| blob | 7bf12315293383a86f78fa783b9fd52fcf3d92e9 |
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 };
155 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
156 Otherwise, return LOC. */
158 static location_t
160 {
163 }
165 /* Similar to protected_set_expr_location, but never modify x in place,
166 if location can and needs to be set, unshare it. */
170 {
176 {
179 }
181 }
182 \f
183 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
184 division and returns the quotient. Otherwise returns
185 NULL_TREE. */
187 tree
189 {
190 widest_int quo;
197 }
198 \f
199 /* This is nonzero if we should defer warnings about undefined
200 overflow. This facility exists because these warnings are a
201 special case. The code to estimate loop iterations does not want
202 to issue any warnings, since it works with expressions which do not
203 occur in user code. Various bits of cleanup code call fold(), but
204 only use the result if it has certain characteristics (e.g., is a
205 constant); that code only wants to issue a warning if the result is
206 used. */
210 /* If a warning about undefined overflow is deferred, this is the
211 warning. Note that this may cause us to turn two warnings into
212 one, but that is fine since it is sufficient to only give one
213 warning per expression. */
217 /* If a warning about undefined overflow is deferred, this is the
218 level at which the warning should be emitted. */
222 /* Start deferring overflow warnings. We could use a stack here to
223 permit nested calls, but at present it is not necessary. */
225 void
227 {
229 }
231 /* Stop deferring overflow warnings. If there is a pending warning,
232 and ISSUE is true, then issue the warning if appropriate. STMT is
233 the statement with which the warning should be associated (used for
234 location information); STMT may be NULL. CODE is the level of the
235 warning--a warn_strict_overflow_code value. This function will use
236 the smaller of CODE and the deferred code when deciding whether to
237 issue the warning. CODE may be zero to mean to always use the
238 deferred code. */
240 void
242 {
244 location_t locus;
249 {
255 }
266 /* Use the smallest code level when deciding to issue the
267 warning. */
276 else
279 }
281 /* Stop deferring overflow warnings, ignoring any deferred
282 warnings. */
284 void
286 {
288 }
290 /* Whether we are deferring overflow warnings. */
292 bool
294 {
296 }
298 /* This is called when we fold something based on the fact that signed
299 overflow is undefined. */
301 void
303 {
305 {
308 {
311 }
312 }
315 }
316 \f
317 /* Return true if the built-in mathematical function specified by CODE
318 is odd, i.e. -f(x) == f(-x). */
320 bool
322 {
324 {
325 CASE_CFN_ASIN:
326 CASE_CFN_ASINH:
327 CASE_CFN_ATAN:
328 CASE_CFN_ATANH:
329 CASE_CFN_CASIN:
330 CASE_CFN_CASINH:
331 CASE_CFN_CATAN:
332 CASE_CFN_CATANH:
333 CASE_CFN_CBRT:
334 CASE_CFN_CPROJ:
335 CASE_CFN_CSIN:
336 CASE_CFN_CSINH:
337 CASE_CFN_CTAN:
338 CASE_CFN_CTANH:
339 CASE_CFN_ERF:
340 CASE_CFN_LLROUND:
341 CASE_CFN_LROUND:
342 CASE_CFN_ROUND:
343 CASE_CFN_ROUNDEVEN:
344 CASE_CFN_ROUNDEVEN_FN:
345 CASE_CFN_SIN:
346 CASE_CFN_SINH:
347 CASE_CFN_TAN:
348 CASE_CFN_TANH:
349 CASE_CFN_TRUNC:
352 CASE_CFN_LLRINT:
353 CASE_CFN_LRINT:
354 CASE_CFN_NEARBYINT:
355 CASE_CFN_RINT:
360 }
362 }
364 /* Check whether we may negate an integer constant T without causing
365 overflow. */
367 bool
369 {
370 tree type;
379 }
381 /* Determine whether an expression T can be cheaply negated using
382 the function negate_expr without introducing undefined overflow. */
384 static bool
386 {
387 tree type;
396 {
401 /* Check that -CST will not overflow type. */
414 /* We want to canonicalize to positive real constants. Pretend
415 that only negative ones can be easily negated. */
423 {
427 /* Steps don't prevent negation. */
434 }
449 /* -(A + B) -> (-B) - A. */
452 /* -(A + B) -> (-A) - B. */
456 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
465 /* INT_MIN/n * n doesn't overflow while negating one operand it does
466 if n is a (negative) power of two. */
477 /* Fall through. */
490 /* In general we can't negate A in A / B, because if A is INT_MIN and
491 B is not 1 we change the sign of the result. */
495 /* In general we can't negate B in A / B, because if A is INT_MIN and
496 B is 1, we may turn this into INT_MIN / -1 which is undefined
497 and actually traps on some architectures. */
506 /* Negate -((double)float) as (double)(-float). */
508 {
512 }
516 /* Negate -f(x) as f(-x). */
522 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
524 {
528 }
533 }
535 }
537 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
538 simplification is possible.
539 If negate_expr_p would return true for T, NULL_TREE will never be
540 returned. */
542 static tree
544 {
546 tree tem;
549 {
550 /* Convert - (~A) to A + 1. */
574 {
579 }
583 {
584 tree_vector_builder elts;
588 {
593 }
596 }
619 {
620 /* -(A + B) -> (-B) - A. */
622 {
626 }
628 /* -(A + B) -> (-A) - B. */
630 {
634 }
635 }
639 /* - (A - B) -> B - A */
650 /* Fall through. */
654 {
663 }
671 /* In general we can't negate A in A / B, because if A is INT_MIN and
672 B is not 1 we change the sign of the result. */
678 /* In general we can't negate B in A / B, because if A is INT_MIN and
679 B is 1, we may turn this into INT_MIN / -1 which is undefined
680 and actually traps on some architectures. */
692 /* Convert -((double)float) into (double)(-float). */
694 {
698 }
702 /* Negate -f(x) as f(-x). */
705 {
711 }
715 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
717 {
720 {
727 }
728 }
733 }
736 }
738 /* A wrapper for fold_negate_expr_1. */
740 static tree
742 {
749 }
751 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T cannot be
752 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
753 return NULL_TREE. */
755 static tree
757 {
759 location_t loc;
772 }
773 \f
774 /* Split a tree IN into a constant, literal and variable parts that could be
775 combined with CODE to make IN. "constant" means an expression with
776 TREE_CONSTANT but that isn't an actual constant. CODE must be a
777 commutative arithmetic operation. Store the constant part into *CONP,
778 the literal in *LITP and return the variable part. If a part isn't
779 present, set it to null. If the tree does not decompose in this way,
780 return the entire tree as the variable part and the other parts as null.
782 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
783 case, we negate an operand that was subtracted. Except if it is a
784 literal for which we use *MINUS_LITP instead.
786 If NEGATE_P is true, we are negating all of IN, again except a literal
787 for which we use *MINUS_LITP instead. If a variable part is of pointer
788 type, it is negated after converting to TYPE. This prevents us from
789 generating illegal MINUS pointer expression. LOC is the location of
790 the converted variable part.
792 If IN is itself a literal or constant, return it as appropriate.
794 Note that we do not guarantee that any of the three values will be the
795 same type as IN, but they will have the same signedness and mode. */
797 static tree
801 {
809 /* Strip any conversions that don't change the machine mode or signedness. */
818 /* We can associate addition and subtraction together (even
819 though the C standard doesn't say so) for integers because
820 the value is not affected. For reals, the value might be
821 affected, so we can't. */
827 {
833 /* First see if either of the operands is a literal, then a constant. */
846 /* If we haven't dealt with either operand, this is not a case we can
847 decompose. Otherwise, VAR is either of the ones remaining, if any. */
852 else
855 /* Now do any needed negations. */
862 }
867 {
868 /* -1 - X is folded to ~X, undo that here. Do _not_ do this
869 when IN is constant. */
872 }
873 else
877 {
890 }
900 }
902 /* Re-associate trees split by the above function. T1 and T2 are
903 either expressions to associate or null. Return the new
904 expression, if any. LOC is the location of the new expression. If
905 we build an operation, do it in TYPE and with CODE. */
907 static tree
909 {
911 {
914 }
918 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
919 try to fold this since we will have infinite recursion. But do
920 deal with any NEGATE_EXPRs. */
924 {
926 {
939 }
941 {
944 }
948 }
952 }
953 \f
954 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
955 for use in int_const_binop, size_binop and size_diffop. */
957 static bool
959 {
966 {
975 }
980 }
982 /* Combine two wide ints ARG1 and ARG2 under operation CODE to produce
983 a new constant in RES. Return FALSE if we don't know how to
984 evaluate CODE at compile-time. */
986 bool
990 {
991 wide_int tmp;
994 {
1016 /* It's unclear from the C standard whether shifts can overflow.
1017 The following code ignores overflow; perhaps a C standard
1018 interpretation ruling is needed. */
1025 {
1029 else
1031 }
1032 else
1037 else
1116 }
1118 }
1120 /* Combine two poly int's ARG1 and ARG2 under operation CODE to
1121 produce a new constant in RES. Return FALSE if we don't know how
1122 to evaluate CODE at compile-time. */
1124 static bool
1128 {
1132 {
1150 else
1157 else
1170 }
1172 }
1174 /* Combine two integer constants ARG1 and ARG2 under operation CODE to
1175 produce a new constant. Return NULL_TREE if we don't know how to
1176 evaluate CODE at compile-time. */
1178 tree
1181 {
1182 poly_wide_int poly_res;
1188 {
1194 }
1203 }
1205 /* Return true if binary operation OP distributes over addition in operand
1206 OPNO, with the other operand being held constant. OPNO counts from 1. */
1208 static bool
1210 {
1212 {
1223 }
1224 }
1226 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1227 constant. We assume ARG1 and ARG2 have the same data type, or at least
1228 are the same kind of constant and the same machine mode. Return zero if
1229 combining the constants is not allowed in the current operating mode. */
1231 static tree
1233 {
1234 /* Sanity check for the recursive cases. */
1242 {
1248 }
1251 {
1252 machine_mode mode;
1253 REAL_VALUE_TYPE d1;
1254 REAL_VALUE_TYPE d2;
1255 REAL_VALUE_TYPE value;
1256 REAL_VALUE_TYPE result;
1260 /* The following codes are handled by real_arithmetic. */
1262 {
1273 }
1281 /* Don't perform operation if we honor signaling NaNs and
1282 either operand is a signaling NaN. */
1288 /* Don't perform operation if it would raise a division
1289 by zero exception. */
1295 /* If either operand is a NaN, just return it. Otherwise, set up
1296 for floating-point trap; we return an overflow. */
1298 {
1299 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1300 is off. */
1304 }
1306 {
1307 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1308 is off. */
1312 }
1317 /* Don't constant fold this floating point operation if
1318 both operands are not NaN but the result is NaN, and
1319 flag_trapping_math. Such operations should raise an
1320 invalid operation exception. */
1328 /* Don't constant fold this floating point operation if
1329 the result has overflowed and flag_trapping_math. */
1337 /* Don't constant fold this floating point operation if the
1338 result may dependent upon the run-time rounding mode and
1339 flag_rounding_math is set, or if GCC's software emulation
1340 is unable to accurately represent the result. */
1350 }
1353 {
1354 FIXED_VALUE_TYPE f1;
1355 FIXED_VALUE_TYPE f2;
1356 FIXED_VALUE_TYPE result;
1361 /* The following codes are handled by fixed_arithmetic. */
1363 {
1375 {
1382 }
1387 }
1394 /* Propagate overflow flags. */
1398 }
1401 {
1410 {
1421 mpc_mul);
1435 mpc_div);
1436 /* Fallthru. */
1442 {
1443 /* Keep this algorithm in sync with
1444 tree-complex.cc:expand_complex_div_straight().
1446 Expand complex division to scalars, straightforward algorithm.
1447 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1448 t = br*br + bi*bi
1449 */
1450 tree magsquared
1454 tree t1
1458 tree t2
1465 }
1466 else
1467 {
1468 /* Keep this algorithm in sync with
1469 tree-complex.cc:expand_complex_div_wide().
1471 Expand complex division to scalars, modified algorithm to minimize
1472 overflow with wide input ranges. */
1478 {
1479 /* In the TRUE branch, we compute
1480 ratio = br/bi;
1481 div = (br * ratio) + bi;
1482 tr = (ar * ratio) + ai;
1483 ti = (ai * ratio) - ar;
1484 tr = tr / div;
1485 ti = ti / div; */
1496 }
1497 else
1498 {
1499 /* In the FALSE branch, we compute
1500 ratio = d/c;
1501 divisor = (d * ratio) + c;
1502 tr = (b * ratio) + a;
1503 ti = b - (a * ratio);
1504 tr = tr / div;
1505 ti = ti / div; */
1517 }
1518 }
1523 }
1527 }
1533 {
1538 /* We can operate directly on the encoding if:
1540 a3 - a2 == a2 - a1 && b3 - b2 == b2 - b1
1541 implies
1542 (a3 op b3) - (a2 op b2) == (a2 op b2) - (a1 op b1)
1544 Addition and subtraction are the supported operators
1545 for which this is true. */
1548 /* We can operate directly on stepped encodings if:
1550 a3 - a2 == a2 - a1
1551 implies:
1552 (a3 op c) - (a2 op c) == (a2 op c) - (a1 op c)
1554 which is true if (x -> x op c) distributes over addition. */
1556 else
1557 /* Similarly in reverse. */
1559 tree_vector_builder elts;
1564 {
1570 /* It is possible that const_binop cannot handle the given
1571 code and return NULL_TREE */
1575 }
1578 }
1580 /* Shifts allow a scalar offset for a vector. */
1583 {
1586 tree_vector_builder elts;
1591 {
1596 /* It is possible that const_binop cannot handle the given
1597 code and return NULL_TREE. */
1601 }
1604 }
1606 }
1608 /* Overload that adds a TYPE parameter to be able to dispatch
1609 to fold_relational_const. */
1611 tree
1613 {
1617 /* ??? Until we make the const_binop worker take the type of the
1618 result as argument put those cases that need it here. */
1620 {
1637 {
1642 }
1648 {
1664 {
1669 ? NOP_EXPR
1676 }
1679 }
1685 {
1708 {
1721 }
1724 }
1727 }
1732 /* Make sure type and arg0 have the same saturating flag. */
1737 }
1739 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1740 Return zero if computing the constants is not possible. */
1742 tree
1744 {
1745 /* Don't perform the operation, other than NEGATE and ABS, if
1746 flag_signaling_nans is on and the operand is a signaling NaN. */
1756 {
1757 CASE_CONVERT:
1764 /* If the source address is 0, and the source address space
1765 cannot have a valid object at 0, fold to dest type null. */
1776 {
1777 /* Can't call fold_negate_const directly here as that doesn't
1778 handle all cases and we might not be able to negate some
1779 constants. */
1784 }
1794 {
1798 }
1806 /* Perform BIT_NOT_EXPR on each element individually. */
1808 {
1809 tree elem;
1811 /* This can cope with stepped encodings because ~x == -1 - x. */
1812 tree_vector_builder elements;
1816 {
1822 }
1825 }
1849 {
1872 else
1877 {
1883 }
1886 }
1895 }
1898 }
1900 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1901 indicates which particular sizetype to create. */
1903 tree
1905 {
1907 }
1908 \f
1909 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1910 is a tree code. The type of the result is taken from the operands.
1911 Both must be equivalent integer types, ala int_binop_types_match_p.
1912 If the operands are constant, so is the result. */
1914 tree
1916 {
1925 /* Handle the special case of two poly_int constants faster. */
1927 {
1928 /* And some specific cases even faster than that. */
1930 {
1937 }
1939 {
1943 }
1945 {
1949 }
1951 /* Handle general case of two integer constants. For sizetype
1952 constant calculations we always want to know about overflow,
1953 even in the unsigned case. */
1957 }
1960 }
1962 /* Given two values, either both of sizetype or both of bitsizetype,
1963 compute the difference between the two values. Return the value
1964 in signed type corresponding to the type of the operands. */
1966 tree
1968 {
1970 tree ctype;
1975 /* If the type is already signed, just do the simple thing. */
1983 else
1986 /* If either operand is not a constant, do the conversions to the signed
1987 type and subtract. The hardware will do the right thing with any
1988 overflow in the subtraction. */
1994 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1995 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1996 overflow) and negate (which can't either). Special-case a result
1997 of zero while we're here. */
2003 else
2007 MINUS_EXPR,
2009 }
2010 \f
2011 /* A subroutine of fold_convert_const handling conversions of an
2012 INTEGER_CST to another integer type. */
2014 static tree
2016 {
2017 /* Given an integer constant, make new constant with new type,
2018 appropriately sign-extended or truncated. Use widest_int
2019 so that any extension is done according ARG1's type. */
2023 }
2025 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2026 to an integer type. */
2028 static tree
2030 {
2032 tree t;
2034 /* The following code implements the floating point to integer
2035 conversion rules required by the Java Language Specification,
2036 that IEEE NaNs are mapped to zero and values that overflow
2037 the target precision saturate, i.e. values greater than
2038 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2039 are mapped to INT_MIN. These semantics are allowed by the
2040 C and C++ standards that simply state that the behavior of
2041 FP-to-integer conversion is unspecified upon overflow. */
2043 wide_int val;
2044 REAL_VALUE_TYPE r;
2048 {
2055 }
2057 /* If R is NaN, return zero and show we have an overflow. */
2059 {
2062 }
2064 /* See if R is less than the lower bound or greater than the
2065 upper bound. */
2068 {
2072 {
2075 }
2076 }
2079 {
2082 {
2085 {
2088 }
2089 }
2090 }
2097 }
2099 /* A subroutine of fold_convert_const handling conversions of a
2100 FIXED_CST to an integer type. */
2102 static tree
2104 {
2105 tree t;
2107 scalar_mode mode;
2109 /* Right shift FIXED_CST to temp by fbit. */
2113 {
2115 HOST_BITS_PER_DOUBLE_INT,
2118 /* Left shift temp to temp_trunc by fbit. */
2120 HOST_BITS_PER_DOUBLE_INT,
2122 }
2123 else
2124 {
2127 }
2129 /* If FIXED_CST is negative, we need to round the value toward 0.
2130 By checking if the fractional bits are not zero to add 1 to temp. */
2136 /* Given a fixed-point constant, make new constant with new type,
2137 appropriately sign-extended or truncated. */
2145 }
2147 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2148 to another floating point type. */
2150 static tree
2152 {
2153 REAL_VALUE_TYPE value;
2154 tree t;
2156 /* Don't perform the operation if flag_signaling_nans is on
2157 and the operand is a signaling NaN. */
2162 /* With flag_rounding_math we should respect the current rounding mode
2163 unless the conversion is exact. */
2171 /* If converting an infinity or NAN to a representation that doesn't
2172 have one, set the overflow bit so that we can produce some kind of
2173 error message at the appropriate point if necessary. It's not the
2174 most user-friendly message, but it's better than nothing. */
2181 /* Regular overflow, conversion produced an infinity in a mode that
2182 can't represent them. */
2187 else
2190 }
2192 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2193 to a floating point type. */
2195 static tree
2197 {
2198 REAL_VALUE_TYPE value;
2199 tree t;
2207 }
2209 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2210 to another fixed-point type. */
2212 static tree
2214 {
2215 FIXED_VALUE_TYPE value;
2216 tree t;
2223 /* Propagate overflow flags. */
2227 }
2229 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2230 to a fixed-point type. */
2232 static tree
2234 {
2235 FIXED_VALUE_TYPE value;
2236 tree t;
2238 double_int di;
2245 else
2253 /* Propagate overflow flags. */
2257 }
2259 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2260 to a fixed-point type. */
2262 static tree
2264 {
2265 FIXED_VALUE_TYPE value;
2266 tree t;
2274 /* Propagate overflow flags. */
2278 }
2280 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2281 type TYPE. If no simplification can be done return NULL_TREE. */
2283 static tree
2285 {
2290 /* We can't widen types, since the runtime value could overflow the
2291 original type before being extended to the new type. */
2302 {
2309 }
2311 {
2313 {
2315 /* Avoid the folding if flag_rounding_math is on and the
2316 conversion is not exact. */
2318 {
2324 }
2326 }
2331 }
2333 {
2340 }
2342 {
2345 {
2348 /* We can't handle steps directly when extending, since the
2349 values need to wrap at the original precision first. */
2350 bool step_ok_p
2354 tree_vector_builder v;
2359 {
2365 }
2367 }
2368 }
2370 }
2372 /* Construct a vector of zero elements of vector type TYPE. */
2374 static tree
2376 {
2377 tree t;
2381 }
2383 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2385 bool
2387 {
2402 {
2424 }
2425 }
2427 /* Convert expression ARG to type TYPE. Used by the middle-end for
2428 simple conversions in preference to calling the front-end's convert. */
2430 tree
2432 {
2434 tree tem;
2445 {
2448 /* Handle conversions between pointers to different address spaces. */
2453 /* fall through */
2458 {
2462 }
2476 {
2480 }
2482 {
2486 }
2488 {
2492 }
2495 {
2513 }
2518 {
2522 }
2525 {
2539 }
2543 {
2552 integer_zero_node));
2554 {
2558 {
2564 }
2572 }
2576 }
2594 }
2595 fold_convert_exit:
2598 }
2599 \f
2600 /* Return false if expr can be assumed not to be an lvalue, true
2601 otherwise. */
2603 static bool
2605 {
2606 /* We only need to wrap lvalue tree codes. */
2608 {
2640 /* Assume the worst for front-end tree codes. */
2644 }
2647 }
2649 /* Return an expr equal to X but certainly not valid as an lvalue. */
2651 tree
2653 {
2654 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2655 us. */
2662 }
2663 \f
2664 /* Given a tree comparison code, return the code that is the logical inverse.
2665 It is generally not safe to do this for floating-point comparisons, except
2666 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2667 ERROR_MARK in this case. */
2669 enum tree_code
2671 {
2677 {
2708 }
2709 }
2711 /* Similar, but return the comparison that results if the operands are
2712 swapped. This is safe for floating-point. */
2714 enum tree_code
2716 {
2718 {
2744 }
2745 }
2748 /* Convert a comparison tree code from an enum tree_code representation
2749 into a compcode bit-based encoding. This function is the inverse of
2750 compcode_to_comparison. */
2752 static enum comparison_code
2754 {
2756 {
2787 }
2788 }
2790 /* Convert a compcode bit-based encoding of a comparison operator back
2791 to GCC's enum tree_code representation. This function is the
2792 inverse of comparison_to_compcode. */
2794 static enum tree_code
2796 {
2798 {
2829 }
2830 }
2832 /* Return true if COND1 tests the opposite condition of COND2. */
2834 bool
2836 {
2839 && (invert_tree_comparison
2846 }
2848 /* Return a tree for the comparison which is the combination of
2849 doing the AND or OR (depending on CODE) of the two operations LCODE
2850 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2851 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2852 if this makes the transformation invalid. */
2854 tree
2859 {
2866 {
2877 }
2880 {
2881 /* Eliminate unordered comparisons, as well as LTGT and ORD
2882 which are not used unless the mode has NaNs. */
2888 }
2890 {
2891 /* Check that the original operation and the optimized ones will trap
2892 under the same condition. */
2903 /* In a short-circuited boolean expression the LHS might be
2904 such that the RHS, if evaluated, will never trap. For
2905 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2906 if neither x nor y is NaN. (This is a mixed blessing: for
2907 example, the expression above will never trap, hence
2908 optimizing it to x < y would be invalid). */
2913 /* If the comparison was short-circuited, and only the RHS
2914 trapped, we may now generate a spurious trap. */
2919 /* If we changed the conditions that cause a trap, we lose. */
2922 }
2928 else
2929 {
2934 }
2935 }
2936 \f
2937 /* Return nonzero if two operands (typically of the same tree node)
2938 are necessarily equal. FLAGS modifies behavior as follows:
2940 If OEP_ONLY_CONST is set, only return nonzero for constants.
2941 This function tests whether the operands are indistinguishable;
2942 it does not test whether they are equal using C's == operation.
2943 The distinction is important for IEEE floating point, because
2944 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2945 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2947 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2948 even though it may hold multiple values during a function.
2949 This is because a GCC tree node guarantees that nothing else is
2950 executed between the evaluation of its "operands" (which may often
2951 be evaluated in arbitrary order). Hence if the operands themselves
2952 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2953 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2954 unset means assuming isochronic (or instantaneous) tree equivalence.
2955 Unless comparing arbitrary expression trees, such as from different
2956 statements, this flag can usually be left unset.
2958 If OEP_PURE_SAME is set, then pure functions with identical arguments
2959 are considered the same. It is used when the caller has other ways
2960 to ensure that global memory is unchanged in between.
2962 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2963 not values of expressions.
2965 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
2966 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
2968 If OEP_BITWISE is set, then require the values to be bitwise identical
2969 rather than simply numerically equal. Do not take advantage of things
2970 like math-related flags or undefined behavior; only return true for
2971 values that are provably bitwise identical in all circumstances.
2973 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2974 any operand with side effect. This is unnecesarily conservative in the
2975 case we know that arg0 and arg1 are in disjoint code paths (such as in
2976 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2977 addresses with TREE_CONSTANT flag set so we know that &var == &var
2978 even if var is volatile. */
2980 bool
2983 {
2991 /* If either is ERROR_MARK, they aren't equal. */
2997 /* Similar, if either does not have a type (like a template id),
2998 they aren't equal. */
3002 /* Bitwise identity makes no sense if the values have different layouts. */
3007 /* We cannot consider pointers to different address space equal. */
3014 /* Check equality of integer constants before bailing out due to
3015 precision differences. */
3017 {
3018 /* Address of INTEGER_CST is not defined; check that we did not forget
3019 to drop the OEP_ADDRESS_OF flags. */
3022 }
3025 {
3026 /* If both types don't have the same signedness, then we can't consider
3027 them equal. We must check this before the STRIP_NOPS calls
3028 because they may change the signedness of the arguments. As pointers
3029 strictly don't have a signedness, require either two pointers or
3030 two non-pointers as well. */
3036 /* If both types don't have the same precision, then it is not safe
3037 to strip NOPs. */
3044 }
3045 #if 0
3046 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
3047 sanity check once the issue is solved. */
3048 else
3049 /* Addresses of conversions and SSA_NAMEs (and many other things)
3050 are not defined. Check that we did not forget to drop the
3051 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
3054 #endif
3056 /* In case both args are comparisons but with different comparison
3057 code, try to swap the comparison operands of one arg to produce
3058 a match and compare that variant. */
3062 {
3070 }
3073 {
3074 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
3076 ;
3078 {
3079 /* If we are interested in comparing addresses ignore
3080 MEM_REF wrappings of the base that can appear just for
3081 TBAA reasons. */
3095 }
3096 else
3098 }
3100 /* When not checking adddresses, this is needed for conversions and for
3101 COMPONENT_REF. Might as well play it safe and always test this. */
3108 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3109 We don't care about side effects in that case because the SAVE_EXPR
3110 takes care of that for us. In all other cases, two expressions are
3111 equal if they have no side effects. If we have two identical
3112 expressions with side effects that should be treated the same due
3113 to the only side effects being identical SAVE_EXPR's, that will
3114 be detected in the recursive calls below.
3115 If we are taking an invariant address of two identical objects
3116 they are necessarily equal as well. */
3123 /* Next handle constant cases, those for which we can return 1 even
3124 if ONLY_CONST is set. */
3127 {
3140 {
3141 /* If we do not distinguish between signed and unsigned zero,
3142 consider them equal. */
3145 }
3149 {
3164 }
3168 flags)
3170 flags));
3181 flags | OEP_ADDRESS_OF
3184 /* In GIMPLE empty constructors are allowed in initializers of
3185 aggregates. */
3189 }
3191 /* Don't handle more cases for OEP_BITWISE, since we can't guarantee that
3192 two instances of undefined behavior will give identical results. */
3196 /* Define macros to test an operand from arg0 and arg1 for equality and a
3197 variant that allows null and views null as being different from any
3198 non-null value. In the latter case, if either is null, the both
3199 must be; otherwise, do the normal comparison. */
3200 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3201 TREE_OPERAND (arg1, N), flags)
3203 #define OP_SAME_WITH_NULL(N) \
3204 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3205 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3208 {
3210 /* Two conversions are equal only if signedness and modes match. */
3212 {
3213 CASE_CONVERT:
3221 }
3231 /* For commutative ops, allow the other order. */
3239 /* If either of the pointer (or reference) expressions we are
3240 dereferencing contain a side effect, these cannot be equal,
3241 but their addresses can be. */
3248 {
3251 {
3255 /* Verify that the access types are compatible. */
3259 }
3264 /* Require the same offset. */
3270 /* Fallthru. */
3278 {
3279 /* Require equal access sizes */
3285 flags)))
3287 /* Verify that access happens in similar types. */
3290 /* Verify that accesses are TBAA compatible. */
3299 /* Verify that alignment is compatible. */
3303 }
3306 /* TARGET_MEM_REF require equal extra operands. */
3317 /* Compare the array index by value if it is constant first as we
3318 may have different types but same value here. */
3324 /* Compare low bound and element size as with OEP_ADDRESS_OF
3325 we have to account for the offset of the ref. */
3330 array_ref_low_bound
3334 array_ref_element_size
3336 flags))));
3339 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3340 may be NULL when we're called to compare MEM_EXPRs. */
3343 {
3346 /* Most of time we only need to compare FIELD_DECLs for equality.
3347 However when determining address look into actual offsets.
3348 These may match for unions and unshared record types. */
3351 {
3354 {
3361 /* Non-FIELD_DECL operands can appear in C++ templates. */
3368 flags))
3370 }
3371 else
3373 }
3374 }
3385 }
3389 {
3391 /* Be sure we pass right ADDRESS_OF flag. */
3408 /* The multiplcation operands are commutative. */
3409 /* FALLTHRU */
3417 /* Otherwise take into account this is a commutative operation. */
3430 /* BIT_INSERT_EXPR has an implict operand as the type precision
3431 of op1. Need to check to make sure they are the same. */
3437 /* FALLTHRU */
3462 /* Virtual table reference. */
3474 {
3479 }
3484 }
3488 {
3492 /* If not both CALL_EXPRs are either internal or normal function
3493 functions, then they are not equal. */
3496 {
3497 /* If the CALL_EXPRs call different internal functions, then they
3498 are not equal. */
3501 }
3502 else
3503 {
3504 /* If the CALL_EXPRs call different functions, then they are not
3505 equal. */
3507 flags))
3509 }
3511 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3512 {
3516 else
3520 }
3522 /* Now see if all the arguments are the same. */
3523 {
3534 /* If we get here and both argument lists are exhausted
3535 then the CALL_EXPRs are equal. */
3537 }
3540 }
3543 /* Consider __builtin_sqrt equal to sqrt. */
3553 {
3554 /* Consider decls with the same name equal. The caller needs
3555 to make sure they refer to the same entity (such as a function
3556 formal parameter). */
3562 }
3567 {
3571 /* In GIMPLE constructors are used only to build vectors from
3572 elements. Individual elements in the constructor must be
3573 indexed in increasing order and form an initial sequence.
3575 We make no effort to compare constructors in generic.
3576 (see sem_variable::equals in ipa-icf which can do so for
3577 constants). */
3582 /* Be sure that vectors constructed have the same representation.
3583 We only tested element precision and modes to match.
3584 Vectors may be BLKmode and thus also check that the number of
3585 parts match. */
3598 {
3603 /* In GIMPLE the indexes can be either NULL or matching i.
3604 Double check this so we won't get false
3605 positives for GENERIC. */
3613 }
3615 }
3618 {
3619 /* Compare the STATEMENT_LISTs. */
3625 {
3626 /* The lists don't have the same number of statements. */
3632 flags & (OEP_LEXICOGRAPHIC
3635 }
3636 }
3641 {
3652 }
3656 }
3658 #undef OP_SAME
3659 #undef OP_SAME_WITH_NULL
3660 }
3662 /* Generate a hash value for an expression. This can be used iteratively
3663 by passing a previous result as the HSTATE argument. */
3665 void
3668 {
3674 {
3677 }
3687 {
3688 /* Alas, constants aren't shared, so we can't rely on pointer
3689 identity. */
3699 {
3703 else
3707 }
3709 {
3713 }
3723 {
3730 }
3732 /* We can just compare by pointer. */
3736 /* The node itself doesn't matter. */
3740 /* Ignore. */
3743 /* A list of expressions, for a CALL_EXPR or as the elements of a
3744 VECTOR_CST. */
3749 {
3755 {
3756 /* In GIMPLE the indexes can be either NULL or matching i. */
3761 }
3763 }
3765 {
3766 tree_stmt_iterator i;
3771 }
3780 /* When referring to a built-in FUNCTION_DECL, use the __builtin__ form.
3781 Otherwise nodes that compare equal according to operand_equal_p might
3782 get different hash codes. However, don't do this for machine specific
3783 or front end builtins, since the function code is overloaded in those
3784 cases. */
3787 {
3790 }
3791 /* FALL THROUGH */
3794 {
3798 }
3802 {
3803 /* DECL's have a unique ID */
3805 }
3807 {
3808 /* For comparisons that can be swapped, use the lower
3809 tree code. */
3816 }
3818 {
3819 /* NOP_EXPR and CONVERT_EXPR are considered equal by
3820 operand_equal_p. */
3824 /* Don't hash the type, that can lead to having nodes which
3825 compare equal according to operand_equal_p, but which
3826 have different hash codes. Make sure to include signedness
3827 in the hash computation. */
3830 }
3831 /* For OEP_ADDRESS_OF, hash MEM_EXPR[&decl, 0] the same as decl. */
3839 /* Don't ICE on FE specific trees, or their arguments etc.
3840 during operand_equal_p hash verification. */
3843 else
3844 {
3850 {
3866 {
3871 else
3872 {
3878 }
3880 }
3894 {
3895 /* The multiplication operands are commutative. */
3902 }
3910 /* For TARGET_EXPR, just hash on the TARGET_EXPR_SLOT.
3911 Usually different TARGET_EXPRs just should use
3912 different temporaries in their slots. */
3917 /* Virtual table reference. */
3925 {
3927 /* We compute mangled names only when free_lang_data is run.
3928 In that case we can hash precisely. */
3931 hstate.add_object
3932 (IDENTIFIER_HASH_VALUE
3934 }
3938 }
3940 /* Don't hash the type, that can lead to having nodes which
3941 compare equal according to operand_equal_p, but which
3942 have different hash codes. */
3944 {
3945 /* Make sure to include signness in the hash computation. */
3948 }
3951 {
3952 /* It's a commutative expression. We want to hash it the same
3953 however it appears. We do this by first hashing both operands
3954 and then rehashing based on the order of their independent
3955 hashes. */
3960 }
3961 else
3965 }
3967 }
3968 }
3970 bool
3973 {
3974 /* When checking and unless comparing DECL names, verify that if
3975 the outermost operand_equal_p call returns non-zero then ARG0
3976 and ARG1 have the same hash value. */
3978 {
3980 {
3982 {
3989 }
3991 }
3992 else
3996 }
3999 }
4004 /* Conveinece wrapper around operand_compare class because usually we do
4005 not need to play with the valueizer. */
4007 bool
4009 {
4011 }
4013 namespace inchash
4014 {
4016 /* Generate a hash value for an expression. This can be used iteratively
4017 by passing a previous result as the HSTATE argument.
4019 This function is intended to produce the same hash for expressions which
4020 would compare equal using operand_equal_p. */
4021 void
4023 {
4025 }
4027 }
4028 \f
4029 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
4030 with a different signedness or a narrower precision. */
4032 static bool
4034 {
4042 /* Discard any conversions that don't change the modes of ARG0 and ARG1
4043 and see if the inner values are the same. This removes any
4044 signedness comparison, which doesn't matter here. */
4052 /* Discard a single widening conversion from ARG1 and see if the inner
4053 value is the same as ARG0. */
4062 }
4063 \f
4064 /* See if ARG is an expression that is either a comparison or is performing
4065 arithmetic on comparisons. The comparisons must only be comparing
4066 two different values, which will be stored in *CVAL1 and *CVAL2; if
4067 they are nonzero it means that some operands have already been found.
4068 No variables may be used anywhere else in the expression except in the
4069 comparisons.
4071 If this is true, return 1. Otherwise, return zero. */
4073 static bool
4075 {
4079 /* We can handle some of the tcc_expression cases here. */
4088 {
4107 /* First see if we can handle the first operand, then the second. For
4108 the second operand, we know *CVAL1 can't be zero. It must be that
4109 one side of the comparison is each of the values; test for the
4110 case where this isn't true by failing if the two operands
4111 are the same. */
4120 ;
4124 ;
4125 else
4129 ;
4133 ;
4134 else
4141 }
4142 }
4143 \f
4144 /* ARG is a tree that is known to contain just arithmetic operations and
4145 comparisons. Evaluate the operations in the tree substituting NEW0 for
4146 any occurrence of OLD0 as an operand of a comparison and likewise for
4147 NEW1 and OLD1. */
4149 static tree
4152 {
4157 /* We can handle some of the tcc_expression cases here. */
4165 {
4180 {
4199 }
4200 /* Fall through - ??? */
4203 {
4207 /* We need to check both for exact equality and tree equality. The
4208 former will be true if the operand has a side-effect. In that
4209 case, we know the operand occurred exactly once. */
4222 }
4226 }
4227 }
4228 \f
4229 /* Return a tree for the case when the result of an expression is RESULT
4230 converted to TYPE and OMITTED was previously an operand of the expression
4231 but is now not needed (e.g., we folded OMITTED * 0).
4233 If OMITTED has side effects, we must evaluate it. Otherwise, just do
4234 the conversion of RESULT to TYPE. */
4236 tree
4238 {
4241 /* If the resulting operand is an empty statement, just return the omitted
4242 statement casted to void. */
4252 }
4254 /* Return a tree for the case when the result of an expression is RESULT
4255 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
4256 of the expression but are now not needed.
4258 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
4259 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
4260 evaluated before OMITTED2. Otherwise, if neither has side effects,
4261 just do the conversion of RESULT to TYPE. */
4263 tree
4266 {
4275 }
4277 \f
4278 /* Return a simplified tree node for the truth-negation of ARG. This
4279 never alters ARG itself. We assume that ARG is an operation that
4280 returns a truth value (0 or 1).
4282 FIXME: one would think we would fold the result, but it causes
4283 problems with the dominator optimizer. */
4285 static tree
4287 {
4292 /* If this is a comparison, we can simply invert it, except for
4293 floating-point non-equality comparisons, in which case we just
4294 enclose a TRUTH_NOT_EXPR around what we have. */
4297 {
4300 && flag_trapping_math
4313 }
4316 {
4335 /* Here we can invert either operand. We invert the first operand
4336 unless the second operand is a TRUTH_NOT_EXPR in which case our
4337 result is the XOR of the first operand with the inside of the
4338 negation of the second operand. */
4343 else
4366 {
4373 /* A COND_EXPR may have a throw as one operand, which
4374 then has void type. Just leave void operands
4375 as they are. */
4381 }
4393 CASE_CONVERT:
4397 /* fall through */
4419 }
4420 }
4422 /* Fold the truth-negation of ARG. This never alters ARG itself. We
4423 assume that ARG is an operation that returns a truth value (0 or 1
4424 for scalars, 0 or -1 for vectors). Return the folded expression if
4425 folding is successful. Otherwise, return NULL_TREE. */
4427 static tree
4429 {
4432 ? BIT_NOT_EXPR
4435 }
4437 /* Return a simplified tree node for the truth-negation of ARG. This
4438 never alters ARG itself. We assume that ARG is an operation that
4439 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
4441 tree
4443 {
4449 ? BIT_NOT_EXPR
4452 }
4453 \f
4454 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
4455 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
4456 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
4457 is the original memory reference used to preserve the alias set of
4458 the access. */
4460 static tree
4464 {
4467 /* Attempt not to lose the access path if possible. */
4469 {
4471 machine_mode nmode;
4473 tree noffset;
4481 && !reversep
4482 && !nreversep
4484 {
4487 }
4488 }
4497 {
4504 }
4519 }
4521 /* Optimize a bit-field compare.
4523 There are two cases: First is a compare against a constant and the
4524 second is a comparison of two items where the fields are at the same
4525 bit position relative to the start of a chunk (byte, halfword, word)
4526 large enough to contain it. In these cases we can avoid the shift
4527 implicit in bitfield extractions.
4529 For constants, we emit a compare of the shifted constant with the
4530 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4531 compared. For two fields at the same position, we do the ANDs with the
4532 similar mask and compare the result of the ANDs.
4534 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4535 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4536 are the left and right operands of the comparison, respectively.
4538 If the optimization described above can be done, we return the resulting
4539 tree. Otherwise we return zero. */
4541 static tree
4544 {
4548 tree unsigned_type;
4551 scalar_int_mode nmode;
4556 tree mask;
4557 tree offset;
4559 /* Get all the information about the extractions being done. If the bit size
4560 is the same as the size of the underlying object, we aren't doing an
4561 extraction at all and so can do nothing. We also don't want to
4562 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4563 then will no longer be able to replace it. */
4578 else
4579 {
4580 /* If this is not a constant, we can only do something if bit positions,
4581 sizes, signedness and storage order are the same. */
4582 rinner
4595 }
4597 /* Honor the C++ memory model and mimic what RTL expansion does. */
4601 {
4605 }
4607 /* See if we can find a mode to refer to this field. We should be able to,
4608 but fail if we can't. */
4616 /* Set signed and unsigned types of the precision of this mode for the
4617 shifts below. */
4620 /* Compute the bit position and size for the new reference and our offset
4621 within it. If the new reference is the same size as the original, we
4622 won't optimize anything, so return zero. */
4632 /* Make the mask to be used against the extracted field. */
4639 {
4643 /* If not comparing with constant, just rework the comparison
4644 and return. */
4652 }
4654 /* Otherwise, we are handling the constant case. See if the constant is too
4655 big for the field. Warn and return a tree for 0 (false) if so. We do
4656 this not only for its own sake, but to avoid having to test for this
4657 error case below. If we didn't, we might generate wrong code.
4659 For unsigned fields, the constant shifted right by the field length should
4660 be all zero. For signed fields, the high-order bits should agree with
4661 the sign bit. */
4664 {
4666 {
4670 }
4671 }
4672 else
4673 {
4676 {
4680 }
4681 }
4686 /* Single-bit compares should always be against zero. */
4688 {
4691 }
4693 /* Make a new bitfield reference, shift the constant over the
4694 appropriate number of bits and mask it with the computed mask
4695 (in case this was a signed field). If we changed it, make a new one. */
4703 mask);
4708 }
4709 \f
4710 /* Subroutine for fold_truth_andor_1: decode a field reference.
4712 If EXP is a comparison reference, we return the innermost reference.
4714 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4715 set to the starting bit number.
4717 If the innermost field can be completely contained in a mode-sized
4718 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4720 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4721 otherwise it is not changed.
4723 *PUNSIGNEDP is set to the signedness of the field.
4725 *PREVERSEP is set to the storage order of the field.
4727 *PMASK is set to the mask used. This is either contained in a
4728 BIT_AND_EXPR or derived from the width of the field.
4730 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4732 Return 0 if this is not a component reference or is one that we can't
4733 do anything with. */
4735 static tree
4740 {
4745 tree unsigned_type;
4748 /* All the optimizations using this function assume integer fields.
4749 There are problems with FP fields since the type_for_size call
4750 below can fail for, e.g., XFmode. */
4754 /* We are interested in the bare arrangement of bits, so strip everything
4755 that doesn't affect the machine mode. However, record the type of the
4756 outermost expression if it may matter below. */
4763 {
4769 }
4780 /* Reject out-of-bound accesses (PR79731). */
4792 /* If the number of bits in the reference is the same as the bitsize of
4793 the outer type, then the outer type gives the signedness. Otherwise
4794 (in case of a small bitfield) the signedness is unchanged. */
4798 /* Compute the mask to access the bitfield. */
4806 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4814 }
4816 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4817 bit positions and MASK is SIGNED. */
4819 static bool
4821 {
4825 /* If this function returns true when the type of the mask is
4826 UNSIGNED, then there will be errors. In particular see
4827 gcc.c-torture/execute/990326-1.c. There does not appear to be
4828 any documentation paper trail as to why this is so. But the pre
4829 wide-int worked with that restriction and it has been preserved
4830 here. */
4835 }
4837 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4838 represents the sign bit of EXP's type. If EXP represents a sign
4839 or zero extension, also test VAL against the unextended type.
4840 The return value is the (sub)expression whose sign bit is VAL,
4841 or NULL_TREE otherwise. */
4843 tree
4845 {
4847 tree t;
4849 /* Tree EXP must have an integral type. */
4854 /* Tree VAL must be an integer constant. */
4863 /* Handle extension from a narrower type. */
4869 }
4871 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4872 to be evaluated unconditionally. */
4874 static bool
4876 {
4877 /* Strip any conversions that don't change the machine mode. */
4886 /* Don't regard global variables as simple. They may be
4887 allocated in ways unknown to the compiler (shared memory,
4888 #pragma weak, etc). */
4891 /* Weakrefs are not safe to be read, since they can be NULL.
4892 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4893 have DECL_WEAK flag set. */
4895 /* Loading a static variable is unduly expensive, but global
4896 registers aren't expensive. */
4898 }
4900 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4901 to be evaluated unconditionally.
4902 I addition to simple_operand_p, we assume that comparisons, conversions,
4903 and logic-not operations are simple, if their operands are simple, too. */
4905 static bool
4907 {
4926 }
4928 \f
4929 /* The following functions are subroutines to fold_range_test and allow it to
4930 try to change a logical combination of comparisons into a range test.
4932 For example, both
4933 X == 2 || X == 3 || X == 4 || X == 5
4934 and
4935 X >= 2 && X <= 5
4936 are converted to
4937 (unsigned) (X - 2) <= 3
4939 We describe each set of comparisons as being either inside or outside
4940 a range, using a variable named like IN_P, and then describe the
4941 range with a lower and upper bound. If one of the bounds is omitted,
4942 it represents either the highest or lowest value of the type.
4944 In the comments below, we represent a range by two numbers in brackets
4945 preceded by a "+" to designate being inside that range, or a "-" to
4946 designate being outside that range, so the condition can be inverted by
4947 flipping the prefix. An omitted bound is represented by a "-". For
4948 example, "- [-, 10]" means being outside the range starting at the lowest
4949 possible value and ending at 10, in other words, being greater than 10.
4950 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4951 always false.
4953 We set up things so that the missing bounds are handled in a consistent
4954 manner so neither a missing bound nor "true" and "false" need to be
4955 handled using a special case. */
4957 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4958 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4959 and UPPER1_P are nonzero if the respective argument is an upper bound
4960 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4961 must be specified for a comparison. ARG1 will be converted to ARG0's
4962 type if both are specified. */
4964 static tree
4967 {
4968 tree tem;
4972 /* If neither arg represents infinity, do the normal operation.
4973 Else, if not a comparison, return infinity. Else handle the special
4974 comparison rules. Note that most of the cases below won't occur, but
4975 are handled for consistency. */
4978 {
4983 }
4988 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4989 for neither. In real maths, we cannot assume open ended ranges are
4990 the same. But, this is computer arithmetic, where numbers are finite.
4991 We can therefore make the transformation of any unbounded range with
4992 the value Z, Z being greater than any representable number. This permits
4993 us to treat unbounded ranges as equal. */
4997 {
5018 }
5021 }
5022 \f
5023 /* Helper routine for make_range. Perform one step for it, return
5024 new expression if the loop should continue or NULL_TREE if it should
5025 stop. */
5027 tree
5031 {
5037 {
5039 /* We can only do something if the range is testing for zero. */
5048 /* We can only do something if the range is testing for zero
5049 and if the second operand is an integer constant. Note that
5050 saying something is "in" the range we make is done by
5051 complementing IN_P since it will set in the initial case of
5052 being not equal to zero; "out" is leaving it alone. */
5059 {
5080 }
5082 /* If this is an unsigned comparison, we also know that EXP is
5083 greater than or equal to zero. We base the range tests we make
5084 on that fact, so we record it here so we can parse existing
5085 range tests. We test arg0_type since often the return type
5086 of, e.g. EQ_EXPR, is boolean. */
5088 {
5092 NULL_TREE))
5097 /* If the high bound is missing, but we have a nonzero low
5098 bound, reverse the range so it goes from zero to the low bound
5099 minus 1. */
5101 {
5106 }
5107 }
5115 /* If flag_wrapv and ARG0_TYPE is signed, make sure
5116 low and high are non-NULL, then normalize will DTRT. */
5119 {
5124 }
5126 /* (-x) IN [a,b] -> x in [-b, -a] */
5138 /* ~ X -> -X - 1 */
5147 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
5148 move a constant to the other side. */
5153 /* If EXP is signed, any overflow in the computation is undefined,
5154 so we don't worry about it so long as our computations on
5155 the bounds don't overflow. For unsigned, overflow is defined
5156 and this is exactly the right thing. */
5168 normalize:
5169 /* Check for an unsigned range which has wrapped around the maximum
5170 value thus making n_high < n_low, and normalize it. */
5172 {
5178 /* If the range is of the form +/- [ x+1, x ], we won't
5179 be able to normalize it. But then, it represents the
5180 whole range or the empty set, so make it
5181 +/- [ -, - ]. */
5185 else
5187 }
5188 else
5196 CASE_CONVERT:
5214 /* If we're converting arg0 from an unsigned type, to exp,
5215 a signed type, we will be doing the comparison as unsigned.
5216 The tests above have already verified that LOW and HIGH
5217 are both positive.
5219 So we have to ensure that we will handle large unsigned
5220 values the same way that the current signed bounds treat
5221 negative values. */
5224 {
5225 tree high_positive;
5226 tree equiv_type;
5227 /* For fixed-point modes, we need to pass the saturating flag
5228 as the 2nd parameter. */
5230 equiv_type
5233 else
5234 equiv_type
5237 /* A range without an upper bound is, naturally, unbounded.
5238 Since convert would have cropped a very large value, use
5239 the max value for the destination type. */
5240 high_positive
5247 high_positive),
5250 /* If the low bound is specified, "and" the range with the
5251 range for which the original unsigned value will be
5252 positive. */
5254 {
5257 integer_zero_node),
5258 high_positive))
5262 }
5263 else
5264 {
5265 /* Otherwise, "or" the range with the range of the input
5266 that will be interpreted as negative. */
5269 integer_zero_node),
5270 high_positive))
5274 }
5275 }
5277 /* Otherwise, if we are converting arg0 from signed type, to exp,
5278 an unsigned type, we will do the comparison as signed. If
5279 high is non-NULL, we punt above if it doesn't fit in the signed
5280 type, so if we get through here, +[-, high] or +[low, high] are
5281 equivalent to +[-, n_high] or +[n_low, n_high]. Similarly,
5282 +[-, -] or -[-, -] are equivalent too. But if low is specified and
5283 high is not, the +[low, -] range is equivalent to union of
5284 +[n_low, -] and +[-, -1] ranges, so +[low, -] is equivalent to
5285 -[0, n_low-1] and similarly -[low, -] to +[0, n_low-1], except for
5286 low being 0, which should be treated as [-, -]. */
5289 && low
5291 {
5294 else
5295 {
5300 }
5301 }
5310 }
5311 }
5313 /* Given EXP, a logical expression, set the range it is testing into
5314 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
5315 actually being tested. *PLOW and *PHIGH will be made of the same
5316 type as the returned expression. If EXP is not a comparison, we
5317 will most likely not be returning a useful value and range. Set
5318 *STRICT_OVERFLOW_P to true if the return value is only valid
5319 because signed overflow is undefined; otherwise, do not change
5320 *STRICT_OVERFLOW_P. */
5322 tree
5325 {
5333 /* Start with simply saying "EXP != 0" and then look at the code of EXP
5334 and see if we can refine the range. Some of the cases below may not
5335 happen, but it doesn't seem worth worrying about this. We "continue"
5336 the outer loop when we've changed something; otherwise we "break"
5337 the switch, which will "break" the while. */
5343 {
5349 {
5357 }
5366 }
5368 /* If EXP is a constant, we can evaluate whether this is true or false. */
5370 {
5377 }
5381 }
5383 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
5384 a bitwise check i.e. when
5385 LOW == 0xXX...X00...0
5386 HIGH == 0xXX...X11...1
5387 Return corresponding mask in MASK and stem in VALUE. */
5389 static bool
5392 {
5415 }
5416 \f
5417 /* Helper routine for build_range_check and match.pd. Return the type to
5418 perform the check or NULL if it shouldn't be optimized. */
5420 tree
5422 {
5423 /* First make sure that arithmetics in this type is valid, then make sure
5424 that it wraps around. */
5429 {
5432 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
5433 for the type in question, as we rely on this here. */
5443 else
5445 }
5449 }
5451 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
5452 type, TYPE, return an expression to test if EXP is in (or out of, depending
5453 on IN_P) the range. Return 0 if the test couldn't be created. */
5455 tree
5458 {
5461 /* Disable this optimization for function pointer expressions
5462 on targets that require function pointer canonicalization. */
5469 {
5475 }
5497 value);
5500 {
5502 {
5506 }
5508 }
5510 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
5512 {
5516 {
5518 {
5521 etype
5523 else
5526 }
5529 }
5530 }
5532 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
5533 This requires wrap-around arithmetics for the type of the expression. */
5550 }
5551 \f
5552 /* Return the predecessor of VAL in its type, handling the infinite case. */
5554 static tree
5556 {
5562 else
5565 }
5567 /* Return the successor of VAL in its type, handling the infinite case. */
5569 static tree
5571 {
5577 else
5580 }
5582 /* Given two ranges, see if we can merge them into one. Return 1 if we
5583 can, 0 if we can't. Set the output range into the specified parameters. */
5585 bool
5588 {
5592 tree tem;
5602 /* Make range 0 be the range that starts first, or ends last if they
5603 start at the same value. Swap them if it isn't. */
5606 || (lowequal
5609 {
5613 }
5615 /* If the second range is != high1 where high1 is the type maximum of
5616 the type, try first merging with < high1 range. */
5618 && high1
5625 {
5630 /* Similarly for the second range != low1 where low1 is the type minimum
5631 of the type, try first merging with > low1 range. */
5636 }
5638 /* Now flag two cases, whether the ranges are disjoint or whether the
5639 second range is totally subsumed in the first. Note that the tests
5640 below are simplified by the ones above. */
5646 /* We now have four cases, depending on whether we are including or
5647 excluding the two ranges. */
5649 {
5650 /* If they don't overlap, the result is false. If the second range
5651 is a subset it is the result. Otherwise, the range is from the start
5652 of the second to the end of the first. */
5657 else
5659 }
5662 {
5663 /* If they don't overlap, the result is the first range. If they are
5664 equal, the result is false. If the second range is a subset of the
5665 first, and the ranges begin at the same place, we go from just after
5666 the end of the second range to the end of the first. If the second
5667 range is not a subset of the first, or if it is a subset and both
5668 ranges end at the same place, the range starts at the start of the
5669 first range and ends just before the second range.
5670 Otherwise, we can't describe this as a single range. */
5676 {
5681 {
5682 /* We are in the weird situation where high0 > high1 but
5683 high1 has no successor. Punt. */
5685 }
5686 }
5688 {
5693 {
5694 /* low0 < low1 but low1 has no predecessor. Punt. */
5696 }
5697 }
5698 else
5700 }
5703 {
5704 /* If they don't overlap, the result is the second range. If the second
5705 is a subset of the first, the result is false. Otherwise,
5706 the range starts just after the first range and ends at the
5707 end of the second. */
5712 else
5713 {
5718 {
5719 /* high1 > high0 but high0 has no successor. Punt. */
5721 }
5722 }
5723 }
5725 else
5726 {
5727 /* The case where we are excluding both ranges. Here the complex case
5728 is if they don't overlap. In that case, the only time we have a
5729 range is if they are adjacent. If the second is a subset of the
5730 first, the result is the first. Otherwise, the range to exclude
5731 starts at the beginning of the first range and ends at the end of the
5732 second. */
5734 {
5739 else
5740 {
5741 /* Canonicalize - [min, x] into - [-, x]. */
5744 {
5747 GET_MODE_BITSIZE
5750 /* FALLTHROUGH */
5763 }
5765 /* Canonicalize - [x, max] into - [x, -]. */
5768 {
5771 GET_MODE_BITSIZE
5774 /* FALLTHROUGH */
5790 }
5792 /* The ranges might be also adjacent between the maximum and
5793 minimum values of the given type. For
5794 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5795 return + [x + 1, y - 1]. */
5797 {
5804 }
5805 else
5807 }
5808 }
5811 else
5813 }
5817 }
5818 \f
5820 /* Subroutine of fold, looking inside expressions of the form
5821 A op B ? A : C, where (ARG00, COMP_CODE, ARG01), ARG1 and ARG2
5822 are the three operands of the COND_EXPR. This function is
5823 being used also to optimize A op B ? C : A, by reversing the
5824 comparison first.
5826 Return a folded expression whose code is not a COND_EXPR
5827 anymore, or NULL_TREE if no folding opportunity is found. */
5829 static tree
5833 {
5835 tree tem;
5840 /* If we have A op 0 ? A : -A, consider applying the following
5841 transformations:
5843 A == 0? A : -A same as -A
5844 A != 0? A : -A same as A
5845 A >= 0? A : -A same as abs (A)
5846 A > 0? A : -A same as abs (A)
5847 A <= 0? A : -A same as -abs (A)
5848 A < 0? A : -A same as -abs (A)
5850 None of these transformations work for modes with signed
5851 zeros. If A is +/-0, the first two transformations will
5852 change the sign of the result (from +0 to -0, or vice
5853 versa). The last four will fix the sign of the result,
5854 even though the original expressions could be positive or
5855 negative, depending on the sign of A.
5857 Note that all these transformations are correct if A is
5858 NaN, since the two alternatives (A and -A) are also NaNs. */
5865 /* In the case that A is of the form X-Y, '-A' (arg2) may
5866 have already been folded to Y-X, check for that. */
5874 {
5886 /* Fall through. */
5897 /* FALLTHRU */
5904 {
5905 /* A <= 0 ? A : -A for A INT_MIN is valid, but -abs(INT_MIN)
5906 is not, invokes UB both in abs and in the negation of it.
5907 So, use ABSU_EXPR instead. */
5912 }
5913 else
5914 {
5917 }
5921 }
5923 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5924 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5925 both transformations are correct when A is NaN: A != 0
5926 is then true, and A == 0 is false. */
5930 {
5935 }
5937 /* Try some transformations of A op B ? A : B.
5939 A == B? A : B same as B
5940 A != B? A : B same as A
5941 A >= B? A : B same as max (A, B)
5942 A > B? A : B same as max (B, A)
5943 A <= B? A : B same as min (A, B)
5944 A < B? A : B same as min (B, A)
5946 As above, these transformations don't work in the presence
5947 of signed zeros. For example, if A and B are zeros of
5948 opposite sign, the first two transformations will change
5949 the sign of the result. In the last four, the original
5950 expressions give different results for (A=+0, B=-0) and
5951 (A=-0, B=+0), but the transformed expressions do not.
5953 The first two transformations are correct if either A or B
5954 is a NaN. In the first transformation, the condition will
5955 be false, and B will indeed be chosen. In the case of the
5956 second transformation, the condition A != B will be true,
5957 and A will be chosen.
5959 The conversions to max() and min() are not correct if B is
5960 a number and A is not. The conditions in the original
5961 expressions will be false, so all four give B. The min()
5962 and max() versions would give a NaN instead. */
5965 /* Avoid these transformations if the COND_EXPR may be used
5966 as an lvalue in the C++ front-end. PR c++/19199. */
5967 && (in_gimple_form
5973 {
5979 {
5988 /* In C++ a ?: expression can be an lvalue, so put the
5989 operand which will be used if they are equal first
5990 so that we can convert this back to the
5991 corresponding COND_EXPR. */
5993 {
6001 }
6008 {
6016 }
6029 }
6030 }
6033 }
6036 \f
6037 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
6038 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
6039 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
6040 false) >= 2)
6041 #endif
6043 /* EXP is some logical combination of boolean tests. See if we can
6044 merge it into some range test. Return the new tree if so. */
6046 static tree
6049 {
6063 /* If op0 is known true or false and this is a short-circuiting
6064 operation we must not merge with op1 since that makes side-effects
6065 unconditional. So special-case this. */
6072 /* If this is an OR operation, invert both sides; we will invert
6073 again at the end. */
6077 /* If both expressions are the same, if we can merge the ranges, and we
6078 can build the range test, return it or it inverted. If one of the
6079 ranges is always true or always false, consider it to be the same
6080 expression as the other. */
6088 {
6092 }
6094 /* On machines where the branch cost is expensive, if this is a
6095 short-circuited branch and the underlying object on both sides
6096 is the same, make a non-short-circuit operation. */
6099 logical_op_non_short_circuit
6106 {
6107 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
6108 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
6109 which cases we can't do this. */
6117 {
6126 {
6129 WARN_STRICT_OVERFLOW_COMPARISON);
6133 }
6134 }
6135 }
6138 }
6139 \f
6140 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
6141 bit value. Arrange things so the extra bits will be set to zero if and
6142 only if C is signed-extended to its full width. If MASK is nonzero,
6143 it is an INTEGER_CST that should be AND'ed with the extra bits. */
6145 static tree
6147 {
6150 tree temp;
6155 /* We work by getting just the sign bit into the low-order bit, then
6156 into the high-order bit, then sign-extend. We then XOR that value
6157 with C. */
6161 /* We must use a signed type in order to get an arithmetic right shift.
6162 However, we must also avoid introducing accidental overflows, so that
6163 a subsequent call to integer_zerop will work. Hence we must
6164 do the type conversion here. At this point, the constant is either
6165 zero or one, and the conversion to a signed type can never overflow.
6166 We could get an overflow if this conversion is done anywhere else. */
6175 /* If necessary, convert the type back to match the type of C. */
6180 }
6181 \f
6182 /* For an expression that has the form
6183 (A && B) || ~B
6184 or
6185 (A || B) && ~B,
6186 we can drop one of the inner expressions and simplify to
6187 A || ~B
6188 or
6189 A && ~B
6190 LOC is the location of the resulting expression. OP is the inner
6191 logical operation; the left-hand side in the examples above, while CMPOP
6192 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
6193 removing a condition that guards another, as in
6194 (A != NULL && A->...) || A == NULL
6195 which we must not transform. If RHS_ONLY is true, only eliminate the
6196 right-most operand of the inner logical operation. */
6198 static tree
6201 {
6219 {
6222 {
6225 }
6226 }
6228 {
6231 {
6234 }
6235 }
6250 }
6252 /* Find ways of folding logical expressions of LHS and RHS:
6253 Try to merge two comparisons to the same innermost item.
6254 Look for range tests like "ch >= '0' && ch <= '9'".
6255 Look for combinations of simple terms on machines with expensive branches
6256 and evaluate the RHS unconditionally.
6258 For example, if we have p->a == 2 && p->b == 4 and we can make an
6259 object large enough to span both A and B, we can do this with a comparison
6260 against the object ANDed with the a mask.
6262 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
6263 operations to do this with one comparison.
6265 We check for both normal comparisons and the BIT_AND_EXPRs made this by
6266 function and the one above.
6268 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
6269 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
6271 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
6272 two operands.
6274 We return the simplified tree or 0 if no optimization is possible. */
6276 static tree
6279 {
6280 /* If this is the "or" of two comparisons, we can do something if
6281 the comparisons are NE_EXPR. If this is the "and", we can do something
6282 if the comparisons are EQ_EXPR. I.e.,
6283 (a->b == 2 && a->c == 4) can become (a->new == NEW).
6285 WANTED_CODE is this operation code. For single bit fields, we can
6286 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
6287 comparison for one-bit fields. */
6308 /* Start by getting the comparison codes. Fail if anything is volatile.
6309 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
6310 it were surrounded with a NE_EXPR. */
6319 {
6323 }
6326 {
6330 }
6341 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
6344 {
6347 {
6352 }
6355 {
6361 }
6362 }
6367 /* If the RHS can be evaluated unconditionally and its operands are
6368 simple, it wins to evaluate the RHS unconditionally on machines
6369 with expensive branches. In this case, this isn't a comparison
6370 that can be merged. */
6377 {
6378 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
6389 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
6399 }
6401 /* See if the comparisons can be merged. Then get all the parameters for
6402 each side. */
6427 /* It must be true that the inner operation on the lhs of each
6428 comparison must be the same if we are to be able to do anything.
6429 Then see if we have constants. If not, the same must be true for
6430 the rhs's. */
6439 {
6442 }
6447 else
6450 /* If either comparison code is not correct for our logical operation,
6451 fail. However, we can convert a one-bit comparison against zero into
6452 the opposite comparison against that bit being set in the field. */
6456 {
6458 {
6459 /* Make the left operand unsigned, since we are only interested
6460 in the value of one bit. Otherwise we are doing the wrong
6461 thing below. */
6464 }
6465 else
6467 }
6469 /* This is analogous to the code for l_const above. */
6471 {
6473 {
6476 }
6477 else
6479 }
6481 /* See if we can find a mode that contains both fields being compared on
6482 the left. If we can't, fail. Otherwise, update all constants and masks
6483 to be relative to a field of that size. */
6497 {
6500 }
6510 {
6519 {
6523 }
6524 }
6526 {
6535 {
6539 }
6540 }
6542 /* If the right sides are not constant, do the same for it. Also,
6543 disallow this optimization if a size, signedness or storage order
6544 mismatch occurs between the left and right sides. */
6546 {
6550 /* Make sure the two fields on the right
6551 correspond to the left without being swapped. */
6568 {
6571 }
6582 /* Make a mask that corresponds to both fields being compared.
6583 Do this for both items being compared. If the operands are the
6584 same size and the bits being compared are in the same position
6585 then we can do this by masking both and comparing the masked
6586 results. */
6593 {
6607 }
6609 /* There is still another way we can do something: If both pairs of
6610 fields being compared are adjacent, we may be able to make a wider
6611 field containing them both.
6613 Note that we still must mask the lhs/rhs expressions. Furthermore,
6614 the mask must be shifted to account for the shift done by
6615 make_bit_field_ref. */
6624 {
6625 tree type;
6643 /* Convert to the smaller type before masking out unwanted bits. */
6646 {
6648 {
6652 }
6654 {
6658 }
6659 }
6668 }
6671 }
6673 /* Handle the case of comparisons with constants. If there is something in
6674 common between the masks, those bits of the constants must be the same.
6675 If not, the condition is always false. Test for this to avoid generating
6676 incorrect code below. */
6681 {
6683 {
6686 }
6687 else
6688 {
6691 }
6692 }
6697 /* Construct the expression we will return. First get the component
6698 reference we will make. Unless the mask is all ones the width of
6699 that field, perform the mask operation. Then compare with the
6700 merged constant. */
6711 }
6712 \f
6713 /* T is an integer expression that is being multiplied, divided, or taken a
6714 modulus (CODE says which and what kind of divide or modulus) by a
6715 constant C. See if we can eliminate that operation by folding it with
6716 other operations already in T. WIDE_TYPE, if non-null, is a type that
6717 should be used for the computation if wider than our type.
6719 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6720 (X * 2) + (Y * 4). We must, however, be assured that either the original
6721 expression would not overflow or that overflow is undefined for the type
6722 in the language in question.
6724 If we return a non-null expression, it is an equivalent form of the
6725 original computation, but need not be in the original type.
6727 We set *STRICT_OVERFLOW_P to true if the return values depends on
6728 signed overflow being undefined. Otherwise we do not change
6729 *STRICT_OVERFLOW_P. */
6731 static tree
6734 {
6735 /* To avoid exponential search depth, refuse to allow recursion past
6736 three levels. Beyond that (1) it's highly unlikely that we'll find
6737 something interesting and (2) we've probably processed it before
6738 when we built the inner expression. */
6741 tree ret;
6746 depth++;
6748 depth--;
6751 }
6753 static tree
6756 {
6768 /* Don't deal with constants of zero here; they confuse the code below. */
6778 /* Note that we need not handle conditional operations here since fold
6779 already handles those cases. So just do arithmetic here. */
6781 {
6783 /* For a constant, we can always simplify if we are a multiply
6784 or (for divide and modulus) if it is a multiple of our constant. */
6788 {
6791 /* If the multiplication overflowed, we lost information on it.
6792 See PR68142 and PR69845. */
6796 }
6802 /* If op0 is an expression ... */
6808 /* ... and has wrapping overflow, and its type is smaller
6809 than ctype, then we cannot pass through as widening. */
6813 /* ... or this is a truncation (t is narrower than op0),
6814 then we cannot pass through this narrowing. */
6817 /* ... or signedness changes for division or modulus,
6818 then we cannot pass through this conversion. */
6822 /* ... or has undefined overflow while the converted to
6823 type has not, we cannot do the operation in the inner type
6824 as that would introduce undefined overflow. */
6829 /* Pass the constant down and see if we can make a simplification. If
6830 we can, replace this expression with the inner simplification for
6831 possible later conversion to our or some other type. */
6842 /* If widening the type changes it from signed to unsigned, then we
6843 must avoid building ABS_EXPR itself as unsigned. */
6845 {
6849 {
6852 }
6854 }
6855 /* If the constant is negative, we cannot simplify this. */
6858 /* FALLTHROUGH */
6860 /* For division and modulus, type can't be unsigned, as e.g.
6861 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6862 For signed types, even with wrapping overflow, this is fine. */
6871 /* If widening the type changes the signedness, then we can't perform
6872 this optimization as that changes the result. */
6876 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6882 {
6889 }
6893 /* If the second operand is constant, this is a multiplication
6894 or floor division, by a power of two, so we can treat it that
6895 way unless the multiplier or divisor overflows. Signed
6896 left-shift overflow is implementation-defined rather than
6897 undefined in C90, so do not convert signed left shift into
6898 multiplication. */
6901 /* const_binop may not detect overflow correctly,
6902 so check for it explicitly here. */
6911 ctype,
6913 t1),
6918 /* See if we can eliminate the operation on both sides. If we can, we
6919 can return a new PLUS or MINUS. If we can't, the only remaining
6920 cases where we can do anything are if the second operand is a
6921 constant. */
6928 /* If not multiplication, we can only do this if both operands
6929 are divisible by c. */
6932 {
6937 }
6939 /* If this was a subtraction, negate OP1 and set it to be an addition.
6940 This simplifies the logic below. */
6942 {
6944 /* If OP1 was not easily negatable, the constant may be OP0. */
6946 {
6949 }
6950 }
6955 /* If either OP1 or C are negative, this optimization is not safe for
6956 some of the division and remainder types while for others we need
6957 to change the code. */
6959 {
6967 }
6969 /* If it's a multiply or a division/modulus operation of a multiple
6970 of our constant, do the operation and verify it doesn't overflow. */
6974 {
6977 /* We allow the constant to overflow with wrapping semantics. */
6981 }
6982 else
6985 /* If we have an unsigned type, we cannot widen the operation since it
6986 will change the result if the original computation overflowed. */
6990 /* The last case is if we are a multiply. In that case, we can
6991 apply the distributive law to commute the multiply and addition
6992 if the multiplication of the constants doesn't overflow
6993 and overflow is defined. With undefined overflow
6994 op0 * c might overflow, while (op0 + orig_op1) * c doesn't.
6995 But fold_plusminus_mult_expr would factor back any power-of-two
6996 value so do not distribute in the first place in this case. */
7004 op1);
7009 /* We have a special case here if we are doing something like
7010 (C * 8) % 4 since we know that's zero. */
7013 /* If the multiplication can overflow we cannot optimize this. */
7018 {
7021 }
7023 /* ... fall through ... */
7027 /* If we can extract our operation from the LHS, do so and return a
7028 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
7029 do something only if the second operand is a constant. */
7045 /* If these are the same operation types, we can associate them
7046 assuming no overflow. */
7048 {
7063 }
7065 /* If these operations "cancel" each other, we have the main
7066 optimizations of this pass, which occur when either constant is a
7067 multiple of the other, in which case we replace this with either an
7068 operation or CODE or TCODE.
7070 If we have an unsigned type, we cannot do this since it will change
7071 the result if the original computation overflowed. */
7078 {
7081 {
7088 }
7091 {
7098 }
7099 }
7104 }
7107 }
7108 \f
7109 /* Return a node which has the indicated constant VALUE (either 0 or
7110 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
7111 and is of the indicated TYPE. */
7113 tree
7115 {
7124 else
7126 }
7129 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
7130 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
7131 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
7132 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
7133 COND is the first argument to CODE; otherwise (as in the example
7134 given here), it is the second argument. TYPE is the type of the
7135 original expression. Return NULL_TREE if no simplification is
7136 possible. */
7138 static tree
7143 {
7151 /* Do not move possibly trapping operations into the conditional as this
7152 pessimizes code and causes gimplification issues when applied late. */
7160 {
7164 /* If this operand throws an expression, then it does not make
7165 sense to try to perform a logical or arithmetic operation
7166 involving it. */
7171 }
7174 {
7179 }
7180 else
7181 /* Detect the case of mixing vector and scalar types - bail out. */
7187 /* This transformation is only worthwhile if we don't have to wrap ARG
7188 in a SAVE_EXPR and the operation can be simplified without recursing
7189 on at least one of the branches once its pushed inside the COND_EXPR. */
7198 {
7202 else
7204 }
7206 {
7210 else
7212 }
7214 /* Check that we have simplified at least one of the branches. */
7219 }
7221 \f
7222 /* Subroutine of fold() that checks for the addition of ARG +/- 0.0.
7224 If !NEGATE, return true if ZERO_ARG is +/-0.0 and, for all ARG of
7225 type TYPE, ARG + ZERO_ARG is the same as ARG. If NEGATE, return true
7226 if ARG - ZERO_ARG is the same as X.
7228 If ARG is NULL, check for any value of type TYPE.
7230 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
7231 and finite. The problematic cases are when X is zero, and its mode
7232 has signed zeros. In the case of rounding towards -infinity,
7233 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
7234 modes, X + 0 is not the same as X because -0 + 0 is 0. */
7236 bool
7239 {
7243 /* Don't allow the fold with -fsignaling-nans. */
7247 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
7251 /* There is no case that is safe for all rounding modes. */
7255 /* In a vector or complex, we would need to check the sign of all zeros. */
7261 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
7265 /* The mode has signed zeros, and we have to honor their sign.
7266 In this situation, there are only two cases we can return true for.
7267 (i) X - 0 is the same as X with default rounding.
7268 (ii) X + 0 is X when X can't possibly be -0.0. */
7270 }
7272 /* Subroutine of match.pd that optimizes comparisons of a division by
7273 a nonzero integer constant against an integer constant, i.e.
7274 X/C1 op C2.
7276 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
7277 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
7279 enum tree_code
7282 {
7287 /* We have to do this the hard way to detect unsigned overflow.
7288 prod = int_const_binop (MULT_EXPR, c1, c2); */
7294 {
7298 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
7301 }
7303 {
7306 {
7325 }
7326 }
7327 else
7328 {
7329 /* A negative divisor reverses the relational operators. */
7334 {
7353 }
7354 }
7367 }
7370 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7371 equality/inequality test, then return a simplified form of the test
7372 using a sign testing. Otherwise return NULL. TYPE is the desired
7373 result type. */
7375 static tree
7378 tree result_type)
7379 {
7380 /* If this is testing a single bit, we can optimize the test. */
7384 {
7385 /* If we have (A & C) != 0 where C is the sign bit of A, convert
7386 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
7390 /* This is only a win if casting to a signed type is cheap,
7391 i.e. when arg00's type is not a partial mode. */
7393 {
7396 result_type,
7399 }
7400 }
7403 }
7405 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7406 equality/inequality test, then return a simplified form of
7407 the test using shifts and logical operations. Otherwise return
7408 NULL. TYPE is the desired result type. */
7410 tree
7413 {
7414 /* If this is testing a single bit, we can optimize the test. */
7418 {
7427 /* First, see if we can fold the single bit test into a sign-bit
7428 test. */
7430 result_type);
7434 /* Otherwise we have (A & C) != 0 where C is a single bit,
7435 convert that into ((A >> C2) & 1). Where C2 = log2(C).
7436 Similarly for (A & C) == 0. */
7438 /* If INNER is a right shift of a constant and it plus BITNUM does
7439 not overflow, adjust BITNUM and INNER. */
7445 {
7448 }
7450 /* If we are going to be able to omit the AND below, we must do our
7451 operations as unsigned. If we must use the AND, we have a choice.
7452 Normally unsigned is faster, but for some machines signed is. */
7470 /* Put the AND last so it can combine with more things. */
7473 /* Make sure to return the proper type. */
7477 }
7479 }
7481 /* Test whether it is preferable to swap two operands, ARG0 and
7482 ARG1, for example because ARG0 is an integer constant and ARG1
7483 isn't. */
7485 bool
7487 {
7501 /* It is preferable to swap two SSA_NAME to ensure a canonical form
7502 for commutative and comparison operators. Ensuring a canonical
7503 form allows the optimizers to find additional redundancies without
7504 having to explicitly check for both orderings. */
7510 /* Put SSA_NAMEs last. */
7516 /* Put variables last. */
7523 }
7526 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7527 means A >= Y && A != MAX, but in this case we know that
7528 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7530 static tree
7532 {
7539 else
7548 {
7551 }
7553 {
7556 }
7557 else
7564 {
7565 /* Convert the pointer types into integer before taking the difference. */
7569 }
7570 else
7577 }
7579 /* Fold a sum or difference of at least one multiplication.
7580 Returns the folded tree or NULL if no simplification could be made. */
7582 static tree
7585 {
7589 /* (A * C) +- (B * C) -> (A+-B) * C.
7590 (A * C) +- A -> A * (C+-1).
7591 We are most concerned about the case where C is a constant,
7592 but other combinations show up during loop reduction. Since
7593 it is not difficult, try all four possibilities. */
7596 {
7599 }
7601 {
7604 }
7605 else
7606 {
7607 /* We cannot generate constant 1 for fract. */
7612 }
7614 {
7617 }
7619 {
7621 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7622 the purpose of this canonicalization. */
7626 {
7629 }
7630 else
7632 }
7633 else
7634 {
7635 /* We cannot generate constant 1 for fract. */
7640 }
7643 /* Prefer factoring a common non-constant. */
7653 /* No identical multiplicands; see if we can find a common
7654 power-of-two factor in non-power-of-two multiplies. This
7655 can help in multi-dimensional array access. */
7657 {
7660 HOST_WIDE_INT tmp;
7662 tree maybe_same;
7664 /* Move min of absolute values to int11. */
7666 {
7671 }
7672 else
7679 /* The remainder should not be a constant, otherwise we
7680 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7681 increased the number of multiplications necessary. */
7683 {
7691 }
7692 }
7699 /* We are neither factoring zero nor minus one. */
7707 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7708 same may be minus one and thus the multiplication may overflow. Perform
7709 the sum operation in an unsigned type. */
7714 /* If the sum evaluated to a constant that is not -INF the multiplication
7715 cannot overflow. */
7722 /* Do not resort to unsigned multiplication because
7723 we lose the no-overflow property of the expression. */
7725 }
7727 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7728 specified by EXPR into the buffer PTR of length LEN bytes.
7729 Return the number of bytes placed in the buffer, or zero
7730 upon failure. */
7732 static int
7734 {
7746 /* Dry run. */
7752 {
7754 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7755 number of bytes. */
7759 {
7766 else
7768 }
7769 else
7773 }
7775 }
7778 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7779 specified by EXPR into the buffer PTR of length LEN bytes.
7780 Return the number of bytes placed in the buffer, or zero
7781 upon failure. */
7783 static int
7785 {
7789 FIXED_VALUE_TYPE value;
7804 }
7807 /* Subroutine of native_encode_expr. Encode the REAL_CST
7808 specified by EXPR into the buffer PTR of length LEN bytes.
7809 Return the number of bytes placed in the buffer, or zero
7810 upon failure. */
7812 static int
7814 {
7820 /* There are always 32 bits in each long, no matter the size of
7821 the hosts long. We handle floating point representations with
7822 up to 192 bits. */
7831 /* Dry run. */
7840 {
7845 {
7852 else
7854 }
7855 else
7856 {
7859 {
7860 /* Reverse bytes within each long, or within the entire float
7861 if it's smaller than a long (for HFmode). */
7864 }
7865 }
7870 }
7872 }
7874 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7875 specified by EXPR into the buffer PTR of length LEN bytes.
7876 Return the number of bytes placed in the buffer, or zero
7877 upon failure. */
7879 static int
7881 {
7883 tree part;
7897 }
7899 /* Like native_encode_vector, but only encode the first COUNT elements.
7900 The other arguments are as for native_encode_vector. */
7902 static int
7905 {
7909 {
7910 /* This is the only case in which elements can be smaller than a byte.
7911 Element 0 is always in the lsb of the containing byte. */
7920 /* Zero the buffer and then set bits later where necessary. */
7929 {
7935 {
7938 }
7939 }
7941 }
7946 {
7948 {
7951 }
7962 }
7964 }
7966 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7967 specified by EXPR into the buffer PTR of length LEN bytes.
7968 Return the number of bytes placed in the buffer, or zero
7969 upon failure. */
7971 static int
7973 {
7978 }
7981 /* Subroutine of native_encode_expr. Encode the STRING_CST
7982 specified by EXPR into the buffer PTR of length LEN bytes.
7983 Return the number of bytes placed in the buffer, or zero
7984 upon failure. */
7986 static int
7988 {
7991 /* Wide-char strings are encoded in target byte-order so native
7992 encoding them is trivial. */
8007 else
8008 {
8011 {
8014 }
8016 }
8018 }
8021 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST, REAL_CST,
8022 FIXED_CST, COMPLEX_CST, STRING_CST, or VECTOR_CST specified by EXPR into
8023 the buffer PTR of size LEN bytes. If PTR is NULL, don't actually store
8024 anything, just do a dry run. Fail either if OFF is -1 and LEN isn't
8025 sufficient to encode the entire EXPR, or if OFF is out of bounds.
8026 Otherwise, start at byte offset OFF and encode at most LEN bytes.
8027 Return the number of bytes placed in the buffer, or zero upon failure. */
8029 int
8031 {
8032 /* We don't support starting at negative offset and -1 is special. */
8037 {
8058 }
8059 }
8061 /* Try to find a type whose byte size is smaller or equal to LEN bytes larger
8062 or equal to FIELDSIZE bytes, with underlying mode precision/size multiple
8063 of BITS_PER_UNIT. As native_{interpret,encode}_int works in term of
8064 machine modes, we can't just use build_nonstandard_integer_type. */
8066 tree
8068 {
8069 machine_mode mode;
8071 {
8078 {
8082 }
8083 }
8089 {
8097 }
8100 }
8102 /* Similar to native_encode_expr, but also handle CONSTRUCTORs, VCEs,
8103 NON_LVALUE_EXPRs and nops. If MASK is non-NULL (then PTR has
8104 to be non-NULL and OFF zero), then in addition to filling the
8105 bytes pointed by PTR with the value also clear any bits pointed
8106 by MASK that are known to be initialized, keep them as is for
8107 e.g. uninitialized padding bits or uninitialized fields. */
8109 int
8112 {
8115 /* We don't support starting at negative offset and -1 is special. */
8123 {
8127 mask);
8142 {
8143 tree min_index;
8161 {
8166 {
8169 }
8174 else
8178 {
8182 offset_int wpos
8190 offset_int wcount
8197 }
8199 {
8202 offset_int wpos
8210 }
8213 {
8215 {
8226 }
8228 {
8232 }
8233 }
8237 do
8238 {
8243 {
8245 {
8248 fieldsize);
8251 }
8253 ptr
8256 fieldsize,
8259 mask
8263 else
8264 {
8267 }
8268 }
8271 {
8272 /* Partial overlap. */
8278 {
8282 fieldsize);
8283 }
8284 else
8285 {
8289 }
8292 }
8294 }
8296 }
8298 }
8301 {
8311 {
8317 {
8320 }
8323 {
8332 }
8336 else
8340 {
8341 tree fld;
8343 {
8356 }
8358 {
8362 }
8365 {
8366 cnt--;
8372 }
8373 }
8378 {
8391 {
8396 }
8397 }
8398 else
8399 {
8404 }
8409 {
8416 else
8422 }
8431 {
8432 /* FIXME: Handle PDP endian. */
8443 {
8446 }
8447 else
8448 {
8456 else
8457 {
8460 }
8461 }
8471 else
8484 /* If the bitfield does not start at byte boundary, handle
8485 the partial byte at the start. */
8488 {
8490 {
8495 {
8498 else
8500 }
8501 }
8502 else
8503 {
8508 {
8511 else
8515 }
8516 }
8517 }
8518 /* If the bitfield does not end at byte boundary, handle
8519 the partial byte at the end. */
8523 {
8525 {
8532 }
8533 else
8534 {
8541 }
8542 }
8546 {
8551 }
8552 else
8553 {
8554 /* Partial overlap. */
8558 {
8561 }
8565 }
8567 }
8572 {
8575 {
8578 {
8582 }
8585 }
8588 fldsize,
8598 }
8599 else
8600 {
8601 /* Partial overlap. */
8607 {
8611 fieldsize);
8612 }
8613 else
8614 {
8618 }
8621 }
8622 }
8624 }
8626 }
8627 }
8630 /* Subroutine of native_interpret_expr. Interpret the contents of
8631 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
8632 If the buffer cannot be interpreted, return NULL_TREE. */
8634 static tree
8636 {
8646 }
8649 /* Subroutine of native_interpret_expr. Interpret the contents of
8650 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
8651 If the buffer cannot be interpreted, return NULL_TREE. */
8653 static tree
8655 {
8658 double_int result;
8659 FIXED_VALUE_TYPE fixed_value;
8669 }
8672 /* Subroutine of native_interpret_expr. Interpret the contents of
8673 the buffer PTR of length LEN as a REAL_CST of type TYPE.
8674 If the buffer cannot be interpreted, return NULL_TREE. */
8676 tree
8678 {
8682 /* There are always 32 bits in each long, no matter the size of
8683 the hosts long. We handle floating point representations with
8684 up to 192 bits. */
8685 REAL_VALUE_TYPE r;
8695 {
8696 /* Both OFFSET and BYTE index within a long;
8697 bitpos indexes the whole float. */
8700 {
8707 else
8709 }
8710 else
8711 {
8714 {
8715 /* Reverse bytes within each long, or within the entire float
8716 if it's smaller than a long (for HFmode). */
8719 }
8720 }
8724 }
8728 }
8731 /* Subroutine of native_interpret_expr. Interpret the contents of
8732 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
8733 If the buffer cannot be interpreted, return NULL_TREE. */
8735 static tree
8737 {
8752 }
8754 /* Read a vector of type TYPE from the target memory image given by BYTES,
8755 which contains LEN bytes. The vector is known to be encodable using
8756 NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements each.
8758 Return the vector on success, otherwise return null. */
8760 static tree
8764 {
8768 {
8769 /* This is the only case in which elements can be smaller than a byte.
8770 Element 0 is always in the lsb of the containing byte. */
8777 {
8784 }
8786 }
8794 {
8800 }
8802 }
8804 /* Subroutine of native_interpret_expr. Interpret the contents of
8805 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
8806 If the buffer cannot be interpreted, return NULL_TREE. */
8808 static tree
8810 {
8811 tree etype;
8822 }
8825 /* Subroutine of fold_view_convert_expr. Interpret the contents of
8826 the buffer PTR of length LEN as a constant of type TYPE. For
8827 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
8828 we return a REAL_CST, etc... If the buffer cannot be interpreted,
8829 return NULL_TREE. */
8831 tree
8833 {
8835 {
8846 {
8847 /* For floating point values in composite modes, punt if this
8848 folding doesn't preserve bit representation. As the mode doesn't
8849 have fixed precision while GCC pretends it does, there could be
8850 valid values that GCC can't really represent accurately.
8851 See PR95450. Even for other modes, e.g. x86 XFmode can have some
8852 bit combinationations which GCC doesn't preserve. */
8860 }
8874 }
8875 }
8877 /* Returns true if we can interpret the contents of a native encoding
8878 as TYPE. */
8880 bool
8882 {
8884 {
8898 }
8899 }
8901 /* Attempt to interpret aggregate of TYPE from bytes encoded in target
8902 byte order at PTR + OFF with LEN bytes. Does not handle unions. */
8904 tree
8907 {
8910 {
8917 {
8921 }
8926 {
8931 {
8936 }
8940 eltsz);
8944 }
8946 }
8950 {
8958 {
8961 {
8962 poly_int64 bitoffset;
8967 else
8977 }
8978 else
8979 {
8997 HOST_WIDE_INT rpos;
9000 else
9001 {
9004 }
9013 }
9014 }
9017 {
9027 }
9031 {
9036 }
9043 {
9047 /* FIXME: Figure out how to handle PDP endian bitfields. */
9053 else
9057 }
9059 }
9061 }
9063 /* Routines for manipulation of native_encode_expr encoded data if the encoded
9064 or extracted constant positions and/or sizes aren't byte aligned. */
9066 /* Shift left the bytes in PTR of SZ elements by AMNT bits, carrying over the
9067 bits between adjacent elements. AMNT should be within
9068 [0, BITS_PER_UNIT).
9069 Example, AMNT = 2:
9070 00011111|11100000 << 2 = 01111111|10000000
9071 PTR[1] | PTR[0] PTR[1] | PTR[0]. */
9073 void
9076 {
9085 {
9091 {
9094 }
9095 }
9096 }
9098 /* Like shift_bytes_in_array_left but for big-endian.
9099 Shift right the bytes in PTR of SZ elements by AMNT bits, carrying over the
9100 bits between adjacent elements. AMNT should be within
9101 [0, BITS_PER_UNIT).
9102 Example, AMNT = 2:
9103 00011111|11100000 >> 2 = 00000111|11111000
9104 PTR[0] | PTR[1] PTR[0] | PTR[1]. */
9106 void
9109 {
9117 {
9124 }
9125 }
9127 /* Try to view-convert VECTOR_CST EXPR to VECTOR_TYPE TYPE by operating
9128 directly on the VECTOR_CST encoding, in a way that works for variable-
9129 length vectors. Return the resulting VECTOR_CST on success or null
9130 on failure. */
9132 static tree
9134 {
9146 /* We can only preserve the semantics of a stepped pattern if the new
9147 vector element is an integer of the same size. */
9152 /* The number of bits needed to encode one element from every pattern
9153 of the original vector. */
9154 unsigned int expr_sequence_bits
9157 /* The number of bits needed to encode one element from every pattern
9158 of the result. */
9159 unsigned int type_sequence_bits
9162 /* Don't try to read more bytes than are available, which can happen
9163 for constant-sized vectors if TYPE has larger elements than EXPR_TYPE.
9164 The general VIEW_CONVERT handling can cope with that case, so there's
9165 no point complicating things here. */
9168 BITS_PER_UNIT);
9173 /* Get enough bytes of EXPR to form the new encoding. */
9181 /* Reencode the bytes as TYPE. */
9185 }
9187 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
9188 TYPE at compile-time. If we're unable to perform the conversion
9189 return NULL_TREE. */
9191 static tree
9193 {
9194 /* We support up to 512-bit values (for V8DFmode). */
9198 /* Check that the host and target are sane. */
9211 }
9213 /* Build an expression for the address of T. Folds away INDIRECT_REF
9214 to avoid confusing the gimplify process. */
9216 tree
9218 {
9219 /* The size of the object is not relevant when talking about its address. */
9224 {
9229 }
9232 {
9237 }
9244 {
9249 }
9250 else
9254 }
9256 /* Build an expression for the address of T. */
9258 tree
9260 {
9264 }
9266 /* Fold a unary expression of code CODE and type TYPE with operand
9267 OP0. Return the folded expression if folding is successful.
9268 Otherwise, return NULL_TREE. */
9270 tree
9272 {
9273 tree tem;
9274 tree arg0;
9282 {
9285 {
9286 /* Don't use STRIP_NOPS, because signedness of argument type
9287 matters. */
9289 }
9290 else
9291 {
9292 /* Strip any conversions that don't change the mode. This
9293 is safe for every expression, except for a comparison
9294 expression because its signedness is derived from its
9295 operands.
9297 Note that this is done as an internal manipulation within
9298 the constant folder, in order to find the simplest
9299 representation of the arguments so that their form can be
9300 studied. In any cases, the appropriate type conversions
9301 should be put back in the tree that will get out of the
9302 constant folder. */
9304 }
9307 {
9310 {
9314 }
9315 }
9316 }
9323 {
9330 {
9344 /* If this was a conversion, and all we did was to move into
9345 inside the COND_EXPR, bring it back out. But leave it if
9346 it is a conversion from integer to integer and the
9347 result precision is no wider than a word since such a
9348 conversion is cheap and may be optimized away by combine,
9349 while it couldn't if it were outside the COND_EXPR. Then return
9350 so we don't get into an infinite recursion loop taking the
9351 conversion out and then back in. */
9363 && (INTEGRAL_TYPE_P
9376 }
9377 }
9380 {
9386 CASE_CONVERT:
9390 {
9391 /* If we have (type) (a CMP b) and type is an integral type, return
9392 new expression involving the new type. Canonicalize
9393 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
9394 non-integral type.
9395 Do not fold the result as that would not simplify further, also
9396 folding again results in recursions. */
9406 }
9408 /* Handle (T *)&A.B.C for A being of type T and B and C
9409 living at offset zero. This occurs frequently in
9410 C++ upcasting and then accessing the base. */
9414 {
9416 tree offset;
9417 machine_mode mode;
9419 tree base
9423 /* If the reference was to a (constant) zero offset, we can use
9424 the address of the base if it has the same base type
9425 as the result type and the pointer type is unqualified. */
9433 }
9437 /* Detect assigning a bitfield. */
9439 && DECL_BIT_FIELD
9441 {
9442 /* Don't leave an assignment inside a conversion
9443 unless assigning a bitfield. */
9445 /* First do the assignment, then return converted constant. */
9450 }
9452 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
9453 constants (if x has signed type, the sign bit cannot be set
9454 in c). This folds extension into the BIT_AND_EXPR.
9455 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
9456 very likely don't have maximal range for their precision and this
9457 transformation effectively doesn't preserve non-maximal ranges. */
9461 {
9472 <= HOST_BITS_PER_WIDE_INT
9474 {
9478 cst &= HOST_WIDE_INT_M1U
9482 && !flag_syntax_only
9485 {
9489 }
9490 }
9492 {
9497 }
9498 }
9500 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
9501 cast (T1)X will fold away. We assume that this happens when X itself
9502 is a cast. */
9506 {
9510 /* If -fsanitize=alignment, avoid this optimization in GENERIC
9511 when the pointed type needs higher alignment than
9512 the p+ first operand's pointed type. */
9521 }
9523 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
9524 of the same precision, and X is an integer type not narrower than
9525 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
9531 {
9537 }
9539 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
9540 type of X and Y (integer types only). */
9545 {
9546 /* Be careful not to introduce new overflows. */
9547 tree mult_type;
9550 else
9554 {
9561 }
9562 }
9568 {
9575 }
9586 /* Convert fabs((double)float) into (double)fabsf(float). */
9589 {
9595 targ0));
9596 }
9600 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
9619 /* Note that the operand of this must be an int
9620 and its values must be 0 or 1.
9621 ("true" is a fixed value perhaps depending on the language,
9622 but we don't handle values other than 1 correctly yet.) */
9629 /* Fold *&X to X if X is an lvalue. */
9631 {
9638 }
9644 }
9647 /* If the operation was a conversion do _not_ mark a resulting constant
9648 with TREE_OVERFLOW if the original constant was not. These conversions
9649 have implementation defined behavior and retaining the TREE_OVERFLOW
9650 flag here would confuse later passes such as VRP. */
9651 tree
9654 {
9663 }
9665 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
9666 operands OP0 and OP1. LOC is the location of the resulting expression.
9667 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
9668 Return the folded expression if folding is successful. Otherwise,
9669 return NULL_TREE. */
9670 static tree
9673 {
9674 tree tem;
9676 /* We only do these simplifications if we are optimizing. */
9680 /* Check for things like (A || B) && (A || C). We can convert this
9681 to A || (B && C). Note that either operator can be any of the four
9682 truth and/or operations and the transformation will still be
9683 valid. Also note that we only care about order for the
9684 ANDIF and ORIF operators. If B contains side effects, this
9685 might change the truth-value of A. */
9692 {
9712 /* This case if tricky because we must either have commutative
9713 operators or else A10 must not have side-effects. */
9719 a01);
9720 }
9722 /* See if we can build a range comparison. */
9728 {
9732 }
9736 {
9740 }
9742 /* Check for the possibility of merging component references. If our
9743 lhs is another similar operation, try to merge its rhs with our
9744 rhs. Then try to merge our lhs and rhs. */
9755 logical_op_non_short_circuit
9763 {
9770 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
9771 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
9772 We don't want to pack more than two leafs to a non-IF AND/OR
9773 expression.
9774 If tree-code of left-hand operand isn't an AND/OR-IF code and not
9775 equal to IF-CODE, then we don't want to add right-hand operand.
9776 If the inner right-hand side of left-hand operand has
9777 side-effects, or isn't simple, then we can't add to it,
9778 as otherwise we might destroy if-sequence. */
9781 /* Needed for sequence points to handle trappings, and
9782 side-effects. */
9784 {
9786 arg1);
9788 tem);
9789 }
9790 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
9791 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
9794 /* Needed for sequence points to handle trappings, and
9795 side-effects. */
9797 {
9802 }
9803 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
9804 into (A OR B).
9805 For sequence point consistancy, we need to check for trapping,
9806 and side-effects. */
9810 }
9813 }
9815 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
9816 by changing CODE to reduce the magnitude of constants involved in
9817 ARG0 of the comparison.
9818 Returns a canonicalized comparison tree if a simplification was
9819 possible, otherwise returns NULL_TREE.
9820 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
9821 valid if signed overflow is undefined. */
9823 static tree
9827 {
9832 /* Match A +- CST code arg1. We can change this only if overflow
9833 is undefined. */
9836 /* In principle pointers also have undefined overflow behavior,
9837 but that causes problems elsewhere. */
9844 /* Identify the constant in arg0 and its sign. */
9848 /* Overflowed constants and zero will cause problems. */
9853 /* See if we can reduce the magnitude of the constant in
9854 arg0 by changing the comparison code. */
9855 /* A - CST < arg1 -> A - CST-1 <= arg1. */
9859 /* A + CST > arg1 -> A + CST-1 >= arg1. */
9863 /* A + CST <= arg1 -> A + CST-1 < arg1. */
9867 /* A - CST >= arg1 -> A - CST-1 > arg1. */
9871 else
9875 /* Now build the constant reduced in magnitude. But not if that
9876 would produce one outside of its types range. */
9892 }
9894 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
9895 overflow further. Try to decrease the magnitude of constants involved
9896 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
9897 and put sole constants at the second argument position.
9898 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
9900 static tree
9903 {
9904 tree t;
9909 /* Try canonicalization by simplifying arg0. */
9914 {
9918 }
9920 /* Try canonicalization by simplifying arg1 using the swapped
9921 comparison. */
9929 }
9931 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
9932 space. This is used to avoid issuing overflow warnings for
9933 expressions like &p->x which cannot wrap. */
9935 static bool
9937 {
9944 poly_wide_int wi_offset;
9950 else
9955 precision);
9970 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
9971 array. */
9980 }
9982 /* Return a positive integer when the symbol DECL is known to have
9983 a nonzero address, zero when it's known not to (e.g., it's a weak
9984 symbol), and a negative integer when the symbol is not yet in the
9985 symbol table and so whether or not its address is zero is unknown.
9986 For function local objects always return positive integer. */
9987 static int
9989 {
9990 /* Normally, don't do anything for variables and functions before symtab is
9991 built; it is quite possible that DECL will be declared weak later.
9992 But if folding_initializer, we need a constant answer now, so create
9993 the symtab entry and prevent later weak declaration. */
9996 = (folding_initializer
10001 /* Function local objects are never NULL. */
10009 }
10011 /* Subroutine of fold_binary. This routine performs all of the
10012 transformations that are common to the equality/inequality
10013 operators (EQ_EXPR and NE_EXPR) and the ordering operators
10014 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
10015 fold_binary should call fold_binary. Fold a comparison with
10016 tree code CODE and type TYPE with operands OP0 and OP1. Return
10017 the folded comparison or NULL_TREE. */
10019 static tree
10022 {
10032 /* For comparisons of pointers we can decompose it to a compile time
10033 comparison of the base objects and the offsets into the object.
10034 This requires at least one operand being an ADDR_EXPR or a
10035 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
10041 {
10044 machine_mode mode;
10048 /* Get base and offset for the access. Strip ADDR_EXPR for
10049 get_inner_reference, but put it back by stripping INDIRECT_REF
10050 off the base object if possible. indirect_baseN will be true
10051 if baseN is not an address but refers to the object itself. */
10054 {
10055 base0
10061 else
10063 }
10065 {
10069 {
10070 base0
10076 else
10078 }
10081 else
10085 {
10092 }
10093 }
10097 {
10098 base1
10104 else
10106 }
10108 {
10112 {
10113 base1
10119 else
10121 }
10124 else
10128 {
10135 }
10136 }
10138 /* If we have equivalent bases we might be able to simplify. */
10142 {
10143 /* We can fold this expression to a constant if the non-constant
10144 offset parts are equal. */
10148 && (equality_code
10149 || (indirect_base0
10152 {
10158 "occur when comparing P +- C1 with "
10160 WARN_STRICT_OVERFLOW_CONDITIONAL);
10163 {
10201 }
10202 }
10203 /* We can simplify the comparison to a comparison of the variable
10204 offset parts if the constant offset parts are equal.
10205 Be careful to use signed sizetype here because otherwise we
10206 mess with array offsets in the wrong way. This is possible
10207 because pointer arithmetic is restricted to retain within an
10208 object and overflow on pointer differences is undefined as of
10209 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
10211 && (equality_code
10212 || (indirect_base0
10215 {
10216 /* By converting to signed sizetype we cover middle-end pointer
10217 arithmetic which operates on unsigned pointer types of size
10218 type size and ARRAY_REF offsets which are properly sign or
10219 zero extended from their type in case it is narrower than
10220 sizetype. */
10223 else
10227 else
10234 "occur when comparing P +- C1 with "
10236 WARN_STRICT_OVERFLOW_COMPARISON);
10239 }
10240 }
10241 /* For equal offsets we can simplify to a comparison of the
10242 base addresses. */
10244 && (indirect_base0
10246 && (indirect_base1
10251 {
10257 }
10258 /* Comparison between an ordinary (non-weak) symbol and a null
10259 pointer can be eliminated since such symbols must have a non
10260 null address. In C, relational expressions between pointers
10261 to objects and null pointers are undefined. The results
10262 below follow the C++ rules with the additional property that
10263 every object pointer compares greater than a null pointer.
10264 */
10267 /* Avoid folding references to struct members at offset 0 to
10268 prevent tests like '&ptr->firstmember == 0' from getting
10269 eliminated. When ptr is null, although the -> expression
10270 is strictly speaking invalid, GCC retains it as a matter
10271 of QoI. See PR c/44555. */
10274 && indirect_base0
10275 /* The caller guarantees that when one of the arguments is
10276 constant (i.e., null in this case) it is second. */
10278 {
10280 {
10291 }
10292 }
10293 }
10295 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
10296 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
10297 the resulting offset is smaller in absolute value than the
10298 original one and has the same sign. */
10307 {
10312 tree cst;
10314 "occur when combining constants around "
10317 /* Put the constant on the side where it doesn't overflow and is
10318 of lower absolute value and of same sign than before. */
10325 {
10328 variable1,
10332 }
10340 {
10346 variable2);
10347 }
10348 }
10354 /* If we are comparing an expression that just has comparisons
10355 of two integer values, arithmetic expressions of those comparisons,
10356 and constants, we can simplify it. There are only three cases
10357 to check: the two values can either be equal, the first can be
10358 greater, or the second can be greater. Fold the expression for
10359 those three values. Since each value must be 0 or 1, we have
10360 eight possibilities, each of which corresponds to the constant 0
10361 or 1 or one of the six possible comparisons.
10363 This handles common cases like (a > b) == 0 but also handles
10364 expressions like ((x > y) - (y > x)) > 0, which supposedly
10365 occur in macroized code. */
10368 {
10372 /* Don't handle degenerate cases here; they should already
10373 have been handled anyway. */
10382 {
10386 /* We can't just pass T to eval_subst in case cval1 or cval2
10387 was the same as ARG1. */
10389 tree high_result
10393 arg1);
10394 tree equal_result
10398 arg1);
10399 tree low_result
10403 arg1);
10405 /* All three of these results should be 0 or 1. Confirm they are.
10406 Then use those values to select the proper code to use. */
10411 {
10412 /* Make a 3-bit mask with the high-order bit being the
10413 value for `>', the next for '=', and the low for '<'. */
10417 {
10419 /* Always false. */
10440 /* Always true. */
10442 }
10445 }
10446 }
10447 }
10450 }
10453 /* Subroutine of fold_binary. Optimize complex multiplications of the
10454 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
10455 argument EXPR represents the expression "z" of type TYPE. */
10457 static tree
10459 {
10464 {
10467 }
10469 {
10472 }
10473 else
10474 {
10478 }
10487 }
10490 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
10491 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
10492 true if successful. */
10494 static bool
10496 {
10501 {
10504 }
10506 {
10512 else
10514 }
10515 else
10521 }
10523 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
10524 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
10525 NULL_TREE otherwise. */
10527 tree
10529 {
10550 {
10551 HOST_WIDE_INT index;
10557 }
10560 {
10566 }
10567 else
10569 }
10571 /* Try to fold a pointer difference of type TYPE two address expressions of
10572 array references AREF0 and AREF1 using location LOC. Return a
10573 simplified expression for the difference or NULL_TREE. */
10575 static tree
10579 {
10584 /* If the bases are array references as well, recurse. If the bases
10585 are pointer indirections compute the difference of the pointers.
10586 If the bases are equal, we are set. */
10589 && (base_offset
10591 use_pointer_diff)))
10594 && (base_offset
10595 = use_pointer_diff
10605 {
10611 base_offset,
10614 }
10616 }
10618 /* If the real or vector real constant CST of type TYPE has an exact
10619 inverse, return it, else return NULL. */
10621 tree
10623 {
10624 REAL_VALUE_TYPE r;
10625 tree unit_type;
10626 machine_mode mode;
10629 {
10639 {
10643 tree_vector_builder elts;
10648 {
10653 }
10656 }
10660 }
10661 }
10663 /* Mask out the tz least significant bits of X of type TYPE where
10664 tz is the number of trailing zeroes in Y. */
10665 static wide_int
10667 {
10672 }
10674 /* Return true when T is an address and is known to be nonzero.
10675 For floating point we further ensure that T is not denormal.
10676 Similar logic is present in nonzero_address in rtlanal.h.
10678 If the return value is based on the assumption that signed overflow
10679 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
10680 change *STRICT_OVERFLOW_P. */
10682 static bool
10684 {
10688 /* Doing something useful for floating point would need more work. */
10694 {
10697 strict_overflow_p);
10703 strict_overflow_p);
10711 }
10714 {
10717 strict_overflow_p);
10725 strict_overflow_p);
10740 strict_overflow_p);
10744 strict_overflow_p);
10747 {
10759 }
10763 }
10765 }
10767 /* Return true when T is an address and is known to be nonzero.
10768 Handle warnings about undefined signed overflow. */
10770 bool
10772 {
10779 "determining that expression is always "
10781 WARN_STRICT_OVERFLOW_MISC);
10783 }
10785 /* Return true if T is known not to be equal to an integer W. */
10787 bool
10789 {
10790 int_range_max vr;
10792 {
10802 else
10808 /* If T has some known zero bits and W has any of those bits set,
10809 then T is known not to be equal to W. */
10817 }
10818 }
10820 /* Fold a binary expression of code CODE and type TYPE with operands
10821 OP0 and OP1. LOC is the location of the resulting expression.
10822 Return the folded expression if folding is successful. Otherwise,
10823 return NULL_TREE. */
10825 tree
10828 {
10843 /* Strip any conversions that don't change the mode. This is
10844 safe for every expression, except for a comparison expression
10845 because its signedness is derived from its operands. So, in
10846 the latter case, only strip conversions that don't change the
10847 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
10848 preserved.
10850 Note that this is done as an internal manipulation within the
10851 constant folder, in order to find the simplest representation
10852 of the arguments so that their form can be studied. In any
10853 cases, the appropriate type conversions should be put back in
10854 the tree that will get out of the constant folder. */
10857 {
10860 }
10861 else
10862 {
10865 }
10867 /* Note that TREE_CONSTANT isn't enough: static var addresses are
10868 constant but we can't do arithmetic on them. */
10870 {
10873 {
10877 }
10878 }
10880 /* If this is a commutative operation, and ARG0 is a constant, move it
10881 to ARG1 to reduce the number of tests below. */
10886 /* Likewise if this is a comparison, and ARG0 is a constant, move it
10887 to ARG1 to reduce the number of tests below. */
10896 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
10898 First check for cases where an arithmetic operation is applied to a
10899 compound, conditional, or comparison operation. Push the arithmetic
10900 operation inside the compound or conditional to see if any folding
10901 can then be done. Convert comparison to conditional for this purpose.
10902 The also optimizes non-constant cases that used to be done in
10903 expand_expr.
10905 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
10906 one of the operands is a comparison and the other is a comparison, a
10907 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
10908 code below would make the expression more complex. Change it to a
10909 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
10910 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
10923 {
10927 boolean_type_node,
10935 }
10939 {
10941 {
10946 tem);
10947 }
10949 {
10954 tem);
10955 }
10960 {
10966 }
10971 {
10977 }
10978 }
10981 {
10983 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
10986 {
10992 }
10994 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
10997 {
10998 tree base;
10999 poly_int64 coffset;
11008 }
11013 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
11019 arg1),
11021 arg0)));
11027 {
11028 /* X + (X / CST) * -CST is X % CST. */
11033 {
11042 cst0));
11043 }
11044 }
11046 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
11047 one. Make sure the type is not saturating and has the signedness of
11048 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11049 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11056 {
11060 }
11063 {
11064 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
11065 (plus (plus (mult) (mult)) (foo)) so that we can
11066 take advantage of the factoring cases below. */
11075 {
11081 else
11094 parg0),
11096 marg)),
11100 return
11106 parg1)));
11107 }
11108 }
11109 else
11110 {
11111 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
11112 to __complex__ ( x, y ). This is not the same for SNaNs or
11113 if signed zeros are involved. */
11117 {
11124 {
11128 {
11134 }
11136 {
11142 }
11143 }
11144 }
11146 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
11147 We associate floats only if the user has specified
11148 -fassociative-math. */
11152 {
11157 {
11158 tree tree0;
11161 }
11162 }
11163 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
11164 We associate floats only if the user has specified
11165 -fassociative-math. */
11169 {
11174 {
11175 tree tree0;
11178 }
11179 }
11180 }
11182 bit_rotate:
11183 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
11184 is a rotate of A by C1 bits. */
11185 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
11186 is a rotate of A by B bits.
11187 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
11188 though in this case CODE must be | and not + or ^, otherwise
11189 it doesn't return A when B is 0. */
11190 {
11192 tree rtype;
11201 /* Only create rotates in complete modes. Other cases are not
11202 expanded properly. */
11205 {
11218 {
11223 }
11228 {
11231 code0 == LSHIFT_EXPR
11234 }
11236 {
11246 {
11250 orig_tree01);
11252 }
11253 }
11257 {
11268 {
11272 orig_tree01);
11274 }
11275 }
11276 }
11277 }
11279 associate:
11280 /* In most languages, can't associate operations on floats through
11281 parentheses. Rather than remember where the parentheses were, we
11282 don't associate floats at all, unless the user has specified
11283 -fassociative-math.
11284 And, we need to make sure type is not saturating. */
11288 {
11294 /* Split both trees into variables, constants, and literals. Then
11295 associate each group together, the constants with literals,
11296 then the result with variables. This increases the chances of
11297 literals being recombined later and of generating relocatable
11298 expressions for the sum of a constant and literal. */
11306 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
11310 /* With undefined overflow prefer doing association in a type
11311 which wraps on overflow, if that is one of the operand types. */
11314 {
11322 }
11324 /* With undefined overflow we can only associate constants with one
11325 variable, and constants whose association doesn't overflow. */
11328 {
11330 {
11331 /* ??? If split_tree would handle NEGATE_EXPR we could
11332 simply reject these cases and the allowed cases would
11333 be the var0/minus_var1 ones. */
11339 {
11342 }
11349 {
11352 }
11358 /* The only case we can still associate with two variables
11359 is if they cancel out. */
11363 }
11369 }
11371 /* Only do something if we found more than two objects. Otherwise,
11372 nothing has changed and we risk infinite recursion. */
11380 {
11392 {
11396 }
11398 {
11402 }
11404 /* Preserve the MINUS_EXPR if the negative part of the literal is
11405 greater than the positive part. Otherwise, the multiplicative
11406 folding code (i.e extract_muldiv) may be fooled in case
11407 unsigned constants are subtracted, like in the following
11408 example: ((X*2 + 4) - 8U)/2. */
11410 {
11414 /* But avoid ending up with only negated parts. */
11416 {
11420 }
11421 else
11422 {
11426 }
11427 }
11429 /* Don't introduce overflows through reassociation. */
11434 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
11441 /* Eliminate minus_con0. */
11443 {
11450 else
11453 }
11455 /* Eliminate minus_var0. */
11457 {
11461 else
11464 }
11466 return
11469 }
11470 }
11476 /* Fold &a[i] - &a[j] to i-j. */
11481 {
11485 code
11489 }
11491 /* Further transformations are not for pointers. */
11495 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
11498 /* If arg0 is e.g. unsigned int and type is int, then this could
11499 introduce UB, because if A is INT_MIN at runtime, the original
11500 expression can be well defined while the latter is not.
11501 See PR83269. */
11510 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
11511 __complex__ ( x, -y ). This is not the same for SNaNs or if
11512 signed zeros are involved. */
11516 {
11523 {
11527 {
11529 arg1r ? arg1r
11534 }
11536 {
11540 arg1i ? arg1i
11543 }
11544 }
11545 }
11547 /* A - B -> A + (-B) if B is easily negatable. */
11551 /* Avoid this transformation if B is a positive REAL_CST. */
11559 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
11560 one. Make sure the type is not saturating and has the signedness of
11561 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11562 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11569 {
11573 }
11579 {
11580 /* Transform x * -C into -x * C if x is easily negatable. */
11595 {
11598 "occur when simplifying "
11600 WARN_STRICT_OVERFLOW_MISC);
11602 }
11604 /* Optimize z * conj(z) for integer complex numbers. */
11611 }
11612 else
11613 {
11614 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
11615 This is not the same for NaNs or if signed zeros are
11616 involved. */
11622 {
11625 return
11631 return
11636 }
11638 /* Optimize z * conj(z) for floating point complex numbers.
11639 Guarded by flag_unsafe_math_optimizations as non-finite
11640 imaginary components don't produce scalar results. */
11649 }
11653 /* Canonicalize (X & C1) | C2. */
11657 {
11662 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
11670 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
11672 {
11675 }
11677 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
11678 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
11679 mode which allows further optimizations. */
11684 {
11689 {
11692 }
11693 }
11696 {
11701 }
11702 }
11704 /* See if this can be simplified into a rotate first. If that
11705 is unsuccessful continue in the association code. */
11709 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
11717 /* See if this can be simplified into a rotate first. If that
11718 is unsuccessful continue in the association code. */
11722 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
11727 {
11728 tree tem2;
11735 }
11736 /* Fold ~X & 1 as (X & 1) == 0. */
11740 {
11741 tree tem2;
11748 }
11749 /* Fold !X & 1 as X == 0. */
11752 {
11756 }
11758 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
11759 multiple of 1 << CST. */
11761 {
11768 }
11770 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
11771 bits from CST2. */
11775 {
11777 wide_int masked
11784 {
11785 /* Avoid the transform if arg1 is a mask of some
11786 mode which allows further optimizations. */
11793 }
11794 }
11796 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11799 {
11804 return
11806 }
11811 /* Don't touch a floating-point divide by zero unless the mode
11812 of the constant can represent infinity. */
11818 /* (-A) / (-B) -> A / B */
11830 /* Fall through */
11833 /* Simplify A / (B << N) where A and B are positive and B is
11834 a power of 2, to A >> (N + log2(B)). */
11839 {
11842 {
11850 WARN_STRICT_OVERFLOW_MISC);
11856 }
11857 }
11859 /* Fall through */
11867 /* Convert -A / -B to A / B when the type is signed and overflow is
11868 undefined. */
11872 {
11875 "when distributing negation across "
11877 WARN_STRICT_OVERFLOW_MISC);
11882 }
11886 {
11889 "when distributing negation across "
11891 WARN_STRICT_OVERFLOW_MISC);
11896 }
11898 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11899 operation, EXACT_DIV_EXPR.
11901 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11902 At one time others generated faster code, it's not clear if they do
11903 after the last round to changes to the DIV code in expmed.cc. */
11914 {
11918 WARN_STRICT_OVERFLOW_MISC);
11920 }
11932 {
11936 WARN_STRICT_OVERFLOW_MISC);
11938 }
11946 /* Since negative shift count is not well-defined,
11947 don't try to compute it in the compiler. */
11953 /* If we have a rotate of a bit operation with the rotate count and
11954 the second operand of the bit operation both constant,
11955 permute the two operations. */
11961 {
11969 }
11971 /* Two consecutive rotates adding up to the some integer
11972 multiple of the precision of the type can be ignored. */
11988 /* Note that the operands of this must be ints
11989 and their values must be 0 or 1.
11990 ("true" is a fixed value perhaps depending on the language.) */
11991 /* If first arg is constant zero, return it. */
11994 /* FALLTHRU */
11996 /* If either arg is constant true, drop it. */
12000 /* Preserve sequence points. */
12003 /* If second arg is constant zero, result is zero, but first arg
12004 must be evaluated. */
12007 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
12008 case will be handled here. */
12012 /* !X && X is always false. */
12016 /* X && !X is always false. */
12021 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
12022 means A >= Y && A != MAX, but in this case we know that
12023 A < X <= MAX. */
12027 {
12035 }
12044 /* Note that the operands of this must be ints
12045 and their values must be 0 or true.
12046 ("true" is a fixed value perhaps depending on the language.) */
12047 /* If first arg is constant true, return it. */
12050 /* FALLTHRU */
12052 /* If either arg is constant zero, drop it. */
12056 /* Preserve sequence points. */
12059 /* If second arg is constant true, result is true, but we must
12060 evaluate first arg. */
12063 /* Likewise for first arg, but note this only occurs here for
12064 TRUTH_OR_EXPR. */
12068 /* !X || X is always true. */
12072 /* X || !X is always true. */
12077 /* (X && !Y) || (!X && Y) is X ^ Y */
12080 {
12097 }
12106 /* If the second arg is constant zero, drop it. */
12109 /* If the second arg is constant true, this is a logical inversion. */
12111 {
12114 }
12115 /* Identical arguments cancel to zero. */
12119 /* !X ^ X is always true. */
12124 /* X ^ !X is always true. */
12140 /* bool_var != 1 becomes !bool_var. */
12147 /* bool_var == 0 becomes !bool_var. */
12154 /* !exp != 0 becomes !exp */
12159 /* If this is an EQ or NE comparison with zero and ARG0 is
12160 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
12161 two operations, but the latter can be done in one less insn
12162 on machines that have only two-operand insns or on which a
12163 constant cannot be the first operand. */
12166 {
12171 {
12179 }
12182 {
12190 }
12191 }
12193 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
12194 C1 is a valid shift constant, and C2 is a power of two, i.e.
12195 a single bit. */
12199 {
12204 {
12209 /* Check for a valid shift count. */
12211 {
12215 /* If (C2 << C1) doesn't overflow, then
12216 ((X >> C1) & C2) != 0 can be rewritten as
12217 (X & (C2 << C1)) != 0. */
12219 {
12226 }
12227 /* Otherwise, for signed (arithmetic) shifts,
12228 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
12229 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
12235 /* Otherwise, of unsigned (logical) shifts,
12236 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
12237 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
12238 else
12242 arg000);
12243 }
12244 }
12245 }
12247 /* If this is a comparison of a field, we may be able to simplify it. */
12250 /* Handle the constant case even without -O
12251 to make sure the warnings are given. */
12253 {
12257 }
12259 /* Optimize comparisons of strlen vs zero to a compare of the
12260 first character of the string vs zero. To wit,
12261 strlen(ptr) == 0 => *ptr == 0
12262 strlen(ptr) != 0 => *ptr != 0
12263 Other cases should reduce to one of these two (or a constant)
12264 due to the return value of strlen being unsigned. */
12266 {
12274 {
12275 tree ptrtype
12277 TYPE_QUAL_CONST));
12283 }
12284 }
12286 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12287 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12291 {
12296 {
12298 {
12301 }
12304 }
12305 }
12307 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12308 (X & C) == 0 when C is a single bit. */
12313 {
12320 arg1));
12321 }
12323 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12324 constant C is a power of two, i.e. a single bit. */
12331 {
12335 }
12337 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12338 when is C is a power of two, i.e. a single bit. */
12345 {
12351 }
12355 {
12358 }
12362 {
12369 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12370 operand_equal_p guarantees no side-effects so we don't need
12371 to use omit_one_operand on Z. */
12375 arg10));
12379 arg11));
12383 arg10));
12387 arg11));
12389 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12392 {
12398 }
12399 }
12401 /* Attempt to simplify equality/inequality comparisons of complex
12402 values. Only lower the comparison if the result is known or
12403 can be simplified to a single scalar comparison. */
12408 {
12413 {
12416 }
12417 else
12418 {
12421 }
12424 {
12427 }
12428 else
12429 {
12432 }
12436 {
12438 {
12443 }
12444 else
12445 {
12450 }
12451 }
12455 {
12457 {
12462 }
12463 else
12464 {
12469 }
12470 }
12471 }
12483 /* Transform comparisons of the form X +- C CMP X. */
12488 {
12493 /* (X - c) > X becomes false. */
12499 /* Likewise (X + c) < X becomes false. */
12505 /* Convert (X - c) <= X to true. */
12512 /* Convert (X + c) >= X to true. */
12518 }
12520 /* If we are comparing an ABS_EXPR with a constant, we can
12521 convert all the cases into explicit comparisons, but they may
12522 well not be faster than doing the ABS and one comparison.
12523 But ABS (X) <= C is a range comparison, which becomes a subtraction
12524 and a comparison, and is probably faster. */
12538 /* Convert ABS_EXPR<x> >= 0 to true. */
12545 {
12548 "when simplifying comparison of "
12550 WARN_STRICT_OVERFLOW_CONDITIONAL);
12553 arg0);
12554 }
12556 /* Convert ABS_EXPR<x> < 0 to false. */
12561 {
12564 "when simplifying comparison of "
12566 WARN_STRICT_OVERFLOW_CONDITIONAL);
12569 arg0);
12570 }
12572 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12573 and similarly for >= into !=. */
12583 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
12584 otherwise Y might be >= # of bits in X's type and thus e.g.
12585 (unsigned char) (1 << Y) for Y 15 might be 0.
12586 If the cast is widening, then 1 << Y should have unsigned type,
12587 otherwise if Y is number of bits in the signed shift type minus 1,
12588 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
12589 31 might be 0xffffffff80000000. */
12602 {
12608 }
12620 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12621 {
12633 }
12638 /* When pedantic, a compound expression can be neither an lvalue
12639 nor an integer constant expression. */
12642 /* Don't let (0, 0) be null pointer constant. */
12648 /* An ASSERT_EXPR should never be passed to fold_binary. */
12654 }
12656 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
12657 ((A & N) + B) & M -> (A + B) & M
12658 Similarly if (N & M) == 0,
12659 ((A | N) + B) & M -> (A + B) & M
12660 and for - instead of + (or unary - instead of +)
12661 and/or ^ instead of |.
12662 If B is constant and (B & M) == 0, fold into A & M.
12664 This function is a helper for match.pd patterns. Return non-NULL
12665 type in which the simplified operation should be performed only
12666 if any optimization is possible.
12668 ARG1 is M above, ARG00 is left operand of +/-, if CODE00 is BIT_*_EXPR,
12669 then ARG00{0,1} are operands of that bitop, otherwise CODE00 is ERROR_MARK.
12670 Similarly for ARG01, CODE01 and ARG01{0,1}, just for the right operand of
12671 +/-. */
12672 tree
12677 {
12692 wide_int cst0;
12694 /* Now we know that arg0 is (C + D) or (C - D) or -C and
12695 arg1 (M) is == (1LL << cst) - 1.
12696 Store C into PMOP[0] and D into PMOP[1]. */
12703 {
12710 {
12713 }
12716 /* If C or D is of the form (A & N) where
12717 (N & M) == M, or of the form (A | N) or
12718 (A ^ N) where (N & M) == 0, replace it with A. */
12724 /* If C or D is a N where (N & M) == 0, it can be
12725 omitted (replaced with 0). */
12730 /* Similarly, with C - N where (-N & M) == 0. */
12738 }
12740 /* Only build anything new if we optimized one or both arguments above. */
12746 else
12748 }
12750 /* Used by contains_label_[p1]. */
12752 struct contains_label_data
12753 {
12756 };
12758 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
12759 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
12760 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
12762 static tree
12764 {
12767 {
12778 {
12786 }
12795 }
12796 }
12798 /* Return whether the sub-tree ST contains a label which is accessible from
12799 outside the sub-tree. */
12801 static bool
12803 {
12807 }
12809 /* Fold a ternary expression of code CODE and type TYPE with operands
12810 OP0, OP1, and OP2. Return the folded expression if folding is
12811 successful. Otherwise, return NULL_TREE. */
12813 tree
12816 {
12817 tree tem;
12824 /* If this is a commutative operation, and OP0 is a constant, move it
12825 to OP1 to reduce the number of tests below. */
12834 /* Strip any conversions that don't change the mode. This is safe
12835 for every expression, except for a comparison expression because
12836 its signedness is derived from its operands. So, in the latter
12837 case, only strip conversions that don't change the signedness.
12839 Note that this is done as an internal manipulation within the
12840 constant folder, in order to find the simplest representation of
12841 the arguments so that their form can be studied. In any cases,
12842 the appropriate type conversions should be put back in the tree
12843 that will get out of the constant folder. */
12845 {
12848 }
12851 {
12854 }
12857 {
12860 }
12863 {
12867 {
12873 }
12878 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12879 so all simple results must be passed through pedantic_non_lvalue. */
12881 {
12884 /* Only optimize constant conditions when the selected branch
12885 has the same type as the COND_EXPR. This avoids optimizing
12886 away "c ? x : throw", where the throw has a void type.
12887 Avoid throwing away that operand which contains label. */
12894 }
12896 {
12903 {
12906 {
12914 }
12919 }
12920 }
12922 /* If we have A op B ? A : C, we may be able to convert this to a
12923 simpler expression, depending on the operation and the values
12924 of B and C. Signed zeros prevent all of these transformations,
12925 for reasons given above each one.
12927 Also try swapping the arguments and inverting the conditional. */
12931 {
12938 }
12943 {
12950 arg00,
12951 arg01,
12955 }
12957 /* If the second operand is simpler than the third, swap them
12958 since that produces better jump optimization results. */
12961 {
12963 /* See if this can be inverted. If it can't, possibly because
12964 it was a floating-point inequality comparison, don't do
12965 anything. */
12969 }
12971 /* Convert A ? 1 : 0 to simply A. */
12976 /* If we try to convert OP0 to our type, the
12977 call to fold will try to move the conversion inside
12978 a COND, which will recurse. In that case, the COND_EXPR
12979 is probably the best choice, so leave it alone. */
12983 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12984 over COND_EXPR in cases such as floating point comparisons. */
12993 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12998 {
12999 /* sign_bit_p looks through both zero and sign extensions,
13000 but for this optimization only sign extensions are
13001 usable. */
13004 {
13007 {
13010 }
13012 }
13013 /* sign_bit_p only checks ARG1 bits within A's precision.
13014 If <sign bit of A> has wider type than A, bits outside
13015 of A's precision in <sign bit of A> need to be checked.
13016 If they are all 0, this optimization needs to be done
13017 in unsigned A's type, if they are all 1 in signed A's type,
13018 otherwise this can't be done. */
13024 {
13026 tree tem_type;
13039 {
13042 }
13044 {
13047 }
13048 else
13050 }
13053 return
13059 arg1)));
13060 }
13062 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13063 already handled above. */
13068 {
13078 op1);
13079 }
13081 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13082 is probably obsolete because the first operand should be a
13083 truth value (that's why we have the two cases above), but let's
13084 leave it in until we can confirm this for all front-ends. */
13092 /* operand_equal_p compares just value, not precision, so e.g.
13093 arg1 could be 8-bit -128 and be power of two, but BIT_AND_EXPR
13094 second operand 32-bit -128, which is not a power of two (or vice
13095 versa. */
13099 /* Disable the transformations below for vectors, since
13100 fold_binary_op_with_conditional_arg may undo them immediately,
13101 yielding an infinite loop. */
13105 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13114 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13119 {
13121 /* Only perform transformation if ARG0 is easily inverted. */
13125 ? BIT_IOR_EXPR
13128 op1);
13129 }
13131 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13136 {
13138 /* Only perform transformation if ARG0 is easily inverted. */
13144 op2);
13145 }
13147 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13159 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13160 of fold_ternary on them. */
13170 {
13172 unsigned HOST_WIDE_INT width
13183 {
13188 {
13190 {
13195 }
13201 }
13202 }
13203 }
13205 /* On constants we can use native encode/interpret to constant
13206 fold (nearly) all BIT_FIELD_REFs. */
13212 {
13215 /* Limit us to a reasonable amount of work. To relax the
13216 other limitations we need bit-shifting of the buffer
13217 and rounding up the size. */
13221 {
13223 unsigned HOST_WIDE_INT len
13228 {
13233 }
13234 }
13235 }
13240 /* Perform constant folding of BIT_INSERT_EXPR. */
13244 {
13245 /* Build a vector of integers from the tree mask. */
13246 vec_perm_builder builder;
13250 /* Create a vec_perm_indices for the integer vector. */
13255 }
13259 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
13262 {
13268 wide_int tem2
13272 }
13277 {
13279 unsigned HOST_WIDE_INT elsize
13282 {
13288 {
13294 }
13295 }
13296 }
13302 }
13304 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
13305 of an array (or vector). *CTOR_IDX if non-NULL is updated with the
13306 constructor element index of the value returned. If the element is
13307 not found NULL_TREE is returned and *CTOR_IDX is updated to
13308 the index of the element after the ACCESS_INDEX position (which
13309 may be outside of the CTOR array). */
13311 tree
13314 {
13320 {
13323 {
13324 /* Static constructors for variably sized objects makes no sense. */
13327 /* ??? When it is obvious that the range is signed, treat it so. */
13332 {
13334 low_bound
13336 SIGNED);
13337 }
13338 else
13339 {
13342 }
13343 }
13344 }
13348 index_sgn);
13360 {
13361 /* Array constructor might explicitly set index, or specify a range,
13362 or leave index NULL meaning that it is next index after previous
13363 one. */
13365 {
13367 max_index = index
13369 else
13370 {
13373 index_sgn);
13374 max_index
13376 index_sgn);
13378 }
13379 }
13381 {
13387 }
13388 else
13391 /* Do we have match? */
13393 {
13395 {
13399 }
13400 }
13402 /* We're past the element we search for. Note during parsing
13403 the elements might not be sorted.
13404 ??? We should use a binary search and a flag on the
13405 CONSTRUCTOR as to whether elements are sorted in declaration
13406 order. */
13408 }
13412 }
13414 /* Perform constant folding and related simplification of EXPR.
13415 The related simplifications include x*1 => x, x*0 => 0, etc.,
13416 and application of the associative law.
13417 NOP_EXPR conversions may be removed freely (as long as we
13418 are careful not to change the type of the overall expression).
13419 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13420 but we can constant-fold them if they have constant operands. */
13422 #ifdef ENABLE_FOLD_CHECKING
13423 # define fold(x) fold_1 (x)
13425 static
13426 #endif
13427 tree
13429 {
13433 tree tem;
13436 /* Return right away if a constant. */
13440 /* CALL_EXPR-like objects with variable numbers of operands are
13441 treated specially. */
13443 {
13445 {
13448 }
13450 }
13453 {
13458 {
13476 }
13477 }
13480 {
13482 {
13489 {
13494 }
13497 }
13499 /* Return a VECTOR_CST if possible. */
13501 {
13507 tree val;
13513 }
13521 }
13523 #ifdef ENABLE_FOLD_CHECKING
13524 #undef fold
13531 /* When --enable-checking=fold, compute a digest of expr before
13532 and after actual fold call to see if fold did not accidentally
13533 change original expr. */
13535 tree
13537 {
13538 tree ret;
13558 }
13560 void
13562 {
13573 }
13575 static void
13577 {
13579 }
13581 static void
13584 {
13590 recursive_label:
13600 {
13601 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
13609 }
13617 {
13618 /* Allow these fields to be modified. */
13619 tree tmp;
13630 {
13633 }
13634 }
13636 {
13637 /* Allow the no-warning bit to be set. Perhaps we shouldn't allow
13638 that and change builtins.cc etc. instead - see PR89543. */
13644 }
13655 {
13658 {
13674 }
13678 {
13691 }
13708 {
13714 }
13717 {
13719 {
13722 }
13724 }
13735 {
13738 }
13748 }
13749 }
13751 /* Helper function for outputting the checksum of a tree T. When
13752 debugging with gdb, you can "define mynext" to be "next" followed
13753 by "call debug_fold_checksum (op0)", then just trace down till the
13754 outputs differ. */
13756 DEBUG_FUNCTION void
13758 {
13773 }
13775 #endif
13777 /* Fold a unary tree expression with code CODE of type TYPE with an
13778 operand OP0. LOC is the location of the resulting expression.
13779 Return a folded expression if successful. Otherwise, return a tree
13780 expression with code CODE of type TYPE with an operand OP0. */
13782 tree
13785 {
13786 tree tem;
13787 #ifdef ENABLE_FOLD_CHECKING
13796 #endif
13802 #ifdef ENABLE_FOLD_CHECKING
13809 #endif
13811 }
13813 /* Fold a binary tree expression with code CODE of type TYPE with
13814 operands OP0 and OP1. LOC is the location of the resulting
13815 expression. Return a folded expression if successful. Otherwise,
13816 return a tree expression with code CODE of type TYPE with operands
13817 OP0 and OP1. */
13819 tree
13822 MEM_STAT_DECL)
13823 {
13824 tree tem;
13825 #ifdef ENABLE_FOLD_CHECKING
13842 #endif
13848 #ifdef ENABLE_FOLD_CHECKING
13863 #endif
13865 }
13867 /* Fold a ternary tree expression with code CODE of type TYPE with
13868 operands OP0, OP1, and OP2. Return a folded expression if
13869 successful. Otherwise, return a tree expression with code CODE of
13870 type TYPE with operands OP0, OP1, and OP2. */
13872 tree
13875 {
13876 tree tem;
13877 #ifdef ENABLE_FOLD_CHECKING
13901 #endif
13908 #ifdef ENABLE_FOLD_CHECKING
13931 #endif
13933 }
13935 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13936 arguments in ARGARRAY, and a null static chain.
13937 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13938 of type TYPE from the given operands as constructed by build_call_array. */
13940 tree
13943 {
13944 tree tem;
13945 #ifdef ENABLE_FOLD_CHECKING
13964 #endif
13970 #ifdef ENABLE_FOLD_CHECKING
13986 #endif
13988 }
13990 /* Perform constant folding and related simplification of initializer
13991 expression EXPR. These behave identically to "fold_buildN" but ignore
13992 potential run-time traps and exceptions that fold must preserve. */
13994 #define START_FOLD_INIT \
13995 int saved_signaling_nans = flag_signaling_nans;\
13996 int saved_trapping_math = flag_trapping_math;\
13997 int saved_rounding_math = flag_rounding_math;\
13998 int saved_trapv = flag_trapv;\
13999 int saved_folding_initializer = folding_initializer;\
14000 flag_signaling_nans = 0;\
14001 flag_trapping_math = 0;\
14002 flag_rounding_math = 0;\
14003 flag_trapv = 0;\
14004 folding_initializer = 1;
14006 #define END_FOLD_INIT \
14007 flag_signaling_nans = saved_signaling_nans;\
14008 flag_trapping_math = saved_trapping_math;\
14009 flag_rounding_math = saved_rounding_math;\
14010 flag_trapv = saved_trapv;\
14011 folding_initializer = saved_folding_initializer;
14013 tree
14015 {
14016 tree result;
14017 START_FOLD_INIT;
14021 END_FOLD_INIT;
14023 }
14025 tree
14028 {
14029 tree result;
14030 START_FOLD_INIT;
14034 END_FOLD_INIT;
14036 }
14038 tree
14041 {
14042 tree result;
14043 START_FOLD_INIT;
14047 END_FOLD_INIT;
14049 }
14051 tree
14054 {
14055 tree result;
14056 START_FOLD_INIT;
14060 END_FOLD_INIT;
14062 }
14064 tree
14067 {
14068 tree result;
14069 START_FOLD_INIT;
14073 END_FOLD_INIT;
14075 }
14077 #undef START_FOLD_INIT
14078 #undef END_FOLD_INIT
14080 /* Determine if first argument is a multiple of second argument. Return 0 if
14081 it is not, or we cannot easily determined it to be.
14083 An example of the sort of thing we care about (at this point; this routine
14084 could surely be made more general, and expanded to do what the *_DIV_EXPR's
14085 fold cases do now) is discovering that
14087 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14089 is a multiple of
14091 SAVE_EXPR (J * 8)
14093 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
14095 This code also handles discovering that
14097 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14099 is a multiple of 8 so we don't have to worry about dealing with a
14100 possible remainder.
14102 Note that we *look* inside a SAVE_EXPR only to determine how it was
14103 calculated; it is not safe for fold to do much of anything else with the
14104 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
14105 at run time. For example, the latter example above *cannot* be implemented
14106 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
14107 evaluation time of the original SAVE_EXPR is not necessarily the same at
14108 the time the new expression is evaluated. The only optimization of this
14109 sort that would be valid is changing
14111 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
14113 divided by 8 to
14115 SAVE_EXPR (I) * SAVE_EXPR (J)
14117 (where the same SAVE_EXPR (J) is used in the original and the
14118 transformed version).
14120 NOWRAP specifies whether all outer operations in TYPE should
14121 be considered not wrapping. Any type conversion within TOP acts
14122 as a barrier and we will fall back to NOWRAP being false.
14123 NOWRAP is mostly used to treat expressions in TYPE_SIZE and friends
14124 as not wrapping even though they are generally using unsigned arithmetic. */
14126 int
14128 {
14139 {
14141 /* Bitwise and provides a power of two multiple. If the mask is
14142 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
14149 /* If the multiplication can wrap we cannot recurse further unless
14150 the bottom is a power of two which is where wrapping does not
14151 matter. */
14157 {
14163 {
14166 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
14168 {
14172 {
14175 }
14176 }
14178 }
14179 }
14184 /* Handle X << CST as X * (1 << CST) and only process the constant. */
14186 {
14189 {
14190 wide_int mul_op
14194 nowrap);
14195 }
14196 }
14201 /* If the addition or subtraction can wrap we cannot recurse further
14202 unless bottom is a power of two which is where wrapping does not
14203 matter. */
14209 /* Handle cases like op0 + 0xfffffffd as op0 - 3 if the expression has
14210 unsigned type. For example, (X / 3) + 0xfffffffd is multiple of 3,
14211 but 0xfffffffd is not. */
14214 && nowrap
14219 /* It is impossible to prove if op0 +- op1 is multiple of bottom
14220 precisely, so be conservative here checking if both op0 and op1
14221 are multiple of bottom. Note we check the second operand first
14222 since it's usually simpler. */
14226 CASE_CONVERT:
14227 /* Can't handle conversions from non-integral or wider integral type. */
14232 /* NOWRAP only extends to operations in the outermost type so
14233 make sure to strip it off here. */
14248 SIGNED);
14254 {
14257 /* Check for special cases to see if top is defined as multiple
14258 of bottom:
14260 top = (X & ~(bottom - 1) ; bottom is power of 2
14262 or
14264 Y = X % bottom
14265 top = X - Y. */
14284 }
14286 /* fall through */
14294 }
14295 }
14297 /* Return true if expression X cannot be (or contain) a NaN or infinity.
14298 This function returns true for integer expressions, and returns
14299 false if uncertain. */
14301 bool
14303 {
14308 {
14331 {
14332 CASE_CFN_FABS:
14334 CASE_CFN_FMAX:
14335 CASE_CFN_FMIN:
14340 }
14344 }
14345 }
14347 /* Return true if expression X evaluates to an infinity.
14348 This function returns false for integer expressions. */
14350 bool
14352 {
14356 {
14369 }
14370 }
14372 /* Return true if expression X could evaluate to an infinity.
14373 This function returns false for integer expressions, and returns
14374 true if uncertain. */
14376 bool
14378 {
14382 {
14395 }
14396 }
14398 /* Return true if expression X evaluates to a signaling NaN.
14399 This function returns false for integer expressions. */
14401 bool
14403 {
14407 {
14418 }
14419 }
14421 /* Return true if expression X could evaluate to a signaling NaN.
14422 This function returns false for integer expressions, and returns
14423 true if uncertain. */
14425 bool
14427 {
14431 {
14451 {
14452 CASE_CFN_FABS:
14454 CASE_CFN_FMAX:
14455 CASE_CFN_FMIN:
14460 }
14463 }
14464 }
14466 /* Return true if expression X evaluates to a NaN.
14467 This function returns false for integer expressions. */
14469 bool
14471 {
14475 {
14486 }
14487 }
14489 /* Return true if expression X could evaluate to a NaN.
14490 This function returns false for integer expressions, and returns
14491 true if uncertain. */
14493 bool
14495 {
14499 {
14524 {
14525 CASE_CFN_FABS:
14527 CASE_CFN_FMAX:
14528 CASE_CFN_FMIN:
14533 }
14536 }
14537 }
14539 /* Return true if expression X could evaluate to -0.0.
14540 This function returns true if uncertain. */
14542 bool
14544 {
14548 {
14563 {
14564 CASE_CFN_FABS:
14568 }
14571 }
14572 /* Ideally !(tree_expr_nonzero_p (X) || tree_expr_nonnegative_p (X))
14573 * but currently those predicates require tree and not const_tree. */
14575 }
14577 #define tree_expr_nonnegative_warnv_p(X, Y) \
14580 #define RECURSE(X) \
14581 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
14583 /* Return true if CODE or TYPE is known to be non-negative. */
14585 static bool
14587 {
14590 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14591 have a signed:1 type (where the value is -1 and 0). */
14594 }
14596 /* Return true if (CODE OP0) is known to be non-negative. If the return
14597 value is based on the assumption that signed overflow is undefined,
14598 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14599 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14601 bool
14604 {
14609 {
14611 /* We can't return 1 if flag_wrapv is set because
14612 ABS_EXPR<INT_MIN> = INT_MIN. */
14616 {
14619 }
14627 CASE_CONVERT:
14628 {
14633 {
14637 {
14641 }
14642 }
14644 {
14650 }
14651 }
14656 }
14658 /* We don't know sign of `t', so be conservative and return false. */
14660 }
14662 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
14663 value is based on the assumption that signed overflow is undefined,
14664 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14665 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14667 bool
14671 {
14676 {
14682 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14683 both unsigned and at least 2 bits shorter than the result. */
14687 {
14692 {
14696 }
14697 }
14702 {
14703 /* x * x is always non-negative for floating point x
14704 or without overflow. */
14707 {
14712 }
14713 }
14715 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14716 both unsigned and their total bits is shorter than the result. */
14720 {
14739 {
14749 }
14750 }
14757 /* Usually RECURSE (op0) || RECURSE (op1) but NaNs complicate
14758 things. */
14783 }
14785 /* We don't know sign of `t', so be conservative and return false. */
14787 }
14789 /* Return true if T is known to be non-negative. If the return
14790 value is based on the assumption that signed overflow is undefined,
14791 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14792 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14794 bool
14796 {
14801 {
14815 /* Limit the depth of recursion to avoid quadratic behavior.
14816 This is expected to catch almost all occurrences in practice.
14817 If this code misses important cases that unbounded recursion
14818 would not, passes that need this information could be revised
14819 to provide it through dataflow propagation. */
14827 }
14828 }
14830 /* Return true if T is known to be non-negative. If the return
14831 value is based on the assumption that signed overflow is undefined,
14832 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14833 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14835 bool
14838 {
14840 {
14841 CASE_CFN_ACOS:
14842 CASE_CFN_ACOSH:
14843 CASE_CFN_CABS:
14844 CASE_CFN_COSH:
14845 CASE_CFN_ERFC:
14846 CASE_CFN_EXP:
14847 CASE_CFN_EXP10:
14848 CASE_CFN_EXP2:
14849 CASE_CFN_FABS:
14850 CASE_CFN_FDIM:
14851 CASE_CFN_HYPOT:
14852 CASE_CFN_POW10:
14853 CASE_CFN_FFS:
14854 CASE_CFN_PARITY:
14855 CASE_CFN_POPCOUNT:
14856 CASE_CFN_CLZ:
14857 CASE_CFN_CLRSB:
14862 /* Always true. */
14865 CASE_CFN_SQRT:
14866 CASE_CFN_SQRT_FN:
14867 /* sqrt(-0.0) is -0.0. */
14872 CASE_CFN_ASINH:
14873 CASE_CFN_ATAN:
14874 CASE_CFN_ATANH:
14875 CASE_CFN_CBRT:
14876 CASE_CFN_CEIL:
14877 CASE_CFN_CEIL_FN:
14878 CASE_CFN_ERF:
14879 CASE_CFN_EXPM1:
14880 CASE_CFN_FLOOR:
14881 CASE_CFN_FLOOR_FN:
14882 CASE_CFN_FMOD:
14883 CASE_CFN_FREXP:
14884 CASE_CFN_ICEIL:
14885 CASE_CFN_IFLOOR:
14886 CASE_CFN_IRINT:
14887 CASE_CFN_IROUND:
14888 CASE_CFN_LCEIL:
14889 CASE_CFN_LDEXP:
14890 CASE_CFN_LFLOOR:
14891 CASE_CFN_LLCEIL:
14892 CASE_CFN_LLFLOOR:
14893 CASE_CFN_LLRINT:
14894 CASE_CFN_LLROUND:
14895 CASE_CFN_LRINT:
14896 CASE_CFN_LROUND:
14897 CASE_CFN_MODF:
14898 CASE_CFN_NEARBYINT:
14899 CASE_CFN_NEARBYINT_FN:
14900 CASE_CFN_RINT:
14901 CASE_CFN_RINT_FN:
14902 CASE_CFN_ROUND:
14903 CASE_CFN_ROUND_FN:
14904 CASE_CFN_ROUNDEVEN:
14905 CASE_CFN_ROUNDEVEN_FN:
14906 CASE_CFN_SCALB:
14907 CASE_CFN_SCALBLN:
14908 CASE_CFN_SCALBN:
14909 CASE_CFN_SIGNBIT:
14910 CASE_CFN_SIGNIFICAND:
14911 CASE_CFN_SINH:
14912 CASE_CFN_TANH:
14913 CASE_CFN_TRUNC:
14914 CASE_CFN_TRUNC_FN:
14915 /* True if the 1st argument is nonnegative. */
14918 CASE_CFN_FMAX:
14919 CASE_CFN_FMAX_FN:
14920 /* Usually RECURSE (arg0) || RECURSE (arg1) but NaNs complicate
14921 things. In the presence of sNaNs, we're only guaranteed to be
14922 non-negative if both operands are non-negative. In the presence
14923 of qNaNs, we're non-negative if either operand is non-negative
14924 and can't be a qNaN, or if both operands are non-negative. */
14933 CASE_CFN_FMIN:
14934 CASE_CFN_FMIN_FN:
14935 /* True if the 1st AND 2nd arguments are nonnegative. */
14938 CASE_CFN_COPYSIGN:
14939 CASE_CFN_COPYSIGN_FN:
14940 /* True if the 2nd argument is nonnegative. */
14943 CASE_CFN_POWI:
14944 /* True if the 1st argument is nonnegative or the second
14945 argument is an even integer. */
14951 CASE_CFN_POW:
14952 /* True if the 1st argument is nonnegative or the second
14953 argument is an even integer valued real. */
14955 {
14956 REAL_VALUE_TYPE c;
14957 HOST_WIDE_INT n;
14962 {
14963 REAL_VALUE_TYPE cint;
14967 }
14968 }
14973 }
14975 }
14977 /* Return true if T is known to be non-negative. If the return
14978 value is based on the assumption that signed overflow is undefined,
14979 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14980 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14982 static bool
14984 {
14990 {
14992 {
14996 /* If the initializer is non-void, then it's a normal expression
14997 that will be assigned to the slot. */
15001 /* Otherwise, the initializer sets the slot in some way. One common
15002 way is an assignment statement at the end of the initializer. */
15004 {
15012 else
15014 }
15020 }
15023 {
15029 arg0,
15030 arg1,
15032 }
15045 }
15046 }
15048 #undef RECURSE
15049 #undef tree_expr_nonnegative_warnv_p
15051 /* Return true if T is known to be non-negative. If the return
15052 value is based on the assumption that signed overflow is undefined,
15053 set *STRICT_OVERFLOW_P to true; otherwise, don't change
15054 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
15056 bool
15058 {
15065 {
15087 }
15090 {
15116 }
15117 }
15119 /* Return true if `t' is known to be non-negative. Handle warnings
15120 about undefined signed overflow. */
15122 bool
15124 {
15131 "determining that expression is always "
15133 WARN_STRICT_OVERFLOW_MISC);
15135 }
15138 /* Return true when (CODE OP0) is an address and is known to be nonzero.
15139 For floating point we further ensure that T is not denormal.
15140 Similar logic is present in nonzero_address in rtlanal.h.
15142 If the return value is based on the assumption that signed overflow
15143 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15144 change *STRICT_OVERFLOW_P. */
15146 bool
15149 {
15151 {
15154 strict_overflow_p);
15157 {
15163 strict_overflow_p));
15164 }
15169 strict_overflow_p);
15173 }
15176 }
15178 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
15179 For floating point we further ensure that T is not denormal.
15180 Similar logic is present in nonzero_address in rtlanal.h.
15182 If the return value is based on the assumption that signed overflow
15183 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15184 change *STRICT_OVERFLOW_P. */
15186 bool
15188 tree type,
15189 tree op0,
15191 {
15194 {
15198 {
15199 /* With the presence of negative values it is hard
15200 to say something. */
15207 /* One of operands must be positive and the other non-negative. */
15208 /* We don't set *STRICT_OVERFLOW_P here: even if this value
15209 overflows, on a twos-complement machine the sum of two
15210 nonnegative numbers can never be zero. */
15212 strict_overflow_p)
15214 strict_overflow_p));
15215 }
15220 {
15222 strict_overflow_p)
15224 strict_overflow_p))
15225 {
15228 }
15229 }
15238 {
15241 }
15248 {
15252 /* When both operands are nonzero, then MAX must be too. */
15254 strict_overflow_p))
15257 /* MAX where operand 0 is positive is positive. */
15259 strict_overflow_p);
15260 }
15261 /* MAX where operand 1 is positive is positive. */
15266 {
15270 }
15275 strict_overflow_p)
15277 strict_overflow_p));
15281 }
15284 }
15286 /* Return true when T is an address and is known to be nonzero.
15287 For floating point we further ensure that T is not denormal.
15288 Similar logic is present in nonzero_address in rtlanal.h.
15290 If the return value is based on the assumption that signed overflow
15291 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15292 change *STRICT_OVERFLOW_P. */
15294 bool
15296 {
15299 {
15304 {
15316 /* For objects in symbol table check if we know they are non-zero.
15317 Don't do anything for variables and functions before symtab is built;
15318 it is quite possible that they will be declared weak later. */
15323 /* Constants are never weak. */
15328 }
15336 {
15340 }
15350 }
15352 }
15354 #define integer_valued_real_p(X) \
15357 #define RECURSE(X) \
15358 ((integer_valued_real_p) (X, depth + 1))
15360 /* Return true if the floating point result of (CODE OP0) has an
15361 integer value. We also allow +Inf, -Inf and NaN to be considered
15362 integer values. Return false for signaling NaN.
15364 DEPTH is the current nesting depth of the query. */
15366 bool
15368 {
15370 {
15377 CASE_CONVERT:
15378 {
15385 }
15389 }
15391 }
15393 /* Return true if the floating point result of (CODE OP0 OP1) has an
15394 integer value. We also allow +Inf, -Inf and NaN to be considered
15395 integer values. Return false for signaling NaN.
15397 DEPTH is the current nesting depth of the query. */
15399 bool
15401 {
15403 {
15413 }
15415 }
15417 /* Return true if the floating point result of calling FNDECL with arguments
15418 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
15419 considered integer values. Return false for signaling NaN. If FNDECL
15420 takes fewer than 2 arguments, the remaining ARGn are null.
15422 DEPTH is the current nesting depth of the query. */
15424 bool
15426 {
15428 {
15429 CASE_CFN_CEIL:
15430 CASE_CFN_CEIL_FN:
15431 CASE_CFN_FLOOR:
15432 CASE_CFN_FLOOR_FN:
15433 CASE_CFN_NEARBYINT:
15434 CASE_CFN_NEARBYINT_FN:
15435 CASE_CFN_RINT:
15436 CASE_CFN_RINT_FN:
15437 CASE_CFN_ROUND:
15438 CASE_CFN_ROUND_FN:
15439 CASE_CFN_ROUNDEVEN:
15440 CASE_CFN_ROUNDEVEN_FN:
15441 CASE_CFN_TRUNC:
15442 CASE_CFN_TRUNC_FN:
15445 CASE_CFN_FMIN:
15446 CASE_CFN_FMIN_FN:
15447 CASE_CFN_FMAX:
15448 CASE_CFN_FMAX_FN:
15453 }
15455 }
15457 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
15458 has an integer value. We also allow +Inf, -Inf and NaN to be
15459 considered integer values. Return false for signaling NaN.
15461 DEPTH is the current nesting depth of the query. */
15463 bool
15465 {
15467 {
15475 /* Limit the depth of recursion to avoid quadratic behavior.
15476 This is expected to catch almost all occurrences in practice.
15477 If this code misses important cases that unbounded recursion
15478 would not, passes that need this information could be revised
15479 to provide it through dataflow propagation. */
15483 depth));
15487 }
15489 }
15491 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
15492 has an integer value. We also allow +Inf, -Inf and NaN to be
15493 considered integer values. Return false for signaling NaN.
15495 DEPTH is the current nesting depth of the query. */
15497 static bool
15499 {
15501 {
15512 }
15514 }
15516 #undef RECURSE
15517 #undef integer_valued_real_p
15519 /* Return true if the floating point expression T has an integer value.
15520 We also allow +Inf, -Inf and NaN to be considered integer values.
15521 Return false for signaling NaN.
15523 DEPTH is the current nesting depth of the query. */
15525 bool
15527 {
15535 {
15551 }
15554 {
15560 {
15569 }
15573 }
15574 }
15576 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
15577 attempt to fold the expression to a constant without modifying TYPE,
15578 OP0 or OP1.
15580 If the expression could be simplified to a constant, then return
15581 the constant. If the expression would not be simplified to a
15582 constant, then return NULL_TREE. */
15584 tree
15586 {
15589 }
15591 /* Given the components of a unary expression CODE, TYPE and OP0,
15592 attempt to fold the expression to a constant without modifying
15593 TYPE or OP0.
15595 If the expression could be simplified to a constant, then return
15596 the constant. If the expression would not be simplified to a
15597 constant, then return NULL_TREE. */
15599 tree
15601 {
15604 }
15606 /* If EXP represents referencing an element in a constant string
15607 (either via pointer arithmetic or array indexing), return the
15608 tree representing the value accessed, otherwise return NULL. */
15610 tree
15612 {
15616 {
15618 tree index;
15619 tree string;
15624 else
15625 {
15629 /* Optimize the special-case of a zero lower bound.
15631 We convert the low_bound to sizetype to avoid some problems
15632 with constant folding. (E.g. suppose the lower bound is 1,
15633 and its mode is QI. Without the conversion,l (ARRAY
15634 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
15635 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
15641 }
15643 scalar_int_mode char_mode;
15655 }
15657 }
15659 /* Folds a read from vector element at IDX of vector ARG. */
15661 tree
15663 {
15668 {
15672 {
15679 }
15680 }
15682 }
15684 /* Return the tree for neg (ARG0) when ARG0 is known to be either
15685 an integer constant, real, or fixed-point constant.
15687 TYPE is the type of the result. */
15689 static tree
15691 {
15695 {
15701 {
15702 FIXED_VALUE_TYPE f;
15707 /* Propagate overflow flags. */
15711 }
15715 {
15722 }
15725 }
15728 }
15730 /* Return the tree for abs (ARG0) when ARG0 is known to be either
15731 an integer constant or real constant.
15733 TYPE is the type of the result. */
15735 tree
15737 {
15741 {
15743 {
15744 /* If the value is unsigned or non-negative, then the absolute value
15745 is the same as the ordinary value. */
15749 ;
15751 /* If the value is negative, then the absolute value is
15752 its negation. */
15753 else
15756 /* Force to the destination type, set TREE_OVERFLOW for signed
15757 TYPE only. */
15759 }
15765 else
15771 }
15774 }
15776 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
15777 constant. TYPE is the type of the result. */
15779 static tree
15781 {
15785 }
15787 /* Given CODE, a relational operator, the target type, TYPE and two
15788 constant operands OP0 and OP1, return the result of the
15789 relational operation. If the result is not a compile time
15790 constant, then return NULL_TREE. */
15792 static tree
15794 {
15797 /* From here on, the only cases we handle are when the result is
15798 known to be a constant. */
15801 {
15805 /* Handle the cases where either operand is a NaN. */
15807 {
15809 {
15837 }
15840 }
15843 }
15846 {
15850 }
15852 /* Handle equality/inequality of complex constants. */
15854 {
15865 else
15867 }
15870 {
15872 {
15873 /* Have vector comparison with scalar boolean result. */
15881 {
15889 }
15891 }
15892 tree_vector_builder elts;
15897 {
15910 }
15913 }
15915 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15917 To compute GT, swap the arguments and do LT.
15918 To compute GE, do LT and invert the result.
15919 To compute LE, swap the arguments, do LT and invert the result.
15920 To compute NE, do EQ and invert the result.
15922 Therefore, the code below must handle only EQ and LT. */
15925 {
15928 }
15930 /* Note that it is safe to invert for real values here because we
15931 have already handled the one case that it matters. */
15935 {
15938 }
15940 /* Compute a result for LT or EQ if args permit;
15941 Otherwise return T. */
15943 {
15946 else
15948 }
15949 else
15955 }
15957 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15958 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15959 itself. */
15961 tree
15963 {
15964 /* If the expression does not have side effects then we don't have to wrap
15965 it with a cleanup point expression. */
15969 /* If the expression is a return, check to see if the expression inside the
15970 return has no side effects or the right hand side of the modify expression
15971 inside the return. If either don't have side effects set we don't need to
15972 wrap the expression in a cleanup point expression. Note we don't check the
15973 left hand side of the modify because it should always be a return decl. */
15975 {
15982 }
15985 }
15987 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15988 of an indirection through OP0, or NULL_TREE if no simplification is
15989 possible. */
15991 tree
15993 {
15995 tree subtype;
15996 poly_uint64 const_op01;
16005 {
16009 /* *&CONST_DECL -> to the value of the const decl. */
16012 /* *&p => p; make sure to handle *&"str"[cst] here. */
16014 {
16018 else
16020 }
16021 /* *(foo *)&fooarray => fooarray[0] */
16024 && (!in_gimple_form
16026 {
16036 }
16037 /* *(foo *)&complexfoo => __real__ complexfoo */
16041 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
16044 {
16048 index);
16049 }
16050 }
16054 {
16060 {
16061 tree op00type;
16065 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
16068 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
16069 but we want to treat offsets with MSB set as negative.
16070 For the code below negative offsets are invalid and
16071 TYPE_SIZE of the element is something unsigned, so
16072 check whether op01 fits into poly_int64, which implies
16073 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
16074 then just use poly_uint64 because we want to treat the
16075 value as unsigned. */
16077 {
16079 poly_uint64 max_offset
16083 {
16088 }
16089 }
16090 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
16093 {
16095 const_op01))
16097 }
16098 /* ((foo *)&fooarray)[1] => fooarray[1] */
16101 {
16110 {
16115 }
16116 }
16117 }
16118 }
16120 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
16123 && (!in_gimple_form
16125 {
16126 tree type_domain;
16136 NULL_TREE);
16137 }
16140 }
16142 /* Builds an expression for an indirection through T, simplifying some
16143 cases. */
16145 tree
16147 {
16155 }
16157 /* Given an INDIRECT_REF T, return either T or a simplified version. */
16159 tree
16161 {
16166 else
16168 }
16170 /* Strip non-trapping, non-side-effecting tree nodes from an expression
16171 whose result is ignored. The type of the returned tree need not be
16172 the same as the original expression. */
16174 tree
16176 {
16182 {
16193 else
16199 {
16215 }
16220 }
16221 }
16223 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
16225 tree
16227 {
16233 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16234 have to do anything. Only do this when we are not given a const,
16235 because in that case, this check is more expensive than just
16236 doing it. */
16238 {
16243 }
16245 /* If divisor is a power of two, simplify this to bit manipulation. */
16247 {
16249 {
16263 }
16264 else
16265 {
16266 tree t;
16272 }
16273 }
16274 else
16275 {
16280 }
16283 }
16285 /* Likewise, but round down. */
16287 tree
16289 {
16296 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16297 have to do anything. Only do this when we are not given a const,
16298 because in that case, this check is more expensive than just
16299 doing it. */
16301 {
16306 }
16308 /* If divisor is a power of two, simplify this to bit manipulation. */
16310 {
16311 tree t;
16315 }
16316 else
16317 {
16322 }
16325 }
16327 /* Returns the pointer to the base of the object addressed by EXP and
16328 extracts the information about the offset of the access, storing it
16329 to PBITPOS and POFFSET. */
16331 static tree
16334 {
16335 tree core;
16336 machine_mode mode;
16338 poly_int64 bitsize;
16342 {
16347 }
16349 {
16355 {
16356 poly_offset_int tem
16362 }
16363 }
16364 else
16365 {
16369 }
16372 }
16374 /* Returns true if addresses of E1 and E2 differ by a constant, false
16375 otherwise. If they do, E1 - E2 is stored in *DIFF. */
16377 bool
16379 {
16394 {
16404 }
16406 {
16407 /* If only one of the offsets is non-constant, the difference cannot
16408 be a constant. */
16410 }
16411 else
16416 }
16418 /* Return OFF converted to a pointer offset type suitable as offset for
16419 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
16420 tree
16422 {
16426 }
16428 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16429 tree
16431 {
16434 }
16436 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16437 tree
16439 {
16442 }
16444 /* Return a pointer to a NUL-terminated string containing the sequence
16445 of bytes corresponding to the representation of the object referred to
16446 by SRC (or a subsequence of such bytes within it if SRC is a reference
16447 to an initialized constant array plus some constant offset).
16448 Set *STRSIZE the number of bytes in the constant sequence including
16449 the terminating NUL byte. *STRSIZE is equal to sizeof(A) - OFFSET
16450 where A is the array that stores the constant sequence that SRC points
16451 to and OFFSET is the byte offset of SRC from the beginning of A. SRC
16452 need not point to a string or even an array of characters but may point
16453 to an object of any type. */
16457 {
16458 /* The offset into the array A storing the string, and A's byte size. */
16459 tree offset_node;
16460 tree mem_size;
16467 else
16474 {
16477 else
16479 }
16484 /* ARRAY_SIZE is the byte size of the array the constant sequence
16485 is stored in and equal to sizeof A. INIT_BYTES is the number
16486 of bytes in the constant sequence used to initialize the array,
16487 including any embedded NULs as well as the terminating NUL (for
16488 strings), but not including any trailing zeros/NULs past
16489 the terminating one appended implicitly to a string literal to
16490 zero out the remainder of the array it's stored in. For example,
16491 given:
16492 const char a[7] = "abc\0d";
16493 n = strlen (a + 1);
16494 ARRAY_SIZE is 7, INIT_BYTES is 6, and OFFSET is 1. For a valid
16495 (i.e., nul-terminated) string with no embedded nuls, INIT_BYTES
16496 is equal to strlen (A) + 1. */
16501 /* Ideally this would turn into a gcc_checking_assert over time. */
16509 {
16510 /* Compute and store the number of characters from the beginning
16511 of the substring at OFFSET to the end, including the terminating
16512 nul. Offsets past the initial length refer to null strings. */
16515 else
16517 }
16518 else
16519 {
16521 /* Support only properly NUL-terminated single byte strings. */
16526 }
16529 }
16531 /* Return a pointer to a NUL-terminated string corresponding to
16532 the expression STR referencing a constant string, possibly
16533 involving a constant offset. Return null if STR either doesn't
16534 reference a constant string or if it involves a nonconstant
16535 offset. */
16539 {
16541 }
16543 /* Given a tree T, compute which bits in T may be nonzero. */
16545 wide_int
16547 {
16549 {
16567 CASE_CONVERT:
16573 {
16578 }
16582 {
16590 }
16594 {
16602 }
16606 }
16609 }
16611 /* Helper function for address compare simplifications in match.pd.
16612 OP0 and OP1 are ADDR_EXPR operands being compared by CODE.
16613 TYPE is the type of comparison operands.
16614 BASE0, BASE1, OFF0 and OFF1 are set by the function.
16615 GENERIC is true if GENERIC folding and false for GIMPLE folding.
16616 Returns 0 if OP0 is known to be unequal to OP1 regardless of OFF{0,1},
16617 1 if bases are known to be equal and OP0 cmp OP1 depends on OFF0 cmp OFF1,
16618 and 2 if unknown. */
16620 int
16624 {
16630 {
16633 }
16635 {
16638 }
16643 /* Punt in GENERIC on variables with value expressions;
16644 the value expressions might point to fields/elements
16645 of other vars etc. */
16651 {
16655 }
16663 /* Assume different STRING_CSTs with the same content will be
16664 merged. */
16673 {
16676 /* If the offsets are equal we can ignore overflow. */
16679 /* Or if we compare using pointers to decls or strings. */
16684 }
16690 /* At this point we know (or assume) the two pointers point at
16691 different objects. */
16695 /* Punt on non-zero offsets from functions. */
16699 /* Or if the bases are neither decls nor string literals. */
16704 /* For initializers, assume addresses of different functions are
16705 different. */
16711 /* Compute whether one address points to the start of one
16712 object and another one to the end of another one. */
16715 {
16718 else
16720 }
16723 else
16724 {
16728 else
16730 }
16732 {
16735 else
16737 }
16740 else
16741 {
16745 else
16747 }
16749 {
16750 /* If one offset is pointing (or could be) to the beginning of one
16751 object and the other is pointing to one past the last byte of the
16752 other object, punt. */
16757 /* If both offsets are the same, there are some cases we know that are
16758 ok. Either if we know they aren't zero, or if we know both sizes
16759 are no zero. */
16765 }
16767 /* At this point, equal is 2 if either one or both pointers are out of
16768 bounds of their object, or one points to start of its object and the
16769 other points to end of its object. This is unspecified behavior
16770 e.g. in C++. Otherwise equal is 0. */
16774 /* When both pointers point to string literals, even when equal is 0,
16775 due to tail merging of string literals the pointers might be the same. */
16777 {
16784 /* If the bytes in the string literals starting at the pointers
16785 differ, the pointers need to be different. */
16790 {
16795 /* If even the bytes in the string literal before the
16796 pointers are the same, the string literals could be
16797 tail merged. */
16799 }
16801 }
16806 /* If this is a pointer comparison, ignore for now even
16807 valid equalities where one pointer is the offset zero
16808 of one object and the other to one past end of another one. */
16812 /* Assume that string literals can't be adjacent to variables
16813 (automatic or global). */
16817 /* Assume that automatic variables can't be adjacent to global
16818 variables. */
16823 }
16825 /* Return the single non-zero element of a CONSTRUCTOR or NULL_TREE. */
16826 tree
16828 {
16837 {
16841 }
16843 }
16845 #if CHECKING_P
16849 /* Helper functions for writing tests of folding trees. */
16851 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
16853 static void
16855 tree constant)
16856 {
16858 }
16860 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
16861 wrapping WRAPPED_EXPR. */
16863 static void
16865 tree wrapped_expr)
16866 {
16871 }
16873 /* Verify that various arithmetic binary operations are folded
16874 correctly. */
16876 static void
16878 {
16884 /* Addition. */
16885 /* 1 <-- (0 + 1) */
16887 one);
16889 one);
16891 /* (nonlvalue)x <-- (x + 0) */
16893 x);
16895 /* Subtraction. */
16896 /* 0 <-- (x - x) */
16898 zero);
16900 x);
16902 /* Multiplication. */
16903 /* 0 <-- (x * 0) */
16905 zero);
16907 /* (nonlvalue)x <-- (x * 1) */
16909 x);
16910 }
16912 /* Verify that various binary operations on vectors are folded
16913 correctly. */
16915 static void
16917 {
16924 /* Verify equality tests that return a scalar boolean result. */
16937 }
16939 /* Verify folding of VEC_DUPLICATE_EXPRs. */
16941 static void
16943 {
16946 /* This will be 1 if VEC_MODE isn't a vector mode. */
16953 }
16955 /* Run all of the selftests within this file. */
16957 void
16959 {
16963 }