| blob | 9f7beae14e504ae9837162faac796d4f8433c044 |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2022 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. */
89 /* Nonzero if we are folding constants inside an initializer or a C++
90 manifestly-constant-evaluated context; zero otherwise.
91 Should be used when folding in initializer enables additional
92 optimizations. */
95 /* Nonzero if we are folding C++ manifestly-constant-evaluated context; zero
96 otherwise.
97 Should be used when certain constructs shouldn't be optimized
98 during folding in that context. */
101 /* The following constants represent a bit based encoding of GCC's
102 comparison operators. This encoding simplifies transformations
103 on relational comparison operators, such as AND and OR. */
121 };
154 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
155 Otherwise, return LOC. */
157 static location_t
159 {
162 }
164 /* Similar to protected_set_expr_location, but never modify x in place,
165 if location can and needs to be set, unshare it. */
169 {
175 {
178 }
180 }
181 \f
182 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
183 division and returns the quotient. Otherwise returns
184 NULL_TREE. */
186 tree
188 {
189 widest_int quo;
196 }
197 \f
198 /* This is nonzero if we should defer warnings about undefined
199 overflow. This facility exists because these warnings are a
200 special case. The code to estimate loop iterations does not want
201 to issue any warnings, since it works with expressions which do not
202 occur in user code. Various bits of cleanup code call fold(), but
203 only use the result if it has certain characteristics (e.g., is a
204 constant); that code only wants to issue a warning if the result is
205 used. */
209 /* If a warning about undefined overflow is deferred, this is the
210 warning. Note that this may cause us to turn two warnings into
211 one, but that is fine since it is sufficient to only give one
212 warning per expression. */
216 /* If a warning about undefined overflow is deferred, this is the
217 level at which the warning should be emitted. */
221 /* Start deferring overflow warnings. We could use a stack here to
222 permit nested calls, but at present it is not necessary. */
224 void
226 {
228 }
230 /* Stop deferring overflow warnings. If there is a pending warning,
231 and ISSUE is true, then issue the warning if appropriate. STMT is
232 the statement with which the warning should be associated (used for
233 location information); STMT may be NULL. CODE is the level of the
234 warning--a warn_strict_overflow_code value. This function will use
235 the smaller of CODE and the deferred code when deciding whether to
236 issue the warning. CODE may be zero to mean to always use the
237 deferred code. */
239 void
241 {
243 location_t locus;
248 {
254 }
265 /* Use the smallest code level when deciding to issue the
266 warning. */
275 else
278 }
280 /* Stop deferring overflow warnings, ignoring any deferred
281 warnings. */
283 void
285 {
287 }
289 /* Whether we are deferring overflow warnings. */
291 bool
293 {
295 }
297 /* This is called when we fold something based on the fact that signed
298 overflow is undefined. */
300 void
302 {
304 {
307 {
310 }
311 }
314 }
315 \f
316 /* Return true if the built-in mathematical function specified by CODE
317 is odd, i.e. -f(x) == f(-x). */
319 bool
321 {
323 {
324 CASE_CFN_ASIN:
325 CASE_CFN_ASINH:
326 CASE_CFN_ATAN:
327 CASE_CFN_ATANH:
328 CASE_CFN_CASIN:
329 CASE_CFN_CASINH:
330 CASE_CFN_CATAN:
331 CASE_CFN_CATANH:
332 CASE_CFN_CBRT:
333 CASE_CFN_CPROJ:
334 CASE_CFN_CSIN:
335 CASE_CFN_CSINH:
336 CASE_CFN_CTAN:
337 CASE_CFN_CTANH:
338 CASE_CFN_ERF:
339 CASE_CFN_LLROUND:
340 CASE_CFN_LROUND:
341 CASE_CFN_ROUND:
342 CASE_CFN_ROUNDEVEN:
343 CASE_CFN_ROUNDEVEN_FN:
344 CASE_CFN_SIN:
345 CASE_CFN_SINH:
346 CASE_CFN_TAN:
347 CASE_CFN_TANH:
348 CASE_CFN_TRUNC:
351 CASE_CFN_LLRINT:
352 CASE_CFN_LRINT:
353 CASE_CFN_NEARBYINT:
354 CASE_CFN_RINT:
359 }
361 }
363 /* Check whether we may negate an integer constant T without causing
364 overflow. */
366 bool
368 {
369 tree type;
378 }
380 /* Determine whether an expression T can be cheaply negated using
381 the function negate_expr without introducing undefined overflow. */
383 static bool
385 {
386 tree type;
395 {
400 /* Check that -CST will not overflow type. */
413 /* We want to canonicalize to positive real constants. Pretend
414 that only negative ones can be easily negated. */
422 {
426 /* Steps don't prevent negation. */
433 }
448 /* -(A + B) -> (-B) - A. */
451 /* -(A + B) -> (-A) - B. */
455 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
464 /* INT_MIN/n * n doesn't overflow while negating one operand it does
465 if n is a (negative) power of two. */
476 /* Fall through. */
489 /* In general we can't negate A in A / B, because if A is INT_MIN and
490 B is not 1 we change the sign of the result. */
494 /* In general we can't negate B in A / B, because if A is INT_MIN and
495 B is 1, we may turn this into INT_MIN / -1 which is undefined
496 and actually traps on some architectures. */
505 /* Negate -((double)float) as (double)(-float). */
507 {
511 }
515 /* Negate -f(x) as f(-x). */
521 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
523 {
527 }
532 }
534 }
536 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
537 simplification is possible.
538 If negate_expr_p would return true for T, NULL_TREE will never be
539 returned. */
541 static tree
543 {
545 tree tem;
548 {
549 /* Convert - (~A) to A + 1. */
573 {
578 }
582 {
583 tree_vector_builder elts;
587 {
592 }
595 }
618 {
619 /* -(A + B) -> (-B) - A. */
621 {
625 }
627 /* -(A + B) -> (-A) - B. */
629 {
633 }
634 }
638 /* - (A - B) -> B - A */
649 /* Fall through. */
653 {
662 }
670 /* In general we can't negate A in A / B, because if A is INT_MIN and
671 B is not 1 we change the sign of the result. */
677 /* In general we can't negate B in A / B, because if A is INT_MIN and
678 B is 1, we may turn this into INT_MIN / -1 which is undefined
679 and actually traps on some architectures. */
691 /* Convert -((double)float) into (double)(-float). */
693 {
697 }
701 /* Negate -f(x) as f(-x). */
704 {
710 }
714 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
716 {
719 {
726 }
727 }
732 }
735 }
737 /* A wrapper for fold_negate_expr_1. */
739 static tree
741 {
748 }
750 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T cannot be
751 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
752 return NULL_TREE. */
754 static tree
756 {
758 location_t loc;
771 }
772 \f
773 /* Split a tree IN into a constant, literal and variable parts that could be
774 combined with CODE to make IN. "constant" means an expression with
775 TREE_CONSTANT but that isn't an actual constant. CODE must be a
776 commutative arithmetic operation. Store the constant part into *CONP,
777 the literal in *LITP and return the variable part. If a part isn't
778 present, set it to null. If the tree does not decompose in this way,
779 return the entire tree as the variable part and the other parts as null.
781 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
782 case, we negate an operand that was subtracted. Except if it is a
783 literal for which we use *MINUS_LITP instead.
785 If NEGATE_P is true, we are negating all of IN, again except a literal
786 for which we use *MINUS_LITP instead. If a variable part is of pointer
787 type, it is negated after converting to TYPE. This prevents us from
788 generating illegal MINUS pointer expression. LOC is the location of
789 the converted variable part.
791 If IN is itself a literal or constant, return it as appropriate.
793 Note that we do not guarantee that any of the three values will be the
794 same type as IN, but they will have the same signedness and mode. */
796 static tree
800 {
808 /* Strip any conversions that don't change the machine mode or signedness. */
817 /* We can associate addition and subtraction together (even
818 though the C standard doesn't say so) for integers because
819 the value is not affected. For reals, the value might be
820 affected, so we can't. */
826 {
832 /* First see if either of the operands is a literal, then a constant. */
845 /* If we haven't dealt with either operand, this is not a case we can
846 decompose. Otherwise, VAR is either of the ones remaining, if any. */
851 else
854 /* Now do any needed negations. */
861 }
866 {
867 /* -1 - X is folded to ~X, undo that here. Do _not_ do this
868 when IN is constant. */
871 }
872 else
876 {
889 }
899 }
901 /* Re-associate trees split by the above function. T1 and T2 are
902 either expressions to associate or null. Return the new
903 expression, if any. LOC is the location of the new expression. If
904 we build an operation, do it in TYPE and with CODE. */
906 static tree
908 {
910 {
913 }
917 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
918 try to fold this since we will have infinite recursion. But do
919 deal with any NEGATE_EXPRs. */
923 {
925 {
938 }
940 {
943 }
947 }
951 }
952 \f
953 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
954 for use in int_const_binop, size_binop and size_diffop. */
956 static bool
958 {
965 {
974 }
979 }
981 /* Combine two wide ints ARG1 and ARG2 under operation CODE to produce
982 a new constant in RES. Return FALSE if we don't know how to
983 evaluate CODE at compile-time. */
985 bool
989 {
990 wide_int tmp;
993 {
1015 /* It's unclear from the C standard whether shifts can overflow.
1016 The following code ignores overflow; perhaps a C standard
1017 interpretation ruling is needed. */
1024 {
1028 else
1030 }
1031 else
1036 else
1115 }
1117 }
1119 /* Combine two poly int's ARG1 and ARG2 under operation CODE to
1120 produce a new constant in RES. Return FALSE if we don't know how
1121 to evaluate CODE at compile-time. */
1123 static bool
1127 {
1131 {
1149 else
1156 else
1169 }
1171 }
1173 /* Combine two integer constants ARG1 and ARG2 under operation CODE to
1174 produce a new constant. Return NULL_TREE if we don't know how to
1175 evaluate CODE at compile-time. */
1177 tree
1180 {
1181 poly_wide_int poly_res;
1187 {
1193 }
1202 }
1204 /* Return true if binary operation OP distributes over addition in operand
1205 OPNO, with the other operand being held constant. OPNO counts from 1. */
1207 static bool
1209 {
1211 {
1222 }
1223 }
1225 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1226 constant. We assume ARG1 and ARG2 have the same data type, or at least
1227 are the same kind of constant and the same machine mode. Return zero if
1228 combining the constants is not allowed in the current operating mode. */
1230 static tree
1232 {
1233 /* Sanity check for the recursive cases. */
1241 {
1247 }
1250 {
1251 machine_mode mode;
1252 REAL_VALUE_TYPE d1;
1253 REAL_VALUE_TYPE d2;
1254 REAL_VALUE_TYPE value;
1255 REAL_VALUE_TYPE result;
1259 /* The following codes are handled by real_arithmetic. */
1261 {
1272 }
1280 /* Don't perform operation if we honor signaling NaNs and
1281 either operand is a signaling NaN. */
1287 /* Don't perform operation if it would raise a division
1288 by zero exception. */
1294 /* If either operand is a NaN, just return it. Otherwise, set up
1295 for floating-point trap; we return an overflow. */
1297 {
1298 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1299 is off. */
1303 }
1305 {
1306 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1307 is off. */
1311 }
1316 /* Don't constant fold this floating point operation if
1317 both operands are not NaN but the result is NaN, and
1318 flag_trapping_math. Such operations should raise an
1319 invalid operation exception. */
1327 /* Don't constant fold this floating point operation if
1328 the result has overflowed and flag_trapping_math. */
1336 /* Don't constant fold this floating point operation if the
1337 result may dependent upon the run-time rounding mode and
1338 flag_rounding_math is set, or if GCC's software emulation
1339 is unable to accurately represent the result. */
1349 }
1352 {
1353 FIXED_VALUE_TYPE f1;
1354 FIXED_VALUE_TYPE f2;
1355 FIXED_VALUE_TYPE result;
1360 /* The following codes are handled by fixed_arithmetic. */
1362 {
1374 {
1381 }
1386 }
1393 /* Propagate overflow flags. */
1397 }
1400 {
1409 {
1420 mpc_mul);
1434 mpc_div);
1435 /* Fallthru. */
1441 {
1442 /* Keep this algorithm in sync with
1443 tree-complex.cc:expand_complex_div_straight().
1445 Expand complex division to scalars, straightforward algorithm.
1446 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1447 t = br*br + bi*bi
1448 */
1449 tree magsquared
1453 tree t1
1457 tree t2
1464 }
1465 else
1466 {
1467 /* Keep this algorithm in sync with
1468 tree-complex.cc:expand_complex_div_wide().
1470 Expand complex division to scalars, modified algorithm to minimize
1471 overflow with wide input ranges. */
1477 {
1478 /* In the TRUE branch, we compute
1479 ratio = br/bi;
1480 div = (br * ratio) + bi;
1481 tr = (ar * ratio) + ai;
1482 ti = (ai * ratio) - ar;
1483 tr = tr / div;
1484 ti = ti / div; */
1495 }
1496 else
1497 {
1498 /* In the FALSE branch, we compute
1499 ratio = d/c;
1500 divisor = (d * ratio) + c;
1501 tr = (b * ratio) + a;
1502 ti = b - (a * ratio);
1503 tr = tr / div;
1504 ti = ti / div; */
1516 }
1517 }
1522 }
1526 }
1532 {
1537 /* We can operate directly on the encoding if:
1539 a3 - a2 == a2 - a1 && b3 - b2 == b2 - b1
1540 implies
1541 (a3 op b3) - (a2 op b2) == (a2 op b2) - (a1 op b1)
1543 Addition and subtraction are the supported operators
1544 for which this is true. */
1547 /* We can operate directly on stepped encodings if:
1549 a3 - a2 == a2 - a1
1550 implies:
1551 (a3 op c) - (a2 op c) == (a2 op c) - (a1 op c)
1553 which is true if (x -> x op c) distributes over addition. */
1555 else
1556 /* Similarly in reverse. */
1558 tree_vector_builder elts;
1563 {
1569 /* It is possible that const_binop cannot handle the given
1570 code and return NULL_TREE */
1574 }
1577 }
1579 /* Shifts allow a scalar offset for a vector. */
1582 {
1585 tree_vector_builder elts;
1590 {
1595 /* It is possible that const_binop cannot handle the given
1596 code and return NULL_TREE. */
1600 }
1603 }
1605 }
1607 /* Overload that adds a TYPE parameter to be able to dispatch
1608 to fold_relational_const. */
1610 tree
1612 {
1616 /* ??? Until we make the const_binop worker take the type of the
1617 result as argument put those cases that need it here. */
1619 {
1636 {
1641 }
1647 {
1663 {
1668 ? NOP_EXPR
1675 }
1678 }
1684 {
1707 {
1720 }
1723 }
1726 }
1731 /* Make sure type and arg0 have the same saturating flag. */
1736 }
1738 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1739 Return zero if computing the constants is not possible. */
1741 tree
1743 {
1744 /* Don't perform the operation, other than NEGATE and ABS, if
1745 flag_signaling_nans is on and the operand is a signaling NaN. */
1755 {
1756 CASE_CONVERT:
1763 /* If the source address is 0, and the source address space
1764 cannot have a valid object at 0, fold to dest type null. */
1775 {
1776 /* Can't call fold_negate_const directly here as that doesn't
1777 handle all cases and we might not be able to negate some
1778 constants. */
1783 }
1793 {
1797 }
1805 /* Perform BIT_NOT_EXPR on each element individually. */
1807 {
1808 tree elem;
1810 /* This can cope with stepped encodings because ~x == -1 - x. */
1811 tree_vector_builder elements;
1815 {
1821 }
1824 }
1848 {
1871 else
1876 {
1882 }
1885 }
1894 }
1897 }
1899 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1900 indicates which particular sizetype to create. */
1902 tree
1904 {
1906 }
1907 \f
1908 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1909 is a tree code. The type of the result is taken from the operands.
1910 Both must be equivalent integer types, ala int_binop_types_match_p.
1911 If the operands are constant, so is the result. */
1913 tree
1915 {
1924 /* Handle the special case of two poly_int constants faster. */
1926 {
1927 /* And some specific cases even faster than that. */
1929 {
1936 }
1938 {
1942 }
1944 {
1948 }
1950 /* Handle general case of two integer constants. For sizetype
1951 constant calculations we always want to know about overflow,
1952 even in the unsigned case. */
1956 }
1959 }
1961 /* Given two values, either both of sizetype or both of bitsizetype,
1962 compute the difference between the two values. Return the value
1963 in signed type corresponding to the type of the operands. */
1965 tree
1967 {
1969 tree ctype;
1974 /* If the type is already signed, just do the simple thing. */
1982 else
1985 /* If either operand is not a constant, do the conversions to the signed
1986 type and subtract. The hardware will do the right thing with any
1987 overflow in the subtraction. */
1993 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1994 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1995 overflow) and negate (which can't either). Special-case a result
1996 of zero while we're here. */
2002 else
2006 MINUS_EXPR,
2008 }
2009 \f
2010 /* A subroutine of fold_convert_const handling conversions of an
2011 INTEGER_CST to another integer type. */
2013 static tree
2015 {
2016 /* Given an integer constant, make new constant with new type,
2017 appropriately sign-extended or truncated. Use widest_int
2018 so that any extension is done according ARG1's type. */
2022 }
2024 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2025 to an integer type. */
2027 static tree
2029 {
2031 tree t;
2033 /* The following code implements the floating point to integer
2034 conversion rules required by the Java Language Specification,
2035 that IEEE NaNs are mapped to zero and values that overflow
2036 the target precision saturate, i.e. values greater than
2037 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2038 are mapped to INT_MIN. These semantics are allowed by the
2039 C and C++ standards that simply state that the behavior of
2040 FP-to-integer conversion is unspecified upon overflow. */
2042 wide_int val;
2043 REAL_VALUE_TYPE r;
2047 {
2054 }
2056 /* If R is NaN, return zero and show we have an overflow. */
2058 {
2061 }
2063 /* See if R is less than the lower bound or greater than the
2064 upper bound. */
2067 {
2071 {
2074 }
2075 }
2078 {
2081 {
2084 {
2087 }
2088 }
2089 }
2096 }
2098 /* A subroutine of fold_convert_const handling conversions of a
2099 FIXED_CST to an integer type. */
2101 static tree
2103 {
2104 tree t;
2106 scalar_mode mode;
2108 /* Right shift FIXED_CST to temp by fbit. */
2112 {
2114 HOST_BITS_PER_DOUBLE_INT,
2117 /* Left shift temp to temp_trunc by fbit. */
2119 HOST_BITS_PER_DOUBLE_INT,
2121 }
2122 else
2123 {
2126 }
2128 /* If FIXED_CST is negative, we need to round the value toward 0.
2129 By checking if the fractional bits are not zero to add 1 to temp. */
2135 /* Given a fixed-point constant, make new constant with new type,
2136 appropriately sign-extended or truncated. */
2144 }
2146 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2147 to another floating point type. */
2149 static tree
2151 {
2152 REAL_VALUE_TYPE value;
2153 tree t;
2155 /* Don't perform the operation if flag_signaling_nans is on
2156 and the operand is a signaling NaN. */
2161 /* With flag_rounding_math we should respect the current rounding mode
2162 unless the conversion is exact. */
2170 /* If converting an infinity or NAN to a representation that doesn't
2171 have one, set the overflow bit so that we can produce some kind of
2172 error message at the appropriate point if necessary. It's not the
2173 most user-friendly message, but it's better than nothing. */
2180 /* Regular overflow, conversion produced an infinity in a mode that
2181 can't represent them. */
2186 else
2189 }
2191 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2192 to a floating point type. */
2194 static tree
2196 {
2197 REAL_VALUE_TYPE value;
2198 tree t;
2206 }
2208 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2209 to another fixed-point type. */
2211 static tree
2213 {
2214 FIXED_VALUE_TYPE value;
2215 tree t;
2222 /* Propagate overflow flags. */
2226 }
2228 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2229 to a fixed-point type. */
2231 static tree
2233 {
2234 FIXED_VALUE_TYPE value;
2235 tree t;
2237 double_int di;
2244 else
2252 /* Propagate overflow flags. */
2256 }
2258 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2259 to a fixed-point type. */
2261 static tree
2263 {
2264 FIXED_VALUE_TYPE value;
2265 tree t;
2273 /* Propagate overflow flags. */
2277 }
2279 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2280 type TYPE. If no simplification can be done return NULL_TREE. */
2282 static tree
2284 {
2289 /* We can't widen types, since the runtime value could overflow the
2290 original type before being extended to the new type. */
2301 {
2308 }
2310 {
2312 {
2314 /* Avoid the folding if flag_rounding_math is on and the
2315 conversion is not exact. */
2317 {
2323 }
2325 }
2330 }
2332 {
2339 }
2341 {
2344 {
2347 /* We can't handle steps directly when extending, since the
2348 values need to wrap at the original precision first. */
2349 bool step_ok_p
2353 tree_vector_builder v;
2358 {
2364 }
2366 }
2367 }
2369 }
2371 /* Construct a vector of zero elements of vector type TYPE. */
2373 static tree
2375 {
2376 tree t;
2380 }
2382 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2384 bool
2386 {
2401 {
2423 }
2424 }
2426 /* Convert expression ARG to type TYPE. Used by the middle-end for
2427 simple conversions in preference to calling the front-end's convert. */
2429 tree
2431 {
2433 tree tem;
2444 {
2447 /* Handle conversions between pointers to different address spaces. */
2452 /* fall through */
2457 {
2461 }
2475 {
2479 }
2481 {
2485 }
2487 {
2491 }
2494 {
2512 }
2517 {
2521 }
2524 {
2538 }
2542 {
2551 integer_zero_node));
2553 {
2557 {
2563 }
2571 }
2575 }
2593 }
2594 fold_convert_exit:
2597 }
2598 \f
2599 /* Return false if expr can be assumed not to be an lvalue, true
2600 otherwise. */
2602 static bool
2604 {
2605 /* We only need to wrap lvalue tree codes. */
2607 {
2639 /* Assume the worst for front-end tree codes. */
2643 }
2646 }
2648 /* Return an expr equal to X but certainly not valid as an lvalue. */
2650 tree
2652 {
2653 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2654 us. */
2661 }
2662 \f
2663 /* Given a tree comparison code, return the code that is the logical inverse.
2664 It is generally not safe to do this for floating-point comparisons, except
2665 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2666 ERROR_MARK in this case. */
2668 enum tree_code
2670 {
2676 {
2707 }
2708 }
2710 /* Similar, but return the comparison that results if the operands are
2711 swapped. This is safe for floating-point. */
2713 enum tree_code
2715 {
2717 {
2743 }
2744 }
2747 /* Convert a comparison tree code from an enum tree_code representation
2748 into a compcode bit-based encoding. This function is the inverse of
2749 compcode_to_comparison. */
2751 static enum comparison_code
2753 {
2755 {
2786 }
2787 }
2789 /* Convert a compcode bit-based encoding of a comparison operator back
2790 to GCC's enum tree_code representation. This function is the
2791 inverse of comparison_to_compcode. */
2793 static enum tree_code
2795 {
2797 {
2828 }
2829 }
2831 /* Return true if COND1 tests the opposite condition of COND2. */
2833 bool
2835 {
2838 && (invert_tree_comparison
2845 }
2847 /* Return a tree for the comparison which is the combination of
2848 doing the AND or OR (depending on CODE) of the two operations LCODE
2849 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2850 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2851 if this makes the transformation invalid. */
2853 tree
2858 {
2865 {
2876 }
2879 {
2880 /* Eliminate unordered comparisons, as well as LTGT and ORD
2881 which are not used unless the mode has NaNs. */
2887 }
2889 {
2890 /* Check that the original operation and the optimized ones will trap
2891 under the same condition. */
2902 /* In a short-circuited boolean expression the LHS might be
2903 such that the RHS, if evaluated, will never trap. For
2904 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2905 if neither x nor y is NaN. (This is a mixed blessing: for
2906 example, the expression above will never trap, hence
2907 optimizing it to x < y would be invalid). */
2912 /* If the comparison was short-circuited, and only the RHS
2913 trapped, we may now generate a spurious trap. */
2918 /* If we changed the conditions that cause a trap, we lose. */
2921 }
2927 else
2928 {
2933 }
2934 }
2935 \f
2936 /* Return nonzero if two operands (typically of the same tree node)
2937 are necessarily equal. FLAGS modifies behavior as follows:
2939 If OEP_ONLY_CONST is set, only return nonzero for constants.
2940 This function tests whether the operands are indistinguishable;
2941 it does not test whether they are equal using C's == operation.
2942 The distinction is important for IEEE floating point, because
2943 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2944 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2946 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2947 even though it may hold multiple values during a function.
2948 This is because a GCC tree node guarantees that nothing else is
2949 executed between the evaluation of its "operands" (which may often
2950 be evaluated in arbitrary order). Hence if the operands themselves
2951 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2952 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2953 unset means assuming isochronic (or instantaneous) tree equivalence.
2954 Unless comparing arbitrary expression trees, such as from different
2955 statements, this flag can usually be left unset.
2957 If OEP_PURE_SAME is set, then pure functions with identical arguments
2958 are considered the same. It is used when the caller has other ways
2959 to ensure that global memory is unchanged in between.
2961 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2962 not values of expressions.
2964 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
2965 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
2967 If OEP_BITWISE is set, then require the values to be bitwise identical
2968 rather than simply numerically equal. Do not take advantage of things
2969 like math-related flags or undefined behavior; only return true for
2970 values that are provably bitwise identical in all circumstances.
2972 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2973 any operand with side effect. This is unnecesarily conservative in the
2974 case we know that arg0 and arg1 are in disjoint code paths (such as in
2975 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2976 addresses with TREE_CONSTANT flag set so we know that &var == &var
2977 even if var is volatile. */
2979 bool
2982 {
2990 /* If either is ERROR_MARK, they aren't equal. */
2996 /* Similar, if either does not have a type (like a template id),
2997 they aren't equal. */
3001 /* Bitwise identity makes no sense if the values have different layouts. */
3006 /* We cannot consider pointers to different address space equal. */
3013 /* Check equality of integer constants before bailing out due to
3014 precision differences. */
3016 {
3017 /* Address of INTEGER_CST is not defined; check that we did not forget
3018 to drop the OEP_ADDRESS_OF flags. */
3021 }
3024 {
3025 /* If both types don't have the same signedness, then we can't consider
3026 them equal. We must check this before the STRIP_NOPS calls
3027 because they may change the signedness of the arguments. As pointers
3028 strictly don't have a signedness, require either two pointers or
3029 two non-pointers as well. */
3035 /* If both types don't have the same precision, then it is not safe
3036 to strip NOPs. */
3043 }
3044 #if 0
3045 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
3046 sanity check once the issue is solved. */
3047 else
3048 /* Addresses of conversions and SSA_NAMEs (and many other things)
3049 are not defined. Check that we did not forget to drop the
3050 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
3053 #endif
3055 /* In case both args are comparisons but with different comparison
3056 code, try to swap the comparison operands of one arg to produce
3057 a match and compare that variant. */
3061 {
3069 }
3072 {
3073 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
3075 ;
3077 {
3078 /* If we are interested in comparing addresses ignore
3079 MEM_REF wrappings of the base that can appear just for
3080 TBAA reasons. */
3094 }
3095 else
3097 }
3099 /* When not checking adddresses, this is needed for conversions and for
3100 COMPONENT_REF. Might as well play it safe and always test this. */
3107 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3108 We don't care about side effects in that case because the SAVE_EXPR
3109 takes care of that for us. In all other cases, two expressions are
3110 equal if they have no side effects. If we have two identical
3111 expressions with side effects that should be treated the same due
3112 to the only side effects being identical SAVE_EXPR's, that will
3113 be detected in the recursive calls below.
3114 If we are taking an invariant address of two identical objects
3115 they are necessarily equal as well. */
3122 /* Next handle constant cases, those for which we can return 1 even
3123 if ONLY_CONST is set. */
3126 {
3139 {
3140 /* If we do not distinguish between signed and unsigned zero,
3141 consider them equal. */
3144 }
3148 {
3163 }
3167 flags)
3169 flags));
3180 flags | OEP_ADDRESS_OF
3183 /* In GIMPLE empty constructors are allowed in initializers of
3184 aggregates. */
3188 }
3190 /* Don't handle more cases for OEP_BITWISE, since we can't guarantee that
3191 two instances of undefined behavior will give identical results. */
3195 /* Define macros to test an operand from arg0 and arg1 for equality and a
3196 variant that allows null and views null as being different from any
3197 non-null value. In the latter case, if either is null, the both
3198 must be; otherwise, do the normal comparison. */
3199 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3200 TREE_OPERAND (arg1, N), flags)
3202 #define OP_SAME_WITH_NULL(N) \
3203 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3204 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3207 {
3209 /* Two conversions are equal only if signedness and modes match. */
3211 {
3212 CASE_CONVERT:
3220 }
3230 /* For commutative ops, allow the other order. */
3238 /* If either of the pointer (or reference) expressions we are
3239 dereferencing contain a side effect, these cannot be equal,
3240 but their addresses can be. */
3247 {
3250 {
3254 /* Verify that the access types are compatible. */
3258 }
3263 /* Require the same offset. */
3269 /* Fallthru. */
3277 {
3278 /* Require equal access sizes */
3284 flags)))
3286 /* Verify that access happens in similar types. */
3289 /* Verify that accesses are TBAA compatible. */
3298 /* Verify that alignment is compatible. */
3302 }
3305 /* TARGET_MEM_REF require equal extra operands. */
3316 /* Compare the array index by value if it is constant first as we
3317 may have different types but same value here. */
3323 /* Compare low bound and element size as with OEP_ADDRESS_OF
3324 we have to account for the offset of the ref. */
3329 array_ref_low_bound
3333 array_ref_element_size
3335 flags))));
3338 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3339 may be NULL when we're called to compare MEM_EXPRs. */
3342 {
3345 /* Most of time we only need to compare FIELD_DECLs for equality.
3346 However when determining address look into actual offsets.
3347 These may match for unions and unshared record types. */
3350 {
3353 {
3360 /* Non-FIELD_DECL operands can appear in C++ templates. */
3367 flags))
3369 }
3370 else
3372 }
3373 }
3384 }
3388 {
3390 /* Be sure we pass right ADDRESS_OF flag. */
3407 /* The multiplcation operands are commutative. */
3408 /* FALLTHRU */
3416 /* Otherwise take into account this is a commutative operation. */
3429 /* BIT_INSERT_EXPR has an implict operand as the type precision
3430 of op1. Need to check to make sure they are the same. */
3436 /* FALLTHRU */
3461 /* Virtual table reference. */
3473 {
3478 }
3483 }
3487 {
3491 /* If not both CALL_EXPRs are either internal or normal function
3492 functions, then they are not equal. */
3495 {
3496 /* If the CALL_EXPRs call different internal functions, then they
3497 are not equal. */
3500 }
3501 else
3502 {
3503 /* If the CALL_EXPRs call different functions, then they are not
3504 equal. */
3506 flags))
3508 }
3510 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3511 {
3515 else
3519 }
3521 /* Now see if all the arguments are the same. */
3522 {
3533 /* If we get here and both argument lists are exhausted
3534 then the CALL_EXPRs are equal. */
3536 }
3539 }
3542 /* Consider __builtin_sqrt equal to sqrt. */
3552 {
3553 /* Consider decls with the same name equal. The caller needs
3554 to make sure they refer to the same entity (such as a function
3555 formal parameter). */
3561 }
3566 {
3570 /* In GIMPLE constructors are used only to build vectors from
3571 elements. Individual elements in the constructor must be
3572 indexed in increasing order and form an initial sequence.
3574 We make no effort to compare constructors in generic.
3575 (see sem_variable::equals in ipa-icf which can do so for
3576 constants). */
3581 /* Be sure that vectors constructed have the same representation.
3582 We only tested element precision and modes to match.
3583 Vectors may be BLKmode and thus also check that the number of
3584 parts match. */
3597 {
3602 /* In GIMPLE the indexes can be either NULL or matching i.
3603 Double check this so we won't get false
3604 positives for GENERIC. */
3612 }
3614 }
3617 {
3618 /* Compare the STATEMENT_LISTs. */
3624 {
3625 /* The lists don't have the same number of statements. */
3631 flags & (OEP_LEXICOGRAPHIC
3634 }
3635 }
3640 {
3651 }
3655 }
3657 #undef OP_SAME
3658 #undef OP_SAME_WITH_NULL
3659 }
3661 /* Generate a hash value for an expression. This can be used iteratively
3662 by passing a previous result as the HSTATE argument. */
3664 void
3667 {
3673 {
3676 }
3686 {
3687 /* Alas, constants aren't shared, so we can't rely on pointer
3688 identity. */
3698 {
3702 else
3706 }
3708 {
3712 }
3722 {
3729 }
3731 /* We can just compare by pointer. */
3735 /* The node itself doesn't matter. */
3739 /* Ignore. */
3742 /* A list of expressions, for a CALL_EXPR or as the elements of a
3743 VECTOR_CST. */
3748 {
3754 {
3755 /* In GIMPLE the indexes can be either NULL or matching i. */
3760 }
3762 }
3764 {
3765 tree_stmt_iterator i;
3770 }
3779 /* When referring to a built-in FUNCTION_DECL, use the __builtin__ form.
3780 Otherwise nodes that compare equal according to operand_equal_p might
3781 get different hash codes. However, don't do this for machine specific
3782 or front end builtins, since the function code is overloaded in those
3783 cases. */
3786 {
3789 }
3790 /* FALL THROUGH */
3793 {
3797 }
3801 {
3802 /* DECL's have a unique ID */
3804 }
3806 {
3807 /* For comparisons that can be swapped, use the lower
3808 tree code. */
3815 }
3817 {
3818 /* NOP_EXPR and CONVERT_EXPR are considered equal by
3819 operand_equal_p. */
3823 /* Don't hash the type, that can lead to having nodes which
3824 compare equal according to operand_equal_p, but which
3825 have different hash codes. Make sure to include signedness
3826 in the hash computation. */
3829 }
3830 /* For OEP_ADDRESS_OF, hash MEM_EXPR[&decl, 0] the same as decl. */
3838 /* Don't ICE on FE specific trees, or their arguments etc.
3839 during operand_equal_p hash verification. */
3842 else
3843 {
3849 {
3865 {
3870 else
3871 {
3877 }
3879 }
3893 {
3894 /* The multiplication operands are commutative. */
3901 }
3909 /* For TARGET_EXPR, just hash on the TARGET_EXPR_SLOT.
3910 Usually different TARGET_EXPRs just should use
3911 different temporaries in their slots. */
3916 /* Virtual table reference. */
3924 {
3926 /* We compute mangled names only when free_lang_data is run.
3927 In that case we can hash precisely. */
3930 hstate.add_object
3931 (IDENTIFIER_HASH_VALUE
3933 }
3937 }
3939 /* Don't hash the type, that can lead to having nodes which
3940 compare equal according to operand_equal_p, but which
3941 have different hash codes. */
3943 {
3944 /* Make sure to include signness in the hash computation. */
3947 }
3950 {
3951 /* It's a commutative expression. We want to hash it the same
3952 however it appears. We do this by first hashing both operands
3953 and then rehashing based on the order of their independent
3954 hashes. */
3959 }
3960 else
3964 }
3966 }
3967 }
3969 bool
3972 {
3973 /* When checking and unless comparing DECL names, verify that if
3974 the outermost operand_equal_p call returns non-zero then ARG0
3975 and ARG1 have the same hash value. */
3977 {
3979 {
3981 {
3988 }
3990 }
3991 else
3995 }
3998 }
4003 /* Conveinece wrapper around operand_compare class because usually we do
4004 not need to play with the valueizer. */
4006 bool
4008 {
4010 }
4012 namespace inchash
4013 {
4015 /* Generate a hash value for an expression. This can be used iteratively
4016 by passing a previous result as the HSTATE argument.
4018 This function is intended to produce the same hash for expressions which
4019 would compare equal using operand_equal_p. */
4020 void
4022 {
4024 }
4026 }
4027 \f
4028 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
4029 with a different signedness or a narrower precision. */
4031 static bool
4033 {
4041 /* Discard any conversions that don't change the modes of ARG0 and ARG1
4042 and see if the inner values are the same. This removes any
4043 signedness comparison, which doesn't matter here. */
4051 /* Discard a single widening conversion from ARG1 and see if the inner
4052 value is the same as ARG0. */
4061 }
4062 \f
4063 /* See if ARG is an expression that is either a comparison or is performing
4064 arithmetic on comparisons. The comparisons must only be comparing
4065 two different values, which will be stored in *CVAL1 and *CVAL2; if
4066 they are nonzero it means that some operands have already been found.
4067 No variables may be used anywhere else in the expression except in the
4068 comparisons.
4070 If this is true, return 1. Otherwise, return zero. */
4072 static bool
4074 {
4078 /* We can handle some of the tcc_expression cases here. */
4087 {
4106 /* First see if we can handle the first operand, then the second. For
4107 the second operand, we know *CVAL1 can't be zero. It must be that
4108 one side of the comparison is each of the values; test for the
4109 case where this isn't true by failing if the two operands
4110 are the same. */
4119 ;
4123 ;
4124 else
4128 ;
4132 ;
4133 else
4140 }
4141 }
4142 \f
4143 /* ARG is a tree that is known to contain just arithmetic operations and
4144 comparisons. Evaluate the operations in the tree substituting NEW0 for
4145 any occurrence of OLD0 as an operand of a comparison and likewise for
4146 NEW1 and OLD1. */
4148 static tree
4151 {
4156 /* We can handle some of the tcc_expression cases here. */
4164 {
4179 {
4198 }
4199 /* Fall through - ??? */
4202 {
4206 /* We need to check both for exact equality and tree equality. The
4207 former will be true if the operand has a side-effect. In that
4208 case, we know the operand occurred exactly once. */
4221 }
4225 }
4226 }
4227 \f
4228 /* Return a tree for the case when the result of an expression is RESULT
4229 converted to TYPE and OMITTED was previously an operand of the expression
4230 but is now not needed (e.g., we folded OMITTED * 0).
4232 If OMITTED has side effects, we must evaluate it. Otherwise, just do
4233 the conversion of RESULT to TYPE. */
4235 tree
4237 {
4240 /* If the resulting operand is an empty statement, just return the omitted
4241 statement casted to void. */
4251 }
4253 /* Return a tree for the case when the result of an expression is RESULT
4254 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
4255 of the expression but are now not needed.
4257 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
4258 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
4259 evaluated before OMITTED2. Otherwise, if neither has side effects,
4260 just do the conversion of RESULT to TYPE. */
4262 tree
4265 {
4274 }
4276 \f
4277 /* Return a simplified tree node for the truth-negation of ARG. This
4278 never alters ARG itself. We assume that ARG is an operation that
4279 returns a truth value (0 or 1).
4281 FIXME: one would think we would fold the result, but it causes
4282 problems with the dominator optimizer. */
4284 static tree
4286 {
4291 /* If this is a comparison, we can simply invert it, except for
4292 floating-point non-equality comparisons, in which case we just
4293 enclose a TRUTH_NOT_EXPR around what we have. */
4296 {
4299 && flag_trapping_math
4312 }
4315 {
4334 /* Here we can invert either operand. We invert the first operand
4335 unless the second operand is a TRUTH_NOT_EXPR in which case our
4336 result is the XOR of the first operand with the inside of the
4337 negation of the second operand. */
4342 else
4365 {
4372 /* A COND_EXPR may have a throw as one operand, which
4373 then has void type. Just leave void operands
4374 as they are. */
4380 }
4392 CASE_CONVERT:
4396 /* fall through */
4418 }
4419 }
4421 /* Fold the truth-negation of ARG. This never alters ARG itself. We
4422 assume that ARG is an operation that returns a truth value (0 or 1
4423 for scalars, 0 or -1 for vectors). Return the folded expression if
4424 folding is successful. Otherwise, return NULL_TREE. */
4426 static tree
4428 {
4431 ? BIT_NOT_EXPR
4434 }
4436 /* Return a simplified tree node for the truth-negation of ARG. This
4437 never alters ARG itself. We assume that ARG is an operation that
4438 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
4440 tree
4442 {
4448 ? BIT_NOT_EXPR
4451 }
4452 \f
4453 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
4454 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
4455 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
4456 is the original memory reference used to preserve the alias set of
4457 the access. */
4459 static tree
4463 {
4466 /* Attempt not to lose the access path if possible. */
4468 {
4470 machine_mode nmode;
4472 tree noffset;
4480 && !reversep
4481 && !nreversep
4483 {
4486 }
4487 }
4496 {
4503 }
4518 }
4520 /* Optimize a bit-field compare.
4522 There are two cases: First is a compare against a constant and the
4523 second is a comparison of two items where the fields are at the same
4524 bit position relative to the start of a chunk (byte, halfword, word)
4525 large enough to contain it. In these cases we can avoid the shift
4526 implicit in bitfield extractions.
4528 For constants, we emit a compare of the shifted constant with the
4529 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4530 compared. For two fields at the same position, we do the ANDs with the
4531 similar mask and compare the result of the ANDs.
4533 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4534 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4535 are the left and right operands of the comparison, respectively.
4537 If the optimization described above can be done, we return the resulting
4538 tree. Otherwise we return zero. */
4540 static tree
4543 {
4547 tree unsigned_type;
4550 scalar_int_mode nmode;
4555 tree mask;
4556 tree offset;
4558 /* Get all the information about the extractions being done. If the bit size
4559 is the same as the size of the underlying object, we aren't doing an
4560 extraction at all and so can do nothing. We also don't want to
4561 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4562 then will no longer be able to replace it. */
4577 else
4578 {
4579 /* If this is not a constant, we can only do something if bit positions,
4580 sizes, signedness and storage order are the same. */
4581 rinner
4594 }
4596 /* Honor the C++ memory model and mimic what RTL expansion does. */
4600 {
4604 }
4606 /* See if we can find a mode to refer to this field. We should be able to,
4607 but fail if we can't. */
4615 /* Set signed and unsigned types of the precision of this mode for the
4616 shifts below. */
4619 /* Compute the bit position and size for the new reference and our offset
4620 within it. If the new reference is the same size as the original, we
4621 won't optimize anything, so return zero. */
4631 /* Make the mask to be used against the extracted field. */
4638 {
4642 /* If not comparing with constant, just rework the comparison
4643 and return. */
4651 }
4653 /* Otherwise, we are handling the constant case. See if the constant is too
4654 big for the field. Warn and return a tree for 0 (false) if so. We do
4655 this not only for its own sake, but to avoid having to test for this
4656 error case below. If we didn't, we might generate wrong code.
4658 For unsigned fields, the constant shifted right by the field length should
4659 be all zero. For signed fields, the high-order bits should agree with
4660 the sign bit. */
4663 {
4665 {
4669 }
4670 }
4671 else
4672 {
4675 {
4679 }
4680 }
4685 /* Single-bit compares should always be against zero. */
4687 {
4690 }
4692 /* Make a new bitfield reference, shift the constant over the
4693 appropriate number of bits and mask it with the computed mask
4694 (in case this was a signed field). If we changed it, make a new one. */
4702 mask);
4707 }
4708 \f
4709 /* Subroutine for fold_truth_andor_1: decode a field reference.
4711 If EXP is a comparison reference, we return the innermost reference.
4713 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4714 set to the starting bit number.
4716 If the innermost field can be completely contained in a mode-sized
4717 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4719 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4720 otherwise it is not changed.
4722 *PUNSIGNEDP is set to the signedness of the field.
4724 *PREVERSEP is set to the storage order of the field.
4726 *PMASK is set to the mask used. This is either contained in a
4727 BIT_AND_EXPR or derived from the width of the field.
4729 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4731 Return 0 if this is not a component reference or is one that we can't
4732 do anything with. */
4734 static tree
4739 {
4744 tree unsigned_type;
4747 /* All the optimizations using this function assume integer fields.
4748 There are problems with FP fields since the type_for_size call
4749 below can fail for, e.g., XFmode. */
4753 /* We are interested in the bare arrangement of bits, so strip everything
4754 that doesn't affect the machine mode. However, record the type of the
4755 outermost expression if it may matter below. */
4762 {
4768 }
4779 /* Reject out-of-bound accesses (PR79731). */
4791 /* If the number of bits in the reference is the same as the bitsize of
4792 the outer type, then the outer type gives the signedness. Otherwise
4793 (in case of a small bitfield) the signedness is unchanged. */
4797 /* Compute the mask to access the bitfield. */
4805 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4813 }
4815 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4816 bit positions and MASK is SIGNED. */
4818 static bool
4820 {
4824 /* If this function returns true when the type of the mask is
4825 UNSIGNED, then there will be errors. In particular see
4826 gcc.c-torture/execute/990326-1.c. There does not appear to be
4827 any documentation paper trail as to why this is so. But the pre
4828 wide-int worked with that restriction and it has been preserved
4829 here. */
4834 }
4836 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4837 represents the sign bit of EXP's type. If EXP represents a sign
4838 or zero extension, also test VAL against the unextended type.
4839 The return value is the (sub)expression whose sign bit is VAL,
4840 or NULL_TREE otherwise. */
4842 tree
4844 {
4846 tree t;
4848 /* Tree EXP must have an integral type. */
4853 /* Tree VAL must be an integer constant. */
4862 /* Handle extension from a narrower type. */
4868 }
4870 /* Subroutine for fold_truth_andor_1 and simple_condition_p: determine if an
4871 operand is simple enough to be evaluated unconditionally. */
4873 static bool
4875 {
4876 /* Strip any conversions that don't change the machine mode. */
4885 /* Don't regard global variables as simple. They may be
4886 allocated in ways unknown to the compiler (shared memory,
4887 #pragma weak, etc). */
4890 /* Weakrefs are not safe to be read, since they can be NULL.
4891 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4892 have DECL_WEAK flag set. */
4894 /* Loading a static variable is unduly expensive, but global
4895 registers aren't expensive. */
4897 }
4899 /* Determine if an operand is simple enough to be evaluated unconditionally.
4900 In addition to simple_operand_p, we assume that comparisons, conversions,
4901 and logic-not operations are simple, if their operands are simple, too. */
4903 bool
4905 {
4924 }
4926 \f
4927 /* The following functions are subroutines to fold_range_test and allow it to
4928 try to change a logical combination of comparisons into a range test.
4930 For example, both
4931 X == 2 || X == 3 || X == 4 || X == 5
4932 and
4933 X >= 2 && X <= 5
4934 are converted to
4935 (unsigned) (X - 2) <= 3
4937 We describe each set of comparisons as being either inside or outside
4938 a range, using a variable named like IN_P, and then describe the
4939 range with a lower and upper bound. If one of the bounds is omitted,
4940 it represents either the highest or lowest value of the type.
4942 In the comments below, we represent a range by two numbers in brackets
4943 preceded by a "+" to designate being inside that range, or a "-" to
4944 designate being outside that range, so the condition can be inverted by
4945 flipping the prefix. An omitted bound is represented by a "-". For
4946 example, "- [-, 10]" means being outside the range starting at the lowest
4947 possible value and ending at 10, in other words, being greater than 10.
4948 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4949 always false.
4951 We set up things so that the missing bounds are handled in a consistent
4952 manner so neither a missing bound nor "true" and "false" need to be
4953 handled using a special case. */
4955 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4956 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4957 and UPPER1_P are nonzero if the respective argument is an upper bound
4958 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4959 must be specified for a comparison. ARG1 will be converted to ARG0's
4960 type if both are specified. */
4962 static tree
4965 {
4966 tree tem;
4970 /* If neither arg represents infinity, do the normal operation.
4971 Else, if not a comparison, return infinity. Else handle the special
4972 comparison rules. Note that most of the cases below won't occur, but
4973 are handled for consistency. */
4976 {
4981 }
4986 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4987 for neither. In real maths, we cannot assume open ended ranges are
4988 the same. But, this is computer arithmetic, where numbers are finite.
4989 We can therefore make the transformation of any unbounded range with
4990 the value Z, Z being greater than any representable number. This permits
4991 us to treat unbounded ranges as equal. */
4995 {
5016 }
5019 }
5020 \f
5021 /* Helper routine for make_range. Perform one step for it, return
5022 new expression if the loop should continue or NULL_TREE if it should
5023 stop. */
5025 tree
5029 {
5035 {
5037 /* We can only do something if the range is testing for zero. */
5046 /* We can only do something if the range is testing for zero
5047 and if the second operand is an integer constant. Note that
5048 saying something is "in" the range we make is done by
5049 complementing IN_P since it will set in the initial case of
5050 being not equal to zero; "out" is leaving it alone. */
5057 {
5078 }
5080 /* If this is an unsigned comparison, we also know that EXP is
5081 greater than or equal to zero. We base the range tests we make
5082 on that fact, so we record it here so we can parse existing
5083 range tests. We test arg0_type since often the return type
5084 of, e.g. EQ_EXPR, is boolean. */
5086 {
5090 NULL_TREE))
5095 /* If the high bound is missing, but we have a nonzero low
5096 bound, reverse the range so it goes from zero to the low bound
5097 minus 1. */
5099 {
5104 }
5105 }
5113 /* If flag_wrapv and ARG0_TYPE is signed, make sure
5114 low and high are non-NULL, then normalize will DTRT. */
5117 {
5122 }
5124 /* (-x) IN [a,b] -> x in [-b, -a] */
5136 /* ~ X -> -X - 1 */
5145 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
5146 move a constant to the other side. */
5151 /* If EXP is signed, any overflow in the computation is undefined,
5152 so we don't worry about it so long as our computations on
5153 the bounds don't overflow. For unsigned, overflow is defined
5154 and this is exactly the right thing. */
5166 normalize:
5167 /* Check for an unsigned range which has wrapped around the maximum
5168 value thus making n_high < n_low, and normalize it. */
5170 {
5176 /* If the range is of the form +/- [ x+1, x ], we won't
5177 be able to normalize it. But then, it represents the
5178 whole range or the empty set, so make it
5179 +/- [ -, - ]. */
5183 else
5185 }
5186 else
5194 CASE_CONVERT:
5212 /* If we're converting arg0 from an unsigned type, to exp,
5213 a signed type, we will be doing the comparison as unsigned.
5214 The tests above have already verified that LOW and HIGH
5215 are both positive.
5217 So we have to ensure that we will handle large unsigned
5218 values the same way that the current signed bounds treat
5219 negative values. */
5222 {
5223 tree high_positive;
5224 tree equiv_type;
5225 /* For fixed-point modes, we need to pass the saturating flag
5226 as the 2nd parameter. */
5228 equiv_type
5231 else
5232 equiv_type
5235 /* A range without an upper bound is, naturally, unbounded.
5236 Since convert would have cropped a very large value, use
5237 the max value for the destination type. */
5238 high_positive
5245 high_positive),
5248 /* If the low bound is specified, "and" the range with the
5249 range for which the original unsigned value will be
5250 positive. */
5252 {
5255 integer_zero_node),
5256 high_positive))
5260 }
5261 else
5262 {
5263 /* Otherwise, "or" the range with the range of the input
5264 that will be interpreted as negative. */
5267 integer_zero_node),
5268 high_positive))
5272 }
5273 }
5275 /* Otherwise, if we are converting arg0 from signed type, to exp,
5276 an unsigned type, we will do the comparison as signed. If
5277 high is non-NULL, we punt above if it doesn't fit in the signed
5278 type, so if we get through here, +[-, high] or +[low, high] are
5279 equivalent to +[-, n_high] or +[n_low, n_high]. Similarly,
5280 +[-, -] or -[-, -] are equivalent too. But if low is specified and
5281 high is not, the +[low, -] range is equivalent to union of
5282 +[n_low, -] and +[-, -1] ranges, so +[low, -] is equivalent to
5283 -[0, n_low-1] and similarly -[low, -] to +[0, n_low-1], except for
5284 low being 0, which should be treated as [-, -]. */
5287 && low
5289 {
5292 else
5293 {
5298 }
5299 }
5308 }
5309 }
5311 /* Given EXP, a logical expression, set the range it is testing into
5312 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
5313 actually being tested. *PLOW and *PHIGH will be made of the same
5314 type as the returned expression. If EXP is not a comparison, we
5315 will most likely not be returning a useful value and range. Set
5316 *STRICT_OVERFLOW_P to true if the return value is only valid
5317 because signed overflow is undefined; otherwise, do not change
5318 *STRICT_OVERFLOW_P. */
5320 tree
5323 {
5331 /* Start with simply saying "EXP != 0" and then look at the code of EXP
5332 and see if we can refine the range. Some of the cases below may not
5333 happen, but it doesn't seem worth worrying about this. We "continue"
5334 the outer loop when we've changed something; otherwise we "break"
5335 the switch, which will "break" the while. */
5341 {
5347 {
5355 }
5364 }
5366 /* If EXP is a constant, we can evaluate whether this is true or false. */
5368 {
5375 }
5379 }
5381 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
5382 a bitwise check i.e. when
5383 LOW == 0xXX...X00...0
5384 HIGH == 0xXX...X11...1
5385 Return corresponding mask in MASK and stem in VALUE. */
5387 static bool
5390 {
5413 }
5414 \f
5415 /* Helper routine for build_range_check and match.pd. Return the type to
5416 perform the check or NULL if it shouldn't be optimized. */
5418 tree
5420 {
5421 /* First make sure that arithmetics in this type is valid, then make sure
5422 that it wraps around. */
5427 {
5430 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
5431 for the type in question, as we rely on this here. */
5441 else
5443 }
5447 }
5449 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
5450 type, TYPE, return an expression to test if EXP is in (or out of, depending
5451 on IN_P) the range. Return 0 if the test couldn't be created. */
5453 tree
5456 {
5459 /* Disable this optimization for function pointer expressions
5460 on targets that require function pointer canonicalization. */
5467 {
5473 }
5495 value);
5498 {
5500 {
5504 }
5506 }
5508 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
5510 {
5514 {
5516 {
5519 etype
5521 else
5524 }
5527 }
5528 }
5530 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
5531 This requires wrap-around arithmetics for the type of the expression. */
5548 }
5549 \f
5550 /* Return the predecessor of VAL in its type, handling the infinite case. */
5552 static tree
5554 {
5560 else
5563 }
5565 /* Return the successor of VAL in its type, handling the infinite case. */
5567 static tree
5569 {
5575 else
5578 }
5580 /* Given two ranges, see if we can merge them into one. Return 1 if we
5581 can, 0 if we can't. Set the output range into the specified parameters. */
5583 bool
5586 {
5590 tree tem;
5600 /* Make range 0 be the range that starts first, or ends last if they
5601 start at the same value. Swap them if it isn't. */
5604 || (lowequal
5607 {
5611 }
5613 /* If the second range is != high1 where high1 is the type maximum of
5614 the type, try first merging with < high1 range. */
5616 && high1
5623 {
5628 /* Similarly for the second range != low1 where low1 is the type minimum
5629 of the type, try first merging with > low1 range. */
5634 }
5636 /* Now flag two cases, whether the ranges are disjoint or whether the
5637 second range is totally subsumed in the first. Note that the tests
5638 below are simplified by the ones above. */
5644 /* We now have four cases, depending on whether we are including or
5645 excluding the two ranges. */
5647 {
5648 /* If they don't overlap, the result is false. If the second range
5649 is a subset it is the result. Otherwise, the range is from the start
5650 of the second to the end of the first. */
5655 else
5657 }
5660 {
5661 /* If they don't overlap, the result is the first range. If they are
5662 equal, the result is false. If the second range is a subset of the
5663 first, and the ranges begin at the same place, we go from just after
5664 the end of the second range to the end of the first. If the second
5665 range is not a subset of the first, or if it is a subset and both
5666 ranges end at the same place, the range starts at the start of the
5667 first range and ends just before the second range.
5668 Otherwise, we can't describe this as a single range. */
5674 {
5679 {
5680 /* We are in the weird situation where high0 > high1 but
5681 high1 has no successor. Punt. */
5683 }
5684 }
5686 {
5691 {
5692 /* low0 < low1 but low1 has no predecessor. Punt. */
5694 }
5695 }
5696 else
5698 }
5701 {
5702 /* If they don't overlap, the result is the second range. If the second
5703 is a subset of the first, the result is false. Otherwise,
5704 the range starts just after the first range and ends at the
5705 end of the second. */
5710 else
5711 {
5716 {
5717 /* high1 > high0 but high0 has no successor. Punt. */
5719 }
5720 }
5721 }
5723 else
5724 {
5725 /* The case where we are excluding both ranges. Here the complex case
5726 is if they don't overlap. In that case, the only time we have a
5727 range is if they are adjacent. If the second is a subset of the
5728 first, the result is the first. Otherwise, the range to exclude
5729 starts at the beginning of the first range and ends at the end of the
5730 second. */
5732 {
5737 else
5738 {
5739 /* Canonicalize - [min, x] into - [-, x]. */
5742 {
5745 GET_MODE_BITSIZE
5748 /* FALLTHROUGH */
5761 }
5763 /* Canonicalize - [x, max] into - [x, -]. */
5766 {
5769 GET_MODE_BITSIZE
5772 /* FALLTHROUGH */
5788 }
5790 /* The ranges might be also adjacent between the maximum and
5791 minimum values of the given type. For
5792 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5793 return + [x + 1, y - 1]. */
5795 {
5802 }
5803 else
5805 }
5806 }
5809 else
5811 }
5815 }
5816 \f
5818 /* Subroutine of fold, looking inside expressions of the form
5819 A op B ? A : C, where (ARG00, COMP_CODE, ARG01), ARG1 and ARG2
5820 are the three operands of the COND_EXPR. This function is
5821 being used also to optimize A op B ? C : A, by reversing the
5822 comparison first.
5824 Return a folded expression whose code is not a COND_EXPR
5825 anymore, or NULL_TREE if no folding opportunity is found. */
5827 static tree
5831 {
5833 tree tem;
5838 /* If we have A op 0 ? A : -A, consider applying the following
5839 transformations:
5841 A == 0? A : -A same as -A
5842 A != 0? A : -A same as A
5843 A >= 0? A : -A same as abs (A)
5844 A > 0? A : -A same as abs (A)
5845 A <= 0? A : -A same as -abs (A)
5846 A < 0? A : -A same as -abs (A)
5848 None of these transformations work for modes with signed
5849 zeros. If A is +/-0, the first two transformations will
5850 change the sign of the result (from +0 to -0, or vice
5851 versa). The last four will fix the sign of the result,
5852 even though the original expressions could be positive or
5853 negative, depending on the sign of A.
5855 Note that all these transformations are correct if A is
5856 NaN, since the two alternatives (A and -A) are also NaNs. */
5863 /* In the case that A is of the form X-Y, '-A' (arg2) may
5864 have already been folded to Y-X, check for that. */
5872 {
5884 /* Fall through. */
5895 /* FALLTHRU */
5902 {
5903 /* A <= 0 ? A : -A for A INT_MIN is valid, but -abs(INT_MIN)
5904 is not, invokes UB both in abs and in the negation of it.
5905 So, use ABSU_EXPR instead. */
5910 }
5911 else
5912 {
5915 }
5919 }
5921 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5922 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5923 both transformations are correct when A is NaN: A != 0
5924 is then true, and A == 0 is false. */
5928 {
5933 }
5935 /* Try some transformations of A op B ? A : B.
5937 A == B? A : B same as B
5938 A != B? A : B same as A
5939 A >= B? A : B same as max (A, B)
5940 A > B? A : B same as max (B, A)
5941 A <= B? A : B same as min (A, B)
5942 A < B? A : B same as min (B, A)
5944 As above, these transformations don't work in the presence
5945 of signed zeros. For example, if A and B are zeros of
5946 opposite sign, the first two transformations will change
5947 the sign of the result. In the last four, the original
5948 expressions give different results for (A=+0, B=-0) and
5949 (A=-0, B=+0), but the transformed expressions do not.
5951 The first two transformations are correct if either A or B
5952 is a NaN. In the first transformation, the condition will
5953 be false, and B will indeed be chosen. In the case of the
5954 second transformation, the condition A != B will be true,
5955 and A will be chosen.
5957 The conversions to max() and min() are not correct if B is
5958 a number and A is not. The conditions in the original
5959 expressions will be false, so all four give B. The min()
5960 and max() versions would give a NaN instead. */
5963 /* Avoid these transformations if the COND_EXPR may be used
5964 as an lvalue in the C++ front-end. PR c++/19199. */
5965 && (in_gimple_form
5971 {
5977 {
5986 /* In C++ a ?: expression can be an lvalue, so put the
5987 operand which will be used if they are equal first
5988 so that we can convert this back to the
5989 corresponding COND_EXPR. */
5991 {
5999 }
6006 {
6014 }
6027 }
6028 }
6031 }
6034 \f
6035 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
6036 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
6037 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
6038 false) >= 2)
6039 #endif
6041 /* EXP is some logical combination of boolean tests. See if we can
6042 merge it into some range test. Return the new tree if so. */
6044 static tree
6047 {
6061 /* If op0 is known true or false and this is a short-circuiting
6062 operation we must not merge with op1 since that makes side-effects
6063 unconditional. So special-case this. */
6070 /* If this is an OR operation, invert both sides; we will invert
6071 again at the end. */
6075 /* If both expressions are the same, if we can merge the ranges, and we
6076 can build the range test, return it or it inverted. If one of the
6077 ranges is always true or always false, consider it to be the same
6078 expression as the other. */
6086 {
6090 }
6092 /* On machines where the branch cost is expensive, if this is a
6093 short-circuited branch and the underlying object on both sides
6094 is the same, make a non-short-circuit operation. */
6097 logical_op_non_short_circuit
6104 {
6105 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
6106 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
6107 which cases we can't do this. */
6115 {
6124 {
6127 WARN_STRICT_OVERFLOW_COMPARISON);
6131 }
6132 }
6133 }
6136 }
6137 \f
6138 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
6139 bit value. Arrange things so the extra bits will be set to zero if and
6140 only if C is signed-extended to its full width. If MASK is nonzero,
6141 it is an INTEGER_CST that should be AND'ed with the extra bits. */
6143 static tree
6145 {
6148 tree temp;
6153 /* We work by getting just the sign bit into the low-order bit, then
6154 into the high-order bit, then sign-extend. We then XOR that value
6155 with C. */
6159 /* We must use a signed type in order to get an arithmetic right shift.
6160 However, we must also avoid introducing accidental overflows, so that
6161 a subsequent call to integer_zerop will work. Hence we must
6162 do the type conversion here. At this point, the constant is either
6163 zero or one, and the conversion to a signed type can never overflow.
6164 We could get an overflow if this conversion is done anywhere else. */
6173 /* If necessary, convert the type back to match the type of C. */
6178 }
6179 \f
6180 /* For an expression that has the form
6181 (A && B) || ~B
6182 or
6183 (A || B) && ~B,
6184 we can drop one of the inner expressions and simplify to
6185 A || ~B
6186 or
6187 A && ~B
6188 LOC is the location of the resulting expression. OP is the inner
6189 logical operation; the left-hand side in the examples above, while CMPOP
6190 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
6191 removing a condition that guards another, as in
6192 (A != NULL && A->...) || A == NULL
6193 which we must not transform. If RHS_ONLY is true, only eliminate the
6194 right-most operand of the inner logical operation. */
6196 static tree
6199 {
6217 {
6220 {
6223 }
6224 }
6226 {
6229 {
6232 }
6233 }
6248 }
6250 /* Find ways of folding logical expressions of LHS and RHS:
6251 Try to merge two comparisons to the same innermost item.
6252 Look for range tests like "ch >= '0' && ch <= '9'".
6253 Look for combinations of simple terms on machines with expensive branches
6254 and evaluate the RHS unconditionally.
6256 For example, if we have p->a == 2 && p->b == 4 and we can make an
6257 object large enough to span both A and B, we can do this with a comparison
6258 against the object ANDed with the a mask.
6260 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
6261 operations to do this with one comparison.
6263 We check for both normal comparisons and the BIT_AND_EXPRs made this by
6264 function and the one above.
6266 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
6267 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
6269 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
6270 two operands.
6272 We return the simplified tree or 0 if no optimization is possible. */
6274 static tree
6277 {
6278 /* If this is the "or" of two comparisons, we can do something if
6279 the comparisons are NE_EXPR. If this is the "and", we can do something
6280 if the comparisons are EQ_EXPR. I.e.,
6281 (a->b == 2 && a->c == 4) can become (a->new == NEW).
6283 WANTED_CODE is this operation code. For single bit fields, we can
6284 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
6285 comparison for one-bit fields. */
6306 /* Start by getting the comparison codes. Fail if anything is volatile.
6307 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
6308 it were surrounded with a NE_EXPR. */
6317 {
6321 }
6324 {
6328 }
6339 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
6342 {
6345 {
6350 }
6353 {
6359 }
6360 }
6365 /* If the RHS can be evaluated unconditionally and its operands are
6366 simple, it wins to evaluate the RHS unconditionally on machines
6367 with expensive branches. In this case, this isn't a comparison
6368 that can be merged. */
6375 {
6376 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
6387 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
6397 }
6399 /* See if the comparisons can be merged. Then get all the parameters for
6400 each side. */
6425 /* It must be true that the inner operation on the lhs of each
6426 comparison must be the same if we are to be able to do anything.
6427 Then see if we have constants. If not, the same must be true for
6428 the rhs's. */
6437 {
6440 }
6445 else
6448 /* If either comparison code is not correct for our logical operation,
6449 fail. However, we can convert a one-bit comparison against zero into
6450 the opposite comparison against that bit being set in the field. */
6454 {
6456 {
6457 /* Make the left operand unsigned, since we are only interested
6458 in the value of one bit. Otherwise we are doing the wrong
6459 thing below. */
6462 }
6463 else
6465 }
6467 /* This is analogous to the code for l_const above. */
6469 {
6471 {
6474 }
6475 else
6477 }
6479 /* See if we can find a mode that contains both fields being compared on
6480 the left. If we can't, fail. Otherwise, update all constants and masks
6481 to be relative to a field of that size. */
6495 {
6498 }
6508 {
6517 {
6521 }
6522 }
6524 {
6533 {
6537 }
6538 }
6540 /* If the right sides are not constant, do the same for it. Also,
6541 disallow this optimization if a size, signedness or storage order
6542 mismatch occurs between the left and right sides. */
6544 {
6548 /* Make sure the two fields on the right
6549 correspond to the left without being swapped. */
6566 {
6569 }
6580 /* Make a mask that corresponds to both fields being compared.
6581 Do this for both items being compared. If the operands are the
6582 same size and the bits being compared are in the same position
6583 then we can do this by masking both and comparing the masked
6584 results. */
6591 {
6605 }
6607 /* There is still another way we can do something: If both pairs of
6608 fields being compared are adjacent, we may be able to make a wider
6609 field containing them both.
6611 Note that we still must mask the lhs/rhs expressions. Furthermore,
6612 the mask must be shifted to account for the shift done by
6613 make_bit_field_ref. */
6622 {
6623 tree type;
6641 /* Convert to the smaller type before masking out unwanted bits. */
6644 {
6646 {
6650 }
6652 {
6656 }
6657 }
6666 }
6669 }
6671 /* Handle the case of comparisons with constants. If there is something in
6672 common between the masks, those bits of the constants must be the same.
6673 If not, the condition is always false. Test for this to avoid generating
6674 incorrect code below. */
6679 {
6681 {
6684 }
6685 else
6686 {
6689 }
6690 }
6695 /* Construct the expression we will return. First get the component
6696 reference we will make. Unless the mask is all ones the width of
6697 that field, perform the mask operation. Then compare with the
6698 merged constant. */
6709 }
6710 \f
6711 /* T is an integer expression that is being multiplied, divided, or taken a
6712 modulus (CODE says which and what kind of divide or modulus) by a
6713 constant C. See if we can eliminate that operation by folding it with
6714 other operations already in T. WIDE_TYPE, if non-null, is a type that
6715 should be used for the computation if wider than our type.
6717 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6718 (X * 2) + (Y * 4). We must, however, be assured that either the original
6719 expression would not overflow or that overflow is undefined for the type
6720 in the language in question.
6722 If we return a non-null expression, it is an equivalent form of the
6723 original computation, but need not be in the original type.
6725 We set *STRICT_OVERFLOW_P to true if the return values depends on
6726 signed overflow being undefined. Otherwise we do not change
6727 *STRICT_OVERFLOW_P. */
6729 static tree
6732 {
6733 /* To avoid exponential search depth, refuse to allow recursion past
6734 three levels. Beyond that (1) it's highly unlikely that we'll find
6735 something interesting and (2) we've probably processed it before
6736 when we built the inner expression. */
6739 tree ret;
6744 depth++;
6746 depth--;
6749 }
6751 static tree
6754 {
6766 /* Don't deal with constants of zero here; they confuse the code below. */
6776 /* Note that we need not handle conditional operations here since fold
6777 already handles those cases. So just do arithmetic here. */
6779 {
6781 /* For a constant, we can always simplify if we are a multiply
6782 or (for divide and modulus) if it is a multiple of our constant. */
6786 {
6789 /* If the multiplication overflowed, we lost information on it.
6790 See PR68142 and PR69845. */
6794 }
6800 /* If op0 is an expression ... */
6806 /* ... and has wrapping overflow, and its type is smaller
6807 than ctype, then we cannot pass through as widening. */
6811 /* ... or this is a truncation (t is narrower than op0),
6812 then we cannot pass through this narrowing. */
6815 /* ... or signedness changes for division or modulus,
6816 then we cannot pass through this conversion. */
6820 /* ... or has undefined overflow while the converted to
6821 type has not, we cannot do the operation in the inner type
6822 as that would introduce undefined overflow. */
6827 /* Pass the constant down and see if we can make a simplification. If
6828 we can, replace this expression with the inner simplification for
6829 possible later conversion to our or some other type. */
6840 /* If widening the type changes it from signed to unsigned, then we
6841 must avoid building ABS_EXPR itself as unsigned. */
6843 {
6847 {
6850 }
6852 }
6853 /* If the constant is negative, we cannot simplify this. */
6856 /* FALLTHROUGH */
6858 /* For division and modulus, type can't be unsigned, as e.g.
6859 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6860 For signed types, even with wrapping overflow, this is fine. */
6869 /* If widening the type changes the signedness, then we can't perform
6870 this optimization as that changes the result. */
6874 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6880 {
6887 }
6891 /* If the second operand is constant, this is a multiplication
6892 or floor division, by a power of two, so we can treat it that
6893 way unless the multiplier or divisor overflows. Signed
6894 left-shift overflow is implementation-defined rather than
6895 undefined in C90, so do not convert signed left shift into
6896 multiplication. */
6899 /* const_binop may not detect overflow correctly,
6900 so check for it explicitly here. */
6909 ctype,
6911 t1),
6916 /* See if we can eliminate the operation on both sides. If we can, we
6917 can return a new PLUS or MINUS. If we can't, the only remaining
6918 cases where we can do anything are if the second operand is a
6919 constant. */
6926 /* If not multiplication, we can only do this if both operands
6927 are divisible by c. */
6930 {
6935 }
6937 /* If this was a subtraction, negate OP1 and set it to be an addition.
6938 This simplifies the logic below. */
6940 {
6942 /* If OP1 was not easily negatable, the constant may be OP0. */
6944 {
6947 }
6948 }
6953 /* If either OP1 or C are negative, this optimization is not safe for
6954 some of the division and remainder types while for others we need
6955 to change the code. */
6957 {
6965 }
6967 /* If it's a multiply or a division/modulus operation of a multiple
6968 of our constant, do the operation and verify it doesn't overflow. */
6972 {
6975 /* We allow the constant to overflow with wrapping semantics. */
6979 }
6980 else
6983 /* If we have an unsigned type, we cannot widen the operation since it
6984 will change the result if the original computation overflowed. */
6988 /* The last case is if we are a multiply. In that case, we can
6989 apply the distributive law to commute the multiply and addition
6990 if the multiplication of the constants doesn't overflow
6991 and overflow is defined. With undefined overflow
6992 op0 * c might overflow, while (op0 + orig_op1) * c doesn't.
6993 But fold_plusminus_mult_expr would factor back any power-of-two
6994 value so do not distribute in the first place in this case. */
7002 op1);
7007 /* We have a special case here if we are doing something like
7008 (C * 8) % 4 since we know that's zero. */
7011 /* If the multiplication can overflow we cannot optimize this. */
7016 {
7019 }
7021 /* ... fall through ... */
7025 /* If we can extract our operation from the LHS, do so and return a
7026 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
7027 do something only if the second operand is a constant. */
7043 /* If these are the same operation types, we can associate them
7044 assuming no overflow. */
7046 {
7061 }
7063 /* If these operations "cancel" each other, we have the main
7064 optimizations of this pass, which occur when either constant is a
7065 multiple of the other, in which case we replace this with either an
7066 operation or CODE or TCODE.
7068 If we have an unsigned type, we cannot do this since it will change
7069 the result if the original computation overflowed. */
7076 {
7079 {
7086 }
7089 {
7096 }
7097 }
7102 }
7105 }
7106 \f
7107 /* Return a node which has the indicated constant VALUE (either 0 or
7108 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
7109 and is of the indicated TYPE. */
7111 tree
7113 {
7122 else
7124 }
7127 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
7128 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
7129 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
7130 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
7131 COND is the first argument to CODE; otherwise (as in the example
7132 given here), it is the second argument. TYPE is the type of the
7133 original expression. Return NULL_TREE if no simplification is
7134 possible. */
7136 static tree
7141 {
7149 /* Do not move possibly trapping operations into the conditional as this
7150 pessimizes code and causes gimplification issues when applied late. */
7158 {
7162 /* If this operand throws an expression, then it does not make
7163 sense to try to perform a logical or arithmetic operation
7164 involving it. */
7169 }
7172 {
7177 }
7178 else
7179 /* Detect the case of mixing vector and scalar types - bail out. */
7185 /* This transformation is only worthwhile if we don't have to wrap ARG
7186 in a SAVE_EXPR and the operation can be simplified without recursing
7187 on at least one of the branches once its pushed inside the COND_EXPR. */
7196 {
7200 else
7202 }
7204 {
7208 else
7210 }
7212 /* Check that we have simplified at least one of the branches. */
7217 }
7219 \f
7220 /* Subroutine of fold() that checks for the addition of ARG +/- 0.0.
7222 If !NEGATE, return true if ZERO_ARG is +/-0.0 and, for all ARG of
7223 type TYPE, ARG + ZERO_ARG is the same as ARG. If NEGATE, return true
7224 if ARG - ZERO_ARG is the same as X.
7226 If ARG is NULL, check for any value of type TYPE.
7228 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
7229 and finite. The problematic cases are when X is zero, and its mode
7230 has signed zeros. In the case of rounding towards -infinity,
7231 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
7232 modes, X + 0 is not the same as X because -0 + 0 is 0. */
7234 bool
7237 {
7241 /* Don't allow the fold with -fsignaling-nans. */
7245 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
7249 /* There is no case that is safe for all rounding modes. */
7253 /* In a vector or complex, we would need to check the sign of all zeros. */
7259 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
7263 /* The mode has signed zeros, and we have to honor their sign.
7264 In this situation, there are only two cases we can return true for.
7265 (i) X - 0 is the same as X with default rounding.
7266 (ii) X + 0 is X when X can't possibly be -0.0. */
7268 }
7270 /* Subroutine of match.pd that optimizes comparisons of a division by
7271 a nonzero integer constant against an integer constant, i.e.
7272 X/C1 op C2.
7274 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
7275 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
7277 enum tree_code
7280 {
7285 /* We have to do this the hard way to detect unsigned overflow.
7286 prod = int_const_binop (MULT_EXPR, c1, c2); */
7292 {
7296 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
7299 }
7301 {
7304 {
7323 }
7324 }
7325 else
7326 {
7327 /* A negative divisor reverses the relational operators. */
7332 {
7351 }
7352 }
7365 }
7368 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7369 equality/inequality test, then return a simplified form of the test
7370 using a sign testing. Otherwise return NULL. TYPE is the desired
7371 result type. */
7373 static tree
7376 tree result_type)
7377 {
7378 /* If this is testing a single bit, we can optimize the test. */
7382 {
7383 /* If we have (A & C) != 0 where C is the sign bit of A, convert
7384 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
7388 /* This is only a win if casting to a signed type is cheap,
7389 i.e. when arg00's type is not a partial mode. */
7391 {
7394 result_type,
7397 }
7398 }
7401 }
7403 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7404 equality/inequality test, then return a simplified form of
7405 the test using shifts and logical operations. Otherwise return
7406 NULL. TYPE is the desired result type. */
7408 tree
7411 {
7412 /* If this is testing a single bit, we can optimize the test. */
7416 {
7425 /* First, see if we can fold the single bit test into a sign-bit
7426 test. */
7428 result_type);
7432 /* Otherwise we have (A & C) != 0 where C is a single bit,
7433 convert that into ((A >> C2) & 1). Where C2 = log2(C).
7434 Similarly for (A & C) == 0. */
7436 /* If INNER is a right shift of a constant and it plus BITNUM does
7437 not overflow, adjust BITNUM and INNER. */
7443 {
7446 }
7448 /* If we are going to be able to omit the AND below, we must do our
7449 operations as unsigned. If we must use the AND, we have a choice.
7450 Normally unsigned is faster, but for some machines signed is. */
7468 /* Put the AND last so it can combine with more things. */
7471 /* Make sure to return the proper type. */
7475 }
7477 }
7479 /* Test whether it is preferable to swap two operands, ARG0 and
7480 ARG1, for example because ARG0 is an integer constant and ARG1
7481 isn't. */
7483 bool
7485 {
7499 /* It is preferable to swap two SSA_NAME to ensure a canonical form
7500 for commutative and comparison operators. Ensuring a canonical
7501 form allows the optimizers to find additional redundancies without
7502 having to explicitly check for both orderings. */
7508 /* Put SSA_NAMEs last. */
7514 /* Put variables last. */
7521 }
7524 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7525 means A >= Y && A != MAX, but in this case we know that
7526 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7528 static tree
7530 {
7537 else
7546 {
7549 }
7551 {
7554 }
7555 else
7562 {
7563 /* Convert the pointer types into integer before taking the difference. */
7567 }
7568 else
7575 }
7577 /* Fold a sum or difference of at least one multiplication.
7578 Returns the folded tree or NULL if no simplification could be made. */
7580 static tree
7583 {
7587 /* (A * C) +- (B * C) -> (A+-B) * C.
7588 (A * C) +- A -> A * (C+-1).
7589 We are most concerned about the case where C is a constant,
7590 but other combinations show up during loop reduction. Since
7591 it is not difficult, try all four possibilities. */
7594 {
7597 }
7599 {
7602 }
7603 else
7604 {
7605 /* We cannot generate constant 1 for fract. */
7610 }
7612 {
7615 }
7617 {
7619 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7620 the purpose of this canonicalization. */
7624 {
7627 }
7628 else
7630 }
7631 else
7632 {
7633 /* We cannot generate constant 1 for fract. */
7638 }
7641 /* Prefer factoring a common non-constant. */
7651 /* No identical multiplicands; see if we can find a common
7652 power-of-two factor in non-power-of-two multiplies. This
7653 can help in multi-dimensional array access. */
7655 {
7658 HOST_WIDE_INT tmp;
7660 tree maybe_same;
7662 /* Move min of absolute values to int11. */
7664 {
7669 }
7670 else
7677 /* The remainder should not be a constant, otherwise we
7678 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7679 increased the number of multiplications necessary. */
7681 {
7689 }
7690 }
7697 /* We are neither factoring zero nor minus one. */
7705 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7706 same may be minus one and thus the multiplication may overflow. Perform
7707 the sum operation in an unsigned type. */
7712 /* If the sum evaluated to a constant that is not -INF the multiplication
7713 cannot overflow. */
7720 /* Do not resort to unsigned multiplication because
7721 we lose the no-overflow property of the expression. */
7723 }
7725 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7726 specified by EXPR into the buffer PTR of length LEN bytes.
7727 Return the number of bytes placed in the buffer, or zero
7728 upon failure. */
7730 static int
7732 {
7744 /* Dry run. */
7750 {
7752 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7753 number of bytes. */
7757 {
7764 else
7766 }
7767 else
7771 }
7773 }
7776 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7777 specified by EXPR into the buffer PTR of length LEN bytes.
7778 Return the number of bytes placed in the buffer, or zero
7779 upon failure. */
7781 static int
7783 {
7787 FIXED_VALUE_TYPE value;
7802 }
7805 /* Subroutine of native_encode_expr. Encode the REAL_CST
7806 specified by EXPR into the buffer PTR of length LEN bytes.
7807 Return the number of bytes placed in the buffer, or zero
7808 upon failure. */
7810 static int
7812 {
7818 /* There are always 32 bits in each long, no matter the size of
7819 the hosts long. We handle floating point representations with
7820 up to 192 bits. */
7829 /* Dry run. */
7838 {
7843 {
7850 else
7852 }
7853 else
7854 {
7857 {
7858 /* Reverse bytes within each long, or within the entire float
7859 if it's smaller than a long (for HFmode). */
7862 }
7863 }
7868 }
7870 }
7872 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7873 specified by EXPR into the buffer PTR of length LEN bytes.
7874 Return the number of bytes placed in the buffer, or zero
7875 upon failure. */
7877 static int
7879 {
7881 tree part;
7895 }
7897 /* Like native_encode_vector, but only encode the first COUNT elements.
7898 The other arguments are as for native_encode_vector. */
7900 static int
7903 {
7907 {
7908 /* This is the only case in which elements can be smaller than a byte.
7909 Element 0 is always in the lsb of the containing byte. */
7918 /* Zero the buffer and then set bits later where necessary. */
7927 {
7933 {
7936 }
7937 }
7939 }
7944 {
7946 {
7949 }
7960 }
7962 }
7964 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7965 specified by EXPR into the buffer PTR of length LEN bytes.
7966 Return the number of bytes placed in the buffer, or zero
7967 upon failure. */
7969 static int
7971 {
7976 }
7979 /* Subroutine of native_encode_expr. Encode the STRING_CST
7980 specified by EXPR into the buffer PTR of length LEN bytes.
7981 Return the number of bytes placed in the buffer, or zero
7982 upon failure. */
7984 static int
7986 {
7989 /* Wide-char strings are encoded in target byte-order so native
7990 encoding them is trivial. */
8005 else
8006 {
8009 {
8012 }
8014 }
8016 }
8019 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST, REAL_CST,
8020 FIXED_CST, COMPLEX_CST, STRING_CST, or VECTOR_CST specified by EXPR into
8021 the buffer PTR of size LEN bytes. If PTR is NULL, don't actually store
8022 anything, just do a dry run. Fail either if OFF is -1 and LEN isn't
8023 sufficient to encode the entire EXPR, or if OFF is out of bounds.
8024 Otherwise, start at byte offset OFF and encode at most LEN bytes.
8025 Return the number of bytes placed in the buffer, or zero upon failure. */
8027 int
8029 {
8030 /* We don't support starting at negative offset and -1 is special. */
8035 {
8056 }
8057 }
8059 /* Try to find a type whose byte size is smaller or equal to LEN bytes larger
8060 or equal to FIELDSIZE bytes, with underlying mode precision/size multiple
8061 of BITS_PER_UNIT. As native_{interpret,encode}_int works in term of
8062 machine modes, we can't just use build_nonstandard_integer_type. */
8064 tree
8066 {
8067 machine_mode mode;
8069 {
8076 {
8080 }
8081 }
8087 {
8095 }
8098 }
8100 /* Similar to native_encode_expr, but also handle CONSTRUCTORs, VCEs,
8101 NON_LVALUE_EXPRs and nops. If MASK is non-NULL (then PTR has
8102 to be non-NULL and OFF zero), then in addition to filling the
8103 bytes pointed by PTR with the value also clear any bits pointed
8104 by MASK that are known to be initialized, keep them as is for
8105 e.g. uninitialized padding bits or uninitialized fields. */
8107 int
8110 {
8113 /* We don't support starting at negative offset and -1 is special. */
8121 {
8125 mask);
8140 {
8141 tree min_index;
8159 {
8164 {
8167 }
8172 else
8176 {
8180 offset_int wpos
8188 offset_int wcount
8195 }
8197 {
8200 offset_int wpos
8208 }
8211 {
8213 {
8224 }
8226 {
8230 }
8231 }
8235 do
8236 {
8241 {
8243 {
8246 fieldsize);
8249 }
8251 ptr
8254 fieldsize,
8257 mask
8261 else
8262 {
8265 }
8266 }
8269 {
8270 /* Partial overlap. */
8276 {
8280 fieldsize);
8281 }
8282 else
8283 {
8287 }
8290 }
8292 }
8294 }
8296 }
8299 {
8309 {
8315 {
8318 }
8321 {
8330 }
8334 else
8338 {
8339 tree fld;
8341 {
8354 }
8356 {
8360 }
8363 {
8364 cnt--;
8370 }
8371 }
8376 {
8389 {
8394 }
8395 }
8396 else
8397 {
8402 }
8407 {
8414 else
8420 }
8429 {
8430 /* FIXME: Handle PDP endian. */
8441 {
8444 }
8445 else
8446 {
8454 else
8455 {
8458 }
8459 }
8469 else
8482 /* If the bitfield does not start at byte boundary, handle
8483 the partial byte at the start. */
8486 {
8488 {
8493 {
8496 else
8498 }
8499 }
8500 else
8501 {
8506 {
8509 else
8513 }
8514 }
8515 }
8516 /* If the bitfield does not end at byte boundary, handle
8517 the partial byte at the end. */
8521 {
8523 {
8530 }
8531 else
8532 {
8539 }
8540 }
8544 {
8549 }
8550 else
8551 {
8552 /* Partial overlap. */
8556 {
8559 }
8563 }
8565 }
8570 {
8573 {
8576 {
8580 }
8583 }
8586 fldsize,
8596 }
8597 else
8598 {
8599 /* Partial overlap. */
8605 {
8609 fieldsize);
8610 }
8611 else
8612 {
8616 }
8619 }
8620 }
8622 }
8624 }
8625 }
8628 /* Subroutine of native_interpret_expr. Interpret the contents of
8629 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
8630 If the buffer cannot be interpreted, return NULL_TREE. */
8632 static tree
8634 {
8644 }
8647 /* Subroutine of native_interpret_expr. Interpret the contents of
8648 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
8649 If the buffer cannot be interpreted, return NULL_TREE. */
8651 static tree
8653 {
8656 double_int result;
8657 FIXED_VALUE_TYPE fixed_value;
8667 }
8670 /* Subroutine of native_interpret_expr. Interpret the contents of
8671 the buffer PTR of length LEN as a REAL_CST of type TYPE.
8672 If the buffer cannot be interpreted, return NULL_TREE. */
8674 tree
8676 {
8680 /* There are always 32 bits in each long, no matter the size of
8681 the hosts long. We handle floating point representations with
8682 up to 192 bits. */
8683 REAL_VALUE_TYPE r;
8693 {
8694 /* Both OFFSET and BYTE index within a long;
8695 bitpos indexes the whole float. */
8698 {
8705 else
8707 }
8708 else
8709 {
8712 {
8713 /* Reverse bytes within each long, or within the entire float
8714 if it's smaller than a long (for HFmode). */
8717 }
8718 }
8722 }
8726 }
8729 /* Subroutine of native_interpret_expr. Interpret the contents of
8730 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
8731 If the buffer cannot be interpreted, return NULL_TREE. */
8733 static tree
8735 {
8750 }
8752 /* Read a vector of type TYPE from the target memory image given by BYTES,
8753 which contains LEN bytes. The vector is known to be encodable using
8754 NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements each.
8756 Return the vector on success, otherwise return null. */
8758 static tree
8762 {
8766 {
8767 /* This is the only case in which elements can be smaller than a byte.
8768 Element 0 is always in the lsb of the containing byte. */
8775 {
8782 }
8784 }
8792 {
8798 }
8800 }
8802 /* Subroutine of native_interpret_expr. Interpret the contents of
8803 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
8804 If the buffer cannot be interpreted, return NULL_TREE. */
8806 static tree
8808 {
8809 tree etype;
8820 }
8823 /* Subroutine of fold_view_convert_expr. Interpret the contents of
8824 the buffer PTR of length LEN as a constant of type TYPE. For
8825 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
8826 we return a REAL_CST, etc... If the buffer cannot be interpreted,
8827 return NULL_TREE. */
8829 tree
8831 {
8833 {
8844 {
8845 /* For floating point values in composite modes, punt if this
8846 folding doesn't preserve bit representation. As the mode doesn't
8847 have fixed precision while GCC pretends it does, there could be
8848 valid values that GCC can't really represent accurately.
8849 See PR95450. Even for other modes, e.g. x86 XFmode can have some
8850 bit combinationations which GCC doesn't preserve. */
8858 }
8872 }
8873 }
8875 /* Returns true if we can interpret the contents of a native encoding
8876 as TYPE. */
8878 bool
8880 {
8882 {
8896 }
8897 }
8899 /* Attempt to interpret aggregate of TYPE from bytes encoded in target
8900 byte order at PTR + OFF with LEN bytes. Does not handle unions. */
8902 tree
8905 {
8908 {
8915 {
8919 }
8924 {
8929 {
8934 }
8938 eltsz);
8942 }
8944 }
8948 {
8956 {
8959 {
8960 poly_int64 bitoffset;
8965 else
8975 }
8976 else
8977 {
8995 HOST_WIDE_INT rpos;
8998 else
8999 {
9002 }
9011 }
9012 }
9015 {
9025 }
9029 {
9034 }
9041 {
9045 /* FIXME: Figure out how to handle PDP endian bitfields. */
9051 else
9055 }
9057 }
9059 }
9061 /* Routines for manipulation of native_encode_expr encoded data if the encoded
9062 or extracted constant positions and/or sizes aren't byte aligned. */
9064 /* Shift left the bytes in PTR of SZ elements by AMNT bits, carrying over the
9065 bits between adjacent elements. AMNT should be within
9066 [0, BITS_PER_UNIT).
9067 Example, AMNT = 2:
9068 00011111|11100000 << 2 = 01111111|10000000
9069 PTR[1] | PTR[0] PTR[1] | PTR[0]. */
9071 void
9074 {
9083 {
9089 {
9092 }
9093 }
9094 }
9096 /* Like shift_bytes_in_array_left but for big-endian.
9097 Shift right the bytes in PTR of SZ elements by AMNT bits, carrying over the
9098 bits between adjacent elements. AMNT should be within
9099 [0, BITS_PER_UNIT).
9100 Example, AMNT = 2:
9101 00011111|11100000 >> 2 = 00000111|11111000
9102 PTR[0] | PTR[1] PTR[0] | PTR[1]. */
9104 void
9107 {
9115 {
9122 }
9123 }
9125 /* Try to view-convert VECTOR_CST EXPR to VECTOR_TYPE TYPE by operating
9126 directly on the VECTOR_CST encoding, in a way that works for variable-
9127 length vectors. Return the resulting VECTOR_CST on success or null
9128 on failure. */
9130 static tree
9132 {
9144 /* We can only preserve the semantics of a stepped pattern if the new
9145 vector element is an integer of the same size. */
9150 /* The number of bits needed to encode one element from every pattern
9151 of the original vector. */
9152 unsigned int expr_sequence_bits
9155 /* The number of bits needed to encode one element from every pattern
9156 of the result. */
9157 unsigned int type_sequence_bits
9160 /* Don't try to read more bytes than are available, which can happen
9161 for constant-sized vectors if TYPE has larger elements than EXPR_TYPE.
9162 The general VIEW_CONVERT handling can cope with that case, so there's
9163 no point complicating things here. */
9166 BITS_PER_UNIT);
9171 /* Get enough bytes of EXPR to form the new encoding. */
9179 /* Reencode the bytes as TYPE. */
9183 }
9185 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
9186 TYPE at compile-time. If we're unable to perform the conversion
9187 return NULL_TREE. */
9189 static tree
9191 {
9192 /* We support up to 512-bit values (for V8DFmode). */
9196 /* Check that the host and target are sane. */
9209 }
9211 /* Build an expression for the address of T. Folds away INDIRECT_REF
9212 to avoid confusing the gimplify process. */
9214 tree
9216 {
9217 /* The size of the object is not relevant when talking about its address. */
9222 {
9227 }
9230 {
9235 }
9242 {
9247 }
9248 else
9252 }
9254 /* Build an expression for the address of T. */
9256 tree
9258 {
9262 }
9264 /* Fold a unary expression of code CODE and type TYPE with operand
9265 OP0. Return the folded expression if folding is successful.
9266 Otherwise, return NULL_TREE. */
9268 tree
9270 {
9271 tree tem;
9272 tree arg0;
9280 {
9283 {
9284 /* Don't use STRIP_NOPS, because signedness of argument type
9285 matters. */
9287 }
9288 else
9289 {
9290 /* Strip any conversions that don't change the mode. This
9291 is safe for every expression, except for a comparison
9292 expression because its signedness is derived from its
9293 operands.
9295 Note that this is done as an internal manipulation within
9296 the constant folder, in order to find the simplest
9297 representation of the arguments so that their form can be
9298 studied. In any cases, the appropriate type conversions
9299 should be put back in the tree that will get out of the
9300 constant folder. */
9302 }
9305 {
9308 {
9312 }
9313 }
9314 }
9321 {
9328 {
9342 /* If this was a conversion, and all we did was to move into
9343 inside the COND_EXPR, bring it back out. But leave it if
9344 it is a conversion from integer to integer and the
9345 result precision is no wider than a word since such a
9346 conversion is cheap and may be optimized away by combine,
9347 while it couldn't if it were outside the COND_EXPR. Then return
9348 so we don't get into an infinite recursion loop taking the
9349 conversion out and then back in. */
9361 && (INTEGRAL_TYPE_P
9374 }
9375 }
9378 {
9384 CASE_CONVERT:
9388 {
9389 /* If we have (type) (a CMP b) and type is an integral type, return
9390 new expression involving the new type. Canonicalize
9391 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
9392 non-integral type.
9393 Do not fold the result as that would not simplify further, also
9394 folding again results in recursions. */
9404 }
9406 /* Handle (T *)&A.B.C for A being of type T and B and C
9407 living at offset zero. This occurs frequently in
9408 C++ upcasting and then accessing the base. */
9412 {
9414 tree offset;
9415 machine_mode mode;
9417 tree base
9421 /* If the reference was to a (constant) zero offset, we can use
9422 the address of the base if it has the same base type
9423 as the result type and the pointer type is unqualified. */
9431 }
9435 /* Detect assigning a bitfield. */
9437 && DECL_BIT_FIELD
9439 {
9440 /* Don't leave an assignment inside a conversion
9441 unless assigning a bitfield. */
9443 /* First do the assignment, then return converted constant. */
9448 }
9450 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
9451 constants (if x has signed type, the sign bit cannot be set
9452 in c). This folds extension into the BIT_AND_EXPR.
9453 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
9454 very likely don't have maximal range for their precision and this
9455 transformation effectively doesn't preserve non-maximal ranges. */
9459 {
9470 <= HOST_BITS_PER_WIDE_INT
9472 {
9476 cst &= HOST_WIDE_INT_M1U
9480 && !flag_syntax_only
9483 {
9487 }
9488 }
9490 {
9495 }
9496 }
9498 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
9499 cast (T1)X will fold away. We assume that this happens when X itself
9500 is a cast. */
9504 {
9508 /* If -fsanitize=alignment, avoid this optimization in GENERIC
9509 when the pointed type needs higher alignment than
9510 the p+ first operand's pointed type. */
9517 /* Similarly, avoid this optimization in GENERIC for -fsanitize=null
9518 when type is a reference type and arg00's type is not,
9519 because arg00 could be validly nullptr and if arg01 doesn't return,
9520 we don't want false positive binding of reference to nullptr. */
9522 && !in_gimple_form
9529 }
9531 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
9532 of the same precision, and X is an integer type not narrower than
9533 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
9539 {
9545 }
9547 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
9548 type of X and Y (integer types only). */
9553 {
9554 /* Be careful not to introduce new overflows. */
9555 tree mult_type;
9558 else
9562 {
9569 }
9570 }
9576 {
9583 }
9594 /* Convert fabs((double)float) into (double)fabsf(float). */
9597 {
9603 targ0));
9604 }
9608 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
9627 /* Note that the operand of this must be an int
9628 and its values must be 0 or 1.
9629 ("true" is a fixed value perhaps depending on the language,
9630 but we don't handle values other than 1 correctly yet.) */
9637 /* Fold *&X to X if X is an lvalue. */
9639 {
9646 }
9652 }
9655 /* If the operation was a conversion do _not_ mark a resulting constant
9656 with TREE_OVERFLOW if the original constant was not. These conversions
9657 have implementation defined behavior and retaining the TREE_OVERFLOW
9658 flag here would confuse later passes such as VRP. */
9659 tree
9662 {
9671 }
9673 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
9674 operands OP0 and OP1. LOC is the location of the resulting expression.
9675 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
9676 Return the folded expression if folding is successful. Otherwise,
9677 return NULL_TREE. */
9678 static tree
9681 {
9682 tree tem;
9684 /* We only do these simplifications if we are optimizing. */
9688 /* Check for things like (A || B) && (A || C). We can convert this
9689 to A || (B && C). Note that either operator can be any of the four
9690 truth and/or operations and the transformation will still be
9691 valid. Also note that we only care about order for the
9692 ANDIF and ORIF operators. If B contains side effects, this
9693 might change the truth-value of A. */
9700 {
9720 /* This case if tricky because we must either have commutative
9721 operators or else A10 must not have side-effects. */
9727 a01);
9728 }
9730 /* See if we can build a range comparison. */
9736 {
9740 }
9744 {
9748 }
9750 /* Check for the possibility of merging component references. If our
9751 lhs is another similar operation, try to merge its rhs with our
9752 rhs. Then try to merge our lhs and rhs. */
9763 logical_op_non_short_circuit
9771 {
9778 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
9779 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
9780 We don't want to pack more than two leafs to a non-IF AND/OR
9781 expression.
9782 If tree-code of left-hand operand isn't an AND/OR-IF code and not
9783 equal to IF-CODE, then we don't want to add right-hand operand.
9784 If the inner right-hand side of left-hand operand has
9785 side-effects, or isn't simple, then we can't add to it,
9786 as otherwise we might destroy if-sequence. */
9789 /* Needed for sequence points to handle trappings, and
9790 side-effects. */
9792 {
9794 arg1);
9796 tem);
9797 }
9798 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
9799 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
9802 /* Needed for sequence points to handle trappings, and
9803 side-effects. */
9805 {
9810 }
9811 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
9812 into (A OR B).
9813 For sequence point consistancy, we need to check for trapping,
9814 and side-effects. */
9818 }
9821 }
9823 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
9824 by changing CODE to reduce the magnitude of constants involved in
9825 ARG0 of the comparison.
9826 Returns a canonicalized comparison tree if a simplification was
9827 possible, otherwise returns NULL_TREE.
9828 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
9829 valid if signed overflow is undefined. */
9831 static tree
9835 {
9840 /* Match A +- CST code arg1. We can change this only if overflow
9841 is undefined. */
9844 /* In principle pointers also have undefined overflow behavior,
9845 but that causes problems elsewhere. */
9852 /* Identify the constant in arg0 and its sign. */
9856 /* Overflowed constants and zero will cause problems. */
9861 /* See if we can reduce the magnitude of the constant in
9862 arg0 by changing the comparison code. */
9863 /* A - CST < arg1 -> A - CST-1 <= arg1. */
9867 /* A + CST > arg1 -> A + CST-1 >= arg1. */
9871 /* A + CST <= arg1 -> A + CST-1 < arg1. */
9875 /* A - CST >= arg1 -> A - CST-1 > arg1. */
9879 else
9883 /* Now build the constant reduced in magnitude. But not if that
9884 would produce one outside of its types range. */
9900 }
9902 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
9903 overflow further. Try to decrease the magnitude of constants involved
9904 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
9905 and put sole constants at the second argument position.
9906 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
9908 static tree
9911 {
9912 tree t;
9917 /* Try canonicalization by simplifying arg0. */
9922 {
9926 }
9928 /* Try canonicalization by simplifying arg1 using the swapped
9929 comparison. */
9937 }
9939 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
9940 space. This is used to avoid issuing overflow warnings for
9941 expressions like &p->x which cannot wrap. */
9943 static bool
9945 {
9952 poly_wide_int wi_offset;
9958 else
9963 precision);
9978 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
9979 array. */
9988 }
9990 /* Return a positive integer when the symbol DECL is known to have
9991 a nonzero address, zero when it's known not to (e.g., it's a weak
9992 symbol), and a negative integer when the symbol is not yet in the
9993 symbol table and so whether or not its address is zero is unknown.
9994 For function local objects always return positive integer. */
9995 static int
9997 {
9998 /* Normally, don't do anything for variables and functions before symtab is
9999 built; it is quite possible that DECL will be declared weak later.
10000 But if folding_initializer, we need a constant answer now, so create
10001 the symtab entry and prevent later weak declaration. */
10004 = (folding_initializer
10009 /* Function local objects are never NULL. */
10017 }
10019 /* Subroutine of fold_binary. This routine performs all of the
10020 transformations that are common to the equality/inequality
10021 operators (EQ_EXPR and NE_EXPR) and the ordering operators
10022 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
10023 fold_binary should call fold_binary. Fold a comparison with
10024 tree code CODE and type TYPE with operands OP0 and OP1. Return
10025 the folded comparison or NULL_TREE. */
10027 static tree
10030 {
10040 /* For comparisons of pointers we can decompose it to a compile time
10041 comparison of the base objects and the offsets into the object.
10042 This requires at least one operand being an ADDR_EXPR or a
10043 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
10049 {
10052 machine_mode mode;
10056 /* Get base and offset for the access. Strip ADDR_EXPR for
10057 get_inner_reference, but put it back by stripping INDIRECT_REF
10058 off the base object if possible. indirect_baseN will be true
10059 if baseN is not an address but refers to the object itself. */
10062 {
10063 base0
10069 else
10071 }
10073 {
10077 {
10078 base0
10084 else
10086 }
10089 else
10093 {
10100 }
10101 }
10105 {
10106 base1
10112 else
10114 }
10116 {
10120 {
10121 base1
10127 else
10129 }
10132 else
10136 {
10143 }
10144 }
10146 /* If we have equivalent bases we might be able to simplify. */
10150 {
10151 /* We can fold this expression to a constant if the non-constant
10152 offset parts are equal. */
10156 && (equality_code
10157 || (indirect_base0
10160 {
10166 "occur when comparing P +- C1 with "
10168 WARN_STRICT_OVERFLOW_CONDITIONAL);
10171 {
10209 }
10210 }
10211 /* We can simplify the comparison to a comparison of the variable
10212 offset parts if the constant offset parts are equal.
10213 Be careful to use signed sizetype here because otherwise we
10214 mess with array offsets in the wrong way. This is possible
10215 because pointer arithmetic is restricted to retain within an
10216 object and overflow on pointer differences is undefined as of
10217 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
10219 && (equality_code
10220 || (indirect_base0
10223 {
10224 /* By converting to signed sizetype we cover middle-end pointer
10225 arithmetic which operates on unsigned pointer types of size
10226 type size and ARRAY_REF offsets which are properly sign or
10227 zero extended from their type in case it is narrower than
10228 sizetype. */
10231 else
10235 else
10242 "occur when comparing P +- C1 with "
10244 WARN_STRICT_OVERFLOW_COMPARISON);
10247 }
10248 }
10249 /* For equal offsets we can simplify to a comparison of the
10250 base addresses. */
10252 && (indirect_base0
10254 && (indirect_base1
10259 {
10265 }
10266 /* Comparison between an ordinary (non-weak) symbol and a null
10267 pointer can be eliminated since such symbols must have a non
10268 null address. In C, relational expressions between pointers
10269 to objects and null pointers are undefined. The results
10270 below follow the C++ rules with the additional property that
10271 every object pointer compares greater than a null pointer.
10272 */
10275 /* Avoid folding references to struct members at offset 0 to
10276 prevent tests like '&ptr->firstmember == 0' from getting
10277 eliminated. When ptr is null, although the -> expression
10278 is strictly speaking invalid, GCC retains it as a matter
10279 of QoI. See PR c/44555. */
10282 && indirect_base0
10283 /* The caller guarantees that when one of the arguments is
10284 constant (i.e., null in this case) it is second. */
10286 {
10288 {
10299 }
10300 }
10301 }
10303 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
10304 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
10305 the resulting offset is smaller in absolute value than the
10306 original one and has the same sign. */
10315 {
10320 tree cst;
10322 "occur when combining constants around "
10325 /* Put the constant on the side where it doesn't overflow and is
10326 of lower absolute value and of same sign than before. */
10333 {
10336 variable1,
10340 }
10348 {
10354 variable2);
10355 }
10356 }
10362 /* If we are comparing an expression that just has comparisons
10363 of two integer values, arithmetic expressions of those comparisons,
10364 and constants, we can simplify it. There are only three cases
10365 to check: the two values can either be equal, the first can be
10366 greater, or the second can be greater. Fold the expression for
10367 those three values. Since each value must be 0 or 1, we have
10368 eight possibilities, each of which corresponds to the constant 0
10369 or 1 or one of the six possible comparisons.
10371 This handles common cases like (a > b) == 0 but also handles
10372 expressions like ((x > y) - (y > x)) > 0, which supposedly
10373 occur in macroized code. */
10376 {
10380 /* Don't handle degenerate cases here; they should already
10381 have been handled anyway. */
10390 {
10394 /* We can't just pass T to eval_subst in case cval1 or cval2
10395 was the same as ARG1. */
10397 tree high_result
10401 arg1);
10402 tree equal_result
10406 arg1);
10407 tree low_result
10411 arg1);
10413 /* All three of these results should be 0 or 1. Confirm they are.
10414 Then use those values to select the proper code to use. */
10419 {
10420 /* Make a 3-bit mask with the high-order bit being the
10421 value for `>', the next for '=', and the low for '<'. */
10425 {
10427 /* Always false. */
10448 /* Always true. */
10450 }
10453 }
10454 }
10455 }
10458 }
10461 /* Subroutine of fold_binary. Optimize complex multiplications of the
10462 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
10463 argument EXPR represents the expression "z" of type TYPE. */
10465 static tree
10467 {
10472 {
10475 }
10477 {
10480 }
10481 else
10482 {
10486 }
10495 }
10498 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
10499 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
10500 true if successful. */
10502 static bool
10504 {
10509 {
10512 }
10514 {
10520 else
10522 }
10523 else
10529 }
10531 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
10532 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
10533 NULL_TREE otherwise. */
10535 tree
10537 {
10558 {
10559 HOST_WIDE_INT index;
10565 }
10568 {
10574 }
10575 else
10577 }
10579 /* Try to fold a pointer difference of type TYPE two address expressions of
10580 array references AREF0 and AREF1 using location LOC. Return a
10581 simplified expression for the difference or NULL_TREE. */
10583 static tree
10587 {
10592 /* If the bases are array references as well, recurse. If the bases
10593 are pointer indirections compute the difference of the pointers.
10594 If the bases are equal, we are set. */
10597 && (base_offset
10599 use_pointer_diff)))
10602 && (base_offset
10603 = use_pointer_diff
10613 {
10619 base_offset,
10622 }
10624 }
10626 /* If the real or vector real constant CST of type TYPE has an exact
10627 inverse, return it, else return NULL. */
10629 tree
10631 {
10632 REAL_VALUE_TYPE r;
10633 tree unit_type;
10634 machine_mode mode;
10637 {
10647 {
10651 tree_vector_builder elts;
10656 {
10661 }
10664 }
10668 }
10669 }
10671 /* Mask out the tz least significant bits of X of type TYPE where
10672 tz is the number of trailing zeroes in Y. */
10673 static wide_int
10675 {
10680 }
10682 /* Return true when T is an address and is known to be nonzero.
10683 For floating point we further ensure that T is not denormal.
10684 Similar logic is present in nonzero_address in rtlanal.h.
10686 If the return value is based on the assumption that signed overflow
10687 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
10688 change *STRICT_OVERFLOW_P. */
10690 static bool
10692 {
10696 /* Doing something useful for floating point would need more work. */
10702 {
10705 strict_overflow_p);
10711 strict_overflow_p);
10719 }
10722 {
10725 strict_overflow_p);
10733 strict_overflow_p);
10748 strict_overflow_p);
10752 strict_overflow_p);
10755 {
10767 }
10771 }
10773 }
10775 /* Return true when T is an address and is known to be nonzero.
10776 Handle warnings about undefined signed overflow. */
10778 bool
10780 {
10787 "determining that expression is always "
10789 WARN_STRICT_OVERFLOW_MISC);
10791 }
10793 /* Return true if T is known not to be equal to an integer W. */
10795 bool
10797 {
10798 int_range_max vr;
10800 {
10810 else
10816 /* If T has some known zero bits and W has any of those bits set,
10817 then T is known not to be equal to W. */
10825 }
10826 }
10828 /* Fold a binary expression of code CODE and type TYPE with operands
10829 OP0 and OP1. LOC is the location of the resulting expression.
10830 Return the folded expression if folding is successful. Otherwise,
10831 return NULL_TREE. */
10833 tree
10836 {
10851 /* Strip any conversions that don't change the mode. This is
10852 safe for every expression, except for a comparison expression
10853 because its signedness is derived from its operands. So, in
10854 the latter case, only strip conversions that don't change the
10855 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
10856 preserved.
10858 Note that this is done as an internal manipulation within the
10859 constant folder, in order to find the simplest representation
10860 of the arguments so that their form can be studied. In any
10861 cases, the appropriate type conversions should be put back in
10862 the tree that will get out of the constant folder. */
10865 {
10868 }
10869 else
10870 {
10873 }
10875 /* Note that TREE_CONSTANT isn't enough: static var addresses are
10876 constant but we can't do arithmetic on them. */
10878 {
10881 {
10885 }
10886 }
10888 /* If this is a commutative operation, and ARG0 is a constant, move it
10889 to ARG1 to reduce the number of tests below. */
10894 /* Likewise if this is a comparison, and ARG0 is a constant, move it
10895 to ARG1 to reduce the number of tests below. */
10904 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
10906 First check for cases where an arithmetic operation is applied to a
10907 compound, conditional, or comparison operation. Push the arithmetic
10908 operation inside the compound or conditional to see if any folding
10909 can then be done. Convert comparison to conditional for this purpose.
10910 The also optimizes non-constant cases that used to be done in
10911 expand_expr.
10913 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
10914 one of the operands is a comparison and the other is a comparison, a
10915 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
10916 code below would make the expression more complex. Change it to a
10917 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
10918 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
10931 {
10935 boolean_type_node,
10943 }
10947 {
10949 {
10954 tem);
10955 }
10957 {
10962 tem);
10963 }
10968 {
10974 }
10979 {
10985 }
10986 }
10989 {
10991 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
10994 {
11000 }
11002 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
11005 {
11006 tree base;
11007 poly_int64 coffset;
11016 }
11021 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
11027 arg1),
11029 arg0)));
11035 {
11036 /* X + (X / CST) * -CST is X % CST. */
11041 {
11050 cst0));
11051 }
11052 }
11054 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
11055 one. Make sure the type is not saturating and has the signedness of
11056 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11057 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11064 {
11068 }
11071 {
11072 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
11073 (plus (plus (mult) (mult)) (foo)) so that we can
11074 take advantage of the factoring cases below. */
11083 {
11089 else
11102 parg0),
11104 marg)),
11108 return
11114 parg1)));
11115 }
11116 }
11117 else
11118 {
11119 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
11120 to __complex__ ( x, y ). This is not the same for SNaNs or
11121 if signed zeros are involved. */
11125 {
11132 {
11136 {
11142 }
11144 {
11150 }
11151 }
11152 }
11154 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
11155 We associate floats only if the user has specified
11156 -fassociative-math. */
11160 {
11165 {
11166 tree tree0;
11169 }
11170 }
11171 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
11172 We associate floats only if the user has specified
11173 -fassociative-math. */
11177 {
11182 {
11183 tree tree0;
11186 }
11187 }
11188 }
11190 bit_rotate:
11191 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
11192 is a rotate of A by C1 bits. */
11193 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
11194 is a rotate of A by B bits.
11195 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
11196 though in this case CODE must be | and not + or ^, otherwise
11197 it doesn't return A when B is 0. */
11198 {
11200 tree rtype;
11209 /* Only create rotates in complete modes. Other cases are not
11210 expanded properly. */
11213 {
11226 {
11231 }
11236 {
11239 code0 == LSHIFT_EXPR
11242 }
11244 {
11254 {
11258 orig_tree01);
11260 }
11261 }
11265 {
11276 {
11280 orig_tree01);
11282 }
11283 }
11284 }
11285 }
11287 associate:
11288 /* In most languages, can't associate operations on floats through
11289 parentheses. Rather than remember where the parentheses were, we
11290 don't associate floats at all, unless the user has specified
11291 -fassociative-math.
11292 And, we need to make sure type is not saturating. */
11296 {
11302 /* Split both trees into variables, constants, and literals. Then
11303 associate each group together, the constants with literals,
11304 then the result with variables. This increases the chances of
11305 literals being recombined later and of generating relocatable
11306 expressions for the sum of a constant and literal. */
11314 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
11318 /* With undefined overflow prefer doing association in a type
11319 which wraps on overflow, if that is one of the operand types. */
11322 {
11330 }
11332 /* With undefined overflow we can only associate constants with one
11333 variable, and constants whose association doesn't overflow. */
11336 {
11338 {
11339 /* ??? If split_tree would handle NEGATE_EXPR we could
11340 simply reject these cases and the allowed cases would
11341 be the var0/minus_var1 ones. */
11347 {
11350 }
11357 {
11360 }
11366 /* The only case we can still associate with two variables
11367 is if they cancel out. */
11371 }
11377 }
11379 /* Only do something if we found more than two objects. Otherwise,
11380 nothing has changed and we risk infinite recursion. */
11388 {
11400 {
11404 }
11406 {
11410 }
11412 /* Preserve the MINUS_EXPR if the negative part of the literal is
11413 greater than the positive part. Otherwise, the multiplicative
11414 folding code (i.e extract_muldiv) may be fooled in case
11415 unsigned constants are subtracted, like in the following
11416 example: ((X*2 + 4) - 8U)/2. */
11418 {
11422 /* But avoid ending up with only negated parts. */
11424 {
11428 }
11429 else
11430 {
11434 }
11435 }
11437 /* Don't introduce overflows through reassociation. */
11442 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
11449 /* Eliminate minus_con0. */
11451 {
11458 else
11461 }
11463 /* Eliminate minus_var0. */
11465 {
11469 else
11472 }
11474 return
11477 }
11478 }
11484 /* Fold &a[i] - &a[j] to i-j. */
11489 {
11493 code
11497 }
11499 /* Further transformations are not for pointers. */
11503 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
11506 /* If arg0 is e.g. unsigned int and type is int, then this could
11507 introduce UB, because if A is INT_MIN at runtime, the original
11508 expression can be well defined while the latter is not.
11509 See PR83269. */
11518 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
11519 __complex__ ( x, -y ). This is not the same for SNaNs or if
11520 signed zeros are involved. */
11524 {
11531 {
11535 {
11537 arg1r ? arg1r
11542 }
11544 {
11548 arg1i ? arg1i
11551 }
11552 }
11553 }
11555 /* A - B -> A + (-B) if B is easily negatable. */
11559 /* Avoid this transformation if B is a positive REAL_CST. */
11567 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
11568 one. Make sure the type is not saturating and has the signedness of
11569 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11570 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11577 {
11581 }
11587 {
11588 /* Transform x * -C into -x * C if x is easily negatable. */
11603 {
11606 "occur when simplifying "
11608 WARN_STRICT_OVERFLOW_MISC);
11610 }
11612 /* Optimize z * conj(z) for integer complex numbers. */
11619 }
11620 else
11621 {
11622 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
11623 This is not the same for NaNs or if signed zeros are
11624 involved. */
11630 {
11633 return
11639 return
11644 }
11646 /* Optimize z * conj(z) for floating point complex numbers.
11647 Guarded by flag_unsafe_math_optimizations as non-finite
11648 imaginary components don't produce scalar results. */
11657 }
11661 /* Canonicalize (X & C1) | C2. */
11665 {
11670 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
11678 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
11680 {
11683 }
11685 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
11686 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
11687 mode which allows further optimizations. */
11692 {
11697 {
11700 }
11701 }
11704 {
11709 }
11710 }
11712 /* See if this can be simplified into a rotate first. If that
11713 is unsuccessful continue in the association code. */
11717 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
11725 /* See if this can be simplified into a rotate first. If that
11726 is unsuccessful continue in the association code. */
11730 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
11735 {
11736 tree tem2;
11743 }
11744 /* Fold ~X & 1 as (X & 1) == 0. */
11748 {
11749 tree tem2;
11756 }
11757 /* Fold !X & 1 as X == 0. */
11760 {
11764 }
11766 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
11767 multiple of 1 << CST. */
11769 {
11776 }
11778 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
11779 bits from CST2. */
11783 {
11785 wide_int masked
11792 {
11793 /* Avoid the transform if arg1 is a mask of some
11794 mode which allows further optimizations. */
11801 }
11802 }
11804 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11807 {
11812 return
11814 }
11819 /* Don't touch a floating-point divide by zero unless the mode
11820 of the constant can represent infinity. */
11826 /* (-A) / (-B) -> A / B */
11838 /* Fall through */
11841 /* Simplify A / (B << N) where A and B are positive and B is
11842 a power of 2, to A >> (N + log2(B)). */
11847 {
11850 {
11858 WARN_STRICT_OVERFLOW_MISC);
11864 }
11865 }
11867 /* Fall through */
11875 /* Convert -A / -B to A / B when the type is signed and overflow is
11876 undefined. */
11880 {
11883 "when distributing negation across "
11885 WARN_STRICT_OVERFLOW_MISC);
11890 }
11894 {
11897 "when distributing negation across "
11899 WARN_STRICT_OVERFLOW_MISC);
11904 }
11906 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11907 operation, EXACT_DIV_EXPR.
11909 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11910 At one time others generated faster code, it's not clear if they do
11911 after the last round to changes to the DIV code in expmed.cc. */
11922 {
11926 WARN_STRICT_OVERFLOW_MISC);
11928 }
11940 {
11944 WARN_STRICT_OVERFLOW_MISC);
11946 }
11954 /* Since negative shift count is not well-defined,
11955 don't try to compute it in the compiler. */
11961 /* If we have a rotate of a bit operation with the rotate count and
11962 the second operand of the bit operation both constant,
11963 permute the two operations. */
11969 {
11977 }
11979 /* Two consecutive rotates adding up to the some integer
11980 multiple of the precision of the type can be ignored. */
11996 /* Note that the operands of this must be ints
11997 and their values must be 0 or 1.
11998 ("true" is a fixed value perhaps depending on the language.) */
11999 /* If first arg is constant zero, return it. */
12002 /* FALLTHRU */
12004 /* If either arg is constant true, drop it. */
12008 /* Preserve sequence points. */
12011 /* If second arg is constant zero, result is zero, but first arg
12012 must be evaluated. */
12015 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
12016 case will be handled here. */
12020 /* !X && X is always false. */
12024 /* X && !X is always false. */
12029 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
12030 means A >= Y && A != MAX, but in this case we know that
12031 A < X <= MAX. */
12035 {
12047 }
12056 /* Note that the operands of this must be ints
12057 and their values must be 0 or true.
12058 ("true" is a fixed value perhaps depending on the language.) */
12059 /* If first arg is constant true, return it. */
12062 /* FALLTHRU */
12064 /* If either arg is constant zero, drop it. */
12068 /* Preserve sequence points. */
12071 /* If second arg is constant true, result is true, but we must
12072 evaluate first arg. */
12075 /* Likewise for first arg, but note this only occurs here for
12076 TRUTH_OR_EXPR. */
12080 /* !X || X is always true. */
12084 /* X || !X is always true. */
12089 /* (X && !Y) || (!X && Y) is X ^ Y */
12092 {
12109 }
12118 /* If the second arg is constant zero, drop it. */
12121 /* If the second arg is constant true, this is a logical inversion. */
12123 {
12126 }
12127 /* Identical arguments cancel to zero. */
12131 /* !X ^ X is always true. */
12136 /* X ^ !X is always true. */
12152 /* bool_var != 1 becomes !bool_var. */
12159 /* bool_var == 0 becomes !bool_var. */
12166 /* !exp != 0 becomes !exp */
12171 /* If this is an EQ or NE comparison with zero and ARG0 is
12172 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
12173 two operations, but the latter can be done in one less insn
12174 on machines that have only two-operand insns or on which a
12175 constant cannot be the first operand. */
12178 {
12183 {
12191 }
12194 {
12202 }
12203 }
12205 /* If this is a comparison of a field, we may be able to simplify it. */
12208 /* Handle the constant case even without -O
12209 to make sure the warnings are given. */
12211 {
12215 }
12217 /* Optimize comparisons of strlen vs zero to a compare of the
12218 first character of the string vs zero. To wit,
12219 strlen(ptr) == 0 => *ptr == 0
12220 strlen(ptr) != 0 => *ptr != 0
12221 Other cases should reduce to one of these two (or a constant)
12222 due to the return value of strlen being unsigned. */
12224 {
12232 {
12233 tree ptrtype
12235 TYPE_QUAL_CONST));
12241 }
12242 }
12244 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12245 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12249 {
12254 {
12256 {
12259 }
12262 }
12263 }
12265 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12266 (X & C) == 0 when C is a single bit. */
12271 {
12278 arg1));
12279 }
12281 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12282 constant C is a power of two, i.e. a single bit. */
12289 {
12293 }
12295 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12296 when is C is a power of two, i.e. a single bit. */
12303 {
12309 }
12313 {
12316 }
12320 {
12327 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12328 operand_equal_p guarantees no side-effects so we don't need
12329 to use omit_one_operand on Z. */
12333 arg10));
12337 arg11));
12341 arg10));
12345 arg11));
12347 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12350 {
12356 }
12357 }
12359 /* Attempt to simplify equality/inequality comparisons of complex
12360 values. Only lower the comparison if the result is known or
12361 can be simplified to a single scalar comparison. */
12366 {
12371 {
12374 }
12375 else
12376 {
12379 }
12382 {
12385 }
12386 else
12387 {
12390 }
12394 {
12396 {
12401 }
12402 else
12403 {
12408 }
12409 }
12413 {
12415 {
12420 }
12421 else
12422 {
12427 }
12428 }
12429 }
12441 /* Transform comparisons of the form X +- C CMP X. */
12446 {
12451 /* (X - c) > X becomes false. */
12457 /* Likewise (X + c) < X becomes false. */
12463 /* Convert (X - c) <= X to true. */
12470 /* Convert (X + c) >= X to true. */
12476 }
12478 /* If we are comparing an ABS_EXPR with a constant, we can
12479 convert all the cases into explicit comparisons, but they may
12480 well not be faster than doing the ABS and one comparison.
12481 But ABS (X) <= C is a range comparison, which becomes a subtraction
12482 and a comparison, and is probably faster. */
12496 /* Convert ABS_EXPR<x> >= 0 to true. */
12503 {
12506 "when simplifying comparison of "
12508 WARN_STRICT_OVERFLOW_CONDITIONAL);
12511 arg0);
12512 }
12514 /* Convert ABS_EXPR<x> < 0 to false. */
12519 {
12522 "when simplifying comparison of "
12524 WARN_STRICT_OVERFLOW_CONDITIONAL);
12527 arg0);
12528 }
12530 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12531 and similarly for >= into !=. */
12541 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
12542 otherwise Y might be >= # of bits in X's type and thus e.g.
12543 (unsigned char) (1 << Y) for Y 15 might be 0.
12544 If the cast is widening, then 1 << Y should have unsigned type,
12545 otherwise if Y is number of bits in the signed shift type minus 1,
12546 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
12547 31 might be 0xffffffff80000000. */
12560 {
12566 }
12578 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12579 {
12591 }
12596 /* When pedantic, a compound expression can be neither an lvalue
12597 nor an integer constant expression. */
12600 /* Don't let (0, 0) be null pointer constant. */
12606 /* An ASSERT_EXPR should never be passed to fold_binary. */
12612 }
12614 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
12615 ((A & N) + B) & M -> (A + B) & M
12616 Similarly if (N & M) == 0,
12617 ((A | N) + B) & M -> (A + B) & M
12618 and for - instead of + (or unary - instead of +)
12619 and/or ^ instead of |.
12620 If B is constant and (B & M) == 0, fold into A & M.
12622 This function is a helper for match.pd patterns. Return non-NULL
12623 type in which the simplified operation should be performed only
12624 if any optimization is possible.
12626 ARG1 is M above, ARG00 is left operand of +/-, if CODE00 is BIT_*_EXPR,
12627 then ARG00{0,1} are operands of that bitop, otherwise CODE00 is ERROR_MARK.
12628 Similarly for ARG01, CODE01 and ARG01{0,1}, just for the right operand of
12629 +/-. */
12630 tree
12635 {
12650 wide_int cst0;
12652 /* Now we know that arg0 is (C + D) or (C - D) or -C and
12653 arg1 (M) is == (1LL << cst) - 1.
12654 Store C into PMOP[0] and D into PMOP[1]. */
12661 {
12668 {
12671 }
12674 /* If C or D is of the form (A & N) where
12675 (N & M) == M, or of the form (A | N) or
12676 (A ^ N) where (N & M) == 0, replace it with A. */
12682 /* If C or D is a N where (N & M) == 0, it can be
12683 omitted (replaced with 0). */
12688 /* Similarly, with C - N where (-N & M) == 0. */
12696 }
12698 /* Only build anything new if we optimized one or both arguments above. */
12704 else
12706 }
12708 /* Used by contains_label_[p1]. */
12710 struct contains_label_data
12711 {
12714 };
12716 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
12717 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
12718 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
12720 static tree
12722 {
12725 {
12736 {
12744 }
12753 }
12754 }
12756 /* Return whether the sub-tree ST contains a label which is accessible from
12757 outside the sub-tree. */
12759 static bool
12761 {
12765 }
12767 /* Fold a ternary expression of code CODE and type TYPE with operands
12768 OP0, OP1, and OP2. Return the folded expression if folding is
12769 successful. Otherwise, return NULL_TREE. */
12771 tree
12774 {
12775 tree tem;
12782 /* If this is a commutative operation, and OP0 is a constant, move it
12783 to OP1 to reduce the number of tests below. */
12792 /* Strip any conversions that don't change the mode. This is safe
12793 for every expression, except for a comparison expression because
12794 its signedness is derived from its operands. So, in the latter
12795 case, only strip conversions that don't change the signedness.
12797 Note that this is done as an internal manipulation within the
12798 constant folder, in order to find the simplest representation of
12799 the arguments so that their form can be studied. In any cases,
12800 the appropriate type conversions should be put back in the tree
12801 that will get out of the constant folder. */
12803 {
12806 }
12809 {
12812 }
12815 {
12818 }
12821 {
12825 {
12831 }
12836 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12837 so all simple results must be passed through pedantic_non_lvalue. */
12839 {
12842 /* Only optimize constant conditions when the selected branch
12843 has the same type as the COND_EXPR. This avoids optimizing
12844 away "c ? x : throw", where the throw has a void type.
12845 Avoid throwing away that operand which contains label. */
12852 }
12854 {
12861 {
12864 {
12872 }
12877 }
12878 }
12880 /* If we have A op B ? A : C, we may be able to convert this to a
12881 simpler expression, depending on the operation and the values
12882 of B and C. Signed zeros prevent all of these transformations,
12883 for reasons given above each one.
12885 Also try swapping the arguments and inverting the conditional. */
12889 {
12896 }
12901 {
12908 arg00,
12909 arg01,
12913 }
12915 /* If the second operand is simpler than the third, swap them
12916 since that produces better jump optimization results. */
12919 {
12921 /* See if this can be inverted. If it can't, possibly because
12922 it was a floating-point inequality comparison, don't do
12923 anything. */
12927 }
12929 /* Convert A ? 1 : 0 to simply A. */
12934 /* If we try to convert OP0 to our type, the
12935 call to fold will try to move the conversion inside
12936 a COND, which will recurse. In that case, the COND_EXPR
12937 is probably the best choice, so leave it alone. */
12941 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12942 over COND_EXPR in cases such as floating point comparisons. */
12951 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12956 {
12957 /* sign_bit_p looks through both zero and sign extensions,
12958 but for this optimization only sign extensions are
12959 usable. */
12962 {
12965 {
12968 }
12970 }
12971 /* sign_bit_p only checks ARG1 bits within A's precision.
12972 If <sign bit of A> has wider type than A, bits outside
12973 of A's precision in <sign bit of A> need to be checked.
12974 If they are all 0, this optimization needs to be done
12975 in unsigned A's type, if they are all 1 in signed A's type,
12976 otherwise this can't be done. */
12982 {
12984 tree tem_type;
12997 {
13000 }
13002 {
13005 }
13006 else
13008 }
13011 return
13017 arg1)));
13018 }
13020 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13021 already handled above. */
13026 {
13036 op1);
13037 }
13039 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13040 is probably obsolete because the first operand should be a
13041 truth value (that's why we have the two cases above), but let's
13042 leave it in until we can confirm this for all front-ends. */
13050 /* operand_equal_p compares just value, not precision, so e.g.
13051 arg1 could be 8-bit -128 and be power of two, but BIT_AND_EXPR
13052 second operand 32-bit -128, which is not a power of two (or vice
13053 versa. */
13057 /* Disable the transformations below for vectors, since
13058 fold_binary_op_with_conditional_arg may undo them immediately,
13059 yielding an infinite loop. */
13063 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13072 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13077 {
13079 /* Only perform transformation if ARG0 is easily inverted. */
13083 ? BIT_IOR_EXPR
13086 op1);
13087 }
13089 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13094 {
13096 /* Only perform transformation if ARG0 is easily inverted. */
13102 op2);
13103 }
13105 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13117 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13118 of fold_ternary on them. */
13128 {
13130 unsigned HOST_WIDE_INT width
13141 {
13146 {
13148 {
13153 }
13159 }
13160 }
13161 }
13163 /* On constants we can use native encode/interpret to constant
13164 fold (nearly) all BIT_FIELD_REFs. */
13170 {
13173 /* Limit us to a reasonable amount of work. To relax the
13174 other limitations we need bit-shifting of the buffer
13175 and rounding up the size. */
13179 {
13181 unsigned HOST_WIDE_INT len
13186 {
13191 }
13192 }
13193 }
13198 /* Perform constant folding of BIT_INSERT_EXPR. */
13202 {
13203 /* Build a vector of integers from the tree mask. */
13204 vec_perm_builder builder;
13208 /* Create a vec_perm_indices for the integer vector. */
13213 }
13217 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
13220 {
13226 wide_int tem2
13230 }
13235 {
13237 unsigned HOST_WIDE_INT elsize
13240 {
13246 {
13252 }
13253 }
13254 }
13260 }
13262 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
13263 of an array (or vector). *CTOR_IDX if non-NULL is updated with the
13264 constructor element index of the value returned. If the element is
13265 not found NULL_TREE is returned and *CTOR_IDX is updated to
13266 the index of the element after the ACCESS_INDEX position (which
13267 may be outside of the CTOR array). */
13269 tree
13272 {
13278 {
13281 {
13282 /* Static constructors for variably sized objects makes no sense. */
13285 /* ??? When it is obvious that the range is signed, treat it so. */
13290 {
13292 low_bound
13294 SIGNED);
13295 }
13296 else
13297 {
13300 }
13301 }
13302 }
13306 index_sgn);
13318 {
13319 /* Array constructor might explicitly set index, or specify a range,
13320 or leave index NULL meaning that it is next index after previous
13321 one. */
13323 {
13325 max_index = index
13327 else
13328 {
13331 index_sgn);
13332 max_index
13334 index_sgn);
13336 }
13337 }
13339 {
13345 }
13346 else
13349 /* Do we have match? */
13351 {
13353 {
13357 }
13358 }
13360 /* We're past the element we search for. Note during parsing
13361 the elements might not be sorted.
13362 ??? We should use a binary search and a flag on the
13363 CONSTRUCTOR as to whether elements are sorted in declaration
13364 order. */
13366 }
13370 }
13372 /* Perform constant folding and related simplification of EXPR.
13373 The related simplifications include x*1 => x, x*0 => 0, etc.,
13374 and application of the associative law.
13375 NOP_EXPR conversions may be removed freely (as long as we
13376 are careful not to change the type of the overall expression).
13377 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13378 but we can constant-fold them if they have constant operands. */
13380 #ifdef ENABLE_FOLD_CHECKING
13381 # define fold(x) fold_1 (x)
13383 static
13384 #endif
13385 tree
13387 {
13391 tree tem;
13394 /* Return right away if a constant. */
13398 /* CALL_EXPR-like objects with variable numbers of operands are
13399 treated specially. */
13401 {
13403 {
13406 }
13408 }
13411 {
13416 {
13434 }
13435 }
13438 {
13440 {
13447 {
13452 }
13455 }
13457 /* Return a VECTOR_CST if possible. */
13459 {
13465 tree val;
13471 }
13479 }
13481 #ifdef ENABLE_FOLD_CHECKING
13482 #undef fold
13489 /* When --enable-checking=fold, compute a digest of expr before
13490 and after actual fold call to see if fold did not accidentally
13491 change original expr. */
13493 tree
13495 {
13496 tree ret;
13516 }
13518 void
13520 {
13531 }
13533 static void
13535 {
13537 }
13539 static void
13542 {
13548 recursive_label:
13558 {
13559 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
13567 }
13575 {
13576 /* Allow these fields to be modified. */
13577 tree tmp;
13588 {
13591 }
13592 }
13594 {
13595 /* Allow the no-warning bit to be set. Perhaps we shouldn't allow
13596 that and change builtins.cc etc. instead - see PR89543. */
13602 }
13613 {
13616 {
13632 }
13636 {
13649 }
13666 {
13672 }
13675 {
13677 {
13680 }
13682 }
13693 {
13696 }
13706 }
13707 }
13709 /* Helper function for outputting the checksum of a tree T. When
13710 debugging with gdb, you can "define mynext" to be "next" followed
13711 by "call debug_fold_checksum (op0)", then just trace down till the
13712 outputs differ. */
13714 DEBUG_FUNCTION void
13716 {
13731 }
13733 #endif
13735 /* Fold a unary tree expression with code CODE of type TYPE with an
13736 operand OP0. LOC is the location of the resulting expression.
13737 Return a folded expression if successful. Otherwise, return a tree
13738 expression with code CODE of type TYPE with an operand OP0. */
13740 tree
13743 {
13744 tree tem;
13745 #ifdef ENABLE_FOLD_CHECKING
13754 #endif
13760 #ifdef ENABLE_FOLD_CHECKING
13767 #endif
13769 }
13771 /* Fold a binary tree expression with code CODE of type TYPE with
13772 operands OP0 and OP1. LOC is the location of the resulting
13773 expression. Return a folded expression if successful. Otherwise,
13774 return a tree expression with code CODE of type TYPE with operands
13775 OP0 and OP1. */
13777 tree
13780 MEM_STAT_DECL)
13781 {
13782 tree tem;
13783 #ifdef ENABLE_FOLD_CHECKING
13800 #endif
13806 #ifdef ENABLE_FOLD_CHECKING
13821 #endif
13823 }
13825 /* Fold a ternary tree expression with code CODE of type TYPE with
13826 operands OP0, OP1, and OP2. Return a folded expression if
13827 successful. Otherwise, return a tree expression with code CODE of
13828 type TYPE with operands OP0, OP1, and OP2. */
13830 tree
13833 {
13834 tree tem;
13835 #ifdef ENABLE_FOLD_CHECKING
13859 #endif
13866 #ifdef ENABLE_FOLD_CHECKING
13889 #endif
13891 }
13893 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13894 arguments in ARGARRAY, and a null static chain.
13895 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13896 of type TYPE from the given operands as constructed by build_call_array. */
13898 tree
13901 {
13902 tree tem;
13903 #ifdef ENABLE_FOLD_CHECKING
13922 #endif
13928 #ifdef ENABLE_FOLD_CHECKING
13944 #endif
13946 }
13948 /* Perform constant folding and related simplification of initializer
13949 expression EXPR. These behave identically to "fold_buildN" but ignore
13950 potential run-time traps and exceptions that fold must preserve. */
13952 #define START_FOLD_INIT \
13953 int saved_signaling_nans = flag_signaling_nans;\
13954 int saved_trapping_math = flag_trapping_math;\
13955 int saved_rounding_math = flag_rounding_math;\
13956 int saved_trapv = flag_trapv;\
13957 int saved_folding_initializer = folding_initializer;\
13958 flag_signaling_nans = 0;\
13959 flag_trapping_math = 0;\
13960 flag_rounding_math = 0;\
13961 flag_trapv = 0;\
13962 folding_initializer = 1;
13964 #define END_FOLD_INIT \
13965 flag_signaling_nans = saved_signaling_nans;\
13966 flag_trapping_math = saved_trapping_math;\
13967 flag_rounding_math = saved_rounding_math;\
13968 flag_trapv = saved_trapv;\
13969 folding_initializer = saved_folding_initializer;
13971 tree
13973 {
13974 tree result;
13975 START_FOLD_INIT;
13979 END_FOLD_INIT;
13981 }
13983 tree
13986 {
13987 tree result;
13988 START_FOLD_INIT;
13992 END_FOLD_INIT;
13994 }
13996 tree
13999 {
14000 tree result;
14001 START_FOLD_INIT;
14005 END_FOLD_INIT;
14007 }
14009 tree
14012 {
14013 tree result;
14014 START_FOLD_INIT;
14018 END_FOLD_INIT;
14020 }
14022 tree
14025 {
14026 tree result;
14027 START_FOLD_INIT;
14031 END_FOLD_INIT;
14033 }
14035 #undef START_FOLD_INIT
14036 #undef END_FOLD_INIT
14038 /* Determine if first argument is a multiple of second argument. Return 0 if
14039 it is not, or we cannot easily determined it to be.
14041 An example of the sort of thing we care about (at this point; this routine
14042 could surely be made more general, and expanded to do what the *_DIV_EXPR's
14043 fold cases do now) is discovering that
14045 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14047 is a multiple of
14049 SAVE_EXPR (J * 8)
14051 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
14053 This code also handles discovering that
14055 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14057 is a multiple of 8 so we don't have to worry about dealing with a
14058 possible remainder.
14060 Note that we *look* inside a SAVE_EXPR only to determine how it was
14061 calculated; it is not safe for fold to do much of anything else with the
14062 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
14063 at run time. For example, the latter example above *cannot* be implemented
14064 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
14065 evaluation time of the original SAVE_EXPR is not necessarily the same at
14066 the time the new expression is evaluated. The only optimization of this
14067 sort that would be valid is changing
14069 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
14071 divided by 8 to
14073 SAVE_EXPR (I) * SAVE_EXPR (J)
14075 (where the same SAVE_EXPR (J) is used in the original and the
14076 transformed version).
14078 NOWRAP specifies whether all outer operations in TYPE should
14079 be considered not wrapping. Any type conversion within TOP acts
14080 as a barrier and we will fall back to NOWRAP being false.
14081 NOWRAP is mostly used to treat expressions in TYPE_SIZE and friends
14082 as not wrapping even though they are generally using unsigned arithmetic. */
14084 int
14086 {
14097 {
14099 /* Bitwise and provides a power of two multiple. If the mask is
14100 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
14107 /* If the multiplication can wrap we cannot recurse further unless
14108 the bottom is a power of two which is where wrapping does not
14109 matter. */
14115 {
14121 {
14124 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
14126 {
14130 {
14133 }
14134 }
14136 }
14137 }
14142 /* Handle X << CST as X * (1 << CST) and only process the constant. */
14144 {
14147 {
14148 wide_int mul_op
14152 nowrap);
14153 }
14154 }
14159 /* If the addition or subtraction can wrap we cannot recurse further
14160 unless bottom is a power of two which is where wrapping does not
14161 matter. */
14167 /* Handle cases like op0 + 0xfffffffd as op0 - 3 if the expression has
14168 unsigned type. For example, (X / 3) + 0xfffffffd is multiple of 3,
14169 but 0xfffffffd is not. */
14172 && nowrap
14177 /* It is impossible to prove if op0 +- op1 is multiple of bottom
14178 precisely, so be conservative here checking if both op0 and op1
14179 are multiple of bottom. Note we check the second operand first
14180 since it's usually simpler. */
14184 CASE_CONVERT:
14185 /* Can't handle conversions from non-integral or wider integral type. */
14190 /* NOWRAP only extends to operations in the outermost type so
14191 make sure to strip it off here. */
14206 SIGNED);
14212 {
14215 /* Check for special cases to see if top is defined as multiple
14216 of bottom:
14218 top = (X & ~(bottom - 1) ; bottom is power of 2
14220 or
14222 Y = X % bottom
14223 top = X - Y. */
14242 }
14244 /* fall through */
14252 }
14253 }
14255 /* Return true if expression X cannot be (or contain) a NaN or infinity.
14256 This function returns true for integer expressions, and returns
14257 false if uncertain. */
14259 bool
14261 {
14266 {
14289 {
14290 CASE_CFN_FABS:
14292 CASE_CFN_FMAX:
14293 CASE_CFN_FMIN:
14298 }
14302 }
14303 }
14305 /* Return true if expression X evaluates to an infinity.
14306 This function returns false for integer expressions. */
14308 bool
14310 {
14314 {
14327 }
14328 }
14330 /* Return true if expression X could evaluate to an infinity.
14331 This function returns false for integer expressions, and returns
14332 true if uncertain. */
14334 bool
14336 {
14340 {
14353 }
14354 }
14356 /* Return true if expression X evaluates to a signaling NaN.
14357 This function returns false for integer expressions. */
14359 bool
14361 {
14365 {
14376 }
14377 }
14379 /* Return true if expression X could evaluate to a signaling NaN.
14380 This function returns false for integer expressions, and returns
14381 true if uncertain. */
14383 bool
14385 {
14389 {
14409 {
14410 CASE_CFN_FABS:
14412 CASE_CFN_FMAX:
14413 CASE_CFN_FMIN:
14418 }
14421 }
14422 }
14424 /* Return true if expression X evaluates to a NaN.
14425 This function returns false for integer expressions. */
14427 bool
14429 {
14433 {
14444 }
14445 }
14447 /* Return true if expression X could evaluate to a NaN.
14448 This function returns false for integer expressions, and returns
14449 true if uncertain. */
14451 bool
14453 {
14457 {
14482 {
14483 CASE_CFN_FABS:
14485 CASE_CFN_FMAX:
14486 CASE_CFN_FMIN:
14491 }
14494 }
14495 }
14497 /* Return true if expression X could evaluate to -0.0.
14498 This function returns true if uncertain. */
14500 bool
14502 {
14506 {
14521 {
14522 CASE_CFN_FABS:
14526 }
14529 }
14530 /* Ideally !(tree_expr_nonzero_p (X) || tree_expr_nonnegative_p (X))
14531 * but currently those predicates require tree and not const_tree. */
14533 }
14535 #define tree_expr_nonnegative_warnv_p(X, Y) \
14538 #define RECURSE(X) \
14539 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
14541 /* Return true if CODE or TYPE is known to be non-negative. */
14543 static bool
14545 {
14548 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14549 have a signed:1 type (where the value is -1 and 0). */
14552 }
14554 /* Return true if (CODE OP0) is known to be non-negative. If the return
14555 value is based on the assumption that signed overflow is undefined,
14556 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14557 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14559 bool
14562 {
14567 {
14569 /* We can't return 1 if flag_wrapv is set because
14570 ABS_EXPR<INT_MIN> = INT_MIN. */
14574 {
14577 }
14585 CASE_CONVERT:
14586 {
14591 {
14595 {
14599 }
14600 }
14602 {
14608 }
14609 }
14614 }
14616 /* We don't know sign of `t', so be conservative and return false. */
14618 }
14620 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
14621 value is based on the assumption that signed overflow is undefined,
14622 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14623 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14625 bool
14629 {
14634 {
14640 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14641 both unsigned and at least 2 bits shorter than the result. */
14645 {
14650 {
14654 }
14655 }
14660 {
14661 /* x * x is always non-negative for floating point x
14662 or without overflow. */
14665 {
14670 }
14671 }
14673 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14674 both unsigned and their total bits is shorter than the result. */
14678 {
14697 {
14707 }
14708 }
14715 /* Usually RECURSE (op0) || RECURSE (op1) but NaNs complicate
14716 things. */
14741 }
14743 /* We don't know sign of `t', so be conservative and return false. */
14745 }
14747 /* Return true if T is known to be non-negative. If the return
14748 value is based on the assumption that signed overflow is undefined,
14749 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14750 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14752 bool
14754 {
14759 {
14773 /* Limit the depth of recursion to avoid quadratic behavior.
14774 This is expected to catch almost all occurrences in practice.
14775 If this code misses important cases that unbounded recursion
14776 would not, passes that need this information could be revised
14777 to provide it through dataflow propagation. */
14785 }
14786 }
14788 /* Return true if T is known to be non-negative. If the return
14789 value is based on the assumption that signed overflow is undefined,
14790 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14791 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14793 bool
14796 {
14798 {
14799 CASE_CFN_ACOS:
14800 CASE_CFN_ACOSH:
14801 CASE_CFN_CABS:
14802 CASE_CFN_COSH:
14803 CASE_CFN_ERFC:
14804 CASE_CFN_EXP:
14805 CASE_CFN_EXP10:
14806 CASE_CFN_EXP2:
14807 CASE_CFN_FABS:
14808 CASE_CFN_FDIM:
14809 CASE_CFN_HYPOT:
14810 CASE_CFN_POW10:
14811 CASE_CFN_FFS:
14812 CASE_CFN_PARITY:
14813 CASE_CFN_POPCOUNT:
14814 CASE_CFN_CLZ:
14815 CASE_CFN_CLRSB:
14820 /* Always true. */
14823 CASE_CFN_SQRT:
14824 CASE_CFN_SQRT_FN:
14825 /* sqrt(-0.0) is -0.0. */
14830 CASE_CFN_ASINH:
14831 CASE_CFN_ATAN:
14832 CASE_CFN_ATANH:
14833 CASE_CFN_CBRT:
14834 CASE_CFN_CEIL:
14835 CASE_CFN_CEIL_FN:
14836 CASE_CFN_ERF:
14837 CASE_CFN_EXPM1:
14838 CASE_CFN_FLOOR:
14839 CASE_CFN_FLOOR_FN:
14840 CASE_CFN_FMOD:
14841 CASE_CFN_FREXP:
14842 CASE_CFN_ICEIL:
14843 CASE_CFN_IFLOOR:
14844 CASE_CFN_IRINT:
14845 CASE_CFN_IROUND:
14846 CASE_CFN_LCEIL:
14847 CASE_CFN_LDEXP:
14848 CASE_CFN_LFLOOR:
14849 CASE_CFN_LLCEIL:
14850 CASE_CFN_LLFLOOR:
14851 CASE_CFN_LLRINT:
14852 CASE_CFN_LLROUND:
14853 CASE_CFN_LRINT:
14854 CASE_CFN_LROUND:
14855 CASE_CFN_MODF:
14856 CASE_CFN_NEARBYINT:
14857 CASE_CFN_NEARBYINT_FN:
14858 CASE_CFN_RINT:
14859 CASE_CFN_RINT_FN:
14860 CASE_CFN_ROUND:
14861 CASE_CFN_ROUND_FN:
14862 CASE_CFN_ROUNDEVEN:
14863 CASE_CFN_ROUNDEVEN_FN:
14864 CASE_CFN_SCALB:
14865 CASE_CFN_SCALBLN:
14866 CASE_CFN_SCALBN:
14867 CASE_CFN_SIGNBIT:
14868 CASE_CFN_SIGNIFICAND:
14869 CASE_CFN_SINH:
14870 CASE_CFN_TANH:
14871 CASE_CFN_TRUNC:
14872 CASE_CFN_TRUNC_FN:
14873 /* True if the 1st argument is nonnegative. */
14876 CASE_CFN_FMAX:
14877 CASE_CFN_FMAX_FN:
14878 /* Usually RECURSE (arg0) || RECURSE (arg1) but NaNs complicate
14879 things. In the presence of sNaNs, we're only guaranteed to be
14880 non-negative if both operands are non-negative. In the presence
14881 of qNaNs, we're non-negative if either operand is non-negative
14882 and can't be a qNaN, or if both operands are non-negative. */
14891 CASE_CFN_FMIN:
14892 CASE_CFN_FMIN_FN:
14893 /* True if the 1st AND 2nd arguments are nonnegative. */
14896 CASE_CFN_COPYSIGN:
14897 CASE_CFN_COPYSIGN_FN:
14898 /* True if the 2nd argument is nonnegative. */
14901 CASE_CFN_POWI:
14902 /* True if the 1st argument is nonnegative or the second
14903 argument is an even integer. */
14909 CASE_CFN_POW:
14910 /* True if the 1st argument is nonnegative or the second
14911 argument is an even integer valued real. */
14913 {
14914 REAL_VALUE_TYPE c;
14915 HOST_WIDE_INT n;
14920 {
14921 REAL_VALUE_TYPE cint;
14925 }
14926 }
14931 }
14933 }
14935 /* Return true if T is known to be non-negative. If the return
14936 value is based on the assumption that signed overflow is undefined,
14937 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14938 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14940 static bool
14942 {
14948 {
14950 {
14954 /* If the initializer is non-void, then it's a normal expression
14955 that will be assigned to the slot. */
14959 /* Otherwise, the initializer sets the slot in some way. One common
14960 way is an assignment statement at the end of the initializer. */
14962 {
14970 else
14972 }
14978 }
14981 {
14987 arg0,
14988 arg1,
14990 }
15003 }
15004 }
15006 #undef RECURSE
15007 #undef tree_expr_nonnegative_warnv_p
15009 /* Return true if T is known to be non-negative. If the return
15010 value is based on the assumption that signed overflow is undefined,
15011 set *STRICT_OVERFLOW_P to true; otherwise, don't change
15012 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
15014 bool
15016 {
15023 {
15045 }
15048 {
15074 }
15075 }
15077 /* Return true if `t' is known to be non-negative. Handle warnings
15078 about undefined signed overflow. */
15080 bool
15082 {
15089 "determining that expression is always "
15091 WARN_STRICT_OVERFLOW_MISC);
15093 }
15096 /* Return true when (CODE OP0) is an address and is known to be nonzero.
15097 For floating point we further ensure that T is not denormal.
15098 Similar logic is present in nonzero_address in rtlanal.h.
15100 If the return value is based on the assumption that signed overflow
15101 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15102 change *STRICT_OVERFLOW_P. */
15104 bool
15107 {
15109 {
15112 strict_overflow_p);
15115 {
15121 strict_overflow_p));
15122 }
15127 strict_overflow_p);
15131 }
15134 }
15136 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
15137 For floating point we further ensure that T is not denormal.
15138 Similar logic is present in nonzero_address in rtlanal.h.
15140 If the return value is based on the assumption that signed overflow
15141 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15142 change *STRICT_OVERFLOW_P. */
15144 bool
15146 tree type,
15147 tree op0,
15149 {
15152 {
15156 {
15157 /* With the presence of negative values it is hard
15158 to say something. */
15165 /* One of operands must be positive and the other non-negative. */
15166 /* We don't set *STRICT_OVERFLOW_P here: even if this value
15167 overflows, on a twos-complement machine the sum of two
15168 nonnegative numbers can never be zero. */
15170 strict_overflow_p)
15172 strict_overflow_p));
15173 }
15178 {
15180 strict_overflow_p)
15182 strict_overflow_p))
15183 {
15186 }
15187 }
15196 {
15199 }
15206 {
15210 /* When both operands are nonzero, then MAX must be too. */
15212 strict_overflow_p))
15215 /* MAX where operand 0 is positive is positive. */
15217 strict_overflow_p);
15218 }
15219 /* MAX where operand 1 is positive is positive. */
15224 {
15228 }
15233 strict_overflow_p)
15235 strict_overflow_p));
15239 }
15242 }
15244 /* Return true when T is an address and is known to be nonzero.
15245 For floating point we further ensure that T is not denormal.
15246 Similar logic is present in nonzero_address in rtlanal.h.
15248 If the return value is based on the assumption that signed overflow
15249 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15250 change *STRICT_OVERFLOW_P. */
15252 bool
15254 {
15257 {
15262 {
15274 /* For objects in symbol table check if we know they are non-zero.
15275 Don't do anything for variables and functions before symtab is built;
15276 it is quite possible that they will be declared weak later. */
15281 /* Constants are never weak. */
15286 }
15294 {
15298 }
15308 }
15310 }
15312 #define integer_valued_real_p(X) \
15315 #define RECURSE(X) \
15316 ((integer_valued_real_p) (X, depth + 1))
15318 /* Return true if the floating point result of (CODE OP0) has an
15319 integer value. We also allow +Inf, -Inf and NaN to be considered
15320 integer values. Return false for signaling NaN.
15322 DEPTH is the current nesting depth of the query. */
15324 bool
15326 {
15328 {
15335 CASE_CONVERT:
15336 {
15343 }
15347 }
15349 }
15351 /* Return true if the floating point result of (CODE OP0 OP1) has an
15352 integer value. We also allow +Inf, -Inf and NaN to be considered
15353 integer values. Return false for signaling NaN.
15355 DEPTH is the current nesting depth of the query. */
15357 bool
15359 {
15361 {
15371 }
15373 }
15375 /* Return true if the floating point result of calling FNDECL with arguments
15376 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
15377 considered integer values. Return false for signaling NaN. If FNDECL
15378 takes fewer than 2 arguments, the remaining ARGn are null.
15380 DEPTH is the current nesting depth of the query. */
15382 bool
15384 {
15386 {
15387 CASE_CFN_CEIL:
15388 CASE_CFN_CEIL_FN:
15389 CASE_CFN_FLOOR:
15390 CASE_CFN_FLOOR_FN:
15391 CASE_CFN_NEARBYINT:
15392 CASE_CFN_NEARBYINT_FN:
15393 CASE_CFN_RINT:
15394 CASE_CFN_RINT_FN:
15395 CASE_CFN_ROUND:
15396 CASE_CFN_ROUND_FN:
15397 CASE_CFN_ROUNDEVEN:
15398 CASE_CFN_ROUNDEVEN_FN:
15399 CASE_CFN_TRUNC:
15400 CASE_CFN_TRUNC_FN:
15403 CASE_CFN_FMIN:
15404 CASE_CFN_FMIN_FN:
15405 CASE_CFN_FMAX:
15406 CASE_CFN_FMAX_FN:
15411 }
15413 }
15415 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
15416 has an integer value. We also allow +Inf, -Inf and NaN to be
15417 considered integer values. Return false for signaling NaN.
15419 DEPTH is the current nesting depth of the query. */
15421 bool
15423 {
15425 {
15433 /* Limit the depth of recursion to avoid quadratic behavior.
15434 This is expected to catch almost all occurrences in practice.
15435 If this code misses important cases that unbounded recursion
15436 would not, passes that need this information could be revised
15437 to provide it through dataflow propagation. */
15441 depth));
15445 }
15447 }
15449 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
15450 has an integer value. We also allow +Inf, -Inf and NaN to be
15451 considered integer values. Return false for signaling NaN.
15453 DEPTH is the current nesting depth of the query. */
15455 static bool
15457 {
15459 {
15470 }
15472 }
15474 #undef RECURSE
15475 #undef integer_valued_real_p
15477 /* Return true if the floating point expression T has an integer value.
15478 We also allow +Inf, -Inf and NaN to be considered integer values.
15479 Return false for signaling NaN.
15481 DEPTH is the current nesting depth of the query. */
15483 bool
15485 {
15493 {
15509 }
15512 {
15518 {
15527 }
15531 }
15532 }
15534 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
15535 attempt to fold the expression to a constant without modifying TYPE,
15536 OP0 or OP1.
15538 If the expression could be simplified to a constant, then return
15539 the constant. If the expression would not be simplified to a
15540 constant, then return NULL_TREE. */
15542 tree
15544 {
15547 }
15549 /* Given the components of a unary expression CODE, TYPE and OP0,
15550 attempt to fold the expression to a constant without modifying
15551 TYPE or OP0.
15553 If the expression could be simplified to a constant, then return
15554 the constant. If the expression would not be simplified to a
15555 constant, then return NULL_TREE. */
15557 tree
15559 {
15562 }
15564 /* If EXP represents referencing an element in a constant string
15565 (either via pointer arithmetic or array indexing), return the
15566 tree representing the value accessed, otherwise return NULL. */
15568 tree
15570 {
15574 {
15576 tree index;
15577 tree string;
15582 else
15583 {
15587 /* Optimize the special-case of a zero lower bound.
15589 We convert the low_bound to sizetype to avoid some problems
15590 with constant folding. (E.g. suppose the lower bound is 1,
15591 and its mode is QI. Without the conversion,l (ARRAY
15592 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
15593 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
15599 }
15601 scalar_int_mode char_mode;
15613 }
15615 }
15617 /* Folds a read from vector element at IDX of vector ARG. */
15619 tree
15621 {
15626 {
15630 {
15637 }
15638 }
15640 }
15642 /* Return the tree for neg (ARG0) when ARG0 is known to be either
15643 an integer constant, real, or fixed-point constant.
15645 TYPE is the type of the result. */
15647 static tree
15649 {
15653 {
15659 {
15660 FIXED_VALUE_TYPE f;
15665 /* Propagate overflow flags. */
15669 }
15673 {
15680 }
15683 }
15686 }
15688 /* Return the tree for abs (ARG0) when ARG0 is known to be either
15689 an integer constant or real constant.
15691 TYPE is the type of the result. */
15693 tree
15695 {
15699 {
15701 {
15702 /* If the value is unsigned or non-negative, then the absolute value
15703 is the same as the ordinary value. */
15707 ;
15709 /* If the value is negative, then the absolute value is
15710 its negation. */
15711 else
15714 /* Force to the destination type, set TREE_OVERFLOW for signed
15715 TYPE only. */
15717 }
15723 else
15729 }
15732 }
15734 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
15735 constant. TYPE is the type of the result. */
15737 static tree
15739 {
15743 }
15745 /* Given CODE, a relational operator, the target type, TYPE and two
15746 constant operands OP0 and OP1, return the result of the
15747 relational operation. If the result is not a compile time
15748 constant, then return NULL_TREE. */
15750 static tree
15752 {
15755 /* From here on, the only cases we handle are when the result is
15756 known to be a constant. */
15759 {
15763 /* Handle the cases where either operand is a NaN. */
15765 {
15767 {
15795 }
15798 }
15801 }
15804 {
15808 }
15810 /* Handle equality/inequality of complex constants. */
15812 {
15823 else
15825 }
15828 {
15830 {
15831 /* Have vector comparison with scalar boolean result. */
15839 {
15847 }
15849 }
15850 tree_vector_builder elts;
15855 {
15868 }
15871 }
15873 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15875 To compute GT, swap the arguments and do LT.
15876 To compute GE, do LT and invert the result.
15877 To compute LE, swap the arguments, do LT and invert the result.
15878 To compute NE, do EQ and invert the result.
15880 Therefore, the code below must handle only EQ and LT. */
15883 {
15886 }
15888 /* Note that it is safe to invert for real values here because we
15889 have already handled the one case that it matters. */
15893 {
15896 }
15898 /* Compute a result for LT or EQ if args permit;
15899 Otherwise return T. */
15901 {
15904 else
15906 }
15907 else
15913 }
15915 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15916 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15917 itself. */
15919 tree
15921 {
15922 /* If the expression does not have side effects then we don't have to wrap
15923 it with a cleanup point expression. */
15927 /* If the expression is a return, check to see if the expression inside the
15928 return has no side effects or the right hand side of the modify expression
15929 inside the return. If either don't have side effects set we don't need to
15930 wrap the expression in a cleanup point expression. Note we don't check the
15931 left hand side of the modify because it should always be a return decl. */
15933 {
15940 }
15943 }
15945 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15946 of an indirection through OP0, or NULL_TREE if no simplification is
15947 possible. */
15949 tree
15951 {
15953 tree subtype;
15954 poly_uint64 const_op01;
15963 {
15967 /* *&CONST_DECL -> to the value of the const decl. */
15970 /* *&p => p; make sure to handle *&"str"[cst] here. */
15972 {
15976 else
15978 }
15979 /* *(foo *)&fooarray => fooarray[0] */
15982 && (!in_gimple_form
15984 {
15994 }
15995 /* *(foo *)&complexfoo => __real__ complexfoo */
15999 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
16002 {
16006 index);
16007 }
16008 }
16012 {
16018 {
16019 tree op00type;
16023 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
16026 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
16027 but we want to treat offsets with MSB set as negative.
16028 For the code below negative offsets are invalid and
16029 TYPE_SIZE of the element is something unsigned, so
16030 check whether op01 fits into poly_int64, which implies
16031 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
16032 then just use poly_uint64 because we want to treat the
16033 value as unsigned. */
16035 {
16037 poly_uint64 max_offset
16041 {
16046 }
16047 }
16048 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
16051 {
16053 const_op01))
16055 }
16056 /* ((foo *)&fooarray)[1] => fooarray[1] */
16059 {
16068 {
16073 }
16074 }
16075 }
16076 }
16078 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
16081 && (!in_gimple_form
16083 {
16084 tree type_domain;
16094 NULL_TREE);
16095 }
16098 }
16100 /* Builds an expression for an indirection through T, simplifying some
16101 cases. */
16103 tree
16105 {
16113 }
16115 /* Given an INDIRECT_REF T, return either T or a simplified version. */
16117 tree
16119 {
16124 else
16126 }
16128 /* Strip non-trapping, non-side-effecting tree nodes from an expression
16129 whose result is ignored. The type of the returned tree need not be
16130 the same as the original expression. */
16132 tree
16134 {
16140 {
16151 else
16157 {
16173 }
16178 }
16179 }
16181 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
16183 tree
16185 {
16191 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16192 have to do anything. Only do this when we are not given a const,
16193 because in that case, this check is more expensive than just
16194 doing it. */
16196 {
16201 }
16203 /* If divisor is a power of two, simplify this to bit manipulation. */
16205 {
16207 {
16221 }
16222 else
16223 {
16224 tree t;
16230 }
16231 }
16232 else
16233 {
16238 }
16241 }
16243 /* Likewise, but round down. */
16245 tree
16247 {
16254 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16255 have to do anything. Only do this when we are not given a const,
16256 because in that case, this check is more expensive than just
16257 doing it. */
16259 {
16264 }
16266 /* If divisor is a power of two, simplify this to bit manipulation. */
16268 {
16269 tree t;
16273 }
16274 else
16275 {
16280 }
16283 }
16285 /* Returns the pointer to the base of the object addressed by EXP and
16286 extracts the information about the offset of the access, storing it
16287 to PBITPOS and POFFSET. */
16289 static tree
16292 {
16293 tree core;
16294 machine_mode mode;
16296 poly_int64 bitsize;
16300 {
16305 }
16307 {
16313 {
16314 poly_offset_int tem
16320 }
16321 }
16322 else
16323 {
16327 }
16330 }
16332 /* Returns true if addresses of E1 and E2 differ by a constant, false
16333 otherwise. If they do, E1 - E2 is stored in *DIFF. */
16335 bool
16337 {
16352 {
16362 }
16364 {
16365 /* If only one of the offsets is non-constant, the difference cannot
16366 be a constant. */
16368 }
16369 else
16374 }
16376 /* Return OFF converted to a pointer offset type suitable as offset for
16377 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
16378 tree
16380 {
16384 }
16386 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16387 tree
16389 {
16392 }
16394 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16395 tree
16397 {
16400 }
16402 /* Return a pointer to a NUL-terminated string containing the sequence
16403 of bytes corresponding to the representation of the object referred to
16404 by SRC (or a subsequence of such bytes within it if SRC is a reference
16405 to an initialized constant array plus some constant offset).
16406 Set *STRSIZE the number of bytes in the constant sequence including
16407 the terminating NUL byte. *STRSIZE is equal to sizeof(A) - OFFSET
16408 where A is the array that stores the constant sequence that SRC points
16409 to and OFFSET is the byte offset of SRC from the beginning of A. SRC
16410 need not point to a string or even an array of characters but may point
16411 to an object of any type. */
16415 {
16416 /* The offset into the array A storing the string, and A's byte size. */
16417 tree offset_node;
16418 tree mem_size;
16425 else
16432 {
16435 else
16437 }
16442 /* ARRAY_SIZE is the byte size of the array the constant sequence
16443 is stored in and equal to sizeof A. INIT_BYTES is the number
16444 of bytes in the constant sequence used to initialize the array,
16445 including any embedded NULs as well as the terminating NUL (for
16446 strings), but not including any trailing zeros/NULs past
16447 the terminating one appended implicitly to a string literal to
16448 zero out the remainder of the array it's stored in. For example,
16449 given:
16450 const char a[7] = "abc\0d";
16451 n = strlen (a + 1);
16452 ARRAY_SIZE is 7, INIT_BYTES is 6, and OFFSET is 1. For a valid
16453 (i.e., nul-terminated) string with no embedded nuls, INIT_BYTES
16454 is equal to strlen (A) + 1. */
16459 /* Ideally this would turn into a gcc_checking_assert over time. */
16467 {
16468 /* Compute and store the number of characters from the beginning
16469 of the substring at OFFSET to the end, including the terminating
16470 nul. Offsets past the initial length refer to null strings. */
16473 else
16475 }
16476 else
16477 {
16479 /* Support only properly NUL-terminated single byte strings. */
16484 }
16487 }
16489 /* Return a pointer to a NUL-terminated string corresponding to
16490 the expression STR referencing a constant string, possibly
16491 involving a constant offset. Return null if STR either doesn't
16492 reference a constant string or if it involves a nonconstant
16493 offset. */
16497 {
16499 }
16501 /* Given a tree T, compute which bits in T may be nonzero. */
16503 wide_int
16505 {
16507 {
16525 CASE_CONVERT:
16531 {
16536 }
16540 {
16548 }
16552 {
16560 }
16564 }
16567 }
16569 /* Helper function for address compare simplifications in match.pd.
16570 OP0 and OP1 are ADDR_EXPR operands being compared by CODE.
16571 TYPE is the type of comparison operands.
16572 BASE0, BASE1, OFF0 and OFF1 are set by the function.
16573 GENERIC is true if GENERIC folding and false for GIMPLE folding.
16574 Returns 0 if OP0 is known to be unequal to OP1 regardless of OFF{0,1},
16575 1 if bases are known to be equal and OP0 cmp OP1 depends on OFF0 cmp OFF1,
16576 and 2 if unknown. */
16578 int
16582 {
16588 {
16591 }
16593 {
16596 }
16601 /* Punt in GENERIC on variables with value expressions;
16602 the value expressions might point to fields/elements
16603 of other vars etc. */
16609 {
16613 }
16621 /* Assume different STRING_CSTs with the same content will be
16622 merged. */
16631 {
16634 /* If the offsets are equal we can ignore overflow. */
16637 /* Or if we compare using pointers to decls or strings. */
16642 }
16648 /* At this point we know (or assume) the two pointers point at
16649 different objects. */
16653 /* Punt on non-zero offsets from functions. */
16657 /* Or if the bases are neither decls nor string literals. */
16662 /* For initializers, assume addresses of different functions are
16663 different. */
16669 /* Compute whether one address points to the start of one
16670 object and another one to the end of another one. */
16673 {
16676 else
16678 }
16681 else
16682 {
16686 else
16688 }
16690 {
16693 else
16695 }
16698 else
16699 {
16703 else
16705 }
16707 {
16708 /* If one offset is pointing (or could be) to the beginning of one
16709 object and the other is pointing to one past the last byte of the
16710 other object, punt. */
16715 /* If both offsets are the same, there are some cases we know that are
16716 ok. Either if we know they aren't zero, or if we know both sizes
16717 are no zero. */
16723 }
16725 /* At this point, equal is 2 if either one or both pointers are out of
16726 bounds of their object, or one points to start of its object and the
16727 other points to end of its object. This is unspecified behavior
16728 e.g. in C++. Otherwise equal is 0. */
16732 /* When both pointers point to string literals, even when equal is 0,
16733 due to tail merging of string literals the pointers might be the same. */
16735 {
16742 /* If the bytes in the string literals starting at the pointers
16743 differ, the pointers need to be different. */
16748 {
16753 /* If even the bytes in the string literal before the
16754 pointers are the same, the string literals could be
16755 tail merged. */
16757 }
16759 }
16764 /* If this is a pointer comparison, ignore for now even
16765 valid equalities where one pointer is the offset zero
16766 of one object and the other to one past end of another one. */
16770 /* Assume that string literals can't be adjacent to variables
16771 (automatic or global). */
16775 /* Assume that automatic variables can't be adjacent to global
16776 variables. */
16781 }
16783 /* Return the single non-zero element of a CONSTRUCTOR or NULL_TREE. */
16784 tree
16786 {
16795 {
16799 }
16801 }
16803 #if CHECKING_P
16807 /* Helper functions for writing tests of folding trees. */
16809 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
16811 static void
16813 tree constant)
16814 {
16816 }
16818 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
16819 wrapping WRAPPED_EXPR. */
16821 static void
16823 tree wrapped_expr)
16824 {
16829 }
16831 /* Verify that various arithmetic binary operations are folded
16832 correctly. */
16834 static void
16836 {
16842 /* Addition. */
16843 /* 1 <-- (0 + 1) */
16845 one);
16847 one);
16849 /* (nonlvalue)x <-- (x + 0) */
16851 x);
16853 /* Subtraction. */
16854 /* 0 <-- (x - x) */
16856 zero);
16858 x);
16860 /* Multiplication. */
16861 /* 0 <-- (x * 0) */
16863 zero);
16865 /* (nonlvalue)x <-- (x * 1) */
16867 x);
16868 }
16870 /* Verify that various binary operations on vectors are folded
16871 correctly. */
16873 static void
16875 {
16882 /* Verify equality tests that return a scalar boolean result. */
16895 }
16897 /* Verify folding of VEC_DUPLICATE_EXPRs. */
16899 static void
16901 {
16904 /* This will be 1 if VEC_MODE isn't a vector mode. */
16911 }
16913 /* Run all of the selftests within this file. */
16915 void
16917 {
16921 }