9458 }
9459 }
9461 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9462 one. Make sure the type is not saturating and has the signedness of
9463 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9464 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9471 {
9475 }
9478 {
9479 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9480 (plus (plus (mult) (mult)) (foo)) so that we can
9481 take advantage of the factoring cases below. */
9490 {
9496 else
9509 parg0),
9511 marg)),
9515 return
9521 parg1)));
9522 }
9523 }
9524 else
9525 {
9526 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9527 to __complex__ ( x, y ). This is not the same for SNaNs or
9528 if signed zeros are involved. */
9532 {
9539 {
9543 {
9549 }
9551 {
9557 }
9558 }
9559 }
9561 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9562 We associate floats only if the user has specified
9563 -fassociative-math. */
9567 {
9572 {
9573 tree tree0;
9576 }
9577 }
9578 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9579 We associate floats only if the user has specified
9580 -fassociative-math. */
9584 {
9589 {
9590 tree tree0;
9593 }
9594 }
9595 }
9597 bit_rotate:
9598 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9599 is a rotate of A by C1 bits. */
9600 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9601 is a rotate of A by B bits.
9602 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
9603 though in this case CODE must be | and not + or ^, otherwise
9604 it doesn't return A when B is 0. */
9605 {
9607 tree rtype;
9616 /* Only create rotates in complete modes. Other cases are not
9617 expanded properly. */
9620 {
9633 {
9638 }
9643 {
9646 code0 == LSHIFT_EXPR
9649 }
9651 {
9661 {
9665 orig_tree01);
9667 }
9668 }
9672 {
9683 {
9687 orig_tree01);
9689 }
9690 }
9691 }
9692 }
9694 associate:
9695 /* In most languages, can't associate operations on floats through
9696 parentheses. Rather than remember where the parentheses were, we
9697 don't associate floats at all, unless the user has specified
9698 -fassociative-math.
9699 And, we need to make sure type is not saturating. */
9703 {
9709 /* Split both trees into variables, constants, and literals. Then
9710 associate each group together, the constants with literals,
9711 then the result with variables. This increases the chances of
9712 literals being recombined later and of generating relocatable
9713 expressions for the sum of a constant and literal. */
9721 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9725 /* With undefined overflow prefer doing association in a type
9726 which wraps on overflow, if that is one of the operand types. */
9729 {
9737 }
9739 /* With undefined overflow we can only associate constants with one
9740 variable, and constants whose association doesn't overflow. */
9743 {
9745 {
9746 /* ??? If split_tree would handle NEGATE_EXPR we could
9747 simply reject these cases and the allowed cases would
9748 be the var0/minus_var1 ones. */
9754 {
9757 }
9764 {
9767 }
9773 /* The only case we can still associate with two variables
9774 is if they cancel out. */
9778 }
9784 }
9786 /* Only do something if we found more than two objects. Otherwise,
9787 nothing has changed and we risk infinite recursion. */
9795 {
9807 {
9811 }
9813 {
9817 }
9819 /* Preserve the MINUS_EXPR if the negative part of the literal is
9820 greater than the positive part. Otherwise, the multiplicative
9821 folding code (i.e extract_muldiv) may be fooled in case
9822 unsigned constants are subtracted, like in the following
9823 example: ((X*2 + 4) - 8U)/2. */
9825 {
9829 /* But avoid ending up with only negated parts. */
9831 {
9835 }
9836 else
9837 {
9841 }
9842 }
9844 /* Don't introduce overflows through reassociation. */
9849 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
9856 /* Eliminate minus_con0. */
9858 {
9865 else
9868 }
9870 /* Eliminate minus_var0. */
9872 {
9876 else
9879 }
9881 return
9884 }
9885 }
9891 /* Fold &a[i] - &a[j] to i-j. */
9896 {
9900 code
9904 }
9906 /* Further transformations are not for pointers. */
9910 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9913 /* If arg0 is e.g. unsigned int and type is int, then this could
9914 introduce UB, because if A is INT_MIN at runtime, the original
9915 expression can be well defined while the latter is not.
9916 See PR83269. */
9925 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
9926 __complex__ ( x, -y ). This is not the same for SNaNs or if
9927 signed zeros are involved. */
9931 {
9938 {
9942 {
9944 arg1r ? arg1r
9949 }
9951 {
9955 arg1i ? arg1i
9958 }
9959 }
9960 }
9962 /* A - B -> A + (-B) if B is easily negatable. */
9966 /* Avoid this transformation if B is a positive REAL_CST. */
9974 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
9975 one. Make sure the type is not saturating and has the signedness of
9976 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9977 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9984 {
9988 }
9994 {
9995 /* Transform x * -C into -x * C if x is easily negatable. */
10010 {
10013 "occur when simplifying "
10015 WARN_STRICT_OVERFLOW_MISC);
10017 }
10019 /* Optimize z * conj(z) for integer complex numbers. */
10026 }
10027 else
10028 {
10029 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10030 This is not the same for NaNs or if signed zeros are
10031 involved. */
10037 {
10040 return
10046 return
10051 }
10053 /* Optimize z * conj(z) for floating point complex numbers.
10054 Guarded by flag_unsafe_math_optimizations as non-finite
10055 imaginary components don't produce scalar results. */
10064 }
10068 /* Canonicalize (X & C1) | C2. */
10072 {
10077 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10085 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10087 {
10090 }
10092 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10093 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10094 mode which allows further optimizations. */
10099 {
10104 {
10107 }
10108 }
10111 {
10116 }
10117 }
10119 /* See if this can be simplified into a rotate first. If that
10120 is unsuccessful continue in the association code. */
10124 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10132 /* See if this can be simplified into a rotate first. If that
10133 is unsuccessful continue in the association code. */
10137 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10142 {
10143 tree tem2;
10150 }
10151 /* Fold ~X & 1 as (X & 1) == 0. */
10155 {
10156 tree tem2;
10163 }
10164 /* Fold !X & 1 as X == 0. */
10167 {
10171 }
10173 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
10174 multiple of 1 << CST. */
10176 {
10183 }
10185 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
10186 bits from CST2. */
10190 {
10192 wide_int masked
10199 {
10200 /* Avoid the transform if arg1 is a mask of some
10201 mode which allows further optimizations. */
10208 }
10209 }
10211 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
10212 ((A & N) + B) & M -> (A + B) & M
10213 Similarly if (N & M) == 0,
10214 ((A | N) + B) & M -> (A + B) & M
10215 and for - instead of + (or unary - instead of +)
10216 and/or ^ instead of |.
10217 If B is constant and (B & M) == 0, fold into A & M. */
10219 {
10228 {
10231 wide_int cst0;
10233 /* Now we know that arg0 is (C + D) or (C - D) or
10234 -C and arg1 (M) is == (1LL << cst) - 1.
10235 Store C into PMOP[0] and D into PMOP[1]. */
10239 {
10242 }
10249 {
10258 {
10261 }
10264 /* If C or D is of the form (A & N) where
10265 (N & M) == M, or of the form (A | N) or
10266 (A ^ N) where (N & M) == 0, replace it with A. */
10270 /* If C or D is a N where (N & M) == 0, it can be
10271 omitted (assumed 0). */
10279 }
10281 /* Only build anything new if we optimized one or both arguments
10282 above. */
10286 {
10289 {
10290 /* Perform the operations in a type that has defined
10291 overflow behavior. */
10297 }
10302 {
10310 else
10312 }
10315 else
10318 /* TEM is now the new binary +, - or unary - replacement. */
10322 }
10323 }
10324 }
10326 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10329 {
10334 return
10336 }
10341 /* Don't touch a floating-point divide by zero unless the mode
10342 of the constant can represent infinity. */
10348 /* (-A) / (-B) -> A / B */
10360 /* Fall through */
10363 /* Simplify A / (B << N) where A and B are positive and B is
10364 a power of 2, to A >> (N + log2(B)). */
10369 {
10372 {
10380 WARN_STRICT_OVERFLOW_MISC);
10386 }
10387 }
10389 /* Fall through */
10397 /* Convert -A / -B to A / B when the type is signed and overflow is
10398 undefined. */
10402 {
10405 "when distributing negation across "
10407 WARN_STRICT_OVERFLOW_MISC);
10412 }
10416 {
10419 "when distributing negation across "
10421 WARN_STRICT_OVERFLOW_MISC);
10426 }
10428 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
10429 operation, EXACT_DIV_EXPR.
10431 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
10432 At one time others generated faster code, it's not clear if they do
10433 after the last round to changes to the DIV code in expmed.c. */
10444 {
10448 WARN_STRICT_OVERFLOW_MISC);
10450 }
10462 {
10466 WARN_STRICT_OVERFLOW_MISC);
10468 }
10476 /* Since negative shift count is not well-defined,
10477 don't try to compute it in the compiler. */
10483 /* If we have a rotate of a bit operation with the rotate count and
10484 the second operand of the bit operation both constant,
10485 permute the two operations. */
10491 {
10499 }
10501 /* Two consecutive rotates adding up to the some integer
10502 multiple of the precision of the type can be ignored. */
10518 /* Note that the operands of this must be ints
10519 and their values must be 0 or 1.
10520 ("true" is a fixed value perhaps depending on the language.) */
10521 /* If first arg is constant zero, return it. */
10524 /* FALLTHRU */
10526 /* If either arg is constant true, drop it. */
10530 /* Preserve sequence points. */
10533 /* If second arg is constant zero, result is zero, but first arg
10534 must be evaluated. */
10537 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
10538 case will be handled here. */
10542 /* !X && X is always false. */
10546 /* X && !X is always false. */
10551 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
10552 means A >= Y && A != MAX, but in this case we know that
10553 A < X <= MAX. */
10557 {
10565 }
10574 /* Note that the operands of this must be ints
10575 and their values must be 0 or true.
10576 ("true" is a fixed value perhaps depending on the language.) */
10577 /* If first arg is constant true, return it. */
10580 /* FALLTHRU */
10582 /* If either arg is constant zero, drop it. */
10586 /* Preserve sequence points. */
10589 /* If second arg is constant true, result is true, but we must
10590 evaluate first arg. */
10593 /* Likewise for first arg, but note this only occurs here for
10594 TRUTH_OR_EXPR. */
10598 /* !X || X is always true. */
10602 /* X || !X is always true. */
10607 /* (X && !Y) || (!X && Y) is X ^ Y */
10610 {
10627 }
10636 /* If the second arg is constant zero, drop it. */
10639 /* If the second arg is constant true, this is a logical inversion. */
10641 {
10644 }
10645 /* Identical arguments cancel to zero. */
10649 /* !X ^ X is always true. */
10654 /* X ^ !X is always true. */
10670 /* bool_var != 1 becomes !bool_var. */
10677 /* bool_var == 0 becomes !bool_var. */
10684 /* !exp != 0 becomes !exp */
10689 /* If this is an EQ or NE comparison with zero and ARG0 is
10690 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
10691 two operations, but the latter can be done in one less insn
10692 on machines that have only two-operand insns or on which a
10693 constant cannot be the first operand. */
10696 {
10701 {
10708 arg1);
10709 }
10712 {
10719 arg1);
10720 }
10721 }
10723 /* If this is an NE or EQ comparison of zero against the result of a
10724 signed MOD operation whose second operand is a power of 2, make
10725 the MOD operation unsigned since it is simpler and equivalent. */
10733 {
10743 }
10745 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
10746 C1 is a valid shift constant, and C2 is a power of two, i.e.
10747 a single bit. */
10751 == INTEGER_CST
10754 {
10759 /* Check for a valid shift count. */
10761 {
10765 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
10766 can be rewritten as (X & (C2 << C1)) != 0. */
10768 {
10773 }
10774 /* Otherwise, for signed (arithmetic) shifts,
10775 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
10776 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
10780 /* Otherwise, of unsigned (logical) shifts,
10781 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
10782 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
10783 else
10787 arg000);
10788 }
10789 }
10791 /* If this is a comparison of a field, we may be able to simplify it. */
10794 /* Handle the constant case even without -O
10795 to make sure the warnings are given. */
10797 {
10801 }
10803 /* Optimize comparisons of strlen vs zero to a compare of the
10804 first character of the string vs zero. To wit,
10805 strlen(ptr) == 0 => *ptr == 0
10806 strlen(ptr) != 0 => *ptr != 0
10807 Other cases should reduce to one of these two (or a constant)
10808 due to the return value of strlen being unsigned. */
10810 {
10819 {
10820 tree ptrtype
10822 TYPE_QUAL_CONST));
10828 }
10829 }
10831 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
10832 of X. Similarly fold (X >> C) == 0 into X >= 0. */
10836 {
10841 {
10843 {
10846 }
10849 }
10850 }
10852 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
10853 (X & C) == 0 when C is a single bit. */
10858 {
10865 arg1));
10866 }
10868 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
10869 constant C is a power of two, i.e. a single bit. */
10876 {
10880 }
10882 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
10883 when is C is a power of two, i.e. a single bit. */
10890 {
10896 }
10900 {
10903 }
10905 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
10908 {
10916 {
10922 }
10924 {
10930 }
10932 {
10938 }
10940 {
10946 }
10947 }
10951 {
10958 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
10959 operand_equal_p guarantees no side-effects so we don't need
10960 to use omit_one_operand on Z. */
10964 arg10));
10968 arg11));
10972 arg10));
10976 arg11));
10978 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
10981 {
10987 }
10988 }
10990 /* Attempt to simplify equality/inequality comparisons of complex
10991 values. Only lower the comparison if the result is known or
10992 can be simplified to a single scalar comparison. */
10997 {
11002 {
11005 }
11006 else
11007 {
11010 }
11013 {
11016 }
11017 else
11018 {
11021 }
11025 {
11027 {
11032 }
11033 else
11034 {
11039 }
11040 }
11044 {
11046 {
11051 }
11052 else
11053 {
11058 }
11059 }
11060 }
11072 /* Transform comparisons of the form X +- C CMP X. */
11077 {
11082 /* (X - c) > X becomes false. */
11088 /* Likewise (X + c) < X becomes false. */
11094 /* Convert (X - c) <= X to true. */
11101 /* Convert (X + c) >= X to true. */
11107 }
11109 /* If we are comparing an ABS_EXPR with a constant, we can
11110 convert all the cases into explicit comparisons, but they may
11111 well not be faster than doing the ABS and one comparison.
11112 But ABS (X) <= C is a range comparison, which becomes a subtraction
11113 and a comparison, and is probably faster. */
11127 /* Convert ABS_EXPR<x> >= 0 to true. */
11134 {
11137 "when simplifying comparison of "
11139 WARN_STRICT_OVERFLOW_CONDITIONAL);
11142 arg0);
11143 }
11145 /* Convert ABS_EXPR<x> < 0 to false. */
11150 {
11153 "when simplifying comparison of "
11155 WARN_STRICT_OVERFLOW_CONDITIONAL);
11158 arg0);
11159 }
11161 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
11162 and similarly for >= into !=. */
11172 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
11173 otherwise Y might be >= # of bits in X's type and thus e.g.
11174 (unsigned char) (1 << Y) for Y 15 might be 0.
11175 If the cast is widening, then 1 << Y should have unsigned type,
11176 otherwise if Y is number of bits in the signed shift type minus 1,
11177 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
11178 31 might be 0xffffffff80000000. */
11189 {
11195 }
11207 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
11208 {
11220 }
11225 /* When pedantic, a compound expression can be neither an lvalue
11226 nor an integer constant expression. */
11229 /* Don't let (0, 0) be null pointer constant. */
11235 /* An ASSERT_EXPR should never be passed to fold_binary. */
11241 }
11243 /* Used by contains_label_[p1]. */
11245 struct contains_label_data
11246 {
11249 };
11251 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
11252 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
11253 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
11255 static tree
11257 {
11260 {
11271 {
11279 }
11288 }
11289 }
11291 /* Return whether the sub-tree ST contains a label which is accessible from
11292 outside the sub-tree. */
11294 static bool
11296 {
11300 }
11302 /* Fold a ternary expression of code CODE and type TYPE with operands
11303 OP0, OP1, and OP2. Return the folded expression if folding is
11304 successful. Otherwise, return NULL_TREE. */
11306 tree
11309 {
11310 tree tem;
11317 /* If this is a commutative operation, and OP0 is a constant, move it
11318 to OP1 to reduce the number of tests below. */
11327 /* Strip any conversions that don't change the mode. This is safe
11328 for every expression, except for a comparison expression because
11329 its signedness is derived from its operands. So, in the latter
11330 case, only strip conversions that don't change the signedness.
11332 Note that this is done as an internal manipulation within the
11333 constant folder, in order to find the simplest representation of
11334 the arguments so that their form can be studied. In any cases,
11335 the appropriate type conversions should be put back in the tree
11336 that will get out of the constant folder. */
11338 {
11341 }
11344 {
11347 }
11350 {
11353 }
11356 {
11360 {
11366 }
11371 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
11372 so all simple results must be passed through pedantic_non_lvalue. */
11374 {
11377 /* Only optimize constant conditions when the selected branch
11378 has the same type as the COND_EXPR. This avoids optimizing
11379 away "c ? x : throw", where the throw has a void type.
11380 Avoid throwing away that operand which contains label. */
11387 }
11389 {
11396 {
11399 {
11407 }
11412 }
11413 }
11415 /* If we have A op B ? A : C, we may be able to convert this to a
11416 simpler expression, depending on the operation and the values
11417 of B and C. Signed zeros prevent all of these transformations,
11418 for reasons given above each one.
11420 Also try swapping the arguments and inverting the conditional. */
11424 {
11428 }
11433 {
11437 {
11441 }
11442 }
11444 /* If the second operand is simpler than the third, swap them
11445 since that produces better jump optimization results. */
11448 {
11450 /* See if this can be inverted. If it can't, possibly because
11451 it was a floating-point inequality comparison, don't do
11452 anything. */
11456 }
11458 /* Convert A ? 1 : 0 to simply A. */
11463 /* If we try to convert OP0 to our type, the
11464 call to fold will try to move the conversion inside
11465 a COND, which will recurse. In that case, the COND_EXPR
11466 is probably the best choice, so leave it alone. */
11470 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
11471 over COND_EXPR in cases such as floating point comparisons. */
11480 arg0)));
11482 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
11487 {
11488 /* sign_bit_p looks through both zero and sign extensions,
11489 but for this optimization only sign extensions are
11490 usable. */
11493 {
11496 {
11499 }
11501 }
11502 /* sign_bit_p only checks ARG1 bits within A's precision.
11503 If <sign bit of A> has wider type than A, bits outside
11504 of A's precision in <sign bit of A> need to be checked.
11505 If they are all 0, this optimization needs to be done
11506 in unsigned A's type, if they are all 1 in signed A's type,
11507 otherwise this can't be done. */
11513 {
11515 tree tem_type;
11528 {
11531 }
11533 {
11536 }
11537 else
11539 }
11542 return
11548 arg1)));
11549 }
11551 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
11552 already handled above. */
11557 {
11567 op1);
11568 }
11570 /* A & N ? N : 0 is simply A & N if N is a power of two. This
11571 is probably obsolete because the first operand should be a
11572 truth value (that's why we have the two cases above), but let's
11573 leave it in until we can confirm this for all front-ends. */
11581 /* operand_equal_p compares just value, not precision, so e.g.
11582 arg1 could be 8-bit -128 and be power of two, but BIT_AND_EXPR
11583 second operand 32-bit -128, which is not a power of two (or vice
11584 versa. */
11591 /* Disable the transformations below for vectors, since
11592 fold_binary_op_with_conditional_arg may undo them immediately,
11593 yielding an infinite loop. */
11597 /* Convert A ? B : 0 into A && B if A and B are truth values. */
11606 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
11611 {
11613 /* Only perform transformation if ARG0 is easily inverted. */
11617 ? BIT_IOR_EXPR
11620 op1);
11621 }
11623 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
11628 {
11630 /* Only perform transformation if ARG0 is easily inverted. */
11636 op2);
11637 }
11639 /* Convert A ? 1 : B into A || B if A and B are truth values. */
11651 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
11652 of fold_ternary on them. */
11662 {
11673 {
11678 {
11680 {
11685 }
11691 }
11692 }
11693 }
11695 /* On constants we can use native encode/interpret to constant
11696 fold (nearly) all BIT_FIELD_REFs. */
11702 {
11705 /* Limit us to a reasonable amount of work. To relax the
11706 other limitations we need bit-shifting of the buffer
11707 and rounding up the size. */
11711 {
11713 unsigned HOST_WIDE_INT len
11718 {
11723 }
11724 }
11725 }
11730 /* For integers we can decompose the FMA if possible. */
11742 {
11743 /* Build a vector of integers from the tree mask. */
11744 vec_perm_builder builder;
11748 /* Create a vec_perm_indices for the integer vector. */
11753 /* Check for cases that fold to OP0 or OP1 in their original
11754 element order. */
11761 {
11765 {
11768 }
11769 }
11775 {
11779 }
11783 /* Generate a canonical form of the selector. */
11785 {
11786 /* Some targets are deficient and fail to expand a single
11787 argument permutation while still allowing an equivalent
11788 2-argument version. */
11792 else
11793 {
11797 else
11798 /* Not directly supported with either encoding,
11799 so use the preferred form. */
11801 }
11803 }
11807 }
11811 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
11814 {
11820 wide_int tem2
11824 }
11829 {
11831 unsigned HOST_WIDE_INT elsize
11834 {
11840 {
11846 }
11847 }
11848 }
11854 }
11856 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
11857 of an array (or vector). */
11859 tree
11861 {
11866 {
11869 {
11870 /* Static constructors for variably sized objects makes no sense. */
11874 }
11875 }
11886 offset_int max_index;
11891 {
11892 /* Array constructor might explicitly set index, or specify a range,
11893 or leave index NULL meaning that it is next index after previous
11894 one. */
11896 {
11899 else
11900 {
11904 }
11905 }
11906 else
11907 {
11913 }
11915 /* Do we have match? */
11919 }
11921 }
11923 /* Perform constant folding and related simplification of EXPR.
11924 The related simplifications include x*1 => x, x*0 => 0, etc.,
11925 and application of the associative law.
11926 NOP_EXPR conversions may be removed freely (as long as we
11927 are careful not to change the type of the overall expression).
11928 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
11929 but we can constant-fold them if they have constant operands. */
11931 #ifdef ENABLE_FOLD_CHECKING
11932 # define fold(x) fold_1 (x)
11934 static
11935 #endif
11936 tree
11938 {
11942 tree tem;
11945 /* Return right away if a constant. */
11949 /* CALL_EXPR-like objects with variable numbers of operands are
11950 treated specially. */
11952 {
11954 {
11957 }
11959 }
11962 {
11967 {
11985 }
11986 }
11989 {
11991 {
11998 {
12003 }
12006 }
12008 /* Return a VECTOR_CST if possible. */
12010 {
12016 tree val;
12022 }
12030 }
12032 #ifdef ENABLE_FOLD_CHECKING
12033 #undef fold
12040 /* When --enable-checking=fold, compute a digest of expr before
12041 and after actual fold call to see if fold did not accidentally
12042 change original expr. */
12044 tree
12046 {
12047 tree ret;
12067 }
12069 void
12071 {
12082 }
12084 static void
12086 {
12088 }
12090 static void
12093 {
12099 recursive_label:
12109 {
12110 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
12115 }
12123 {
12124 /* Allow these fields to be modified. */
12125 tree tmp;
12134 {
12137 }
12138 }
12149 {
12152 {
12168 }
12172 {
12185 }
12202 {
12208 }
12211 {
12213 {
12216 }
12218 }
12229 {
12232 }
12242 }
12243 }
12245 /* Helper function for outputting the checksum of a tree T. When
12246 debugging with gdb, you can "define mynext" to be "next" followed
12247 by "call debug_fold_checksum (op0)", then just trace down till the
12248 outputs differ. */
12250 DEBUG_FUNCTION void
12252 {
12267 }
12269 #endif
12271 /* Fold a unary tree expression with code CODE of type TYPE with an
12272 operand OP0. LOC is the location of the resulting expression.
12273 Return a folded expression if successful. Otherwise, return a tree
12274 expression with code CODE of type TYPE with an operand OP0. */
12276 tree
12279 {
12280 tree tem;
12281 #ifdef ENABLE_FOLD_CHECKING
12290 #endif
12296 #ifdef ENABLE_FOLD_CHECKING
12303 #endif
12305 }
12307 /* Fold a binary tree expression with code CODE of type TYPE with
12308 operands OP0 and OP1. LOC is the location of the resulting
12309 expression. Return a folded expression if successful. Otherwise,
12310 return a tree expression with code CODE of type TYPE with operands
12311 OP0 and OP1. */
12313 tree
12316 MEM_STAT_DECL)
12317 {
12318 tree tem;
12319 #ifdef ENABLE_FOLD_CHECKING
12336 #endif
12342 #ifdef ENABLE_FOLD_CHECKING
12357 #endif
12359 }
12361 /* Fold a ternary tree expression with code CODE of type TYPE with
12362 operands OP0, OP1, and OP2. Return a folded expression if
12363 successful. Otherwise, return a tree expression with code CODE of
12364 type TYPE with operands OP0, OP1, and OP2. */
12366 tree
12369 {
12370 tree tem;
12371 #ifdef ENABLE_FOLD_CHECKING
12395 #endif
12402 #ifdef ENABLE_FOLD_CHECKING
12425 #endif
12427 }
12429 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
12430 arguments in ARGARRAY, and a null static chain.
12431 Return a folded expression if successful. Otherwise, return a CALL_EXPR
12432 of type TYPE from the given operands as constructed by build_call_array. */
12434 tree
12437 {
12438 tree tem;
12439 #ifdef ENABLE_FOLD_CHECKING
12458 #endif
12464 #ifdef ENABLE_FOLD_CHECKING
12480 #endif
12482 }
12484 /* Perform constant folding and related simplification of initializer
12485 expression EXPR. These behave identically to "fold_buildN" but ignore
12486 potential run-time traps and exceptions that fold must preserve. */
12488 #define START_FOLD_INIT \
12489 int saved_signaling_nans = flag_signaling_nans;\
12490 int saved_trapping_math = flag_trapping_math;\
12491 int saved_rounding_math = flag_rounding_math;\
12492 int saved_trapv = flag_trapv;\
12493 int saved_folding_initializer = folding_initializer;\
12494 flag_signaling_nans = 0;\
12495 flag_trapping_math = 0;\
12496 flag_rounding_math = 0;\
12497 flag_trapv = 0;\
12498 folding_initializer = 1;
12500 #define END_FOLD_INIT \
12501 flag_signaling_nans = saved_signaling_nans;\
12502 flag_trapping_math = saved_trapping_math;\
12503 flag_rounding_math = saved_rounding_math;\
12504 flag_trapv = saved_trapv;\
12505 folding_initializer = saved_folding_initializer;
12507 tree
12510 {
12511 tree result;
12512 START_FOLD_INIT;
12516 END_FOLD_INIT;
12518 }
12520 tree
12523 {
12524 tree result;
12525 START_FOLD_INIT;
12529 END_FOLD_INIT;
12531 }
12533 tree
12536 {
12537 tree result;
12538 START_FOLD_INIT;
12542 END_FOLD_INIT;
12544 }
12546 #undef START_FOLD_INIT
12547 #undef END_FOLD_INIT
12549 /* Determine if first argument is a multiple of second argument. Return 0 if
12550 it is not, or we cannot easily determined it to be.
12552 An example of the sort of thing we care about (at this point; this routine
12553 could surely be made more general, and expanded to do what the *_DIV_EXPR's
12554 fold cases do now) is discovering that
12556 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12558 is a multiple of
12560 SAVE_EXPR (J * 8)
12562 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
12564 This code also handles discovering that
12566 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12568 is a multiple of 8 so we don't have to worry about dealing with a
12569 possible remainder.
12571 Note that we *look* inside a SAVE_EXPR only to determine how it was
12572 calculated; it is not safe for fold to do much of anything else with the
12573 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
12574 at run time. For example, the latter example above *cannot* be implemented
12575 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
12576 evaluation time of the original SAVE_EXPR is not necessarily the same at
12577 the time the new expression is evaluated. The only optimization of this
12578 sort that would be valid is changing
12580 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
12582 divided by 8 to
12584 SAVE_EXPR (I) * SAVE_EXPR (J)
12586 (where the same SAVE_EXPR (J) is used in the original and the
12587 transformed version). */
12589 int
12591 {
12602 {
12604 /* Bitwise and provides a power of two multiple. If the mask is
12605 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
12613 {
12619 {
12622 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
12624 {
12628 {
12631 }
12632 }
12634 }
12635 }
12640 /* It is impossible to prove if op0 - op1 is multiple of bottom
12641 precisely, so be conservative here checking if both op0 and op1
12642 are multiple of bottom. Note we check the second operand first
12643 since it's usually simpler. */
12648 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
12649 as op0 - 3 if the expression has unsigned type. For example,
12650 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
12660 {
12662 /* const_binop may not detect overflow correctly,
12663 so check for it explicitly here. */
12671 }
12675 /* Can't handle conversions from non-integral or wider integral type. */
12681 /* fall through */
12698 SIGNED);
12704 {
12707 /* Check for special cases to see if top is defined as multiple
12708 of bottom:
12710 top = (X & ~(bottom - 1) ; bottom is power of 2
12712 or
12714 Y = X % bottom
12715 top = X - Y. */
12734 }
12736 /* fall through */
12744 }
12745 }
12747 #define tree_expr_nonnegative_warnv_p(X, Y) \
12750 #define RECURSE(X) \
12751 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
12753 /* Return true if CODE or TYPE is known to be non-negative. */
12755 static bool
12757 {
12760 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
12761 have a signed:1 type (where the value is -1 and 0). */
12764 }
12766 /* Return true if (CODE OP0) is known to be non-negative. If the return
12767 value is based on the assumption that signed overflow is undefined,
12768 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12769 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12771 bool
12774 {
12779 {
12781 /* We can't return 1 if flag_wrapv is set because
12782 ABS_EXPR<INT_MIN> = INT_MIN. */
12786 {
12789 }
12797 CASE_CONVERT:
12798 {
12803 {
12807 {
12811 }
12812 }
12814 {
12820 }
12821 }
12826 }
12828 /* We don't know sign of `t', so be conservative and return false. */
12830 }
12832 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
12833 value is based on the assumption that signed overflow is undefined,
12834 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12835 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12837 bool
12841 {
12846 {
12852 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
12853 both unsigned and at least 2 bits shorter than the result. */
12857 {
12862 {
12866 }
12867 }
12872 {
12873 /* x * x is always non-negative for floating point x
12874 or without overflow. */
12877 {
12882 }
12883 }
12885 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
12886 both unsigned and their total bits is shorter than the result. */
12890 {
12909 {
12919 }
12920 }
12947 }
12949 /* We don't know sign of `t', so be conservative and return false. */
12951 }
12953 /* Return true if T is known to be non-negative. If the return
12954 value is based on the assumption that signed overflow is undefined,
12955 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12956 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12958 bool
12960 {
12965 {
12979 /* Limit the depth of recursion to avoid quadratic behavior.
12980 This is expected to catch almost all occurrences in practice.
12981 If this code misses important cases that unbounded recursion
12982 would not, passes that need this information could be revised
12983 to provide it through dataflow propagation. */
12991 }
12992 }
12994 /* Return true if T is known to be non-negative. If the return
12995 value is based on the assumption that signed overflow is undefined,
12996 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12997 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12999 bool
13002 {
13004 {
13005 CASE_CFN_ACOS:
13006 CASE_CFN_ACOSH:
13007 CASE_CFN_CABS:
13008 CASE_CFN_COSH:
13009 CASE_CFN_ERFC:
13010 CASE_CFN_EXP:
13011 CASE_CFN_EXP10:
13012 CASE_CFN_EXP2:
13013 CASE_CFN_FABS:
13014 CASE_CFN_FDIM:
13015 CASE_CFN_HYPOT:
13016 CASE_CFN_POW10:
13017 CASE_CFN_FFS:
13018 CASE_CFN_PARITY:
13019 CASE_CFN_POPCOUNT:
13020 CASE_CFN_CLZ:
13021 CASE_CFN_CLRSB:
13024 /* Always true. */
13027 CASE_CFN_SQRT:
13028 CASE_CFN_SQRT_FN:
13029 /* sqrt(-0.0) is -0.0. */
13034 CASE_CFN_ASINH:
13035 CASE_CFN_ATAN:
13036 CASE_CFN_ATANH:
13037 CASE_CFN_CBRT:
13038 CASE_CFN_CEIL:
13039 CASE_CFN_CEIL_FN:
13040 CASE_CFN_ERF:
13041 CASE_CFN_EXPM1:
13042 CASE_CFN_FLOOR:
13043 CASE_CFN_FLOOR_FN:
13044 CASE_CFN_FMOD:
13045 CASE_CFN_FREXP:
13046 CASE_CFN_ICEIL:
13047 CASE_CFN_IFLOOR:
13048 CASE_CFN_IRINT:
13049 CASE_CFN_IROUND:
13050 CASE_CFN_LCEIL:
13051 CASE_CFN_LDEXP:
13052 CASE_CFN_LFLOOR:
13053 CASE_CFN_LLCEIL:
13054 CASE_CFN_LLFLOOR:
13055 CASE_CFN_LLRINT:
13056 CASE_CFN_LLROUND:
13057 CASE_CFN_LRINT:
13058 CASE_CFN_LROUND:
13059 CASE_CFN_MODF:
13060 CASE_CFN_NEARBYINT:
13061 CASE_CFN_NEARBYINT_FN:
13062 CASE_CFN_RINT:
13063 CASE_CFN_RINT_FN:
13064 CASE_CFN_ROUND:
13065 CASE_CFN_ROUND_FN:
13066 CASE_CFN_SCALB:
13067 CASE_CFN_SCALBLN:
13068 CASE_CFN_SCALBN:
13069 CASE_CFN_SIGNBIT:
13070 CASE_CFN_SIGNIFICAND:
13071 CASE_CFN_SINH:
13072 CASE_CFN_TANH:
13073 CASE_CFN_TRUNC:
13074 CASE_CFN_TRUNC_FN:
13075 /* True if the 1st argument is nonnegative. */
13078 CASE_CFN_FMAX:
13079 CASE_CFN_FMAX_FN:
13080 /* True if the 1st OR 2nd arguments are nonnegative. */
13083 CASE_CFN_FMIN:
13084 CASE_CFN_FMIN_FN:
13085 /* True if the 1st AND 2nd arguments are nonnegative. */
13088 CASE_CFN_COPYSIGN:
13089 CASE_CFN_COPYSIGN_FN:
13090 /* True if the 2nd argument is nonnegative. */
13093 CASE_CFN_POWI:
13094 /* True if the 1st argument is nonnegative or the second
13095 argument is an even integer. */
13101 CASE_CFN_POW:
13102 /* True if the 1st argument is nonnegative or the second
13103 argument is an even integer valued real. */
13105 {
13106 REAL_VALUE_TYPE c;
13107 HOST_WIDE_INT n;
13112 {
13113 REAL_VALUE_TYPE cint;
13117 }
13118 }
13123 }
13125 }
13127 /* Return true if T is known to be non-negative. If the return
13128 value is based on the assumption that signed overflow is undefined,
13129 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13130 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13132 static bool
13134 {
13140 {
13142 {
13146 /* If the initializer is non-void, then it's a normal expression
13147 that will be assigned to the slot. */
13151 /* Otherwise, the initializer sets the slot in some way. One common
13152 way is an assignment statement at the end of the initializer. */
13154 {
13162 else
13164 }
13170 }
13173 {
13179 arg0,
13180 arg1,
13182 }
13195 }
13196 }
13198 #undef RECURSE
13199 #undef tree_expr_nonnegative_warnv_p
13201 /* Return true if T is known to be non-negative. If the return
13202 value is based on the assumption that signed overflow is undefined,
13203 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13204 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13206 bool
13208 {
13215 {
13237 }
13240 {
13266 }
13267 }
13269 /* Return true if `t' is known to be non-negative. Handle warnings
13270 about undefined signed overflow. */
13272 bool
13274 {
13281 "determining that expression is always "
13283 WARN_STRICT_OVERFLOW_MISC);
13285 }
13288 /* Return true when (CODE OP0) is an address and is known to be nonzero.
13289 For floating point we further ensure that T is not denormal.
13290 Similar logic is present in nonzero_address in rtlanal.h.
13292 If the return value is based on the assumption that signed overflow
13293 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13294 change *STRICT_OVERFLOW_P. */
13296 bool
13299 {
13301 {
13304 strict_overflow_p);
13307 {
13313 strict_overflow_p));
13314 }
13319 strict_overflow_p);
13323 }
13326 }
13328 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
13329 For floating point we further ensure that T is not denormal.
13330 Similar logic is present in nonzero_address in rtlanal.h.
13332 If the return value is based on the assumption that signed overflow
13333 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13334 change *STRICT_OVERFLOW_P. */
13336 bool
13338 tree type,
13339 tree op0,
13341 {
13344 {
13348 {
13349 /* With the presence of negative values it is hard
13350 to say something. */
13357 /* One of operands must be positive and the other non-negative. */
13358 /* We don't set *STRICT_OVERFLOW_P here: even if this value
13359 overflows, on a twos-complement machine the sum of two
13360 nonnegative numbers can never be zero. */
13362 strict_overflow_p)
13364 strict_overflow_p));
13365 }
13370 {
13372 strict_overflow_p)
13374 strict_overflow_p))
13375 {
13378 }
13379 }
13388 {
13391 }
13398 {
13402 /* When both operands are nonzero, then MAX must be too. */
13404 strict_overflow_p))
13407 /* MAX where operand 0 is positive is positive. */
13409 strict_overflow_p);
13410 }
13411 /* MAX where operand 1 is positive is positive. */
13416 {
13420 }
13425 strict_overflow_p)
13427 strict_overflow_p));
13431 }
13434 }
13436 /* Return true when T is an address and is known to be nonzero.
13437 For floating point we further ensure that T is not denormal.
13438 Similar logic is present in nonzero_address in rtlanal.h.
13440 If the return value is based on the assumption that signed overflow
13441 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13442 change *STRICT_OVERFLOW_P. */
13444 bool
13446 {
13449 {
13454 {
13466 /* For objects in symbol table check if we know they are non-zero.
13467 Don't do anything for variables and functions before symtab is built;
13468 it is quite possible that they will be declared weak later. */
13473 /* Constants are never weak. */
13478 }
13486 {
13490 }
13500 }
13502 }
13504 #define integer_valued_real_p(X) \
13507 #define RECURSE(X) \
13508 ((integer_valued_real_p) (X, depth + 1))
13510 /* Return true if the floating point result of (CODE OP0) has an
13511 integer value. We also allow +Inf, -Inf and NaN to be considered
13512 integer values. Return false for signaling NaN.
13514 DEPTH is the current nesting depth of the query. */
13516 bool
13518 {
13520 {
13527 CASE_CONVERT:
13528 {
13535 }
13539 }
13541 }
13543 /* Return true if the floating point result of (CODE OP0 OP1) has an
13544 integer value. We also allow +Inf, -Inf and NaN to be considered
13545 integer values. Return false for signaling NaN.
13547 DEPTH is the current nesting depth of the query. */
13549 bool
13551 {
13553 {
13563 }
13565 }
13567 /* Return true if the floating point result of calling FNDECL with arguments
13568 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
13569 considered integer values. Return false for signaling NaN. If FNDECL
13570 takes fewer than 2 arguments, the remaining ARGn are null.
13572 DEPTH is the current nesting depth of the query. */
13574 bool
13576 {
13578 {
13579 CASE_CFN_CEIL:
13580 CASE_CFN_CEIL_FN:
13581 CASE_CFN_FLOOR:
13582 CASE_CFN_FLOOR_FN:
13583 CASE_CFN_NEARBYINT:
13584 CASE_CFN_NEARBYINT_FN:
13585 CASE_CFN_RINT:
13586 CASE_CFN_RINT_FN:
13587 CASE_CFN_ROUND:
13588 CASE_CFN_ROUND_FN:
13589 CASE_CFN_TRUNC:
13590 CASE_CFN_TRUNC_FN:
13593 CASE_CFN_FMIN:
13594 CASE_CFN_FMIN_FN:
13595 CASE_CFN_FMAX:
13596 CASE_CFN_FMAX_FN:
13601 }
13603 }
13605 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
13606 has an integer value. We also allow +Inf, -Inf and NaN to be
13607 considered integer values. Return false for signaling NaN.
13609 DEPTH is the current nesting depth of the query. */
13611 bool
13613 {
13615 {
13623 /* Limit the depth of recursion to avoid quadratic behavior.
13624 This is expected to catch almost all occurrences in practice.
13625 If this code misses important cases that unbounded recursion
13626 would not, passes that need this information could be revised
13627 to provide it through dataflow propagation. */
13631 depth));
13635 }
13637 }
13639 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
13640 has an integer value. We also allow +Inf, -Inf and NaN to be
13641 considered integer values. Return false for signaling NaN.
13643 DEPTH is the current nesting depth of the query. */
13645 static bool
13647 {
13649 {
13660 }
13662 }
13664 #undef RECURSE
13665 #undef integer_valued_real_p
13667 /* Return true if the floating point expression T has an integer value.
13668 We also allow +Inf, -Inf and NaN to be considered integer values.
13669 Return false for signaling NaN.
13671 DEPTH is the current nesting depth of the query. */
13673 bool
13675 {
13681 {
13697 }
13700 {
13706 {
13715 }
13719 }
13720 }
13722 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
13723 attempt to fold the expression to a constant without modifying TYPE,
13724 OP0 or OP1.
13726 If the expression could be simplified to a constant, then return
13727 the constant. If the expression would not be simplified to a
13728 constant, then return NULL_TREE. */
13730 tree
13732 {
13735 }
13737 /* Given the components of a unary expression CODE, TYPE and OP0,
13738 attempt to fold the expression to a constant without modifying
13739 TYPE or OP0.
13741 If the expression could be simplified to a constant, then return
13742 the constant. If the expression would not be simplified to a
13743 constant, then return NULL_TREE. */
13745 tree
13747 {
13750 }
13752 /* If EXP represents referencing an element in a constant string
13753 (either via pointer arithmetic or array indexing), return the
13754 tree representing the value accessed, otherwise return NULL. */
13756 tree
13758 {
13762 {
13764 tree index;
13765 tree string;
13770 else
13771 {
13775 /* Optimize the special-case of a zero lower bound.
13777 We convert the low_bound to sizetype to avoid some problems
13778 with constant folding. (E.g. suppose the lower bound is 1,
13779 and its mode is QI. Without the conversion,l (ARRAY
13780 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
13781 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
13787 }
13789 scalar_int_mode char_mode;
13801 }
13803 }
13805 /* Return the tree for neg (ARG0) when ARG0 is known to be either
13806 an integer constant, real, or fixed-point constant.
13808 TYPE is the type of the result. */
13810 static tree
13812 {
13816 {
13822 {
13823 FIXED_VALUE_TYPE f;
13828 /* Propagate overflow flags. */
13832 }
13836 {
13843 }
13846 }
13849 }
13851 /* Return the tree for abs (ARG0) when ARG0 is known to be either
13852 an integer constant or real constant.
13854 TYPE is the type of the result. */
13856 tree
13858 {
13862 {
13864 {
13865 /* If the value is unsigned or non-negative, then the absolute value
13866 is the same as the ordinary value. */
13870 /* If the value is negative, then the absolute value is
13871 its negation. */
13872 else
13873 {
13878 }
13879 }
13885 else
13891 }
13894 }
13896 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
13897 constant. TYPE is the type of the result. */
13899 static tree
13901 {
13905 }
13907 /* Given CODE, a relational operator, the target type, TYPE and two
13908 constant operands OP0 and OP1, return the result of the
13909 relational operation. If the result is not a compile time
13910 constant, then return NULL_TREE. */
13912 static tree
13914 {
13917 /* From here on, the only cases we handle are when the result is
13918 known to be a constant. */
13921 {
13925 /* Handle the cases where either operand is a NaN. */
13927 {
13929 {
13957 }
13960 }
13963 }
13966 {
13970 }
13972 /* Handle equality/inequality of complex constants. */
13974 {
13985 else
13987 }
13990 {
13992 {
13993 /* Have vector comparison with scalar boolean result. */
14001 {
14009 }
14011 }
14012 tree_vector_builder elts;
14017 {
14030 }
14033 }
14035 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
14037 To compute GT, swap the arguments and do LT.
14038 To compute GE, do LT and invert the result.
14039 To compute LE, swap the arguments, do LT and invert the result.
14040 To compute NE, do EQ and invert the result.
14042 Therefore, the code below must handle only EQ and LT. */
14045 {
14048 }
14050 /* Note that it is safe to invert for real values here because we
14051 have already handled the one case that it matters. */
14055 {
14058 }
14060 /* Compute a result for LT or EQ if args permit;
14061 Otherwise return T. */
14063 {
14066 else
14068 }
14069 else
14075 }
14077 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
14078 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
14079 itself. */
14081 tree
14083 {
14084 /* If the expression does not have side effects then we don't have to wrap
14085 it with a cleanup point expression. */
14089 /* If the expression is a return, check to see if the expression inside the
14090 return has no side effects or the right hand side of the modify expression
14091 inside the return. If either don't have side effects set we don't need to
14092 wrap the expression in a cleanup point expression. Note we don't check the
14093 left hand side of the modify because it should always be a return decl. */
14095 {
14102 }
14105 }
14107 /* Given a pointer value OP0 and a type TYPE, return a simplified version
14108 of an indirection through OP0, or NULL_TREE if no simplification is
14109 possible. */
14111 tree
14113 {
14115 tree subtype;
14116 poly_uint64 const_op01;
14125 {
14129 /* *&CONST_DECL -> to the value of the const decl. */
14132 /* *&p => p; make sure to handle *&"str"[cst] here. */
14134 {
14138 else
14140 }
14141 /* *(foo *)&fooarray => fooarray[0] */
14144 && (!in_gimple_form
14146 {
14156 }
14157 /* *(foo *)&complexfoo => __real__ complexfoo */
14161 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14164 {
14168 index);
14169 }
14170 }
14174 {
14180 {
14181 tree op00type;
14185 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
14188 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
14189 but we want to treat offsets with MSB set as negative.
14190 For the code below negative offsets are invalid and
14191 TYPE_SIZE of the element is something unsigned, so
14192 check whether op01 fits into poly_int64, which implies
14193 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
14194 then just use poly_uint64 because we want to treat the
14195 value as unsigned. */
14197 {
14199 poly_uint64 max_offset
14203 {
14208 }
14209 }
14210 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
14213 {
14215 const_op01))
14217 }
14218 /* ((foo *)&fooarray)[1] => fooarray[1] */
14221 {
14228 offset_int remainder;
14231 {
14236 }
14237 }
14238 }
14239 }
14241 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
14244 && (!in_gimple_form
14246 {
14247 tree type_domain;
14257 NULL_TREE);
14258 }
14261 }
14263 /* Builds an expression for an indirection through T, simplifying some
14264 cases. */
14266 tree
14268 {
14276 }
14278 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14280 tree
14282 {
14287 else
14289 }
14291 /* Strip non-trapping, non-side-effecting tree nodes from an expression
14292 whose result is ignored. The type of the returned tree need not be
14293 the same as the original expression. */
14295 tree
14297 {
14303 {
14314 else
14320 {
14336 }
14341 }
14342 }
14344 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
14346 tree
14348 {
14354 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14355 have to do anything. Only do this when we are not given a const,
14356 because in that case, this check is more expensive than just
14357 doing it. */
14359 {
14364 }
14366 /* If divisor is a power of two, simplify this to bit manipulation. */
14368 {
14370 {
14384 }
14385 else
14386 {
14387 tree t;
14393 }
14394 }
14395 else
14396 {
14401 }
14404 }
14406 /* Likewise, but round down. */
14408 tree
14410 {
14417 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14418 have to do anything. Only do this when we are not given a const,
14419 because in that case, this check is more expensive than just
14420 doing it. */
14422 {
14427 }
14429 /* If divisor is a power of two, simplify this to bit manipulation. */
14431 {
14432 tree t;
14436 }
14437 else
14438 {
14443 }
14446 }
14448 /* Returns the pointer to the base of the object addressed by EXP and
14449 extracts the information about the offset of the access, storing it
14450 to PBITPOS and POFFSET. */
14452 static tree
14455 {
14456 tree core;
14457 machine_mode mode;
14459 poly_int64 bitsize;
14463 {
14468 }
14470 {
14476 {
14477 poly_offset_int tem
14483 }
14484 }
14485 else
14486 {
14490 }
14493 }
14495 /* Returns true if addresses of E1 and E2 differ by a constant, false
14496 otherwise. If they do, E1 - E2 is stored in *DIFF. */
14498 bool
14500 {
14515 {
14525 }
14527 {
14528 /* If only one of the offsets is non-constant, the difference cannot
14529 be a constant. */
14531 }
14532 else
14537 }
14539 /* Return OFF converted to a pointer offset type suitable as offset for
14540 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
14541 tree
14543 {
14545 }
14547 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14548 tree
14550 {
14553 }
14555 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14556 tree
14558 {
14561 }
14563 /* Return a char pointer for a C string if it is a string constant
14564 or sum of string constant and integer constant. We only support
14565 string constants properly terminated with '\0' character.
14566 If STRLEN is a valid pointer, length (including terminating character)
14567 of returned string is stored to the argument. */
14571 {
14572 tree offset_node;
14583 {
14586 else
14588 }
14593 /* Support only properly null-terminated strings. */
14602 }
14604 #if CHECKING_P
14608 /* Helper functions for writing tests of folding trees. */
14610 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
14612 static void
14614 tree constant)
14615 {
14617 }
14619 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
14620 wrapping WRAPPED_EXPR. */
14622 static void
14624 tree wrapped_expr)
14625 {
14630 }
14632 /* Verify that various arithmetic binary operations are folded
14633 correctly. */
14635 static void
14637 {
14643 /* Addition. */
14644 /* 1 <-- (0 + 1) */
14646 one);
14648 one);
14650 /* (nonlvalue)x <-- (x + 0) */
14652 x);
14654 /* Subtraction. */
14655 /* 0 <-- (x - x) */
14657 zero);
14659 x);
14661 /* Multiplication. */
14662 /* 0 <-- (x * 0) */
14664 zero);
14666 /* (nonlvalue)x <-- (x * 1) */
14668 x);
14669 }
14671 /* Verify that various binary operations on vectors are folded
14672 correctly. */
14674 static void
14676 {
14682 /* Verify equality tests that return a scalar boolean result. */
14688 }
14690 /* Verify folding of VEC_DUPLICATE_EXPRs. */
14692 static void
14694 {
14697 /* This will be 1 if VEC_MODE isn't a vector mode. */
14704 }
14706 /* Run all of the selftests within this file. */
14708 void
14710 {
14714 }