| blob | 6472f10309482c75bfef299268b746edd594916a |
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. */
479 /* In general we can't negate B in A / B, because if A is INT_MIN and
480 B is 1, we may turn this into INT_MIN / -1 which is undefined
481 and actually traps on some architectures. */
490 /* Negate -((double)float) as (double)(-float). */
492 {
496 }
500 /* Negate -f(x) as f(-x). */
506 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
508 {
512 }
517 }
519 }
521 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
522 simplification is possible.
523 If negate_expr_p would return true for T, NULL_TREE will never be
524 returned. */
526 static tree
528 {
530 tree tem;
533 {
534 /* Convert - (~A) to A + 1. */
558 {
563 }
567 {
568 tree_vector_builder elts;
572 {
577 }
580 }
603 {
604 /* -(A + B) -> (-B) - A. */
606 {
610 }
612 /* -(A + B) -> (-A) - B. */
614 {
618 }
619 }
623 /* - (A - B) -> B - A */
634 /* Fall through. */
638 {
647 }
659 /* In general we can't negate B in A / B, because if A is INT_MIN and
660 B is 1, we may turn this into INT_MIN / -1 which is undefined
661 and actually traps on some architectures. */
673 /* Convert -((double)float) into (double)(-float). */
675 {
679 }
683 /* Negate -f(x) as f(-x). */
686 {
692 }
696 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
698 {
701 {
708 }
709 }
714 }
717 }
719 /* A wrapper for fold_negate_expr_1. */
721 static tree
723 {
730 }
732 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
733 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
734 return NULL_TREE. */
736 static tree
738 {
740 location_t loc;
753 }
754 \f
755 /* Split a tree IN into a constant, literal and variable parts that could be
756 combined with CODE to make IN. "constant" means an expression with
757 TREE_CONSTANT but that isn't an actual constant. CODE must be a
758 commutative arithmetic operation. Store the constant part into *CONP,
759 the literal in *LITP and return the variable part. If a part isn't
760 present, set it to null. If the tree does not decompose in this way,
761 return the entire tree as the variable part and the other parts as null.
763 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
764 case, we negate an operand that was subtracted. Except if it is a
765 literal for which we use *MINUS_LITP instead.
767 If NEGATE_P is true, we are negating all of IN, again except a literal
768 for which we use *MINUS_LITP instead. If a variable part is of pointer
769 type, it is negated after converting to TYPE. This prevents us from
770 generating illegal MINUS pointer expression. LOC is the location of
771 the converted variable part.
773 If IN is itself a literal or constant, return it as appropriate.
775 Note that we do not guarantee that any of the three values will be the
776 same type as IN, but they will have the same signedness and mode. */
778 static tree
782 {
790 /* Strip any conversions that don't change the machine mode or signedness. */
799 /* We can associate addition and subtraction together (even
800 though the C standard doesn't say so) for integers because
801 the value is not affected. For reals, the value might be
802 affected, so we can't. */
808 {
814 /* First see if either of the operands is a literal, then a constant. */
827 /* If we haven't dealt with either operand, this is not a case we can
828 decompose. Otherwise, VAR is either of the ones remaining, if any. */
833 else
836 /* Now do any needed negations. */
843 }
848 {
849 /* -1 - X is folded to ~X, undo that here. Do _not_ do this
850 when IN is constant. */
853 }
854 else
858 {
871 }
881 }
883 /* Re-associate trees split by the above function. T1 and T2 are
884 either expressions to associate or null. Return the new
885 expression, if any. LOC is the location of the new expression. If
886 we build an operation, do it in TYPE and with CODE. */
888 static tree
890 {
892 {
895 }
899 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
900 try to fold this since we will have infinite recursion. But do
901 deal with any NEGATE_EXPRs. */
905 {
907 {
920 }
922 {
925 }
929 }
933 }
934 \f
935 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
936 for use in int_const_binop, size_binop and size_diffop. */
938 static bool
940 {
947 {
956 }
961 }
963 /* Subroutine of int_const_binop_1 that handles two INTEGER_CSTs. */
965 static tree
968 {
969 wide_int res;
970 tree t;
979 {
995 {
999 else
1001 }
1004 /* It's unclear from the C standard whether shifts can overflow.
1005 The following code ignores overflow; perhaps a C standard
1006 interpretation ruling is needed. */
1008 else
1015 {
1019 else
1021 }
1025 else
1104 }
1112 }
1114 /* Combine two integer constants PARG1 and PARG2 under operation CODE
1115 to produce a new constant. Return NULL_TREE if we don't know how
1116 to evaluate CODE at compile-time. */
1118 static tree
1121 {
1128 {
1129 poly_wide_int res;
1134 {
1152 else
1159 else
1172 }
1177 }
1180 }
1182 tree
1184 {
1186 }
1188 /* Return true if binary operation OP distributes over addition in operand
1189 OPNO, with the other operand being held constant. OPNO counts from 1. */
1191 static bool
1193 {
1195 {
1206 }
1207 }
1209 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1210 constant. We assume ARG1 and ARG2 have the same data type, or at least
1211 are the same kind of constant and the same machine mode. Return zero if
1212 combining the constants is not allowed in the current operating mode. */
1214 static tree
1216 {
1217 /* Sanity check for the recursive cases. */
1225 {
1231 }
1234 {
1235 machine_mode mode;
1236 REAL_VALUE_TYPE d1;
1237 REAL_VALUE_TYPE d2;
1238 REAL_VALUE_TYPE value;
1239 REAL_VALUE_TYPE result;
1243 /* The following codes are handled by real_arithmetic. */
1245 {
1256 }
1264 /* Don't perform operation if we honor signaling NaNs and
1265 either operand is a signaling NaN. */
1271 /* Don't perform operation if it would raise a division
1272 by zero exception. */
1278 /* If either operand is a NaN, just return it. Otherwise, set up
1279 for floating-point trap; we return an overflow. */
1281 {
1282 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1283 is off. */
1287 }
1289 {
1290 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1291 is off. */
1295 }
1300 /* Don't constant fold this floating point operation if
1301 the result has overflowed and flag_trapping_math. */
1309 /* Don't constant fold this floating point operation if the
1310 result may dependent upon the run-time rounding mode and
1311 flag_rounding_math is set, or if GCC's software emulation
1312 is unable to accurately represent the result. */
1322 }
1325 {
1326 FIXED_VALUE_TYPE f1;
1327 FIXED_VALUE_TYPE f2;
1328 FIXED_VALUE_TYPE result;
1333 /* The following codes are handled by fixed_arithmetic. */
1335 {
1347 {
1354 }
1359 }
1366 /* Propagate overflow flags. */
1370 }
1373 {
1382 {
1393 mpc_mul);
1407 mpc_div);
1408 /* Fallthru. */
1414 {
1415 /* Keep this algorithm in sync with
1416 tree-complex.c:expand_complex_div_straight().
1418 Expand complex division to scalars, straightforward algorithm.
1419 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1420 t = br*br + bi*bi
1421 */
1422 tree magsquared
1426 tree t1
1430 tree t2
1437 }
1438 else
1439 {
1440 /* Keep this algorithm in sync with
1441 tree-complex.c:expand_complex_div_wide().
1443 Expand complex division to scalars, modified algorithm to minimize
1444 overflow with wide input ranges. */
1450 {
1451 /* In the TRUE branch, we compute
1452 ratio = br/bi;
1453 div = (br * ratio) + bi;
1454 tr = (ar * ratio) + ai;
1455 ti = (ai * ratio) - ar;
1456 tr = tr / div;
1457 ti = ti / div; */
1468 }
1469 else
1470 {
1471 /* In the FALSE branch, we compute
1472 ratio = d/c;
1473 divisor = (d * ratio) + c;
1474 tr = (b * ratio) + a;
1475 ti = b - (a * ratio);
1476 tr = tr / div;
1477 ti = ti / div; */
1489 }
1490 }
1495 }
1499 }
1505 {
1510 /* We can operate directly on the encoding if:
1512 a3 - a2 == a2 - a1 && b3 - b2 == b2 - b1
1513 implies
1514 (a3 op b3) - (a2 op b2) == (a2 op b2) - (a1 op b1)
1516 Addition and subtraction are the supported operators
1517 for which this is true. */
1520 /* We can operate directly on stepped encodings if:
1522 a3 - a2 == a2 - a1
1523 implies:
1524 (a3 op c) - (a2 op c) == (a2 op c) - (a1 op c)
1526 which is true if (x -> x op c) distributes over addition. */
1528 else
1529 /* Similarly in reverse. */
1531 tree_vector_builder elts;
1536 {
1542 /* It is possible that const_binop cannot handle the given
1543 code and return NULL_TREE */
1547 }
1550 }
1552 /* Shifts allow a scalar offset for a vector. */
1555 {
1558 tree_vector_builder elts;
1563 {
1568 /* It is possible that const_binop cannot handle the given
1569 code and return NULL_TREE. */
1573 }
1576 }
1578 }
1580 /* Overload that adds a TYPE parameter to be able to dispatch
1581 to fold_relational_const. */
1583 tree
1585 {
1589 /* ??? Until we make the const_binop worker take the type of the
1590 result as argument put those cases that need it here. */
1592 {
1609 {
1614 }
1619 {
1635 {
1645 }
1648 }
1654 {
1677 {
1690 }
1693 }
1696 }
1701 /* Make sure type and arg0 have the same saturating flag. */
1706 }
1708 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1709 Return zero if computing the constants is not possible. */
1711 tree
1713 {
1714 /* Don't perform the operation, other than NEGATE and ABS, if
1715 flag_signaling_nans is on and the operand is a signaling NaN. */
1724 {
1725 CASE_CONVERT:
1732 /* If the source address is 0, and the source address space
1733 cannot have a valid object at 0, fold to dest type null. */
1744 {
1745 /* Can't call fold_negate_const directly here as that doesn't
1746 handle all cases and we might not be able to negate some
1747 constants. */
1752 }
1761 {
1765 }
1773 /* Perform BIT_NOT_EXPR on each element individually. */
1775 {
1776 tree elem;
1778 /* This can cope with stepped encodings because ~x == -1 - x. */
1779 tree_vector_builder elements;
1783 {
1789 }
1792 }
1814 {
1833 else
1838 {
1844 }
1847 }
1856 }
1859 }
1861 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1862 indicates which particular sizetype to create. */
1864 tree
1866 {
1868 }
1869 \f
1870 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1871 is a tree code. The type of the result is taken from the operands.
1872 Both must be equivalent integer types, ala int_binop_types_match_p.
1873 If the operands are constant, so is the result. */
1875 tree
1877 {
1886 /* Handle the special case of two poly_int constants faster. */
1888 {
1889 /* And some specific cases even faster than that. */
1891 {
1896 }
1898 {
1901 }
1903 {
1906 }
1908 /* Handle general case of two integer constants. For sizetype
1909 constant calculations we always want to know about overflow,
1910 even in the unsigned case. */
1914 }
1917 }
1919 /* Given two values, either both of sizetype or both of bitsizetype,
1920 compute the difference between the two values. Return the value
1921 in signed type corresponding to the type of the operands. */
1923 tree
1925 {
1927 tree ctype;
1932 /* If the type is already signed, just do the simple thing. */
1940 else
1943 /* If either operand is not a constant, do the conversions to the signed
1944 type and subtract. The hardware will do the right thing with any
1945 overflow in the subtraction. */
1951 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1952 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1953 overflow) and negate (which can't either). Special-case a result
1954 of zero while we're here. */
1960 else
1964 MINUS_EXPR,
1966 }
1967 \f
1968 /* A subroutine of fold_convert_const handling conversions of an
1969 INTEGER_CST to another integer type. */
1971 static tree
1973 {
1974 /* Given an integer constant, make new constant with new type,
1975 appropriately sign-extended or truncated. Use widest_int
1976 so that any extension is done according ARG1's type. */
1980 }
1982 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1983 to an integer type. */
1985 static tree
1987 {
1989 tree t;
1991 /* The following code implements the floating point to integer
1992 conversion rules required by the Java Language Specification,
1993 that IEEE NaNs are mapped to zero and values that overflow
1994 the target precision saturate, i.e. values greater than
1995 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
1996 are mapped to INT_MIN. These semantics are allowed by the
1997 C and C++ standards that simply state that the behavior of
1998 FP-to-integer conversion is unspecified upon overflow. */
2000 wide_int val;
2001 REAL_VALUE_TYPE r;
2005 {
2012 }
2014 /* If R is NaN, return zero and show we have an overflow. */
2016 {
2019 }
2021 /* See if R is less than the lower bound or greater than the
2022 upper bound. */
2025 {
2029 {
2032 }
2033 }
2036 {
2039 {
2042 {
2045 }
2046 }
2047 }
2054 }
2056 /* A subroutine of fold_convert_const handling conversions of a
2057 FIXED_CST to an integer type. */
2059 static tree
2061 {
2062 tree t;
2064 scalar_mode mode;
2066 /* Right shift FIXED_CST to temp by fbit. */
2070 {
2072 HOST_BITS_PER_DOUBLE_INT,
2075 /* Left shift temp to temp_trunc by fbit. */
2077 HOST_BITS_PER_DOUBLE_INT,
2079 }
2080 else
2081 {
2084 }
2086 /* If FIXED_CST is negative, we need to round the value toward 0.
2087 By checking if the fractional bits are not zero to add 1 to temp. */
2093 /* Given a fixed-point constant, make new constant with new type,
2094 appropriately sign-extended or truncated. */
2102 }
2104 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2105 to another floating point type. */
2107 static tree
2109 {
2110 REAL_VALUE_TYPE value;
2111 tree t;
2113 /* Don't perform the operation if flag_signaling_nans is on
2114 and the operand is a signaling NaN. */
2122 /* If converting an infinity or NAN to a representation that doesn't
2123 have one, set the overflow bit so that we can produce some kind of
2124 error message at the appropriate point if necessary. It's not the
2125 most user-friendly message, but it's better than nothing. */
2132 /* Regular overflow, conversion produced an infinity in a mode that
2133 can't represent them. */
2138 else
2141 }
2143 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2144 to a floating point type. */
2146 static tree
2148 {
2149 REAL_VALUE_TYPE value;
2150 tree t;
2158 }
2160 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2161 to another fixed-point type. */
2163 static tree
2165 {
2166 FIXED_VALUE_TYPE value;
2167 tree t;
2174 /* Propagate overflow flags. */
2178 }
2180 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2181 to a fixed-point type. */
2183 static tree
2185 {
2186 FIXED_VALUE_TYPE value;
2187 tree t;
2189 double_int di;
2196 else
2204 /* Propagate overflow flags. */
2208 }
2210 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2211 to a fixed-point type. */
2213 static tree
2215 {
2216 FIXED_VALUE_TYPE value;
2217 tree t;
2225 /* Propagate overflow flags. */
2229 }
2231 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2232 type TYPE. If no simplification can be done return NULL_TREE. */
2234 static tree
2236 {
2241 /* We can't widen types, since the runtime value could overflow the
2242 original type before being extended to the new type. */
2253 {
2260 }
2262 {
2269 }
2271 {
2278 }
2280 {
2283 {
2286 /* We can't handle steps directly when extending, since the
2287 values need to wrap at the original precision first. */
2288 bool step_ok_p
2292 tree_vector_builder v;
2297 {
2303 }
2305 }
2306 }
2308 }
2310 /* Construct a vector of zero elements of vector type TYPE. */
2312 static tree
2314 {
2315 tree t;
2319 }
2321 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2323 bool
2325 {
2340 {
2355 }
2356 }
2358 /* Convert expression ARG to type TYPE. Used by the middle-end for
2359 simple conversions in preference to calling the front-end's convert. */
2361 tree
2363 {
2365 tree tem;
2376 {
2379 /* Handle conversions between pointers to different address spaces. */
2384 /* fall through */
2389 {
2393 }
2407 {
2411 }
2413 {
2417 }
2419 {
2423 }
2426 {
2444 }
2449 {
2453 }
2456 {
2470 }
2474 {
2483 integer_zero_node));
2485 {
2489 {
2495 }
2503 }
2507 }
2525 }
2526 fold_convert_exit:
2529 }
2530 \f
2531 /* Return false if expr can be assumed not to be an lvalue, true
2532 otherwise. */
2534 static bool
2536 {
2537 /* We only need to wrap lvalue tree codes. */
2539 {
2570 /* Assume the worst for front-end tree codes. */
2574 }
2577 }
2579 /* Return an expr equal to X but certainly not valid as an lvalue. */
2581 tree
2583 {
2584 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2585 us. */
2592 }
2594 /* When pedantic, return an expr equal to X but certainly not valid as a
2595 pedantic lvalue. Otherwise, return X. */
2597 static tree
2599 {
2601 }
2602 \f
2603 /* Given a tree comparison code, return the code that is the logical inverse.
2604 It is generally not safe to do this for floating-point comparisons, except
2605 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2606 ERROR_MARK in this case. */
2608 enum tree_code
2610 {
2616 {
2647 }
2648 }
2650 /* Similar, but return the comparison that results if the operands are
2651 swapped. This is safe for floating-point. */
2653 enum tree_code
2655 {
2657 {
2683 }
2684 }
2687 /* Convert a comparison tree code from an enum tree_code representation
2688 into a compcode bit-based encoding. This function is the inverse of
2689 compcode_to_comparison. */
2691 static enum comparison_code
2693 {
2695 {
2726 }
2727 }
2729 /* Convert a compcode bit-based encoding of a comparison operator back
2730 to GCC's enum tree_code representation. This function is the
2731 inverse of comparison_to_compcode. */
2733 static enum tree_code
2735 {
2737 {
2768 }
2769 }
2771 /* Return a tree for the comparison which is the combination of
2772 doing the AND or OR (depending on CODE) of the two operations LCODE
2773 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2774 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2775 if this makes the transformation invalid. */
2777 tree
2782 {
2789 {
2800 }
2803 {
2804 /* Eliminate unordered comparisons, as well as LTGT and ORD
2805 which are not used unless the mode has NaNs. */
2811 }
2813 {
2814 /* Check that the original operation and the optimized ones will trap
2815 under the same condition. */
2826 /* In a short-circuited boolean expression the LHS might be
2827 such that the RHS, if evaluated, will never trap. For
2828 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2829 if neither x nor y is NaN. (This is a mixed blessing: for
2830 example, the expression above will never trap, hence
2831 optimizing it to x < y would be invalid). */
2836 /* If the comparison was short-circuited, and only the RHS
2837 trapped, we may now generate a spurious trap. */
2842 /* If we changed the conditions that cause a trap, we lose. */
2845 }
2851 else
2852 {
2857 }
2858 }
2859 \f
2860 /* Return nonzero if two operands (typically of the same tree node)
2861 are necessarily equal. FLAGS modifies behavior as follows:
2863 If OEP_ONLY_CONST is set, only return nonzero for constants.
2864 This function tests whether the operands are indistinguishable;
2865 it does not test whether they are equal using C's == operation.
2866 The distinction is important for IEEE floating point, because
2867 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2868 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2870 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2871 even though it may hold multiple values during a function.
2872 This is because a GCC tree node guarantees that nothing else is
2873 executed between the evaluation of its "operands" (which may often
2874 be evaluated in arbitrary order). Hence if the operands themselves
2875 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2876 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2877 unset means assuming isochronic (or instantaneous) tree equivalence.
2878 Unless comparing arbitrary expression trees, such as from different
2879 statements, this flag can usually be left unset.
2881 If OEP_PURE_SAME is set, then pure functions with identical arguments
2882 are considered the same. It is used when the caller has other ways
2883 to ensure that global memory is unchanged in between.
2885 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2886 not values of expressions.
2888 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
2889 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
2891 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2892 any operand with side effect. This is unnecesarily conservative in the
2893 case we know that arg0 and arg1 are in disjoint code paths (such as in
2894 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2895 addresses with TREE_CONSTANT flag set so we know that &var == &var
2896 even if var is volatile. */
2898 int
2900 {
2901 /* When checking, verify at the outermost operand_equal_p call that
2902 if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
2903 hash value. */
2905 {
2907 {
2909 {
2916 }
2918 }
2919 else
2921 }
2923 /* If either is ERROR_MARK, they aren't equal. */
2929 /* Similar, if either does not have a type (like a released SSA name),
2930 they aren't equal. */
2934 /* We cannot consider pointers to different address space equal. */
2941 /* Check equality of integer constants before bailing out due to
2942 precision differences. */
2944 {
2945 /* Address of INTEGER_CST is not defined; check that we did not forget
2946 to drop the OEP_ADDRESS_OF flags. */
2949 }
2952 {
2953 /* If both types don't have the same signedness, then we can't consider
2954 them equal. We must check this before the STRIP_NOPS calls
2955 because they may change the signedness of the arguments. As pointers
2956 strictly don't have a signedness, require either two pointers or
2957 two non-pointers as well. */
2963 /* If both types don't have the same precision, then it is not safe
2964 to strip NOPs. */
2971 }
2972 #if 0
2973 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
2974 sanity check once the issue is solved. */
2975 else
2976 /* Addresses of conversions and SSA_NAMEs (and many other things)
2977 are not defined. Check that we did not forget to drop the
2978 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
2981 #endif
2983 /* In case both args are comparisons but with different comparison
2984 code, try to swap the comparison operands of one arg to produce
2985 a match and compare that variant. */
2989 {
2997 }
3000 {
3001 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
3003 ;
3005 {
3006 /* If we are interested in comparing addresses ignore
3007 MEM_REF wrappings of the base that can appear just for
3008 TBAA reasons. */
3022 }
3023 else
3025 }
3027 /* When not checking adddresses, this is needed for conversions and for
3028 COMPONENT_REF. Might as well play it safe and always test this. */
3035 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3036 We don't care about side effects in that case because the SAVE_EXPR
3037 takes care of that for us. In all other cases, two expressions are
3038 equal if they have no side effects. If we have two identical
3039 expressions with side effects that should be treated the same due
3040 to the only side effects being identical SAVE_EXPR's, that will
3041 be detected in the recursive calls below.
3042 If we are taking an invariant address of two identical objects
3043 they are necessarily equal as well. */
3050 /* Next handle constant cases, those for which we can return 1 even
3051 if ONLY_CONST is set. */
3054 {
3068 {
3069 /* If we do not distinguish between signed and unsigned zero,
3070 consider them equal. */
3073 }
3077 {
3092 }
3096 flags)
3098 flags));
3109 flags | OEP_ADDRESS_OF
3112 /* In GIMPLE empty constructors are allowed in initializers of
3113 aggregates. */
3117 }
3122 /* Define macros to test an operand from arg0 and arg1 for equality and a
3123 variant that allows null and views null as being different from any
3124 non-null value. In the latter case, if either is null, the both
3125 must be; otherwise, do the normal comparison. */
3126 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3127 TREE_OPERAND (arg1, N), flags)
3129 #define OP_SAME_WITH_NULL(N) \
3130 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3131 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3134 {
3136 /* Two conversions are equal only if signedness and modes match. */
3138 {
3139 CASE_CONVERT:
3147 }
3157 /* For commutative ops, allow the other order. */
3165 /* If either of the pointer (or reference) expressions we are
3166 dereferencing contain a side effect, these cannot be equal,
3167 but their addresses can be. */
3174 {
3184 /* Require the same offset. */
3190 /* Fallthru. */
3198 {
3199 /* Require equal access sizes */
3205 flags)))
3207 /* Verify that access happens in similar types. */
3210 /* Verify that accesses are TBAA compatible. */
3219 /* Verify that alignment is compatible. */
3223 }
3226 /* TARGET_MEM_REF require equal extra operands. */
3237 /* Compare the array index by value if it is constant first as we
3238 may have different types but same value here. */
3244 /* Compare low bound and element size as with OEP_ADDRESS_OF
3245 we have to account for the offset of the ref. */
3250 array_ref_low_bound
3254 array_ref_element_size
3256 flags))));
3259 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3260 may be NULL when we're called to compare MEM_EXPRs. */
3275 }
3279 {
3281 /* Be sure we pass right ADDRESS_OF flag. */
3299 /* The multiplcation operands are commutative. */
3300 /* FALLTHRU */
3308 /* Otherwise take into account this is a commutative operation. */
3321 /* BIT_INSERT_EXPR has an implict operand as the type precision
3322 of op1. Need to check to make sure they are the same. */
3328 /* FALLTHRU */
3353 }
3357 {
3361 /* If not both CALL_EXPRs are either internal or normal function
3362 functions, then they are not equal. */
3365 {
3366 /* If the CALL_EXPRs call different internal functions, then they
3367 are not equal. */
3370 }
3371 else
3372 {
3373 /* If the CALL_EXPRs call different functions, then they are not
3374 equal. */
3376 flags))
3378 }
3380 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3381 {
3385 else
3389 }
3391 /* Now see if all the arguments are the same. */
3392 {
3403 /* If we get here and both argument lists are exhausted
3404 then the CALL_EXPRs are equal. */
3406 }
3409 }
3412 /* Consider __builtin_sqrt equal to sqrt. */
3420 {
3421 /* In GIMPLE constructors are used only to build vectors from
3422 elements. Individual elements in the constructor must be
3423 indexed in increasing order and form an initial sequence.
3425 We make no effort to compare constructors in generic.
3426 (see sem_variable::equals in ipa-icf which can do so for
3427 constants). */
3432 /* Be sure that vectors constructed have the same representation.
3433 We only tested element precision and modes to match.
3434 Vectors may be BLKmode and thus also check that the number of
3435 parts match. */
3448 {
3453 /* In GIMPLE the indexes can be either NULL or matching i.
3454 Double check this so we won't get false
3455 positives for GENERIC. */
3463 }
3465 }
3468 {
3469 /* Compare the STATEMENT_LISTs. */
3475 {
3476 /* The lists don't have the same number of statements. */
3482 flags & (OEP_LEXICOGRAPHIC
3485 }
3486 }
3491 {
3502 }
3506 }
3508 #undef OP_SAME
3509 #undef OP_SAME_WITH_NULL
3510 }
3511 \f
3512 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
3513 with a different signedness or a narrower precision. */
3515 static bool
3517 {
3525 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3526 and see if the inner values are the same. This removes any
3527 signedness comparison, which doesn't matter here. */
3535 /* Discard a single widening conversion from ARG1 and see if the inner
3536 value is the same as ARG0. */
3545 }
3546 \f
3547 /* See if ARG is an expression that is either a comparison or is performing
3548 arithmetic on comparisons. The comparisons must only be comparing
3549 two different values, which will be stored in *CVAL1 and *CVAL2; if
3550 they are nonzero it means that some operands have already been found.
3551 No variables may be used anywhere else in the expression except in the
3552 comparisons.
3554 If this is true, return 1. Otherwise, return zero. */
3556 static int
3558 {
3562 /* We can handle some of the tcc_expression cases here. */
3571 {
3590 /* First see if we can handle the first operand, then the second. For
3591 the second operand, we know *CVAL1 can't be zero. It must be that
3592 one side of the comparison is each of the values; test for the
3593 case where this isn't true by failing if the two operands
3594 are the same. */
3603 ;
3607 ;
3608 else
3612 ;
3616 ;
3617 else
3624 }
3625 }
3626 \f
3627 /* ARG is a tree that is known to contain just arithmetic operations and
3628 comparisons. Evaluate the operations in the tree substituting NEW0 for
3629 any occurrence of OLD0 as an operand of a comparison and likewise for
3630 NEW1 and OLD1. */
3632 static tree
3635 {
3640 /* We can handle some of the tcc_expression cases here. */
3648 {
3663 {
3682 }
3683 /* Fall through - ??? */
3686 {
3690 /* We need to check both for exact equality and tree equality. The
3691 former will be true if the operand has a side-effect. In that
3692 case, we know the operand occurred exactly once. */
3705 }
3709 }
3710 }
3711 \f
3712 /* Return a tree for the case when the result of an expression is RESULT
3713 converted to TYPE and OMITTED was previously an operand of the expression
3714 but is now not needed (e.g., we folded OMITTED * 0).
3716 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3717 the conversion of RESULT to TYPE. */
3719 tree
3721 {
3724 /* If the resulting operand is an empty statement, just return the omitted
3725 statement casted to void. */
3735 }
3737 /* Return a tree for the case when the result of an expression is RESULT
3738 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3739 of the expression but are now not needed.
3741 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3742 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3743 evaluated before OMITTED2. Otherwise, if neither has side effects,
3744 just do the conversion of RESULT to TYPE. */
3746 tree
3749 {
3758 }
3760 \f
3761 /* Return a simplified tree node for the truth-negation of ARG. This
3762 never alters ARG itself. We assume that ARG is an operation that
3763 returns a truth value (0 or 1).
3765 FIXME: one would think we would fold the result, but it causes
3766 problems with the dominator optimizer. */
3768 static tree
3770 {
3775 /* If this is a comparison, we can simply invert it, except for
3776 floating-point non-equality comparisons, in which case we just
3777 enclose a TRUTH_NOT_EXPR around what we have. */
3780 {
3783 && flag_trapping_math
3797 }
3800 {
3819 /* Here we can invert either operand. We invert the first operand
3820 unless the second operand is a TRUTH_NOT_EXPR in which case our
3821 result is the XOR of the first operand with the inside of the
3822 negation of the second operand. */
3827 else
3850 {
3857 /* A COND_EXPR may have a throw as one operand, which
3858 then has void type. Just leave void operands
3859 as they are. */
3865 }
3877 CASE_CONVERT:
3881 /* fall through */
3903 }
3904 }
3906 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3907 assume that ARG is an operation that returns a truth value (0 or 1
3908 for scalars, 0 or -1 for vectors). Return the folded expression if
3909 folding is successful. Otherwise, return NULL_TREE. */
3911 static tree
3913 {
3916 ? BIT_NOT_EXPR
3919 }
3921 /* Return a simplified tree node for the truth-negation of ARG. This
3922 never alters ARG itself. We assume that ARG is an operation that
3923 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3925 tree
3927 {
3933 ? BIT_NOT_EXPR
3936 }
3937 \f
3938 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3939 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
3940 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
3941 is the original memory reference used to preserve the alias set of
3942 the access. */
3944 static tree
3948 {
3951 /* Attempt not to lose the access path if possible. */
3953 {
3955 machine_mode nmode;
3957 tree noffset;
3965 && !reversep
3966 && !nreversep
3968 {
3971 }
3972 }
3981 {
3988 }
4003 }
4005 /* Optimize a bit-field compare.
4007 There are two cases: First is a compare against a constant and the
4008 second is a comparison of two items where the fields are at the same
4009 bit position relative to the start of a chunk (byte, halfword, word)
4010 large enough to contain it. In these cases we can avoid the shift
4011 implicit in bitfield extractions.
4013 For constants, we emit a compare of the shifted constant with the
4014 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4015 compared. For two fields at the same position, we do the ANDs with the
4016 similar mask and compare the result of the ANDs.
4018 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4019 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4020 are the left and right operands of the comparison, respectively.
4022 If the optimization described above can be done, we return the resulting
4023 tree. Otherwise we return zero. */
4025 static tree
4028 {
4032 tree unsigned_type;
4035 scalar_int_mode nmode;
4040 tree mask;
4041 tree offset;
4043 /* Get all the information about the extractions being done. If the bit size
4044 is the same as the size of the underlying object, we aren't doing an
4045 extraction at all and so can do nothing. We also don't want to
4046 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4047 then will no longer be able to replace it. */
4062 else
4063 {
4064 /* If this is not a constant, we can only do something if bit positions,
4065 sizes, signedness and storage order are the same. */
4066 rinner
4079 }
4081 /* Honor the C++ memory model and mimic what RTL expansion does. */
4085 {
4089 }
4091 /* See if we can find a mode to refer to this field. We should be able to,
4092 but fail if we can't. */
4100 /* Set signed and unsigned types of the precision of this mode for the
4101 shifts below. */
4104 /* Compute the bit position and size for the new reference and our offset
4105 within it. If the new reference is the same size as the original, we
4106 won't optimize anything, so return zero. */
4116 /* Make the mask to be used against the extracted field. */
4123 {
4127 /* If not comparing with constant, just rework the comparison
4128 and return. */
4136 }
4138 /* Otherwise, we are handling the constant case. See if the constant is too
4139 big for the field. Warn and return a tree for 0 (false) if so. We do
4140 this not only for its own sake, but to avoid having to test for this
4141 error case below. If we didn't, we might generate wrong code.
4143 For unsigned fields, the constant shifted right by the field length should
4144 be all zero. For signed fields, the high-order bits should agree with
4145 the sign bit. */
4148 {
4150 {
4154 }
4155 }
4156 else
4157 {
4160 {
4164 }
4165 }
4170 /* Single-bit compares should always be against zero. */
4172 {
4175 }
4177 /* Make a new bitfield reference, shift the constant over the
4178 appropriate number of bits and mask it with the computed mask
4179 (in case this was a signed field). If we changed it, make a new one. */
4187 mask);
4192 }
4193 \f
4194 /* Subroutine for fold_truth_andor_1: decode a field reference.
4196 If EXP is a comparison reference, we return the innermost reference.
4198 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4199 set to the starting bit number.
4201 If the innermost field can be completely contained in a mode-sized
4202 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4204 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4205 otherwise it is not changed.
4207 *PUNSIGNEDP is set to the signedness of the field.
4209 *PREVERSEP is set to the storage order of the field.
4211 *PMASK is set to the mask used. This is either contained in a
4212 BIT_AND_EXPR or derived from the width of the field.
4214 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4216 Return 0 if this is not a component reference or is one that we can't
4217 do anything with. */
4219 static tree
4224 {
4229 tree unsigned_type;
4232 /* All the optimizations using this function assume integer fields.
4233 There are problems with FP fields since the type_for_size call
4234 below can fail for, e.g., XFmode. */
4238 /* We are interested in the bare arrangement of bits, so strip everything
4239 that doesn't affect the machine mode. However, record the type of the
4240 outermost expression if it may matter below. */
4247 {
4253 }
4264 /* Reject out-of-bound accesses (PR79731). */
4272 /* If the number of bits in the reference is the same as the bitsize of
4273 the outer type, then the outer type gives the signedness. Otherwise
4274 (in case of a small bitfield) the signedness is unchanged. */
4278 /* Compute the mask to access the bitfield. */
4287 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4295 }
4297 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4298 bit positions and MASK is SIGNED. */
4300 static int
4302 {
4306 /* If this function returns true when the type of the mask is
4307 UNSIGNED, then there will be errors. In particular see
4308 gcc.c-torture/execute/990326-1.c. There does not appear to be
4309 any documentation paper trail as to why this is so. But the pre
4310 wide-int worked with that restriction and it has been preserved
4311 here. */
4316 }
4318 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4319 represents the sign bit of EXP's type. If EXP represents a sign
4320 or zero extension, also test VAL against the unextended type.
4321 The return value is the (sub)expression whose sign bit is VAL,
4322 or NULL_TREE otherwise. */
4324 tree
4326 {
4328 tree t;
4330 /* Tree EXP must have an integral type. */
4335 /* Tree VAL must be an integer constant. */
4344 /* Handle extension from a narrower type. */
4350 }
4352 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4353 to be evaluated unconditionally. */
4355 static int
4357 {
4358 /* Strip any conversions that don't change the machine mode. */
4367 /* Don't regard global variables as simple. They may be
4368 allocated in ways unknown to the compiler (shared memory,
4369 #pragma weak, etc). */
4372 /* Weakrefs are not safe to be read, since they can be NULL.
4373 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4374 have DECL_WEAK flag set. */
4376 /* Loading a static variable is unduly expensive, but global
4377 registers aren't expensive. */
4379 }
4381 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4382 to be evaluated unconditionally.
4383 I addition to simple_operand_p, we assume that comparisons, conversions,
4384 and logic-not operations are simple, if their operands are simple, too. */
4386 static bool
4388 {
4408 }
4410 \f
4411 /* The following functions are subroutines to fold_range_test and allow it to
4412 try to change a logical combination of comparisons into a range test.
4414 For example, both
4415 X == 2 || X == 3 || X == 4 || X == 5
4416 and
4417 X >= 2 && X <= 5
4418 are converted to
4419 (unsigned) (X - 2) <= 3
4421 We describe each set of comparisons as being either inside or outside
4422 a range, using a variable named like IN_P, and then describe the
4423 range with a lower and upper bound. If one of the bounds is omitted,
4424 it represents either the highest or lowest value of the type.
4426 In the comments below, we represent a range by two numbers in brackets
4427 preceded by a "+" to designate being inside that range, or a "-" to
4428 designate being outside that range, so the condition can be inverted by
4429 flipping the prefix. An omitted bound is represented by a "-". For
4430 example, "- [-, 10]" means being outside the range starting at the lowest
4431 possible value and ending at 10, in other words, being greater than 10.
4432 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4433 always false.
4435 We set up things so that the missing bounds are handled in a consistent
4436 manner so neither a missing bound nor "true" and "false" need to be
4437 handled using a special case. */
4439 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4440 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4441 and UPPER1_P are nonzero if the respective argument is an upper bound
4442 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4443 must be specified for a comparison. ARG1 will be converted to ARG0's
4444 type if both are specified. */
4446 static tree
4449 {
4450 tree tem;
4454 /* If neither arg represents infinity, do the normal operation.
4455 Else, if not a comparison, return infinity. Else handle the special
4456 comparison rules. Note that most of the cases below won't occur, but
4457 are handled for consistency. */
4460 {
4465 }
4470 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4471 for neither. In real maths, we cannot assume open ended ranges are
4472 the same. But, this is computer arithmetic, where numbers are finite.
4473 We can therefore make the transformation of any unbounded range with
4474 the value Z, Z being greater than any representable number. This permits
4475 us to treat unbounded ranges as equal. */
4479 {
4500 }
4503 }
4504 \f
4505 /* Helper routine for make_range. Perform one step for it, return
4506 new expression if the loop should continue or NULL_TREE if it should
4507 stop. */
4509 tree
4513 {
4519 {
4521 /* We can only do something if the range is testing for zero. */
4530 /* We can only do something if the range is testing for zero
4531 and if the second operand is an integer constant. Note that
4532 saying something is "in" the range we make is done by
4533 complementing IN_P since it will set in the initial case of
4534 being not equal to zero; "out" is leaving it alone. */
4541 {
4562 }
4564 /* If this is an unsigned comparison, we also know that EXP is
4565 greater than or equal to zero. We base the range tests we make
4566 on that fact, so we record it here so we can parse existing
4567 range tests. We test arg0_type since often the return type
4568 of, e.g. EQ_EXPR, is boolean. */
4570 {
4574 NULL_TREE))
4579 /* If the high bound is missing, but we have a nonzero low
4580 bound, reverse the range so it goes from zero to the low bound
4581 minus 1. */
4583 {
4588 }
4589 }
4597 /* If flag_wrapv and ARG0_TYPE is signed, make sure
4598 low and high are non-NULL, then normalize will DTRT. */
4601 {
4606 }
4608 /* (-x) IN [a,b] -> x in [-b, -a] */
4620 /* ~ X -> -X - 1 */
4629 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4630 move a constant to the other side. */
4635 /* If EXP is signed, any overflow in the computation is undefined,
4636 so we don't worry about it so long as our computations on
4637 the bounds don't overflow. For unsigned, overflow is defined
4638 and this is exactly the right thing. */
4650 normalize:
4651 /* Check for an unsigned range which has wrapped around the maximum
4652 value thus making n_high < n_low, and normalize it. */
4654 {
4660 /* If the range is of the form +/- [ x+1, x ], we won't
4661 be able to normalize it. But then, it represents the
4662 whole range or the empty set, so make it
4663 +/- [ -, - ]. */
4667 else
4669 }
4670 else
4678 CASE_CONVERT:
4696 /* If we're converting arg0 from an unsigned type, to exp,
4697 a signed type, we will be doing the comparison as unsigned.
4698 The tests above have already verified that LOW and HIGH
4699 are both positive.
4701 So we have to ensure that we will handle large unsigned
4702 values the same way that the current signed bounds treat
4703 negative values. */
4706 {
4707 tree high_positive;
4708 tree equiv_type;
4709 /* For fixed-point modes, we need to pass the saturating flag
4710 as the 2nd parameter. */
4712 equiv_type
4715 else
4716 equiv_type
4719 /* A range without an upper bound is, naturally, unbounded.
4720 Since convert would have cropped a very large value, use
4721 the max value for the destination type. */
4722 high_positive
4729 high_positive),
4732 /* If the low bound is specified, "and" the range with the
4733 range for which the original unsigned value will be
4734 positive. */
4736 {
4739 integer_zero_node),
4740 high_positive))
4744 }
4745 else
4746 {
4747 /* Otherwise, "or" the range with the range of the input
4748 that will be interpreted as negative. */
4751 integer_zero_node),
4752 high_positive))
4756 }
4757 }
4766 }
4767 }
4769 /* Given EXP, a logical expression, set the range it is testing into
4770 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4771 actually being tested. *PLOW and *PHIGH will be made of the same
4772 type as the returned expression. If EXP is not a comparison, we
4773 will most likely not be returning a useful value and range. Set
4774 *STRICT_OVERFLOW_P to true if the return value is only valid
4775 because signed overflow is undefined; otherwise, do not change
4776 *STRICT_OVERFLOW_P. */
4778 tree
4781 {
4789 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4790 and see if we can refine the range. Some of the cases below may not
4791 happen, but it doesn't seem worth worrying about this. We "continue"
4792 the outer loop when we've changed something; otherwise we "break"
4793 the switch, which will "break" the while. */
4799 {
4805 {
4813 }
4822 }
4824 /* If EXP is a constant, we can evaluate whether this is true or false. */
4826 {
4833 }
4837 }
4839 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
4840 a bitwise check i.e. when
4841 LOW == 0xXX...X00...0
4842 HIGH == 0xXX...X11...1
4843 Return corresponding mask in MASK and stem in VALUE. */
4845 static bool
4848 {
4871 }
4872 \f
4873 /* Helper routine for build_range_check and match.pd. Return the type to
4874 perform the check or NULL if it shouldn't be optimized. */
4876 tree
4878 {
4879 /* First make sure that arithmetics in this type is valid, then make sure
4880 that it wraps around. */
4886 {
4889 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4890 for the type in question, as we rely on this here. */
4900 else
4902 }
4904 }
4906 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4907 type, TYPE, return an expression to test if EXP is in (or out of, depending
4908 on IN_P) the range. Return 0 if the test couldn't be created. */
4910 tree
4913 {
4916 /* Disable this optimization for function pointer expressions
4917 on targets that require function pointer canonicalization. */
4924 {
4930 }
4952 value);
4955 {
4957 {
4961 }
4963 }
4965 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4967 {
4971 {
4973 {
4976 etype
4978 else
4981 }
4984 }
4985 }
4987 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4988 This requires wrap-around arithmetics for the type of the expression. */
5008 }
5009 \f
5010 /* Return the predecessor of VAL in its type, handling the infinite case. */
5012 static tree
5014 {
5020 else
5023 }
5025 /* Return the successor of VAL in its type, handling the infinite case. */
5027 static tree
5029 {
5035 else
5038 }
5040 /* Given two ranges, see if we can merge them into one. Return 1 if we
5041 can, 0 if we can't. Set the output range into the specified parameters. */
5043 bool
5046 {
5050 tree tem;
5060 /* Make range 0 be the range that starts first, or ends last if they
5061 start at the same value. Swap them if it isn't. */
5064 || (lowequal
5067 {
5071 }
5073 /* Now flag two cases, whether the ranges are disjoint or whether the
5074 second range is totally subsumed in the first. Note that the tests
5075 below are simplified by the ones above. */
5081 /* We now have four cases, depending on whether we are including or
5082 excluding the two ranges. */
5084 {
5085 /* If they don't overlap, the result is false. If the second range
5086 is a subset it is the result. Otherwise, the range is from the start
5087 of the second to the end of the first. */
5092 else
5094 }
5097 {
5098 /* If they don't overlap, the result is the first range. If they are
5099 equal, the result is false. If the second range is a subset of the
5100 first, and the ranges begin at the same place, we go from just after
5101 the end of the second range to the end of the first. If the second
5102 range is not a subset of the first, or if it is a subset and both
5103 ranges end at the same place, the range starts at the start of the
5104 first range and ends just before the second range.
5105 Otherwise, we can't describe this as a single range. */
5111 {
5116 {
5117 /* We are in the weird situation where high0 > high1 but
5118 high1 has no successor. Punt. */
5120 }
5121 }
5123 {
5128 {
5129 /* low0 < low1 but low1 has no predecessor. Punt. */
5131 }
5132 }
5133 else
5135 }
5138 {
5139 /* If they don't overlap, the result is the second range. If the second
5140 is a subset of the first, the result is false. Otherwise,
5141 the range starts just after the first range and ends at the
5142 end of the second. */
5147 else
5148 {
5153 {
5154 /* high1 > high0 but high0 has no successor. Punt. */
5156 }
5157 }
5158 }
5160 else
5161 {
5162 /* The case where we are excluding both ranges. Here the complex case
5163 is if they don't overlap. In that case, the only time we have a
5164 range is if they are adjacent. If the second is a subset of the
5165 first, the result is the first. Otherwise, the range to exclude
5166 starts at the beginning of the first range and ends at the end of the
5167 second. */
5169 {
5174 else
5175 {
5176 /* Canonicalize - [min, x] into - [-, x]. */
5179 {
5182 GET_MODE_BITSIZE
5185 /* FALLTHROUGH */
5198 }
5200 /* Canonicalize - [x, max] into - [x, -]. */
5203 {
5206 GET_MODE_BITSIZE
5209 /* FALLTHROUGH */
5225 }
5227 /* The ranges might be also adjacent between the maximum and
5228 minimum values of the given type. For
5229 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5230 return + [x + 1, y - 1]. */
5232 {
5239 }
5240 else
5242 }
5243 }
5246 else
5248 }
5252 }
5253 \f
5255 /* Subroutine of fold, looking inside expressions of the form
5256 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5257 of the COND_EXPR. This function is being used also to optimize
5258 A op B ? C : A, by reversing the comparison first.
5260 Return a folded expression whose code is not a COND_EXPR
5261 anymore, or NULL_TREE if no folding opportunity is found. */
5263 static tree
5266 {
5271 tree tem;
5276 /* If we have A op 0 ? A : -A, consider applying the following
5277 transformations:
5279 A == 0? A : -A same as -A
5280 A != 0? A : -A same as A
5281 A >= 0? A : -A same as abs (A)
5282 A > 0? A : -A same as abs (A)
5283 A <= 0? A : -A same as -abs (A)
5284 A < 0? A : -A same as -abs (A)
5286 None of these transformations work for modes with signed
5287 zeros. If A is +/-0, the first two transformations will
5288 change the sign of the result (from +0 to -0, or vice
5289 versa). The last four will fix the sign of the result,
5290 even though the original expressions could be positive or
5291 negative, depending on the sign of A.
5293 Note that all these transformations are correct if A is
5294 NaN, since the two alternatives (A and -A) are also NaNs. */
5301 /* In the case that A is of the form X-Y, '-A' (arg2) may
5302 have already been folded to Y-X, check for that. */
5310 {
5322 /* Fall through. */
5333 /* FALLTHRU */
5343 }
5345 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5346 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5347 both transformations are correct when A is NaN: A != 0
5348 is then true, and A == 0 is false. */
5352 {
5357 }
5359 /* Try some transformations of A op B ? A : B.
5361 A == B? A : B same as B
5362 A != B? A : B same as A
5363 A >= B? A : B same as max (A, B)
5364 A > B? A : B same as max (B, A)
5365 A <= B? A : B same as min (A, B)
5366 A < B? A : B same as min (B, A)
5368 As above, these transformations don't work in the presence
5369 of signed zeros. For example, if A and B are zeros of
5370 opposite sign, the first two transformations will change
5371 the sign of the result. In the last four, the original
5372 expressions give different results for (A=+0, B=-0) and
5373 (A=-0, B=+0), but the transformed expressions do not.
5375 The first two transformations are correct if either A or B
5376 is a NaN. In the first transformation, the condition will
5377 be false, and B will indeed be chosen. In the case of the
5378 second transformation, the condition A != B will be true,
5379 and A will be chosen.
5381 The conversions to max() and min() are not correct if B is
5382 a number and A is not. The conditions in the original
5383 expressions will be false, so all four give B. The min()
5384 and max() versions would give a NaN instead. */
5387 /* Avoid these transformations if the COND_EXPR may be used
5388 as an lvalue in the C++ front-end. PR c++/19199. */
5389 && (in_gimple_form
5395 {
5401 {
5410 /* In C++ a ?: expression can be an lvalue, so put the
5411 operand which will be used if they are equal first
5412 so that we can convert this back to the
5413 corresponding COND_EXPR. */
5415 {
5423 }
5430 {
5438 }
5451 }
5452 }
5455 }
5458 \f
5459 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5460 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5461 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5462 false) >= 2)
5463 #endif
5465 /* EXP is some logical combination of boolean tests. See if we can
5466 merge it into some range test. Return the new tree if so. */
5468 static tree
5471 {
5487 /* If this is an OR operation, invert both sides; we will invert
5488 again at the end. */
5492 /* If both expressions are the same, if we can merge the ranges, and we
5493 can build the range test, return it or it inverted. If one of the
5494 ranges is always true or always false, consider it to be the same
5495 expression as the other. */
5503 {
5507 }
5509 /* On machines where the branch cost is expensive, if this is a
5510 short-circuited branch and the underlying object on both sides
5511 is the same, make a non-short-circuit operation. */
5513 && !flag_sanitize_coverage
5518 {
5519 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5520 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5521 which cases we can't do this. */
5529 {
5538 {
5541 WARN_STRICT_OVERFLOW_COMPARISON);
5545 }
5546 }
5547 }
5550 }
5551 \f
5552 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
5553 bit value. Arrange things so the extra bits will be set to zero if and
5554 only if C is signed-extended to its full width. If MASK is nonzero,
5555 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5557 static tree
5559 {
5562 tree temp;
5567 /* We work by getting just the sign bit into the low-order bit, then
5568 into the high-order bit, then sign-extend. We then XOR that value
5569 with C. */
5573 /* We must use a signed type in order to get an arithmetic right shift.
5574 However, we must also avoid introducing accidental overflows, so that
5575 a subsequent call to integer_zerop will work. Hence we must
5576 do the type conversion here. At this point, the constant is either
5577 zero or one, and the conversion to a signed type can never overflow.
5578 We could get an overflow if this conversion is done anywhere else. */
5587 /* If necessary, convert the type back to match the type of C. */
5592 }
5593 \f
5594 /* For an expression that has the form
5595 (A && B) || ~B
5596 or
5597 (A || B) && ~B,
5598 we can drop one of the inner expressions and simplify to
5599 A || ~B
5600 or
5601 A && ~B
5602 LOC is the location of the resulting expression. OP is the inner
5603 logical operation; the left-hand side in the examples above, while CMPOP
5604 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5605 removing a condition that guards another, as in
5606 (A != NULL && A->...) || A == NULL
5607 which we must not transform. If RHS_ONLY is true, only eliminate the
5608 right-most operand of the inner logical operation. */
5610 static tree
5613 {
5631 {
5634 {
5637 }
5638 }
5640 {
5643 {
5646 }
5647 }
5662 }
5664 /* Find ways of folding logical expressions of LHS and RHS:
5665 Try to merge two comparisons to the same innermost item.
5666 Look for range tests like "ch >= '0' && ch <= '9'".
5667 Look for combinations of simple terms on machines with expensive branches
5668 and evaluate the RHS unconditionally.
5670 For example, if we have p->a == 2 && p->b == 4 and we can make an
5671 object large enough to span both A and B, we can do this with a comparison
5672 against the object ANDed with the a mask.
5674 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5675 operations to do this with one comparison.
5677 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5678 function and the one above.
5680 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5681 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5683 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5684 two operands.
5686 We return the simplified tree or 0 if no optimization is possible. */
5688 static tree
5691 {
5692 /* If this is the "or" of two comparisons, we can do something if
5693 the comparisons are NE_EXPR. If this is the "and", we can do something
5694 if the comparisons are EQ_EXPR. I.e.,
5695 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5697 WANTED_CODE is this operation code. For single bit fields, we can
5698 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5699 comparison for one-bit fields. */
5720 /* Start by getting the comparison codes. Fail if anything is volatile.
5721 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5722 it were surrounded with a NE_EXPR. */
5731 {
5735 }
5738 {
5742 }
5753 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5756 {
5759 {
5764 }
5767 {
5773 }
5774 }
5779 /* If the RHS can be evaluated unconditionally and its operands are
5780 simple, it wins to evaluate the RHS unconditionally on machines
5781 with expensive branches. In this case, this isn't a comparison
5782 that can be merged. */
5789 {
5790 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5801 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5811 }
5813 /* See if the comparisons can be merged. Then get all the parameters for
5814 each side. */
5839 /* It must be true that the inner operation on the lhs of each
5840 comparison must be the same if we are to be able to do anything.
5841 Then see if we have constants. If not, the same must be true for
5842 the rhs's. */
5851 {
5854 }
5859 else
5862 /* If either comparison code is not correct for our logical operation,
5863 fail. However, we can convert a one-bit comparison against zero into
5864 the opposite comparison against that bit being set in the field. */
5868 {
5870 {
5871 /* Make the left operand unsigned, since we are only interested
5872 in the value of one bit. Otherwise we are doing the wrong
5873 thing below. */
5876 }
5877 else
5879 }
5881 /* This is analogous to the code for l_const above. */
5883 {
5885 {
5888 }
5889 else
5891 }
5893 /* See if we can find a mode that contains both fields being compared on
5894 the left. If we can't, fail. Otherwise, update all constants and masks
5895 to be relative to a field of that size. */
5909 {
5912 }
5920 {
5927 {
5931 }
5932 }
5934 {
5941 {
5945 }
5946 }
5948 /* If the right sides are not constant, do the same for it. Also,
5949 disallow this optimization if a size or signedness mismatch occurs
5950 between the left and right sides. */
5952 {
5955 /* Make sure the two fields on the right
5956 correspond to the left without being swapped. */
5973 {
5976 }
5985 /* Make a mask that corresponds to both fields being compared.
5986 Do this for both items being compared. If the operands are the
5987 same size and the bits being compared are in the same position
5988 then we can do this by masking both and comparing the masked
5989 results. */
5996 {
6010 }
6012 /* There is still another way we can do something: If both pairs of
6013 fields being compared are adjacent, we may be able to make a wider
6014 field containing them both.
6016 Note that we still must mask the lhs/rhs expressions. Furthermore,
6017 the mask must be shifted to account for the shift done by
6018 make_bit_field_ref. */
6027 {
6028 tree type;
6044 /* Convert to the smaller type before masking out unwanted bits. */
6047 {
6049 {
6053 }
6055 {
6059 }
6060 }
6069 }
6072 }
6074 /* Handle the case of comparisons with constants. If there is something in
6075 common between the masks, those bits of the constants must be the same.
6076 If not, the condition is always false. Test for this to avoid generating
6077 incorrect code below. */
6082 {
6084 {
6087 }
6088 else
6089 {
6092 }
6093 }
6098 /* Construct the expression we will return. First get the component
6099 reference we will make. Unless the mask is all ones the width of
6100 that field, perform the mask operation. Then compare with the
6101 merged constant. */
6112 }
6113 \f
6114 /* T is an integer expression that is being multiplied, divided, or taken a
6115 modulus (CODE says which and what kind of divide or modulus) by a
6116 constant C. See if we can eliminate that operation by folding it with
6117 other operations already in T. WIDE_TYPE, if non-null, is a type that
6118 should be used for the computation if wider than our type.
6120 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6121 (X * 2) + (Y * 4). We must, however, be assured that either the original
6122 expression would not overflow or that overflow is undefined for the type
6123 in the language in question.
6125 If we return a non-null expression, it is an equivalent form of the
6126 original computation, but need not be in the original type.
6128 We set *STRICT_OVERFLOW_P to true if the return values depends on
6129 signed overflow being undefined. Otherwise we do not change
6130 *STRICT_OVERFLOW_P. */
6132 static tree
6135 {
6136 /* To avoid exponential search depth, refuse to allow recursion past
6137 three levels. Beyond that (1) it's highly unlikely that we'll find
6138 something interesting and (2) we've probably processed it before
6139 when we built the inner expression. */
6142 tree ret;
6147 depth++;
6149 depth--;
6152 }
6154 static tree
6157 {
6169 /* Don't deal with constants of zero here; they confuse the code below. */
6179 /* Note that we need not handle conditional operations here since fold
6180 already handles those cases. So just do arithmetic here. */
6182 {
6184 /* For a constant, we can always simplify if we are a multiply
6185 or (for divide and modulus) if it is a multiple of our constant. */
6189 {
6192 /* If the multiplication overflowed, we lost information on it.
6193 See PR68142 and PR69845. */
6197 }
6201 /* If op0 is an expression ... */
6207 /* ... and has wrapping overflow, and its type is smaller
6208 than ctype, then we cannot pass through as widening. */
6213 /* ... or this is a truncation (t is narrower than op0),
6214 then we cannot pass through this narrowing. */
6217 /* ... or signedness changes for division or modulus,
6218 then we cannot pass through this conversion. */
6222 /* ... or has undefined overflow while the converted to
6223 type has not, we cannot do the operation in the inner type
6224 as that would introduce undefined overflow. */
6230 /* Pass the constant down and see if we can make a simplification. If
6231 we can, replace this expression with the inner simplification for
6232 possible later conversion to our or some other type. */
6243 /* If widening the type changes it from signed to unsigned, then we
6244 must avoid building ABS_EXPR itself as unsigned. */
6246 {
6250 {
6253 }
6255 }
6256 /* If the constant is negative, we cannot simplify this. */
6259 /* FALLTHROUGH */
6261 /* For division and modulus, type can't be unsigned, as e.g.
6262 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6263 For signed types, even with wrapping overflow, this is fine. */
6272 /* If widening the type changes the signedness, then we can't perform
6273 this optimization as that changes the result. */
6277 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6283 {
6290 }
6294 /* If the second operand is constant, this is a multiplication
6295 or floor division, by a power of two, so we can treat it that
6296 way unless the multiplier or divisor overflows. Signed
6297 left-shift overflow is implementation-defined rather than
6298 undefined in C90, so do not convert signed left shift into
6299 multiplication. */
6302 /* const_binop may not detect overflow correctly,
6303 so check for it explicitly here. */
6312 ctype,
6314 t1),
6319 /* See if we can eliminate the operation on both sides. If we can, we
6320 can return a new PLUS or MINUS. If we can't, the only remaining
6321 cases where we can do anything are if the second operand is a
6322 constant. */
6329 /* If not multiplication, we can only do this if both operands
6330 are divisible by c. */
6333 {
6338 }
6340 /* If this was a subtraction, negate OP1 and set it to be an addition.
6341 This simplifies the logic below. */
6343 {
6345 /* If OP1 was not easily negatable, the constant may be OP0. */
6347 {
6350 }
6351 }
6356 /* If either OP1 or C are negative, this optimization is not safe for
6357 some of the division and remainder types while for others we need
6358 to change the code. */
6360 {
6368 }
6370 /* If it's a multiply or a division/modulus operation of a multiple
6371 of our constant, do the operation and verify it doesn't overflow. */
6375 {
6378 /* We allow the constant to overflow with wrapping semantics. */
6382 }
6383 else
6386 /* If we have an unsigned type, we cannot widen the operation since it
6387 will change the result if the original computation overflowed. */
6391 /* The last case is if we are a multiply. In that case, we can
6392 apply the distributive law to commute the multiply and addition
6393 if the multiplication of the constants doesn't overflow
6394 and overflow is defined. With undefined overflow
6395 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
6401 op1);
6406 /* We have a special case here if we are doing something like
6407 (C * 8) % 4 since we know that's zero. */
6410 /* If the multiplication can overflow we cannot optimize this. */
6415 {
6418 }
6420 /* ... fall through ... */
6424 /* If we can extract our operation from the LHS, do so and return a
6425 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6426 do something only if the second operand is a constant. */
6442 /* If these are the same operation types, we can associate them
6443 assuming no overflow. */
6445 {
6460 }
6462 /* If these operations "cancel" each other, we have the main
6463 optimizations of this pass, which occur when either constant is a
6464 multiple of the other, in which case we replace this with either an
6465 operation or CODE or TCODE.
6467 If we have an unsigned type, we cannot do this since it will change
6468 the result if the original computation overflowed. */
6475 {
6478 {
6485 }
6488 {
6495 }
6496 }
6501 }
6504 }
6505 \f
6506 /* Return a node which has the indicated constant VALUE (either 0 or
6507 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6508 and is of the indicated TYPE. */
6510 tree
6512 {
6521 else
6523 }
6526 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6527 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6528 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6529 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6530 COND is the first argument to CODE; otherwise (as in the example
6531 given here), it is the second argument. TYPE is the type of the
6532 original expression. Return NULL_TREE if no simplification is
6533 possible. */
6535 static tree
6540 {
6550 {
6554 /* If this operand throws an expression, then it does not make
6555 sense to try to perform a logical or arithmetic operation
6556 involving it. */
6561 }
6564 {
6569 }
6570 else
6571 /* Detect the case of mixing vector and scalar types - bail out. */
6577 /* This transformation is only worthwhile if we don't have to wrap ARG
6578 in a SAVE_EXPR and the operation can be simplified without recursing
6579 on at least one of the branches once its pushed inside the COND_EXPR. */
6588 {
6592 else
6594 }
6596 {
6600 else
6602 }
6604 /* Check that we have simplified at least one of the branches. */
6609 }
6611 \f
6612 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6614 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6615 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6616 ADDEND is the same as X.
6618 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6619 and finite. The problematic cases are when X is zero, and its mode
6620 has signed zeros. In the case of rounding towards -infinity,
6621 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6622 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6624 bool
6626 {
6630 /* Don't allow the fold with -fsignaling-nans. */
6634 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6638 /* In a vector or complex, we would need to check the sign of all zeros. */
6642 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6646 /* The mode has signed zeros, and we have to honor their sign.
6647 In this situation, there is only one case we can return true for.
6648 X - 0 is the same as X unless rounding towards -infinity is
6649 supported. */
6651 }
6653 /* Subroutine of match.pd that optimizes comparisons of a division by
6654 a nonzero integer constant against an integer constant, i.e.
6655 X/C1 op C2.
6657 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6658 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
6660 enum tree_code
6663 {
6668 /* We have to do this the hard way to detect unsigned overflow.
6669 prod = int_const_binop (MULT_EXPR, c1, c2); */
6675 {
6679 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6682 }
6684 {
6687 {
6706 }
6707 }
6708 else
6709 {
6710 /* A negative divisor reverses the relational operators. */
6715 {
6734 }
6735 }
6748 }
6751 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6752 equality/inequality test, then return a simplified form of the test
6753 using a sign testing. Otherwise return NULL. TYPE is the desired
6754 result type. */
6756 static tree
6759 tree result_type)
6760 {
6761 /* If this is testing a single bit, we can optimize the test. */
6765 {
6766 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6767 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6771 /* This is only a win if casting to a signed type is cheap,
6772 i.e. when arg00's type is not a partial mode. */
6774 {
6777 result_type,
6780 }
6781 }
6784 }
6786 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6787 equality/inequality test, then return a simplified form of
6788 the test using shifts and logical operations. Otherwise return
6789 NULL. TYPE is the desired result type. */
6791 tree
6794 {
6795 /* If this is testing a single bit, we can optimize the test. */
6799 {
6808 /* First, see if we can fold the single bit test into a sign-bit
6809 test. */
6811 result_type);
6815 /* Otherwise we have (A & C) != 0 where C is a single bit,
6816 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6817 Similarly for (A & C) == 0. */
6819 /* If INNER is a right shift of a constant and it plus BITNUM does
6820 not overflow, adjust BITNUM and INNER. */
6826 {
6829 }
6831 /* If we are going to be able to omit the AND below, we must do our
6832 operations as unsigned. If we must use the AND, we have a choice.
6833 Normally unsigned is faster, but for some machines signed is. */
6851 /* Put the AND last so it can combine with more things. */
6854 /* Make sure to return the proper type. */
6858 }
6860 }
6862 /* Test whether it is preferable two swap two operands, ARG0 and
6863 ARG1, for example because ARG0 is an integer constant and ARG1
6864 isn't. */
6866 bool
6868 {
6882 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6883 for commutative and comparison operators. Ensuring a canonical
6884 form allows the optimizers to find additional redundancies without
6885 having to explicitly check for both orderings. */
6891 /* Put SSA_NAMEs last. */
6897 /* Put variables last. */
6904 }
6907 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6908 means A >= Y && A != MAX, but in this case we know that
6909 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6911 static tree
6913 {
6920 else
6929 {
6932 }
6934 {
6937 }
6938 else
6945 {
6946 /* Convert the pointer types into integer before taking the difference. */
6950 }
6951 else
6958 }
6960 /* Fold a sum or difference of at least one multiplication.
6961 Returns the folded tree or NULL if no simplification could be made. */
6963 static tree
6966 {
6970 /* (A * C) +- (B * C) -> (A+-B) * C.
6971 (A * C) +- A -> A * (C+-1).
6972 We are most concerned about the case where C is a constant,
6973 but other combinations show up during loop reduction. Since
6974 it is not difficult, try all four possibilities. */
6977 {
6980 }
6982 {
6985 }
6986 else
6987 {
6988 /* We cannot generate constant 1 for fract. */
6993 }
6995 {
6998 }
7000 {
7002 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7003 the purpose of this canonicalization. */
7007 {
7010 }
7011 else
7013 }
7014 else
7015 {
7016 /* We cannot generate constant 1 for fract. */
7021 }
7024 /* Prefer factoring a common non-constant. */
7034 /* No identical multiplicands; see if we can find a common
7035 power-of-two factor in non-power-of-two multiplies. This
7036 can help in multi-dimensional array access. */
7039 {
7042 tree maybe_same;
7046 /* Move min of absolute values to int11. */
7048 {
7053 }
7054 else
7058 /* The remainder should not be a constant, otherwise we
7059 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7060 increased the number of multiplications necessary. */
7062 {
7070 }
7071 }
7078 /* We are neither factoring zero nor minus one. */
7086 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7087 same may be minus one and thus the multiplication may overflow. Perform
7088 the sum operation in an unsigned type. */
7093 /* If the sum evaluated to a constant that is not -INF the multiplication
7094 cannot overflow. */
7101 /* Do not resort to unsigned multiplication because
7102 we lose the no-overflow property of the expression. */
7104 }
7106 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7107 specified by EXPR into the buffer PTR of length LEN bytes.
7108 Return the number of bytes placed in the buffer, or zero
7109 upon failure. */
7111 static int
7113 {
7125 /* Dry run. */
7131 {
7133 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7134 number of bytes. */
7138 {
7145 else
7147 }
7148 else
7152 }
7154 }
7157 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7158 specified by EXPR into the buffer PTR of length LEN bytes.
7159 Return the number of bytes placed in the buffer, or zero
7160 upon failure. */
7162 static int
7164 {
7168 FIXED_VALUE_TYPE value;
7183 }
7186 /* Subroutine of native_encode_expr. Encode the REAL_CST
7187 specified by EXPR into the buffer PTR of length LEN bytes.
7188 Return the number of bytes placed in the buffer, or zero
7189 upon failure. */
7191 static int
7193 {
7199 /* There are always 32 bits in each long, no matter the size of
7200 the hosts long. We handle floating point representations with
7201 up to 192 bits. */
7210 /* Dry run. */
7219 {
7224 {
7231 else
7233 }
7234 else
7235 {
7238 {
7239 /* Reverse bytes within each long, or within the entire float
7240 if it's smaller than a long (for HFmode). */
7243 }
7244 }
7249 }
7251 }
7253 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7254 specified by EXPR into the buffer PTR of length LEN bytes.
7255 Return the number of bytes placed in the buffer, or zero
7256 upon failure. */
7258 static int
7260 {
7262 tree part;
7276 }
7279 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7280 specified by EXPR into the buffer PTR of length LEN bytes.
7281 Return the number of bytes placed in the buffer, or zero
7282 upon failure. */
7284 static int
7286 {
7297 {
7299 {
7302 }
7313 }
7315 }
7318 /* Subroutine of native_encode_expr. Encode the STRING_CST
7319 specified by EXPR into the buffer PTR of length LEN bytes.
7320 Return the number of bytes placed in the buffer, or zero
7321 upon failure. */
7323 static int
7325 {
7328 /* Wide-char strings are encoded in target byte-order so native
7329 encoding them is trivial. */
7344 {
7347 {
7350 }
7353 }
7354 else
7357 }
7360 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7361 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7362 buffer PTR of length LEN bytes. If PTR is NULL, don't actually store
7363 anything, just do a dry run. If OFF is not -1 then start
7364 the encoding at byte offset OFF and encode at most LEN bytes.
7365 Return the number of bytes placed in the buffer, or zero upon failure. */
7367 int
7369 {
7370 /* We don't support starting at negative offset and -1 is special. */
7375 {
7396 }
7397 }
7400 /* Subroutine of native_interpret_expr. Interpret the contents of
7401 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7402 If the buffer cannot be interpreted, return NULL_TREE. */
7404 static tree
7406 {
7416 }
7419 /* Subroutine of native_interpret_expr. Interpret the contents of
7420 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7421 If the buffer cannot be interpreted, return NULL_TREE. */
7423 static tree
7425 {
7428 double_int result;
7429 FIXED_VALUE_TYPE fixed_value;
7439 }
7442 /* Subroutine of native_interpret_expr. Interpret the contents of
7443 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7444 If the buffer cannot be interpreted, return NULL_TREE. */
7446 static tree
7448 {
7452 /* There are always 32 bits in each long, no matter the size of
7453 the hosts long. We handle floating point representations with
7454 up to 192 bits. */
7455 REAL_VALUE_TYPE r;
7465 {
7466 /* Both OFFSET and BYTE index within a long;
7467 bitpos indexes the whole float. */
7470 {
7477 else
7479 }
7480 else
7481 {
7484 {
7485 /* Reverse bytes within each long, or within the entire float
7486 if it's smaller than a long (for HFmode). */
7489 }
7490 }
7494 }
7498 }
7501 /* Subroutine of native_interpret_expr. Interpret the contents of
7502 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7503 If the buffer cannot be interpreted, return NULL_TREE. */
7505 static tree
7507 {
7522 }
7525 /* Subroutine of native_interpret_expr. Interpret the contents of
7526 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7527 If the buffer cannot be interpreted, return NULL_TREE. */
7529 static tree
7531 {
7544 {
7549 }
7551 }
7554 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7555 the buffer PTR of length LEN as a constant of type TYPE. For
7556 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7557 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7558 return NULL_TREE. */
7560 tree
7562 {
7564 {
7586 }
7587 }
7589 /* Returns true if we can interpret the contents of a native encoding
7590 as TYPE. */
7592 static bool
7594 {
7596 {
7609 }
7610 }
7613 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7614 TYPE at compile-time. If we're unable to perform the conversion
7615 return NULL_TREE. */
7617 static tree
7619 {
7620 /* We support up to 512-bit values (for V8DFmode). */
7624 /* Check that the host and target are sane. */
7633 }
7635 /* Build an expression for the address of T. Folds away INDIRECT_REF
7636 to avoid confusing the gimplify process. */
7638 tree
7640 {
7641 /* The size of the object is not relevant when talking about its address. */
7646 {
7651 }
7661 {
7666 }
7667 else
7671 }
7673 /* Build an expression for the address of T. */
7675 tree
7677 {
7681 }
7683 /* Fold a unary expression of code CODE and type TYPE with operand
7684 OP0. Return the folded expression if folding is successful.
7685 Otherwise, return NULL_TREE. */
7687 tree
7689 {
7690 tree tem;
7691 tree arg0;
7699 {
7702 {
7703 /* Don't use STRIP_NOPS, because signedness of argument type
7704 matters. */
7706 }
7707 else
7708 {
7709 /* Strip any conversions that don't change the mode. This
7710 is safe for every expression, except for a comparison
7711 expression because its signedness is derived from its
7712 operands.
7714 Note that this is done as an internal manipulation within
7715 the constant folder, in order to find the simplest
7716 representation of the arguments so that their form can be
7717 studied. In any cases, the appropriate type conversions
7718 should be put back in the tree that will get out of the
7719 constant folder. */
7721 }
7724 {
7727 {
7731 }
7732 }
7733 }
7740 {
7747 {
7761 /* If this was a conversion, and all we did was to move into
7762 inside the COND_EXPR, bring it back out. But leave it if
7763 it is a conversion from integer to integer and the
7764 result precision is no wider than a word since such a
7765 conversion is cheap and may be optimized away by combine,
7766 while it couldn't if it were outside the COND_EXPR. Then return
7767 so we don't get into an infinite recursion loop taking the
7768 conversion out and then back in. */
7780 && (INTEGRAL_TYPE_P
7793 }
7794 }
7797 {
7803 CASE_CONVERT:
7807 {
7808 /* If we have (type) (a CMP b) and type is an integral type, return
7809 new expression involving the new type. Canonicalize
7810 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7811 non-integral type.
7812 Do not fold the result as that would not simplify further, also
7813 folding again results in recursions. */
7823 }
7825 /* Handle (T *)&A.B.C for A being of type T and B and C
7826 living at offset zero. This occurs frequently in
7827 C++ upcasting and then accessing the base. */
7831 {
7833 tree offset;
7834 machine_mode mode;
7836 tree base
7840 /* If the reference was to a (constant) zero offset, we can use
7841 the address of the base if it has the same base type
7842 as the result type and the pointer type is unqualified. */
7850 }
7854 /* Detect assigning a bitfield. */
7856 && DECL_BIT_FIELD
7858 {
7859 /* Don't leave an assignment inside a conversion
7860 unless assigning a bitfield. */
7862 /* First do the assignment, then return converted constant. */
7867 }
7869 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7870 constants (if x has signed type, the sign bit cannot be set
7871 in c). This folds extension into the BIT_AND_EXPR.
7872 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7873 very likely don't have maximal range for their precision and this
7874 transformation effectively doesn't preserve non-maximal ranges. */
7878 {
7889 <= HOST_BITS_PER_WIDE_INT
7891 {
7895 cst &= HOST_WIDE_INT_M1U
7899 && !flag_syntax_only
7902 {
7906 }
7907 }
7909 {
7914 }
7915 }
7917 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
7918 cast (T1)X will fold away. We assume that this happens when X itself
7919 is a cast. */
7923 {
7927 return fold_build_pointer_plus_loc
7929 }
7931 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7932 of the same precision, and X is an integer type not narrower than
7933 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7939 {
7945 }
7947 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7948 type of X and Y (integer types only). */
7953 {
7954 /* Be careful not to introduce new overflows. */
7955 tree mult_type;
7958 else
7962 {
7969 }
7970 }
7976 {
7983 }
7994 /* Convert fabs((double)float) into (double)fabsf(float). */
7997 {
8003 targ0));
8004 }
8008 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8027 /* Note that the operand of this must be an int
8028 and its values must be 0 or 1.
8029 ("true" is a fixed value perhaps depending on the language,
8030 but we don't handle values other than 1 correctly yet.) */
8037 /* Fold *&X to X if X is an lvalue. */
8039 {
8046 }
8052 }
8055 /* If the operation was a conversion do _not_ mark a resulting constant
8056 with TREE_OVERFLOW if the original constant was not. These conversions
8057 have implementation defined behavior and retaining the TREE_OVERFLOW
8058 flag here would confuse later passes such as VRP. */
8059 tree
8062 {
8071 }
8073 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
8074 operands OP0 and OP1. LOC is the location of the resulting expression.
8075 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
8076 Return the folded expression if folding is successful. Otherwise,
8077 return NULL_TREE. */
8078 static tree
8081 {
8082 tree tem;
8084 /* We only do these simplifications if we are optimizing. */
8088 /* Check for things like (A || B) && (A || C). We can convert this
8089 to A || (B && C). Note that either operator can be any of the four
8090 truth and/or operations and the transformation will still be
8091 valid. Also note that we only care about order for the
8092 ANDIF and ORIF operators. If B contains side effects, this
8093 might change the truth-value of A. */
8100 {
8120 /* This case if tricky because we must either have commutative
8121 operators or else A10 must not have side-effects. */
8127 a01);
8128 }
8130 /* See if we can build a range comparison. */
8136 {
8140 }
8144 {
8148 }
8150 /* Check for the possibility of merging component references. If our
8151 lhs is another similar operation, try to merge its rhs with our
8152 rhs. Then try to merge our lhs and rhs. */
8162 && !flag_sanitize_coverage
8167 {
8174 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8175 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8176 We don't want to pack more than two leafs to a non-IF AND/OR
8177 expression.
8178 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8179 equal to IF-CODE, then we don't want to add right-hand operand.
8180 If the inner right-hand side of left-hand operand has
8181 side-effects, or isn't simple, then we can't add to it,
8182 as otherwise we might destroy if-sequence. */
8185 /* Needed for sequence points to handle trappings, and
8186 side-effects. */
8188 {
8190 arg1);
8192 tem);
8193 }
8194 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8195 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8198 /* Needed for sequence points to handle trappings, and
8199 side-effects. */
8201 {
8206 }
8207 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8208 into (A OR B).
8209 For sequence point consistancy, we need to check for trapping,
8210 and side-effects. */
8214 }
8217 }
8219 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8220 by changing CODE to reduce the magnitude of constants involved in
8221 ARG0 of the comparison.
8222 Returns a canonicalized comparison tree if a simplification was
8223 possible, otherwise returns NULL_TREE.
8224 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8225 valid if signed overflow is undefined. */
8227 static tree
8231 {
8236 /* Match A +- CST code arg1. We can change this only if overflow
8237 is undefined. */
8240 /* In principle pointers also have undefined overflow behavior,
8241 but that causes problems elsewhere. */
8248 /* Identify the constant in arg0 and its sign. */
8252 /* Overflowed constants and zero will cause problems. */
8257 /* See if we can reduce the magnitude of the constant in
8258 arg0 by changing the comparison code. */
8259 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8263 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8267 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8271 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8275 else
8279 /* Now build the constant reduced in magnitude. But not if that
8280 would produce one outside of its types range. */
8296 }
8298 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8299 overflow further. Try to decrease the magnitude of constants involved
8300 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8301 and put sole constants at the second argument position.
8302 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8304 static tree
8307 {
8308 tree t;
8313 /* Try canonicalization by simplifying arg0. */
8318 {
8322 }
8324 /* Try canonicalization by simplifying arg1 using the swapped
8325 comparison. */
8333 }
8335 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8336 space. This is used to avoid issuing overflow warnings for
8337 expressions like &p->x which can not wrap. */
8339 static bool
8341 {
8348 poly_wide_int wi_offset;
8354 else
8359 precision);
8374 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8375 array. */
8384 }
8386 /* Return a positive integer when the symbol DECL is known to have
8387 a nonzero address, zero when it's known not to (e.g., it's a weak
8388 symbol), and a negative integer when the symbol is not yet in the
8389 symbol table and so whether or not its address is zero is unknown.
8390 For function local objects always return positive integer. */
8391 static int
8393 {
8398 /* Function local objects are never NULL. */
8406 }
8408 /* Subroutine of fold_binary. This routine performs all of the
8409 transformations that are common to the equality/inequality
8410 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8411 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8412 fold_binary should call fold_binary. Fold a comparison with
8413 tree code CODE and type TYPE with operands OP0 and OP1. Return
8414 the folded comparison or NULL_TREE. */
8416 static tree
8419 {
8429 /* For comparisons of pointers we can decompose it to a compile time
8430 comparison of the base objects and the offsets into the object.
8431 This requires at least one operand being an ADDR_EXPR or a
8432 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8438 {
8441 machine_mode mode;
8445 /* Get base and offset for the access. Strip ADDR_EXPR for
8446 get_inner_reference, but put it back by stripping INDIRECT_REF
8447 off the base object if possible. indirect_baseN will be true
8448 if baseN is not an address but refers to the object itself. */
8451 {
8452 base0
8458 else
8460 }
8462 {
8466 {
8467 base0
8473 else
8475 }
8478 else
8482 {
8489 }
8490 }
8494 {
8495 base1
8501 else
8503 }
8505 {
8509 {
8510 base1
8516 else
8518 }
8521 else
8525 {
8532 }
8533 }
8535 /* If we have equivalent bases we might be able to simplify. */
8539 {
8540 /* We can fold this expression to a constant if the non-constant
8541 offset parts are equal. */
8545 && (equality_code
8546 || (indirect_base0
8549 {
8555 "occur when comparing P +- C1 with "
8557 WARN_STRICT_OVERFLOW_CONDITIONAL);
8560 {
8598 }
8599 }
8600 /* We can simplify the comparison to a comparison of the variable
8601 offset parts if the constant offset parts are equal.
8602 Be careful to use signed sizetype here because otherwise we
8603 mess with array offsets in the wrong way. This is possible
8604 because pointer arithmetic is restricted to retain within an
8605 object and overflow on pointer differences is undefined as of
8606 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8608 && (equality_code
8609 || (indirect_base0
8612 {
8613 /* By converting to signed sizetype we cover middle-end pointer
8614 arithmetic which operates on unsigned pointer types of size
8615 type size and ARRAY_REF offsets which are properly sign or
8616 zero extended from their type in case it is narrower than
8617 sizetype. */
8620 else
8624 else
8631 "occur when comparing P +- C1 with "
8633 WARN_STRICT_OVERFLOW_COMPARISON);
8636 }
8637 }
8638 /* For equal offsets we can simplify to a comparison of the
8639 base addresses. */
8641 && (indirect_base0
8643 && (indirect_base1
8648 {
8654 }
8655 /* Comparison between an ordinary (non-weak) symbol and a null
8656 pointer can be eliminated since such symbols must have a non
8657 null address. In C, relational expressions between pointers
8658 to objects and null pointers are undefined. The results
8659 below follow the C++ rules with the additional property that
8660 every object pointer compares greater than a null pointer.
8661 */
8664 /* Avoid folding references to struct members at offset 0 to
8665 prevent tests like '&ptr->firstmember == 0' from getting
8666 eliminated. When ptr is null, although the -> expression
8667 is strictly speaking invalid, GCC retains it as a matter
8668 of QoI. See PR c/44555. */
8671 && indirect_base0
8672 /* The caller guarantees that when one of the arguments is
8673 constant (i.e., null in this case) it is second. */
8675 {
8677 {
8688 }
8689 }
8690 }
8692 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8693 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8694 the resulting offset is smaller in absolute value than the
8695 original one and has the same sign. */
8704 {
8709 tree cst;
8711 "occur when combining constants around "
8714 /* Put the constant on the side where it doesn't overflow and is
8715 of lower absolute value and of same sign than before. */
8722 {
8725 variable1,
8729 }
8737 {
8743 variable2);
8744 }
8745 }
8751 /* If we are comparing an expression that just has comparisons
8752 of two integer values, arithmetic expressions of those comparisons,
8753 and constants, we can simplify it. There are only three cases
8754 to check: the two values can either be equal, the first can be
8755 greater, or the second can be greater. Fold the expression for
8756 those three values. Since each value must be 0 or 1, we have
8757 eight possibilities, each of which corresponds to the constant 0
8758 or 1 or one of the six possible comparisons.
8760 This handles common cases like (a > b) == 0 but also handles
8761 expressions like ((x > y) - (y > x)) > 0, which supposedly
8762 occur in macroized code. */
8765 {
8769 /* Don't handle degenerate cases here; they should already
8770 have been handled anyway. */
8779 {
8783 /* We can't just pass T to eval_subst in case cval1 or cval2
8784 was the same as ARG1. */
8786 tree high_result
8790 arg1);
8791 tree equal_result
8795 arg1);
8796 tree low_result
8800 arg1);
8802 /* All three of these results should be 0 or 1. Confirm they are.
8803 Then use those values to select the proper code to use. */
8808 {
8809 /* Make a 3-bit mask with the high-order bit being the
8810 value for `>', the next for '=', and the low for '<'. */
8814 {
8816 /* Always false. */
8837 /* Always true. */
8839 }
8842 }
8843 }
8844 }
8847 }
8850 /* Subroutine of fold_binary. Optimize complex multiplications of the
8851 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
8852 argument EXPR represents the expression "z" of type TYPE. */
8854 static tree
8856 {
8861 {
8864 }
8866 {
8869 }
8870 else
8871 {
8875 }
8884 }
8887 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
8888 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
8889 true if successful. */
8891 static bool
8893 {
8898 {
8901 }
8903 {
8909 else
8911 }
8912 else
8918 }
8920 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
8921 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
8922 NULL_TREE otherwise. */
8924 static tree
8926 {
8947 {
8948 HOST_WIDE_INT index;
8954 }
8957 {
8963 }
8964 else
8966 }
8968 /* Try to fold a pointer difference of type TYPE two address expressions of
8969 array references AREF0 and AREF1 using location LOC. Return a
8970 simplified expression for the difference or NULL_TREE. */
8972 static tree
8976 {
8981 /* If the bases are array references as well, recurse. If the bases
8982 are pointer indirections compute the difference of the pointers.
8983 If the bases are equal, we are set. */
8986 && (base_offset
8988 use_pointer_diff)))
8991 && (base_offset
8992 = use_pointer_diff
9002 {
9008 base_offset,
9011 }
9013 }
9015 /* If the real or vector real constant CST of type TYPE has an exact
9016 inverse, return it, else return NULL. */
9018 tree
9020 {
9021 REAL_VALUE_TYPE r;
9022 tree unit_type;
9023 machine_mode mode;
9026 {
9036 {
9040 tree_vector_builder elts;
9045 {
9050 }
9053 }
9057 }
9058 }
9060 /* Mask out the tz least significant bits of X of type TYPE where
9061 tz is the number of trailing zeroes in Y. */
9062 static wide_int
9064 {
9069 }
9071 /* Return true when T is an address and is known to be nonzero.
9072 For floating point we further ensure that T is not denormal.
9073 Similar logic is present in nonzero_address in rtlanal.h.
9075 If the return value is based on the assumption that signed overflow
9076 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
9077 change *STRICT_OVERFLOW_P. */
9079 static bool
9081 {
9085 /* Doing something useful for floating point would need more work. */
9091 {
9094 strict_overflow_p);
9100 strict_overflow_p);
9108 }
9111 {
9114 strict_overflow_p);
9122 strict_overflow_p);
9137 strict_overflow_p);
9141 strict_overflow_p);
9144 {
9156 }
9160 }
9162 }
9164 /* Return true when T is an address and is known to be nonzero.
9165 Handle warnings about undefined signed overflow. */
9167 bool
9169 {
9176 "determining that expression is always "
9178 WARN_STRICT_OVERFLOW_MISC);
9180 }
9182 /* Return true if T is known not to be equal to an integer W. */
9184 bool
9186 {
9188 value_range_type rtype;
9190 {
9199 {
9204 }
9209 /* If T has some known zero bits and W has any of those bits set,
9210 then T is known not to be equal to W. */
9218 }
9219 }
9221 /* Fold a binary expression of code CODE and type TYPE with operands
9222 OP0 and OP1. LOC is the location of the resulting expression.
9223 Return the folded expression if folding is successful. Otherwise,
9224 return NULL_TREE. */
9226 tree
9229 {
9244 /* Strip any conversions that don't change the mode. This is
9245 safe for every expression, except for a comparison expression
9246 because its signedness is derived from its operands. So, in
9247 the latter case, only strip conversions that don't change the
9248 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9249 preserved.
9251 Note that this is done as an internal manipulation within the
9252 constant folder, in order to find the simplest representation
9253 of the arguments so that their form can be studied. In any
9254 cases, the appropriate type conversions should be put back in
9255 the tree that will get out of the constant folder. */
9258 {
9261 }
9262 else
9263 {
9266 }
9268 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9269 constant but we can't do arithmetic on them. */
9271 {
9274 {
9278 }
9279 }
9281 /* If this is a commutative operation, and ARG0 is a constant, move it
9282 to ARG1 to reduce the number of tests below. */
9287 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9288 to ARG1 to reduce the number of tests below. */
9297 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9299 First check for cases where an arithmetic operation is applied to a
9300 compound, conditional, or comparison operation. Push the arithmetic
9301 operation inside the compound or conditional to see if any folding
9302 can then be done. Convert comparison to conditional for this purpose.
9303 The also optimizes non-constant cases that used to be done in
9304 expand_expr.
9306 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9307 one of the operands is a comparison and the other is a comparison, a
9308 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9309 code below would make the expression more complex. Change it to a
9310 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9311 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9324 {
9328 boolean_type_node,
9336 }
9340 {
9342 {
9347 tem);
9348 }
9350 {
9355 tem);
9356 }
9361 {
9367 }
9372 {
9378 }
9379 }
9382 {
9384 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9387 {
9393 }
9395 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9398 {
9399 tree base;
9400 poly_int64 coffset;
9409 }
9414 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9420 arg1),
9422 arg0)));
9428 {
9429 /* X + (X / CST) * -CST is X % CST. */
9434 {
9443 cst0));
9444 }
9445 }
9447 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9448 one. Make sure the type is not saturating and has the signedness of
9449 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9450 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9457 {
9461 }
9464 {
9465 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9466 (plus (plus (mult) (mult)) (foo)) so that we can
9467 take advantage of the factoring cases below. */
9476 {
9482 else
9495 parg0),
9497 marg)),
9501 return
9507 parg1)));
9508 }
9509 }
9510 else
9511 {
9512 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9513 to __complex__ ( x, y ). This is not the same for SNaNs or
9514 if signed zeros are involved. */
9518 {
9525 {
9529 {
9535 }
9537 {
9543 }
9544 }
9545 }
9547 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9548 We associate floats only if the user has specified
9549 -fassociative-math. */
9553 {
9558 {
9559 tree tree0;
9562 }
9563 }
9564 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9565 We associate floats only if the user has specified
9566 -fassociative-math. */
9570 {
9575 {
9576 tree tree0;
9579 }
9580 }
9581 }
9583 bit_rotate:
9584 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9585 is a rotate of A by C1 bits. */
9586 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9587 is a rotate of A by B bits.
9588 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
9589 though in this case CODE must be | and not + or ^, otherwise
9590 it doesn't return A when B is 0. */
9591 {
9593 tree rtype;
9602 /* Only create rotates in complete modes. Other cases are not
9603 expanded properly. */
9606 {
9619 {
9624 }
9629 {
9632 code0 == LSHIFT_EXPR
9635 }
9637 {
9647 {
9651 orig_tree01);
9653 }
9654 }
9658 {
9669 {
9673 orig_tree01);
9675 }
9676 }
9677 }
9678 }
9680 associate:
9681 /* In most languages, can't associate operations on floats through
9682 parentheses. Rather than remember where the parentheses were, we
9683 don't associate floats at all, unless the user has specified
9684 -fassociative-math.
9685 And, we need to make sure type is not saturating. */
9689 {
9695 /* Split both trees into variables, constants, and literals. Then
9696 associate each group together, the constants with literals,
9697 then the result with variables. This increases the chances of
9698 literals being recombined later and of generating relocatable
9699 expressions for the sum of a constant and literal. */
9707 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9711 /* With undefined overflow prefer doing association in a type
9712 which wraps on overflow, if that is one of the operand types. */
9715 {
9723 }
9725 /* With undefined overflow we can only associate constants with one
9726 variable, and constants whose association doesn't overflow. */
9729 {
9731 {
9732 /* ??? If split_tree would handle NEGATE_EXPR we could
9733 simply reject these cases and the allowed cases would
9734 be the var0/minus_var1 ones. */
9740 {
9743 }
9750 {
9753 }
9759 /* The only case we can still associate with two variables
9760 is if they cancel out. */
9764 }
9770 }
9772 /* Only do something if we found more than two objects. Otherwise,
9773 nothing has changed and we risk infinite recursion. */
9781 {
9793 {
9797 }
9799 {
9803 }
9805 /* Preserve the MINUS_EXPR if the negative part of the literal is
9806 greater than the positive part. Otherwise, the multiplicative
9807 folding code (i.e extract_muldiv) may be fooled in case
9808 unsigned constants are subtracted, like in the following
9809 example: ((X*2 + 4) - 8U)/2. */
9811 {
9815 /* But avoid ending up with only negated parts. */
9817 {
9821 }
9822 else
9823 {
9827 }
9828 }
9830 /* Don't introduce overflows through reassociation. */
9835 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
9842 /* Eliminate minus_con0. */
9844 {
9851 else
9854 }
9856 /* Eliminate minus_var0. */
9858 {
9862 else
9865 }
9867 return
9870 }
9871 }
9877 /* Fold &a[i] - &a[j] to i-j. */
9882 {
9886 code
9890 }
9892 /* Further transformations are not for pointers. */
9896 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9899 /* If arg0 is e.g. unsigned int and type is int, then this could
9900 introduce UB, because if A is INT_MIN at runtime, the original
9901 expression can be well defined while the latter is not.
9902 See PR83269. */
9911 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
9912 __complex__ ( x, -y ). This is not the same for SNaNs or if
9913 signed zeros are involved. */
9917 {
9924 {
9928 {
9930 arg1r ? arg1r
9935 }
9937 {
9941 arg1i ? arg1i
9944 }
9945 }
9946 }
9948 /* A - B -> A + (-B) if B is easily negatable. */
9952 /* Avoid this transformation if B is a positive REAL_CST. */
9960 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
9961 one. Make sure the type is not saturating and has the signedness of
9962 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9963 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9970 {
9974 }
9980 {
9981 /* Transform x * -C into -x * C if x is easily negatable. */
9996 {
9999 "occur when simplifying "
10001 WARN_STRICT_OVERFLOW_MISC);
10003 }
10005 /* Optimize z * conj(z) for integer complex numbers. */
10012 }
10013 else
10014 {
10015 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10016 This is not the same for NaNs or if signed zeros are
10017 involved. */
10023 {
10026 return
10032 return
10037 }
10039 /* Optimize z * conj(z) for floating point complex numbers.
10040 Guarded by flag_unsafe_math_optimizations as non-finite
10041 imaginary components don't produce scalar results. */
10050 }
10054 /* Canonicalize (X & C1) | C2. */
10058 {
10063 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10071 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10073 {
10076 }
10078 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10079 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10080 mode which allows further optimizations. */
10085 {
10090 {
10093 }
10094 }
10097 {
10102 }
10103 }
10105 /* See if this can be simplified into a rotate first. If that
10106 is unsuccessful continue in the association code. */
10110 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10118 /* See if this can be simplified into a rotate first. If that
10119 is unsuccessful continue in the association code. */
10123 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10128 {
10129 tree tem2;
10136 }
10137 /* Fold ~X & 1 as (X & 1) == 0. */
10141 {
10142 tree tem2;
10149 }
10150 /* Fold !X & 1 as X == 0. */
10153 {
10157 }
10159 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
10160 multiple of 1 << CST. */
10162 {
10169 }
10171 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
10172 bits from CST2. */
10176 {
10178 wide_int masked
10185 {
10186 /* Avoid the transform if arg1 is a mask of some
10187 mode which allows further optimizations. */
10194 }
10195 }
10197 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
10198 ((A & N) + B) & M -> (A + B) & M
10199 Similarly if (N & M) == 0,
10200 ((A | N) + B) & M -> (A + B) & M
10201 and for - instead of + (or unary - instead of +)
10202 and/or ^ instead of |.
10203 If B is constant and (B & M) == 0, fold into A & M. */
10205 {
10214 {
10217 wide_int cst0;
10219 /* Now we know that arg0 is (C + D) or (C - D) or
10220 -C and arg1 (M) is == (1LL << cst) - 1.
10221 Store C into PMOP[0] and D into PMOP[1]. */
10225 {
10228 }
10235 {
10244 {
10247 }
10250 /* If C or D is of the form (A & N) where
10251 (N & M) == M, or of the form (A | N) or
10252 (A ^ N) where (N & M) == 0, replace it with A. */
10256 /* If C or D is a N where (N & M) == 0, it can be
10257 omitted (assumed 0). */
10265 }
10267 /* Only build anything new if we optimized one or both arguments
10268 above. */
10272 {
10275 {
10276 /* Perform the operations in a type that has defined
10277 overflow behavior. */
10283 }
10288 {
10296 else
10298 }
10301 else
10304 /* TEM is now the new binary +, - or unary - replacement. */
10308 }
10309 }
10310 }
10312 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10315 {
10320 return
10322 }
10327 /* Don't touch a floating-point divide by zero unless the mode
10328 of the constant can represent infinity. */
10334 /* (-A) / (-B) -> A / B */
10346 /* Fall through */
10349 /* Simplify A / (B << N) where A and B are positive and B is
10350 a power of 2, to A >> (N + log2(B)). */
10355 {
10358 {
10366 WARN_STRICT_OVERFLOW_MISC);
10372 }
10373 }
10375 /* Fall through */
10383 /* Convert -A / -B to A / B when the type is signed and overflow is
10384 undefined. */
10388 {
10391 "when distributing negation across "
10393 WARN_STRICT_OVERFLOW_MISC);
10398 }
10402 {
10405 "when distributing negation across "
10407 WARN_STRICT_OVERFLOW_MISC);
10412 }
10414 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
10415 operation, EXACT_DIV_EXPR.
10417 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
10418 At one time others generated faster code, it's not clear if they do
10419 after the last round to changes to the DIV code in expmed.c. */
10430 {
10434 WARN_STRICT_OVERFLOW_MISC);
10436 }
10448 {
10452 WARN_STRICT_OVERFLOW_MISC);
10454 }
10462 /* Since negative shift count is not well-defined,
10463 don't try to compute it in the compiler. */
10469 /* If we have a rotate of a bit operation with the rotate count and
10470 the second operand of the bit operation both constant,
10471 permute the two operations. */
10477 {
10485 }
10487 /* Two consecutive rotates adding up to the some integer
10488 multiple of the precision of the type can be ignored. */
10504 /* Note that the operands of this must be ints
10505 and their values must be 0 or 1.
10506 ("true" is a fixed value perhaps depending on the language.) */
10507 /* If first arg is constant zero, return it. */
10510 /* FALLTHRU */
10512 /* If either arg is constant true, drop it. */
10516 /* Preserve sequence points. */
10519 /* If second arg is constant zero, result is zero, but first arg
10520 must be evaluated. */
10523 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
10524 case will be handled here. */
10528 /* !X && X is always false. */
10532 /* X && !X is always false. */
10537 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
10538 means A >= Y && A != MAX, but in this case we know that
10539 A < X <= MAX. */
10543 {
10551 }
10560 /* Note that the operands of this must be ints
10561 and their values must be 0 or true.
10562 ("true" is a fixed value perhaps depending on the language.) */
10563 /* If first arg is constant true, return it. */
10566 /* FALLTHRU */
10568 /* If either arg is constant zero, drop it. */
10572 /* Preserve sequence points. */
10575 /* If second arg is constant true, result is true, but we must
10576 evaluate first arg. */
10579 /* Likewise for first arg, but note this only occurs here for
10580 TRUTH_OR_EXPR. */
10584 /* !X || X is always true. */
10588 /* X || !X is always true. */
10593 /* (X && !Y) || (!X && Y) is X ^ Y */
10596 {
10613 }
10622 /* If the second arg is constant zero, drop it. */
10625 /* If the second arg is constant true, this is a logical inversion. */
10627 {
10630 }
10631 /* Identical arguments cancel to zero. */
10635 /* !X ^ X is always true. */
10640 /* X ^ !X is always true. */
10656 /* bool_var != 1 becomes !bool_var. */
10663 /* bool_var == 0 becomes !bool_var. */
10670 /* !exp != 0 becomes !exp */
10675 /* If this is an EQ or NE comparison with zero and ARG0 is
10676 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
10677 two operations, but the latter can be done in one less insn
10678 on machines that have only two-operand insns or on which a
10679 constant cannot be the first operand. */
10682 {
10687 {
10694 arg1);
10695 }
10698 {
10705 arg1);
10706 }
10707 }
10709 /* If this is an NE or EQ comparison of zero against the result of a
10710 signed MOD operation whose second operand is a power of 2, make
10711 the MOD operation unsigned since it is simpler and equivalent. */
10719 {
10729 }
10731 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
10732 C1 is a valid shift constant, and C2 is a power of two, i.e.
10733 a single bit. */
10737 == INTEGER_CST
10740 {
10745 /* Check for a valid shift count. */
10747 {
10751 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
10752 can be rewritten as (X & (C2 << C1)) != 0. */
10754 {
10759 }
10760 /* Otherwise, for signed (arithmetic) shifts,
10761 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
10762 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
10766 /* Otherwise, of unsigned (logical) shifts,
10767 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
10768 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
10769 else
10773 arg000);
10774 }
10775 }
10777 /* If this is a comparison of a field, we may be able to simplify it. */
10780 /* Handle the constant case even without -O
10781 to make sure the warnings are given. */
10783 {
10787 }
10789 /* Optimize comparisons of strlen vs zero to a compare of the
10790 first character of the string vs zero. To wit,
10791 strlen(ptr) == 0 => *ptr == 0
10792 strlen(ptr) != 0 => *ptr != 0
10793 Other cases should reduce to one of these two (or a constant)
10794 due to the return value of strlen being unsigned. */
10797 {
10805 {
10810 }
10811 }
10813 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
10814 of X. Similarly fold (X >> C) == 0 into X >= 0. */
10818 {
10823 {
10825 {
10828 }
10831 }
10832 }
10834 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
10835 (X & C) == 0 when C is a single bit. */
10840 {
10847 arg1));
10848 }
10850 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
10851 constant C is a power of two, i.e. a single bit. */
10858 {
10862 }
10864 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
10865 when is C is a power of two, i.e. a single bit. */
10872 {
10878 }
10882 {
10885 }
10887 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
10890 {
10898 {
10904 }
10906 {
10912 }
10914 {
10920 }
10922 {
10928 }
10929 }
10933 {
10940 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
10941 operand_equal_p guarantees no side-effects so we don't need
10942 to use omit_one_operand on Z. */
10946 arg10));
10950 arg11));
10954 arg10));
10958 arg11));
10960 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
10963 {
10969 }
10970 }
10972 /* Attempt to simplify equality/inequality comparisons of complex
10973 values. Only lower the comparison if the result is known or
10974 can be simplified to a single scalar comparison. */
10979 {
10984 {
10987 }
10988 else
10989 {
10992 }
10995 {
10998 }
10999 else
11000 {
11003 }
11007 {
11009 {
11014 }
11015 else
11016 {
11021 }
11022 }
11026 {
11028 {
11033 }
11034 else
11035 {
11040 }
11041 }
11042 }
11054 /* Transform comparisons of the form X +- C CMP X. */
11059 {
11064 /* (X - c) > X becomes false. */
11070 /* Likewise (X + c) < X becomes false. */
11076 /* Convert (X - c) <= X to true. */
11083 /* Convert (X + c) >= X to true. */
11089 }
11091 /* If we are comparing an ABS_EXPR with a constant, we can
11092 convert all the cases into explicit comparisons, but they may
11093 well not be faster than doing the ABS and one comparison.
11094 But ABS (X) <= C is a range comparison, which becomes a subtraction
11095 and a comparison, and is probably faster. */
11109 /* Convert ABS_EXPR<x> >= 0 to true. */
11116 {
11119 "when simplifying comparison of "
11121 WARN_STRICT_OVERFLOW_CONDITIONAL);
11124 arg0);
11125 }
11127 /* Convert ABS_EXPR<x> < 0 to false. */
11132 {
11135 "when simplifying comparison of "
11137 WARN_STRICT_OVERFLOW_CONDITIONAL);
11140 arg0);
11141 }
11143 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
11144 and similarly for >= into !=. */
11154 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
11155 otherwise Y might be >= # of bits in X's type and thus e.g.
11156 (unsigned char) (1 << Y) for Y 15 might be 0.
11157 If the cast is widening, then 1 << Y should have unsigned type,
11158 otherwise if Y is number of bits in the signed shift type minus 1,
11159 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
11160 31 might be 0xffffffff80000000. */
11171 {
11177 }
11189 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
11190 {
11202 }
11207 /* When pedantic, a compound expression can be neither an lvalue
11208 nor an integer constant expression. */
11211 /* Don't let (0, 0) be null pointer constant. */
11217 /* An ASSERT_EXPR should never be passed to fold_binary. */
11223 }
11225 /* Used by contains_label_[p1]. */
11227 struct contains_label_data
11228 {
11231 };
11233 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
11234 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
11235 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
11237 static tree
11239 {
11242 {
11253 {
11261 }
11270 }
11271 }
11273 /* Return whether the sub-tree ST contains a label which is accessible from
11274 outside the sub-tree. */
11276 static bool
11278 {
11282 }
11284 /* Fold a ternary expression of code CODE and type TYPE with operands
11285 OP0, OP1, and OP2. Return the folded expression if folding is
11286 successful. Otherwise, return NULL_TREE. */
11288 tree
11291 {
11292 tree tem;
11299 /* If this is a commutative operation, and OP0 is a constant, move it
11300 to OP1 to reduce the number of tests below. */
11309 /* Strip any conversions that don't change the mode. This is safe
11310 for every expression, except for a comparison expression because
11311 its signedness is derived from its operands. So, in the latter
11312 case, only strip conversions that don't change the signedness.
11314 Note that this is done as an internal manipulation within the
11315 constant folder, in order to find the simplest representation of
11316 the arguments so that their form can be studied. In any cases,
11317 the appropriate type conversions should be put back in the tree
11318 that will get out of the constant folder. */
11320 {
11323 }
11326 {
11329 }
11332 {
11335 }
11338 {
11342 {
11348 }
11353 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
11354 so all simple results must be passed through pedantic_non_lvalue. */
11356 {
11359 /* Only optimize constant conditions when the selected branch
11360 has the same type as the COND_EXPR. This avoids optimizing
11361 away "c ? x : throw", where the throw has a void type.
11362 Avoid throwing away that operand which contains label. */
11369 }
11371 {
11378 {
11381 {
11389 }
11394 }
11395 }
11397 /* If we have A op B ? A : C, we may be able to convert this to a
11398 simpler expression, depending on the operation and the values
11399 of B and C. Signed zeros prevent all of these transformations,
11400 for reasons given above each one.
11402 Also try swapping the arguments and inverting the conditional. */
11406 {
11410 }
11415 {
11419 {
11423 }
11424 }
11426 /* If the second operand is simpler than the third, swap them
11427 since that produces better jump optimization results. */
11430 {
11432 /* See if this can be inverted. If it can't, possibly because
11433 it was a floating-point inequality comparison, don't do
11434 anything. */
11438 }
11440 /* Convert A ? 1 : 0 to simply A. */
11445 /* If we try to convert OP0 to our type, the
11446 call to fold will try to move the conversion inside
11447 a COND, which will recurse. In that case, the COND_EXPR
11448 is probably the best choice, so leave it alone. */
11452 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
11453 over COND_EXPR in cases such as floating point comparisons. */
11462 arg0)));
11464 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
11469 {
11470 /* sign_bit_p looks through both zero and sign extensions,
11471 but for this optimization only sign extensions are
11472 usable. */
11475 {
11478 {
11481 }
11483 }
11484 /* sign_bit_p only checks ARG1 bits within A's precision.
11485 If <sign bit of A> has wider type than A, bits outside
11486 of A's precision in <sign bit of A> need to be checked.
11487 If they are all 0, this optimization needs to be done
11488 in unsigned A's type, if they are all 1 in signed A's type,
11489 otherwise this can't be done. */
11495 {
11497 tree tem_type;
11510 {
11513 }
11515 {
11518 }
11519 else
11521 }
11524 return
11530 arg1)));
11531 }
11533 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
11534 already handled above. */
11539 {
11549 op1);
11550 }
11552 /* A & N ? N : 0 is simply A & N if N is a power of two. This
11553 is probably obsolete because the first operand should be a
11554 truth value (that's why we have the two cases above), but let's
11555 leave it in until we can confirm this for all front-ends. */
11567 /* Disable the transformations below for vectors, since
11568 fold_binary_op_with_conditional_arg may undo them immediately,
11569 yielding an infinite loop. */
11573 /* Convert A ? B : 0 into A && B if A and B are truth values. */
11582 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
11587 {
11589 /* Only perform transformation if ARG0 is easily inverted. */
11593 ? BIT_IOR_EXPR
11596 op1);
11597 }
11599 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
11604 {
11606 /* Only perform transformation if ARG0 is easily inverted. */
11612 op2);
11613 }
11615 /* Convert A ? 1 : B into A || B if A and B are truth values. */
11627 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
11628 of fold_ternary on them. */
11638 {
11649 {
11654 {
11656 {
11661 }
11667 }
11668 }
11669 }
11671 /* On constants we can use native encode/interpret to constant
11672 fold (nearly) all BIT_FIELD_REFs. */
11678 {
11681 /* Limit us to a reasonable amount of work. To relax the
11682 other limitations we need bit-shifting of the buffer
11683 and rounding up the size. */
11687 {
11689 unsigned HOST_WIDE_INT len
11694 {
11699 }
11700 }
11701 }
11706 /* For integers we can decompose the FMA if possible. */
11718 {
11719 /* Build a vector of integers from the tree mask. */
11720 vec_perm_builder builder;
11724 /* Create a vec_perm_indices for the integer vector. */
11729 /* Check for cases that fold to OP0 or OP1 in their original
11730 element order. */
11737 {
11741 {
11744 }
11745 }
11751 {
11755 }
11759 /* Generate a canonical form of the selector. */
11761 {
11762 /* Some targets are deficient and fail to expand a single
11763 argument permutation while still allowing an equivalent
11764 2-argument version. */
11768 else
11769 {
11773 else
11774 /* Not directly supported with either encoding,
11775 so use the preferred form. */
11777 }
11779 }
11783 }
11787 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
11790 {
11796 wide_int tem2
11800 }
11805 {
11807 unsigned HOST_WIDE_INT elsize
11810 {
11816 {
11822 }
11823 }
11824 }
11830 }
11832 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
11833 of an array (or vector). */
11835 tree
11837 {
11842 {
11845 {
11846 /* Static constructors for variably sized objects makes no sense. */
11850 }
11851 }
11862 offset_int max_index;
11867 {
11868 /* Array constructor might explicitly set index, or specify a range,
11869 or leave index NULL meaning that it is next index after previous
11870 one. */
11872 {
11875 else
11876 {
11880 }
11881 }
11882 else
11883 {
11889 }
11891 /* Do we have match? */
11895 }
11897 }
11899 /* Perform constant folding and related simplification of EXPR.
11900 The related simplifications include x*1 => x, x*0 => 0, etc.,
11901 and application of the associative law.
11902 NOP_EXPR conversions may be removed freely (as long as we
11903 are careful not to change the type of the overall expression).
11904 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
11905 but we can constant-fold them if they have constant operands. */
11907 #ifdef ENABLE_FOLD_CHECKING
11908 # define fold(x) fold_1 (x)
11910 static
11911 #endif
11912 tree
11914 {
11918 tree tem;
11921 /* Return right away if a constant. */
11925 /* CALL_EXPR-like objects with variable numbers of operands are
11926 treated specially. */
11928 {
11930 {
11933 }
11935 }
11938 {
11943 {
11961 }
11962 }
11965 {
11967 {
11974 {
11979 }
11982 }
11984 /* Return a VECTOR_CST if possible. */
11986 {
11992 tree val;
11998 }
12006 }
12008 #ifdef ENABLE_FOLD_CHECKING
12009 #undef fold
12016 /* When --enable-checking=fold, compute a digest of expr before
12017 and after actual fold call to see if fold did not accidentally
12018 change original expr. */
12020 tree
12022 {
12023 tree ret;
12043 }
12045 void
12047 {
12058 }
12060 static void
12062 {
12064 }
12066 static void
12069 {
12075 recursive_label:
12085 {
12086 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
12091 }
12099 {
12100 /* Allow these fields to be modified. */
12101 tree tmp;
12110 {
12113 }
12114 }
12125 {
12128 {
12144 }
12148 {
12161 }
12178 {
12184 }
12187 {
12189 {
12192 }
12194 }
12205 {
12208 }
12218 }
12219 }
12221 /* Helper function for outputting the checksum of a tree T. When
12222 debugging with gdb, you can "define mynext" to be "next" followed
12223 by "call debug_fold_checksum (op0)", then just trace down till the
12224 outputs differ. */
12226 DEBUG_FUNCTION void
12228 {
12243 }
12245 #endif
12247 /* Fold a unary tree expression with code CODE of type TYPE with an
12248 operand OP0. LOC is the location of the resulting expression.
12249 Return a folded expression if successful. Otherwise, return a tree
12250 expression with code CODE of type TYPE with an operand OP0. */
12252 tree
12255 {
12256 tree tem;
12257 #ifdef ENABLE_FOLD_CHECKING
12266 #endif
12272 #ifdef ENABLE_FOLD_CHECKING
12279 #endif
12281 }
12283 /* Fold a binary tree expression with code CODE of type TYPE with
12284 operands OP0 and OP1. LOC is the location of the resulting
12285 expression. Return a folded expression if successful. Otherwise,
12286 return a tree expression with code CODE of type TYPE with operands
12287 OP0 and OP1. */
12289 tree
12292 MEM_STAT_DECL)
12293 {
12294 tree tem;
12295 #ifdef ENABLE_FOLD_CHECKING
12312 #endif
12318 #ifdef ENABLE_FOLD_CHECKING
12333 #endif
12335 }
12337 /* Fold a ternary tree expression with code CODE of type TYPE with
12338 operands OP0, OP1, and OP2. Return a folded expression if
12339 successful. Otherwise, return a tree expression with code CODE of
12340 type TYPE with operands OP0, OP1, and OP2. */
12342 tree
12345 {
12346 tree tem;
12347 #ifdef ENABLE_FOLD_CHECKING
12371 #endif
12378 #ifdef ENABLE_FOLD_CHECKING
12401 #endif
12403 }
12405 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
12406 arguments in ARGARRAY, and a null static chain.
12407 Return a folded expression if successful. Otherwise, return a CALL_EXPR
12408 of type TYPE from the given operands as constructed by build_call_array. */
12410 tree
12413 {
12414 tree tem;
12415 #ifdef ENABLE_FOLD_CHECKING
12434 #endif
12440 #ifdef ENABLE_FOLD_CHECKING
12456 #endif
12458 }
12460 /* Perform constant folding and related simplification of initializer
12461 expression EXPR. These behave identically to "fold_buildN" but ignore
12462 potential run-time traps and exceptions that fold must preserve. */
12464 #define START_FOLD_INIT \
12465 int saved_signaling_nans = flag_signaling_nans;\
12466 int saved_trapping_math = flag_trapping_math;\
12467 int saved_rounding_math = flag_rounding_math;\
12468 int saved_trapv = flag_trapv;\
12469 int saved_folding_initializer = folding_initializer;\
12470 flag_signaling_nans = 0;\
12471 flag_trapping_math = 0;\
12472 flag_rounding_math = 0;\
12473 flag_trapv = 0;\
12474 folding_initializer = 1;
12476 #define END_FOLD_INIT \
12477 flag_signaling_nans = saved_signaling_nans;\
12478 flag_trapping_math = saved_trapping_math;\
12479 flag_rounding_math = saved_rounding_math;\
12480 flag_trapv = saved_trapv;\
12481 folding_initializer = saved_folding_initializer;
12483 tree
12486 {
12487 tree result;
12488 START_FOLD_INIT;
12492 END_FOLD_INIT;
12494 }
12496 tree
12499 {
12500 tree result;
12501 START_FOLD_INIT;
12505 END_FOLD_INIT;
12507 }
12509 tree
12512 {
12513 tree result;
12514 START_FOLD_INIT;
12518 END_FOLD_INIT;
12520 }
12522 #undef START_FOLD_INIT
12523 #undef END_FOLD_INIT
12525 /* Determine if first argument is a multiple of second argument. Return 0 if
12526 it is not, or we cannot easily determined it to be.
12528 An example of the sort of thing we care about (at this point; this routine
12529 could surely be made more general, and expanded to do what the *_DIV_EXPR's
12530 fold cases do now) is discovering that
12532 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12534 is a multiple of
12536 SAVE_EXPR (J * 8)
12538 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
12540 This code also handles discovering that
12542 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12544 is a multiple of 8 so we don't have to worry about dealing with a
12545 possible remainder.
12547 Note that we *look* inside a SAVE_EXPR only to determine how it was
12548 calculated; it is not safe for fold to do much of anything else with the
12549 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
12550 at run time. For example, the latter example above *cannot* be implemented
12551 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
12552 evaluation time of the original SAVE_EXPR is not necessarily the same at
12553 the time the new expression is evaluated. The only optimization of this
12554 sort that would be valid is changing
12556 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
12558 divided by 8 to
12560 SAVE_EXPR (I) * SAVE_EXPR (J)
12562 (where the same SAVE_EXPR (J) is used in the original and the
12563 transformed version). */
12565 int
12567 {
12578 {
12580 /* Bitwise and provides a power of two multiple. If the mask is
12581 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
12589 {
12595 {
12598 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
12600 {
12604 {
12607 }
12608 }
12610 }
12611 }
12616 /* It is impossible to prove if op0 - op1 is multiple of bottom
12617 precisely, so be conservative here checking if both op0 and op1
12618 are multiple of bottom. Note we check the second operand first
12619 since it's usually simpler. */
12624 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
12625 as op0 - 3 if the expression has unsigned type. For example,
12626 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
12636 {
12638 /* const_binop may not detect overflow correctly,
12639 so check for it explicitly here. */
12647 }
12651 /* Can't handle conversions from non-integral or wider integral type. */
12657 /* fall through */
12674 SIGNED);
12680 {
12683 /* Check for special cases to see if top is defined as multiple
12684 of bottom:
12686 top = (X & ~(bottom - 1) ; bottom is power of 2
12688 or
12690 Y = X % bottom
12691 top = X - Y. */
12710 }
12712 /* fall through */
12720 }
12721 }
12723 #define tree_expr_nonnegative_warnv_p(X, Y) \
12726 #define RECURSE(X) \
12727 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
12729 /* Return true if CODE or TYPE is known to be non-negative. */
12731 static bool
12733 {
12736 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
12737 have a signed:1 type (where the value is -1 and 0). */
12740 }
12742 /* Return true if (CODE OP0) is known to be non-negative. If the return
12743 value is based on the assumption that signed overflow is undefined,
12744 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12745 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12747 bool
12750 {
12755 {
12757 /* We can't return 1 if flag_wrapv is set because
12758 ABS_EXPR<INT_MIN> = INT_MIN. */
12762 {
12765 }
12773 CASE_CONVERT:
12774 {
12779 {
12783 {
12787 }
12788 }
12790 {
12796 }
12797 }
12802 }
12804 /* We don't know sign of `t', so be conservative and return false. */
12806 }
12808 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
12809 value is based on the assumption that signed overflow is undefined,
12810 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12811 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12813 bool
12817 {
12822 {
12828 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
12829 both unsigned and at least 2 bits shorter than the result. */
12833 {
12838 {
12842 }
12843 }
12848 {
12849 /* x * x is always non-negative for floating point x
12850 or without overflow. */
12853 {
12858 }
12859 }
12861 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
12862 both unsigned and their total bits is shorter than the result. */
12866 {
12885 {
12895 }
12896 }
12923 }
12925 /* We don't know sign of `t', so be conservative and return false. */
12927 }
12929 /* Return true if T is known to be non-negative. If the return
12930 value is based on the assumption that signed overflow is undefined,
12931 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12932 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12934 bool
12936 {
12941 {
12955 /* Limit the depth of recursion to avoid quadratic behavior.
12956 This is expected to catch almost all occurrences in practice.
12957 If this code misses important cases that unbounded recursion
12958 would not, passes that need this information could be revised
12959 to provide it through dataflow propagation. */
12967 }
12968 }
12970 /* Return true if T is known to be non-negative. If the return
12971 value is based on the assumption that signed overflow is undefined,
12972 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12973 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12975 bool
12978 {
12980 {
12981 CASE_CFN_ACOS:
12982 CASE_CFN_ACOSH:
12983 CASE_CFN_CABS:
12984 CASE_CFN_COSH:
12985 CASE_CFN_ERFC:
12986 CASE_CFN_EXP:
12987 CASE_CFN_EXP10:
12988 CASE_CFN_EXP2:
12989 CASE_CFN_FABS:
12990 CASE_CFN_FDIM:
12991 CASE_CFN_HYPOT:
12992 CASE_CFN_POW10:
12993 CASE_CFN_FFS:
12994 CASE_CFN_PARITY:
12995 CASE_CFN_POPCOUNT:
12996 CASE_CFN_CLZ:
12997 CASE_CFN_CLRSB:
13000 /* Always true. */
13003 CASE_CFN_SQRT:
13004 CASE_CFN_SQRT_FN:
13005 /* sqrt(-0.0) is -0.0. */
13010 CASE_CFN_ASINH:
13011 CASE_CFN_ATAN:
13012 CASE_CFN_ATANH:
13013 CASE_CFN_CBRT:
13014 CASE_CFN_CEIL:
13015 CASE_CFN_CEIL_FN:
13016 CASE_CFN_ERF:
13017 CASE_CFN_EXPM1:
13018 CASE_CFN_FLOOR:
13019 CASE_CFN_FLOOR_FN:
13020 CASE_CFN_FMOD:
13021 CASE_CFN_FREXP:
13022 CASE_CFN_ICEIL:
13023 CASE_CFN_IFLOOR:
13024 CASE_CFN_IRINT:
13025 CASE_CFN_IROUND:
13026 CASE_CFN_LCEIL:
13027 CASE_CFN_LDEXP:
13028 CASE_CFN_LFLOOR:
13029 CASE_CFN_LLCEIL:
13030 CASE_CFN_LLFLOOR:
13031 CASE_CFN_LLRINT:
13032 CASE_CFN_LLROUND:
13033 CASE_CFN_LRINT:
13034 CASE_CFN_LROUND:
13035 CASE_CFN_MODF:
13036 CASE_CFN_NEARBYINT:
13037 CASE_CFN_NEARBYINT_FN:
13038 CASE_CFN_RINT:
13039 CASE_CFN_RINT_FN:
13040 CASE_CFN_ROUND:
13041 CASE_CFN_ROUND_FN:
13042 CASE_CFN_SCALB:
13043 CASE_CFN_SCALBLN:
13044 CASE_CFN_SCALBN:
13045 CASE_CFN_SIGNBIT:
13046 CASE_CFN_SIGNIFICAND:
13047 CASE_CFN_SINH:
13048 CASE_CFN_TANH:
13049 CASE_CFN_TRUNC:
13050 CASE_CFN_TRUNC_FN:
13051 /* True if the 1st argument is nonnegative. */
13054 CASE_CFN_FMAX:
13055 CASE_CFN_FMAX_FN:
13056 /* True if the 1st OR 2nd arguments are nonnegative. */
13059 CASE_CFN_FMIN:
13060 CASE_CFN_FMIN_FN:
13061 /* True if the 1st AND 2nd arguments are nonnegative. */
13064 CASE_CFN_COPYSIGN:
13065 CASE_CFN_COPYSIGN_FN:
13066 /* True if the 2nd argument is nonnegative. */
13069 CASE_CFN_POWI:
13070 /* True if the 1st argument is nonnegative or the second
13071 argument is an even integer. */
13077 CASE_CFN_POW:
13078 /* True if the 1st argument is nonnegative or the second
13079 argument is an even integer valued real. */
13081 {
13082 REAL_VALUE_TYPE c;
13083 HOST_WIDE_INT n;
13088 {
13089 REAL_VALUE_TYPE cint;
13093 }
13094 }
13099 }
13101 }
13103 /* Return true if T is known to be non-negative. If the return
13104 value is based on the assumption that signed overflow is undefined,
13105 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13106 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13108 static bool
13110 {
13116 {
13118 {
13122 /* If the initializer is non-void, then it's a normal expression
13123 that will be assigned to the slot. */
13127 /* Otherwise, the initializer sets the slot in some way. One common
13128 way is an assignment statement at the end of the initializer. */
13130 {
13138 else
13140 }
13146 }
13149 {
13155 arg0,
13156 arg1,
13158 }
13171 }
13172 }
13174 #undef RECURSE
13175 #undef tree_expr_nonnegative_warnv_p
13177 /* Return true if T is known to be non-negative. If the return
13178 value is based on the assumption that signed overflow is undefined,
13179 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13180 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13182 bool
13184 {
13191 {
13213 }
13216 {
13242 }
13243 }
13245 /* Return true if `t' is known to be non-negative. Handle warnings
13246 about undefined signed overflow. */
13248 bool
13250 {
13257 "determining that expression is always "
13259 WARN_STRICT_OVERFLOW_MISC);
13261 }
13264 /* Return true when (CODE OP0) is an address and is known to be nonzero.
13265 For floating point we further ensure that T is not denormal.
13266 Similar logic is present in nonzero_address in rtlanal.h.
13268 If the return value is based on the assumption that signed overflow
13269 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13270 change *STRICT_OVERFLOW_P. */
13272 bool
13275 {
13277 {
13280 strict_overflow_p);
13283 {
13289 strict_overflow_p));
13290 }
13295 strict_overflow_p);
13299 }
13302 }
13304 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
13305 For floating point we further ensure that T is not denormal.
13306 Similar logic is present in nonzero_address in rtlanal.h.
13308 If the return value is based on the assumption that signed overflow
13309 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13310 change *STRICT_OVERFLOW_P. */
13312 bool
13314 tree type,
13315 tree op0,
13317 {
13320 {
13324 {
13325 /* With the presence of negative values it is hard
13326 to say something. */
13333 /* One of operands must be positive and the other non-negative. */
13334 /* We don't set *STRICT_OVERFLOW_P here: even if this value
13335 overflows, on a twos-complement machine the sum of two
13336 nonnegative numbers can never be zero. */
13338 strict_overflow_p)
13340 strict_overflow_p));
13341 }
13346 {
13348 strict_overflow_p)
13350 strict_overflow_p))
13351 {
13354 }
13355 }
13364 {
13367 }
13374 {
13378 /* When both operands are nonzero, then MAX must be too. */
13380 strict_overflow_p))
13383 /* MAX where operand 0 is positive is positive. */
13385 strict_overflow_p);
13386 }
13387 /* MAX where operand 1 is positive is positive. */
13392 {
13396 }
13401 strict_overflow_p)
13403 strict_overflow_p));
13407 }
13410 }
13412 /* Return true when T is an address and is known to be nonzero.
13413 For floating point we further ensure that T is not denormal.
13414 Similar logic is present in nonzero_address in rtlanal.h.
13416 If the return value is based on the assumption that signed overflow
13417 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13418 change *STRICT_OVERFLOW_P. */
13420 bool
13422 {
13425 {
13430 {
13442 /* For objects in symbol table check if we know they are non-zero.
13443 Don't do anything for variables and functions before symtab is built;
13444 it is quite possible that they will be declared weak later. */
13449 /* Constants are never weak. */
13454 }
13462 {
13466 }
13476 }
13478 }
13480 #define integer_valued_real_p(X) \
13483 #define RECURSE(X) \
13484 ((integer_valued_real_p) (X, depth + 1))
13486 /* Return true if the floating point result of (CODE OP0) has an
13487 integer value. We also allow +Inf, -Inf and NaN to be considered
13488 integer values. Return false for signaling NaN.
13490 DEPTH is the current nesting depth of the query. */
13492 bool
13494 {
13496 {
13503 CASE_CONVERT:
13504 {
13511 }
13515 }
13517 }
13519 /* Return true if the floating point result of (CODE OP0 OP1) has an
13520 integer value. We also allow +Inf, -Inf and NaN to be considered
13521 integer values. Return false for signaling NaN.
13523 DEPTH is the current nesting depth of the query. */
13525 bool
13527 {
13529 {
13539 }
13541 }
13543 /* Return true if the floating point result of calling FNDECL with arguments
13544 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
13545 considered integer values. Return false for signaling NaN. If FNDECL
13546 takes fewer than 2 arguments, the remaining ARGn are null.
13548 DEPTH is the current nesting depth of the query. */
13550 bool
13552 {
13554 {
13555 CASE_CFN_CEIL:
13556 CASE_CFN_CEIL_FN:
13557 CASE_CFN_FLOOR:
13558 CASE_CFN_FLOOR_FN:
13559 CASE_CFN_NEARBYINT:
13560 CASE_CFN_NEARBYINT_FN:
13561 CASE_CFN_RINT:
13562 CASE_CFN_RINT_FN:
13563 CASE_CFN_ROUND:
13564 CASE_CFN_ROUND_FN:
13565 CASE_CFN_TRUNC:
13566 CASE_CFN_TRUNC_FN:
13569 CASE_CFN_FMIN:
13570 CASE_CFN_FMIN_FN:
13571 CASE_CFN_FMAX:
13572 CASE_CFN_FMAX_FN:
13577 }
13579 }
13581 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
13582 has an integer value. We also allow +Inf, -Inf and NaN to be
13583 considered integer values. Return false for signaling NaN.
13585 DEPTH is the current nesting depth of the query. */
13587 bool
13589 {
13591 {
13599 /* Limit the depth of recursion to avoid quadratic behavior.
13600 This is expected to catch almost all occurrences in practice.
13601 If this code misses important cases that unbounded recursion
13602 would not, passes that need this information could be revised
13603 to provide it through dataflow propagation. */
13607 depth));
13611 }
13613 }
13615 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
13616 has an integer value. We also allow +Inf, -Inf and NaN to be
13617 considered integer values. Return false for signaling NaN.
13619 DEPTH is the current nesting depth of the query. */
13621 static bool
13623 {
13625 {
13636 }
13638 }
13640 #undef RECURSE
13641 #undef integer_valued_real_p
13643 /* Return true if the floating point expression T has an integer value.
13644 We also allow +Inf, -Inf and NaN to be considered integer values.
13645 Return false for signaling NaN.
13647 DEPTH is the current nesting depth of the query. */
13649 bool
13651 {
13657 {
13673 }
13676 {
13682 {
13691 }
13695 }
13696 }
13698 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
13699 attempt to fold the expression to a constant without modifying TYPE,
13700 OP0 or OP1.
13702 If the expression could be simplified to a constant, then return
13703 the constant. If the expression would not be simplified to a
13704 constant, then return NULL_TREE. */
13706 tree
13708 {
13711 }
13713 /* Given the components of a unary expression CODE, TYPE and OP0,
13714 attempt to fold the expression to a constant without modifying
13715 TYPE or OP0.
13717 If the expression could be simplified to a constant, then return
13718 the constant. If the expression would not be simplified to a
13719 constant, then return NULL_TREE. */
13721 tree
13723 {
13726 }
13728 /* If EXP represents referencing an element in a constant string
13729 (either via pointer arithmetic or array indexing), return the
13730 tree representing the value accessed, otherwise return NULL. */
13732 tree
13734 {
13738 {
13740 tree index;
13741 tree string;
13746 else
13747 {
13751 /* Optimize the special-case of a zero lower bound.
13753 We convert the low_bound to sizetype to avoid some problems
13754 with constant folding. (E.g. suppose the lower bound is 1,
13755 and its mode is QI. Without the conversion,l (ARRAY
13756 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
13757 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
13763 }
13765 scalar_int_mode char_mode;
13777 }
13779 }
13781 /* Return the tree for neg (ARG0) when ARG0 is known to be either
13782 an integer constant, real, or fixed-point constant.
13784 TYPE is the type of the result. */
13786 static tree
13788 {
13792 {
13798 {
13799 FIXED_VALUE_TYPE f;
13804 /* Propagate overflow flags. */
13808 }
13812 {
13819 }
13822 }
13825 }
13827 /* Return the tree for abs (ARG0) when ARG0 is known to be either
13828 an integer constant or real constant.
13830 TYPE is the type of the result. */
13832 tree
13834 {
13838 {
13840 {
13841 /* If the value is unsigned or non-negative, then the absolute value
13842 is the same as the ordinary value. */
13846 /* If the value is negative, then the absolute value is
13847 its negation. */
13848 else
13849 {
13854 }
13855 }
13861 else
13867 }
13870 }
13872 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
13873 constant. TYPE is the type of the result. */
13875 static tree
13877 {
13881 }
13883 /* Given CODE, a relational operator, the target type, TYPE and two
13884 constant operands OP0 and OP1, return the result of the
13885 relational operation. If the result is not a compile time
13886 constant, then return NULL_TREE. */
13888 static tree
13890 {
13893 /* From here on, the only cases we handle are when the result is
13894 known to be a constant. */
13897 {
13901 /* Handle the cases where either operand is a NaN. */
13903 {
13905 {
13933 }
13936 }
13939 }
13942 {
13946 }
13948 /* Handle equality/inequality of complex constants. */
13950 {
13961 else
13963 }
13966 {
13968 {
13969 /* Have vector comparison with scalar boolean result. */
13977 {
13985 }
13987 }
13988 tree_vector_builder elts;
13993 {
14006 }
14009 }
14011 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
14013 To compute GT, swap the arguments and do LT.
14014 To compute GE, do LT and invert the result.
14015 To compute LE, swap the arguments, do LT and invert the result.
14016 To compute NE, do EQ and invert the result.
14018 Therefore, the code below must handle only EQ and LT. */
14021 {
14024 }
14026 /* Note that it is safe to invert for real values here because we
14027 have already handled the one case that it matters. */
14031 {
14034 }
14036 /* Compute a result for LT or EQ if args permit;
14037 Otherwise return T. */
14039 {
14042 else
14044 }
14045 else
14051 }
14053 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
14054 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
14055 itself. */
14057 tree
14059 {
14060 /* If the expression does not have side effects then we don't have to wrap
14061 it with a cleanup point expression. */
14065 /* If the expression is a return, check to see if the expression inside the
14066 return has no side effects or the right hand side of the modify expression
14067 inside the return. If either don't have side effects set we don't need to
14068 wrap the expression in a cleanup point expression. Note we don't check the
14069 left hand side of the modify because it should always be a return decl. */
14071 {
14078 }
14081 }
14083 /* Given a pointer value OP0 and a type TYPE, return a simplified version
14084 of an indirection through OP0, or NULL_TREE if no simplification is
14085 possible. */
14087 tree
14089 {
14091 tree subtype;
14092 poly_uint64 const_op01;
14101 {
14105 /* *&CONST_DECL -> to the value of the const decl. */
14108 /* *&p => p; make sure to handle *&"str"[cst] here. */
14110 {
14114 else
14116 }
14117 /* *(foo *)&fooarray => fooarray[0] */
14120 && (!in_gimple_form
14122 {
14132 }
14133 /* *(foo *)&complexfoo => __real__ complexfoo */
14137 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14140 {
14144 index);
14145 }
14146 }
14150 {
14156 {
14157 tree op00type;
14161 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
14164 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
14165 but we want to treat offsets with MSB set as negative.
14166 For the code below negative offsets are invalid and
14167 TYPE_SIZE of the element is something unsigned, so
14168 check whether op01 fits into poly_int64, which implies
14169 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
14170 then just use poly_uint64 because we want to treat the
14171 value as unsigned. */
14173 {
14175 poly_uint64 max_offset
14179 {
14184 }
14185 }
14186 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
14189 {
14191 const_op01))
14193 }
14194 /* ((foo *)&fooarray)[1] => fooarray[1] */
14197 {
14204 offset_int remainder;
14207 {
14212 }
14213 }
14214 }
14215 }
14217 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
14220 && (!in_gimple_form
14222 {
14223 tree type_domain;
14233 NULL_TREE);
14234 }
14237 }
14239 /* Builds an expression for an indirection through T, simplifying some
14240 cases. */
14242 tree
14244 {
14252 }
14254 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14256 tree
14258 {
14263 else
14265 }
14267 /* Strip non-trapping, non-side-effecting tree nodes from an expression
14268 whose result is ignored. The type of the returned tree need not be
14269 the same as the original expression. */
14271 tree
14273 {
14279 {
14290 else
14296 {
14312 }
14317 }
14318 }
14320 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
14322 tree
14324 {
14330 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14331 have to do anything. Only do this when we are not given a const,
14332 because in that case, this check is more expensive than just
14333 doing it. */
14335 {
14340 }
14342 /* If divisor is a power of two, simplify this to bit manipulation. */
14344 {
14346 {
14360 }
14361 else
14362 {
14363 tree t;
14369 }
14370 }
14371 else
14372 {
14377 }
14380 }
14382 /* Likewise, but round down. */
14384 tree
14386 {
14393 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14394 have to do anything. Only do this when we are not given a const,
14395 because in that case, this check is more expensive than just
14396 doing it. */
14398 {
14403 }
14405 /* If divisor is a power of two, simplify this to bit manipulation. */
14407 {
14408 tree t;
14412 }
14413 else
14414 {
14419 }
14422 }
14424 /* Returns the pointer to the base of the object addressed by EXP and
14425 extracts the information about the offset of the access, storing it
14426 to PBITPOS and POFFSET. */
14428 static tree
14431 {
14432 tree core;
14433 machine_mode mode;
14435 poly_int64 bitsize;
14439 {
14444 }
14446 {
14452 {
14453 poly_offset_int tem
14459 }
14460 }
14461 else
14462 {
14466 }
14469 }
14471 /* Returns true if addresses of E1 and E2 differ by a constant, false
14472 otherwise. If they do, E1 - E2 is stored in *DIFF. */
14474 bool
14476 {
14491 {
14501 }
14503 {
14504 /* If only one of the offsets is non-constant, the difference cannot
14505 be a constant. */
14507 }
14508 else
14513 }
14515 /* Return OFF converted to a pointer offset type suitable as offset for
14516 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
14517 tree
14519 {
14521 }
14523 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14524 tree
14526 {
14529 }
14531 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14532 tree
14534 {
14537 }
14539 /* Return a char pointer for a C string if it is a string constant
14540 or sum of string constant and integer constant. We only support
14541 string constants properly terminated with '\0' character.
14542 If STRLEN is a valid pointer, length (including terminating character)
14543 of returned string is stored to the argument. */
14547 {
14548 tree offset_node;
14559 {
14562 else
14564 }
14569 /* Support only properly null-terminated strings. */
14578 }
14580 #if CHECKING_P
14584 /* Helper functions for writing tests of folding trees. */
14586 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
14588 static void
14590 tree constant)
14591 {
14593 }
14595 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
14596 wrapping WRAPPED_EXPR. */
14598 static void
14600 tree wrapped_expr)
14601 {
14606 }
14608 /* Verify that various arithmetic binary operations are folded
14609 correctly. */
14611 static void
14613 {
14619 /* Addition. */
14620 /* 1 <-- (0 + 1) */
14622 one);
14624 one);
14626 /* (nonlvalue)x <-- (x + 0) */
14628 x);
14630 /* Subtraction. */
14631 /* 0 <-- (x - x) */
14633 zero);
14635 x);
14637 /* Multiplication. */
14638 /* 0 <-- (x * 0) */
14640 zero);
14642 /* (nonlvalue)x <-- (x * 1) */
14644 x);
14645 }
14647 /* Verify that various binary operations on vectors are folded
14648 correctly. */
14650 static void
14652 {
14658 /* Verify equality tests that return a scalar boolean result. */
14664 }
14666 /* Verify folding of VEC_DUPLICATE_EXPRs. */
14668 static void
14670 {
14673 /* This will be 1 if VEC_MODE isn't a vector mode. */
14680 }
14682 /* Run all of the selftests within this file. */
14684 void
14686 {
14690 }