| blob | ec28b431eb8f499988deff99d73dc8bef9f6378c |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2019 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /*@@ This file should be rewritten to use an arbitrary precision
21 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
22 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
23 @@ The routines that translate from the ap rep should
24 @@ warn if precision et. al. is lost.
25 @@ This would also make life easier when this technology is used
26 @@ for cross-compilers. */
28 /* The entry points in this file are fold, size_int_wide and size_binop.
30 fold takes a tree as argument and returns a simplified tree.
32 size_binop takes a tree code for an arithmetic operation
33 and two operands that are trees, and produces a tree for the
34 result, assuming the type comes from `sizetype'.
36 size_int takes an integer value, and creates a tree constant
37 with type from `sizetype'.
39 Note: Since the folders get called on non-gimple code as well as
40 gimple code, we need to handle GIMPLE tuples as well as their
41 corresponding tree equivalents. */
87 /* Nonzero if we are folding constants inside an initializer; zero
88 otherwise. */
91 /* The following constants represent a bit based encoding of GCC's
92 comparison operators. This encoding simplifies transformations
93 on relational comparison operators, such as AND and OR. */
111 };
144 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
145 Otherwise, return LOC. */
147 static location_t
149 {
152 }
154 /* Similar to protected_set_expr_location, but never modify x in place,
155 if location can and needs to be set, unshare it. */
159 {
165 {
168 }
170 }
171 \f
172 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
173 division and returns the quotient. Otherwise returns
174 NULL_TREE. */
176 tree
178 {
179 widest_int quo;
186 }
187 \f
188 /* This is nonzero if we should defer warnings about undefined
189 overflow. This facility exists because these warnings are a
190 special case. The code to estimate loop iterations does not want
191 to issue any warnings, since it works with expressions which do not
192 occur in user code. Various bits of cleanup code call fold(), but
193 only use the result if it has certain characteristics (e.g., is a
194 constant); that code only wants to issue a warning if the result is
195 used. */
199 /* If a warning about undefined overflow is deferred, this is the
200 warning. Note that this may cause us to turn two warnings into
201 one, but that is fine since it is sufficient to only give one
202 warning per expression. */
206 /* If a warning about undefined overflow is deferred, this is the
207 level at which the warning should be emitted. */
211 /* Start deferring overflow warnings. We could use a stack here to
212 permit nested calls, but at present it is not necessary. */
214 void
216 {
218 }
220 /* Stop deferring overflow warnings. If there is a pending warning,
221 and ISSUE is true, then issue the warning if appropriate. STMT is
222 the statement with which the warning should be associated (used for
223 location information); STMT may be NULL. CODE is the level of the
224 warning--a warn_strict_overflow_code value. This function will use
225 the smaller of CODE and the deferred code when deciding whether to
226 issue the warning. CODE may be zero to mean to always use the
227 deferred code. */
229 void
231 {
233 location_t locus;
238 {
244 }
255 /* Use the smallest code level when deciding to issue the
256 warning. */
265 else
268 }
270 /* Stop deferring overflow warnings, ignoring any deferred
271 warnings. */
273 void
275 {
277 }
279 /* Whether we are deferring overflow warnings. */
281 bool
283 {
285 }
287 /* This is called when we fold something based on the fact that signed
288 overflow is undefined. */
290 void
292 {
294 {
297 {
300 }
301 }
304 }
305 \f
306 /* Return true if the built-in mathematical function specified by CODE
307 is odd, i.e. -f(x) == f(-x). */
309 bool
311 {
313 {
314 CASE_CFN_ASIN:
315 CASE_CFN_ASINH:
316 CASE_CFN_ATAN:
317 CASE_CFN_ATANH:
318 CASE_CFN_CASIN:
319 CASE_CFN_CASINH:
320 CASE_CFN_CATAN:
321 CASE_CFN_CATANH:
322 CASE_CFN_CBRT:
323 CASE_CFN_CPROJ:
324 CASE_CFN_CSIN:
325 CASE_CFN_CSINH:
326 CASE_CFN_CTAN:
327 CASE_CFN_CTANH:
328 CASE_CFN_ERF:
329 CASE_CFN_LLROUND:
330 CASE_CFN_LROUND:
331 CASE_CFN_ROUND:
332 CASE_CFN_SIN:
333 CASE_CFN_SINH:
334 CASE_CFN_TAN:
335 CASE_CFN_TANH:
336 CASE_CFN_TRUNC:
339 CASE_CFN_LLRINT:
340 CASE_CFN_LRINT:
341 CASE_CFN_NEARBYINT:
342 CASE_CFN_RINT:
347 }
349 }
351 /* Check whether we may negate an integer constant T without causing
352 overflow. */
354 bool
356 {
357 tree type;
366 }
368 /* Determine whether an expression T can be cheaply negated using
369 the function negate_expr without introducing undefined overflow. */
371 static bool
373 {
374 tree type;
383 {
388 /* Check that -CST will not overflow type. */
401 /* We want to canonicalize to positive real constants. Pretend
402 that only negative ones can be easily negated. */
410 {
414 /* Steps don't prevent negation. */
421 }
436 /* -(A + B) -> (-B) - A. */
439 /* -(A + B) -> (-A) - B. */
443 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
452 /* INT_MIN/n * n doesn't overflow while negating one operand it does
453 if n is a (negative) power of two. */
464 /* Fall through. */
477 /* In general we can't negate A in A / B, because if A is INT_MIN and
478 B is not 1 we change the sign of the result. */
482 /* In general we can't negate B in A / B, because if A is INT_MIN and
483 B is 1, we may turn this into INT_MIN / -1 which is undefined
484 and actually traps on some architectures. */
493 /* Negate -((double)float) as (double)(-float). */
495 {
499 }
503 /* Negate -f(x) as f(-x). */
509 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
511 {
515 }
520 }
522 }
524 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
525 simplification is possible.
526 If negate_expr_p would return true for T, NULL_TREE will never be
527 returned. */
529 static tree
531 {
533 tree tem;
536 {
537 /* Convert - (~A) to A + 1. */
561 {
566 }
570 {
571 tree_vector_builder elts;
575 {
580 }
583 }
606 {
607 /* -(A + B) -> (-B) - A. */
609 {
613 }
615 /* -(A + B) -> (-A) - B. */
617 {
621 }
622 }
626 /* - (A - B) -> B - A */
637 /* Fall through. */
641 {
650 }
658 /* In general we can't negate A in A / B, because if A is INT_MIN and
659 B is not 1 we change the sign of the result. */
665 /* In general we can't negate B in A / B, because if A is INT_MIN and
666 B is 1, we may turn this into INT_MIN / -1 which is undefined
667 and actually traps on some architectures. */
679 /* Convert -((double)float) into (double)(-float). */
681 {
685 }
689 /* Negate -f(x) as f(-x). */
692 {
698 }
702 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
704 {
707 {
714 }
715 }
720 }
723 }
725 /* A wrapper for fold_negate_expr_1. */
727 static tree
729 {
736 }
738 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T cannot be
739 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
740 return NULL_TREE. */
742 static tree
744 {
746 location_t loc;
759 }
760 \f
761 /* Split a tree IN into a constant, literal and variable parts that could be
762 combined with CODE to make IN. "constant" means an expression with
763 TREE_CONSTANT but that isn't an actual constant. CODE must be a
764 commutative arithmetic operation. Store the constant part into *CONP,
765 the literal in *LITP and return the variable part. If a part isn't
766 present, set it to null. If the tree does not decompose in this way,
767 return the entire tree as the variable part and the other parts as null.
769 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
770 case, we negate an operand that was subtracted. Except if it is a
771 literal for which we use *MINUS_LITP instead.
773 If NEGATE_P is true, we are negating all of IN, again except a literal
774 for which we use *MINUS_LITP instead. If a variable part is of pointer
775 type, it is negated after converting to TYPE. This prevents us from
776 generating illegal MINUS pointer expression. LOC is the location of
777 the converted variable part.
779 If IN is itself a literal or constant, return it as appropriate.
781 Note that we do not guarantee that any of the three values will be the
782 same type as IN, but they will have the same signedness and mode. */
784 static tree
788 {
796 /* Strip any conversions that don't change the machine mode or signedness. */
805 /* We can associate addition and subtraction together (even
806 though the C standard doesn't say so) for integers because
807 the value is not affected. For reals, the value might be
808 affected, so we can't. */
814 {
820 /* First see if either of the operands is a literal, then a constant. */
833 /* If we haven't dealt with either operand, this is not a case we can
834 decompose. Otherwise, VAR is either of the ones remaining, if any. */
839 else
842 /* Now do any needed negations. */
849 }
854 {
855 /* -1 - X is folded to ~X, undo that here. Do _not_ do this
856 when IN is constant. */
859 }
860 else
864 {
877 }
887 }
889 /* Re-associate trees split by the above function. T1 and T2 are
890 either expressions to associate or null. Return the new
891 expression, if any. LOC is the location of the new expression. If
892 we build an operation, do it in TYPE and with CODE. */
894 static tree
896 {
898 {
901 }
905 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
906 try to fold this since we will have infinite recursion. But do
907 deal with any NEGATE_EXPRs. */
911 {
913 {
926 }
928 {
931 }
935 }
939 }
940 \f
941 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
942 for use in int_const_binop, size_binop and size_diffop. */
944 static bool
946 {
953 {
962 }
967 }
969 /* Combine two wide ints ARG1 and ARG2 under operation CODE to produce
970 a new constant in RES. Return FALSE if we don't know how to
971 evaluate CODE at compile-time. */
973 bool
977 {
978 wide_int tmp;
981 {
997 {
1001 else
1003 }
1004 else
1008 /* It's unclear from the C standard whether shifts can overflow.
1009 The following code ignores overflow; perhaps a C standard
1010 interpretation ruling is needed. */
1012 else
1019 {
1023 else
1025 }
1026 else
1031 else
1110 }
1112 }
1114 /* Combine two poly int's ARG1 and ARG2 under operation CODE to
1115 produce a new constant in RES. Return FALSE if we don't know how
1116 to evaluate CODE at compile-time. */
1118 static bool
1122 {
1126 {
1144 else
1151 else
1164 }
1166 }
1168 /* Combine two integer constants ARG1 and ARG2 under operation CODE to
1169 produce a new constant. Return NULL_TREE if we don't know how to
1170 evaluate CODE at compile-time. */
1172 tree
1175 {
1177 poly_wide_int poly_res;
1183 {
1188 }
1197 }
1199 /* Return true if binary operation OP distributes over addition in operand
1200 OPNO, with the other operand being held constant. OPNO counts from 1. */
1202 static bool
1204 {
1206 {
1217 }
1218 }
1220 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1221 constant. We assume ARG1 and ARG2 have the same data type, or at least
1222 are the same kind of constant and the same machine mode. Return zero if
1223 combining the constants is not allowed in the current operating mode. */
1225 static tree
1227 {
1228 /* Sanity check for the recursive cases. */
1236 {
1242 }
1245 {
1246 machine_mode mode;
1247 REAL_VALUE_TYPE d1;
1248 REAL_VALUE_TYPE d2;
1249 REAL_VALUE_TYPE value;
1250 REAL_VALUE_TYPE result;
1254 /* The following codes are handled by real_arithmetic. */
1256 {
1267 }
1275 /* Don't perform operation if we honor signaling NaNs and
1276 either operand is a signaling NaN. */
1282 /* Don't perform operation if it would raise a division
1283 by zero exception. */
1289 /* If either operand is a NaN, just return it. Otherwise, set up
1290 for floating-point trap; we return an overflow. */
1292 {
1293 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1294 is off. */
1298 }
1300 {
1301 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1302 is off. */
1306 }
1311 /* Don't constant fold this floating point operation if
1312 the result has overflowed and flag_trapping_math. */
1320 /* Don't constant fold this floating point operation if the
1321 result may dependent upon the run-time rounding mode and
1322 flag_rounding_math is set, or if GCC's software emulation
1323 is unable to accurately represent the result. */
1333 }
1336 {
1337 FIXED_VALUE_TYPE f1;
1338 FIXED_VALUE_TYPE f2;
1339 FIXED_VALUE_TYPE result;
1344 /* The following codes are handled by fixed_arithmetic. */
1346 {
1358 {
1365 }
1370 }
1377 /* Propagate overflow flags. */
1381 }
1384 {
1393 {
1404 mpc_mul);
1418 mpc_div);
1419 /* Fallthru. */
1425 {
1426 /* Keep this algorithm in sync with
1427 tree-complex.c:expand_complex_div_straight().
1429 Expand complex division to scalars, straightforward algorithm.
1430 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1431 t = br*br + bi*bi
1432 */
1433 tree magsquared
1437 tree t1
1441 tree t2
1448 }
1449 else
1450 {
1451 /* Keep this algorithm in sync with
1452 tree-complex.c:expand_complex_div_wide().
1454 Expand complex division to scalars, modified algorithm to minimize
1455 overflow with wide input ranges. */
1461 {
1462 /* In the TRUE branch, we compute
1463 ratio = br/bi;
1464 div = (br * ratio) + bi;
1465 tr = (ar * ratio) + ai;
1466 ti = (ai * ratio) - ar;
1467 tr = tr / div;
1468 ti = ti / div; */
1479 }
1480 else
1481 {
1482 /* In the FALSE branch, we compute
1483 ratio = d/c;
1484 divisor = (d * ratio) + c;
1485 tr = (b * ratio) + a;
1486 ti = b - (a * ratio);
1487 tr = tr / div;
1488 ti = ti / div; */
1500 }
1501 }
1506 }
1510 }
1516 {
1521 /* We can operate directly on the encoding if:
1523 a3 - a2 == a2 - a1 && b3 - b2 == b2 - b1
1524 implies
1525 (a3 op b3) - (a2 op b2) == (a2 op b2) - (a1 op b1)
1527 Addition and subtraction are the supported operators
1528 for which this is true. */
1531 /* We can operate directly on stepped encodings if:
1533 a3 - a2 == a2 - a1
1534 implies:
1535 (a3 op c) - (a2 op c) == (a2 op c) - (a1 op c)
1537 which is true if (x -> x op c) distributes over addition. */
1539 else
1540 /* Similarly in reverse. */
1542 tree_vector_builder elts;
1547 {
1553 /* It is possible that const_binop cannot handle the given
1554 code and return NULL_TREE */
1558 }
1561 }
1563 /* Shifts allow a scalar offset for a vector. */
1566 {
1569 tree_vector_builder elts;
1574 {
1579 /* It is possible that const_binop cannot handle the given
1580 code and return NULL_TREE. */
1584 }
1587 }
1589 }
1591 /* Overload that adds a TYPE parameter to be able to dispatch
1592 to fold_relational_const. */
1594 tree
1596 {
1600 /* ??? Until we make the const_binop worker take the type of the
1601 result as argument put those cases that need it here. */
1603 {
1620 {
1625 }
1631 {
1647 {
1652 ? NOP_EXPR
1659 }
1662 }
1668 {
1691 {
1704 }
1707 }
1710 }
1715 /* Make sure type and arg0 have the same saturating flag. */
1720 }
1722 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1723 Return zero if computing the constants is not possible. */
1725 tree
1727 {
1728 /* Don't perform the operation, other than NEGATE and ABS, if
1729 flag_signaling_nans is on and the operand is a signaling NaN. */
1739 {
1740 CASE_CONVERT:
1747 /* If the source address is 0, and the source address space
1748 cannot have a valid object at 0, fold to dest type null. */
1759 {
1760 /* Can't call fold_negate_const directly here as that doesn't
1761 handle all cases and we might not be able to negate some
1762 constants. */
1767 }
1777 {
1781 }
1789 /* Perform BIT_NOT_EXPR on each element individually. */
1791 {
1792 tree elem;
1794 /* This can cope with stepped encodings because ~x == -1 - x. */
1795 tree_vector_builder elements;
1799 {
1805 }
1808 }
1832 {
1855 else
1860 {
1866 }
1869 }
1878 }
1881 }
1883 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1884 indicates which particular sizetype to create. */
1886 tree
1888 {
1890 }
1891 \f
1892 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1893 is a tree code. The type of the result is taken from the operands.
1894 Both must be equivalent integer types, ala int_binop_types_match_p.
1895 If the operands are constant, so is the result. */
1897 tree
1899 {
1908 /* Handle the special case of two poly_int constants faster. */
1910 {
1911 /* And some specific cases even faster than that. */
1913 {
1920 }
1922 {
1926 }
1928 {
1932 }
1934 /* Handle general case of two integer constants. For sizetype
1935 constant calculations we always want to know about overflow,
1936 even in the unsigned case. */
1940 }
1943 }
1945 /* Given two values, either both of sizetype or both of bitsizetype,
1946 compute the difference between the two values. Return the value
1947 in signed type corresponding to the type of the operands. */
1949 tree
1951 {
1953 tree ctype;
1958 /* If the type is already signed, just do the simple thing. */
1966 else
1969 /* If either operand is not a constant, do the conversions to the signed
1970 type and subtract. The hardware will do the right thing with any
1971 overflow in the subtraction. */
1977 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1978 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1979 overflow) and negate (which can't either). Special-case a result
1980 of zero while we're here. */
1986 else
1990 MINUS_EXPR,
1992 }
1993 \f
1994 /* A subroutine of fold_convert_const handling conversions of an
1995 INTEGER_CST to another integer type. */
1997 static tree
1999 {
2000 /* Given an integer constant, make new constant with new type,
2001 appropriately sign-extended or truncated. Use widest_int
2002 so that any extension is done according ARG1's type. */
2006 }
2008 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2009 to an integer type. */
2011 static tree
2013 {
2015 tree t;
2017 /* The following code implements the floating point to integer
2018 conversion rules required by the Java Language Specification,
2019 that IEEE NaNs are mapped to zero and values that overflow
2020 the target precision saturate, i.e. values greater than
2021 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2022 are mapped to INT_MIN. These semantics are allowed by the
2023 C and C++ standards that simply state that the behavior of
2024 FP-to-integer conversion is unspecified upon overflow. */
2026 wide_int val;
2027 REAL_VALUE_TYPE r;
2031 {
2038 }
2040 /* If R is NaN, return zero and show we have an overflow. */
2042 {
2045 }
2047 /* See if R is less than the lower bound or greater than the
2048 upper bound. */
2051 {
2055 {
2058 }
2059 }
2062 {
2065 {
2068 {
2071 }
2072 }
2073 }
2080 }
2082 /* A subroutine of fold_convert_const handling conversions of a
2083 FIXED_CST to an integer type. */
2085 static tree
2087 {
2088 tree t;
2090 scalar_mode mode;
2092 /* Right shift FIXED_CST to temp by fbit. */
2096 {
2098 HOST_BITS_PER_DOUBLE_INT,
2101 /* Left shift temp to temp_trunc by fbit. */
2103 HOST_BITS_PER_DOUBLE_INT,
2105 }
2106 else
2107 {
2110 }
2112 /* If FIXED_CST is negative, we need to round the value toward 0.
2113 By checking if the fractional bits are not zero to add 1 to temp. */
2119 /* Given a fixed-point constant, make new constant with new type,
2120 appropriately sign-extended or truncated. */
2128 }
2130 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2131 to another floating point type. */
2133 static tree
2135 {
2136 REAL_VALUE_TYPE value;
2137 tree t;
2139 /* Don't perform the operation if flag_signaling_nans is on
2140 and the operand is a signaling NaN. */
2148 /* If converting an infinity or NAN to a representation that doesn't
2149 have one, set the overflow bit so that we can produce some kind of
2150 error message at the appropriate point if necessary. It's not the
2151 most user-friendly message, but it's better than nothing. */
2158 /* Regular overflow, conversion produced an infinity in a mode that
2159 can't represent them. */
2164 else
2167 }
2169 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2170 to a floating point type. */
2172 static tree
2174 {
2175 REAL_VALUE_TYPE value;
2176 tree t;
2184 }
2186 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2187 to another fixed-point type. */
2189 static tree
2191 {
2192 FIXED_VALUE_TYPE value;
2193 tree t;
2200 /* Propagate overflow flags. */
2204 }
2206 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2207 to a fixed-point type. */
2209 static tree
2211 {
2212 FIXED_VALUE_TYPE value;
2213 tree t;
2215 double_int di;
2222 else
2230 /* Propagate overflow flags. */
2234 }
2236 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2237 to a fixed-point type. */
2239 static tree
2241 {
2242 FIXED_VALUE_TYPE value;
2243 tree t;
2251 /* Propagate overflow flags. */
2255 }
2257 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2258 type TYPE. If no simplification can be done return NULL_TREE. */
2260 static tree
2262 {
2267 /* We can't widen types, since the runtime value could overflow the
2268 original type before being extended to the new type. */
2279 {
2286 }
2288 {
2295 }
2297 {
2304 }
2306 {
2309 {
2312 /* We can't handle steps directly when extending, since the
2313 values need to wrap at the original precision first. */
2314 bool step_ok_p
2318 tree_vector_builder v;
2323 {
2329 }
2331 }
2332 }
2334 }
2336 /* Construct a vector of zero elements of vector type TYPE. */
2338 static tree
2340 {
2341 tree t;
2345 }
2347 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2349 bool
2351 {
2366 {
2383 }
2384 }
2386 /* Convert expression ARG to type TYPE. Used by the middle-end for
2387 simple conversions in preference to calling the front-end's convert. */
2389 tree
2391 {
2393 tree tem;
2404 {
2407 /* Handle conversions between pointers to different address spaces. */
2412 /* fall through */
2417 {
2421 }
2435 {
2439 }
2441 {
2445 }
2447 {
2451 }
2454 {
2472 }
2477 {
2481 }
2484 {
2498 }
2502 {
2511 integer_zero_node));
2513 {
2517 {
2523 }
2531 }
2535 }
2553 }
2554 fold_convert_exit:
2557 }
2558 \f
2559 /* Return false if expr can be assumed not to be an lvalue, true
2560 otherwise. */
2562 static bool
2564 {
2565 /* We only need to wrap lvalue tree codes. */
2567 {
2598 /* Assume the worst for front-end tree codes. */
2602 }
2605 }
2607 /* Return an expr equal to X but certainly not valid as an lvalue. */
2609 tree
2611 {
2612 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2613 us. */
2620 }
2622 /* When pedantic, return an expr equal to X but certainly not valid as a
2623 pedantic lvalue. Otherwise, return X. */
2625 static tree
2627 {
2629 }
2630 \f
2631 /* Given a tree comparison code, return the code that is the logical inverse.
2632 It is generally not safe to do this for floating-point comparisons, except
2633 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2634 ERROR_MARK in this case. */
2636 enum tree_code
2638 {
2644 {
2675 }
2676 }
2678 /* Similar, but return the comparison that results if the operands are
2679 swapped. This is safe for floating-point. */
2681 enum tree_code
2683 {
2685 {
2711 }
2712 }
2715 /* Convert a comparison tree code from an enum tree_code representation
2716 into a compcode bit-based encoding. This function is the inverse of
2717 compcode_to_comparison. */
2719 static enum comparison_code
2721 {
2723 {
2754 }
2755 }
2757 /* Convert a compcode bit-based encoding of a comparison operator back
2758 to GCC's enum tree_code representation. This function is the
2759 inverse of comparison_to_compcode. */
2761 static enum tree_code
2763 {
2765 {
2796 }
2797 }
2799 /* Return true if COND1 tests the opposite condition of COND2. */
2801 bool
2803 {
2806 && (invert_tree_comparison
2813 }
2815 /* Return a tree for the comparison which is the combination of
2816 doing the AND or OR (depending on CODE) of the two operations LCODE
2817 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2818 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2819 if this makes the transformation invalid. */
2821 tree
2826 {
2833 {
2844 }
2847 {
2848 /* Eliminate unordered comparisons, as well as LTGT and ORD
2849 which are not used unless the mode has NaNs. */
2855 }
2857 {
2858 /* Check that the original operation and the optimized ones will trap
2859 under the same condition. */
2870 /* In a short-circuited boolean expression the LHS might be
2871 such that the RHS, if evaluated, will never trap. For
2872 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2873 if neither x nor y is NaN. (This is a mixed blessing: for
2874 example, the expression above will never trap, hence
2875 optimizing it to x < y would be invalid). */
2880 /* If the comparison was short-circuited, and only the RHS
2881 trapped, we may now generate a spurious trap. */
2886 /* If we changed the conditions that cause a trap, we lose. */
2889 }
2895 else
2896 {
2901 }
2902 }
2903 \f
2904 /* Return nonzero if two operands (typically of the same tree node)
2905 are necessarily equal. FLAGS modifies behavior as follows:
2907 If OEP_ONLY_CONST is set, only return nonzero for constants.
2908 This function tests whether the operands are indistinguishable;
2909 it does not test whether they are equal using C's == operation.
2910 The distinction is important for IEEE floating point, because
2911 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2912 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2914 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2915 even though it may hold multiple values during a function.
2916 This is because a GCC tree node guarantees that nothing else is
2917 executed between the evaluation of its "operands" (which may often
2918 be evaluated in arbitrary order). Hence if the operands themselves
2919 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2920 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2921 unset means assuming isochronic (or instantaneous) tree equivalence.
2922 Unless comparing arbitrary expression trees, such as from different
2923 statements, this flag can usually be left unset.
2925 If OEP_PURE_SAME is set, then pure functions with identical arguments
2926 are considered the same. It is used when the caller has other ways
2927 to ensure that global memory is unchanged in between.
2929 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2930 not values of expressions.
2932 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
2933 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
2935 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2936 any operand with side effect. This is unnecesarily conservative in the
2937 case we know that arg0 and arg1 are in disjoint code paths (such as in
2938 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2939 addresses with TREE_CONSTANT flag set so we know that &var == &var
2940 even if var is volatile. */
2942 int
2944 {
2945 /* When checking, verify at the outermost operand_equal_p call that
2946 if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
2947 hash value. */
2949 {
2951 {
2953 {
2960 }
2962 }
2963 else
2965 }
2970 /* If either is ERROR_MARK, they aren't equal. */
2976 /* Similar, if either does not have a type (like a released SSA name),
2977 they aren't equal. */
2981 /* We cannot consider pointers to different address space equal. */
2988 /* Check equality of integer constants before bailing out due to
2989 precision differences. */
2991 {
2992 /* Address of INTEGER_CST is not defined; check that we did not forget
2993 to drop the OEP_ADDRESS_OF flags. */
2996 }
2999 {
3000 /* If both types don't have the same signedness, then we can't consider
3001 them equal. We must check this before the STRIP_NOPS calls
3002 because they may change the signedness of the arguments. As pointers
3003 strictly don't have a signedness, require either two pointers or
3004 two non-pointers as well. */
3010 /* If both types don't have the same precision, then it is not safe
3011 to strip NOPs. */
3018 }
3019 #if 0
3020 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
3021 sanity check once the issue is solved. */
3022 else
3023 /* Addresses of conversions and SSA_NAMEs (and many other things)
3024 are not defined. Check that we did not forget to drop the
3025 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
3028 #endif
3030 /* In case both args are comparisons but with different comparison
3031 code, try to swap the comparison operands of one arg to produce
3032 a match and compare that variant. */
3036 {
3044 }
3047 {
3048 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
3050 ;
3052 {
3053 /* If we are interested in comparing addresses ignore
3054 MEM_REF wrappings of the base that can appear just for
3055 TBAA reasons. */
3069 }
3070 else
3072 }
3074 /* When not checking adddresses, this is needed for conversions and for
3075 COMPONENT_REF. Might as well play it safe and always test this. */
3082 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3083 We don't care about side effects in that case because the SAVE_EXPR
3084 takes care of that for us. In all other cases, two expressions are
3085 equal if they have no side effects. If we have two identical
3086 expressions with side effects that should be treated the same due
3087 to the only side effects being identical SAVE_EXPR's, that will
3088 be detected in the recursive calls below.
3089 If we are taking an invariant address of two identical objects
3090 they are necessarily equal as well. */
3097 /* Next handle constant cases, those for which we can return 1 even
3098 if ONLY_CONST is set. */
3101 {
3115 {
3116 /* If we do not distinguish between signed and unsigned zero,
3117 consider them equal. */
3120 }
3124 {
3139 }
3143 flags)
3145 flags));
3156 flags | OEP_ADDRESS_OF
3159 /* In GIMPLE empty constructors are allowed in initializers of
3160 aggregates. */
3164 }
3169 /* Define macros to test an operand from arg0 and arg1 for equality and a
3170 variant that allows null and views null as being different from any
3171 non-null value. In the latter case, if either is null, the both
3172 must be; otherwise, do the normal comparison. */
3173 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3174 TREE_OPERAND (arg1, N), flags)
3176 #define OP_SAME_WITH_NULL(N) \
3177 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3178 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3181 {
3183 /* Two conversions are equal only if signedness and modes match. */
3185 {
3186 CASE_CONVERT:
3194 }
3204 /* For commutative ops, allow the other order. */
3212 /* If either of the pointer (or reference) expressions we are
3213 dereferencing contain a side effect, these cannot be equal,
3214 but their addresses can be. */
3221 {
3224 {
3228 /* Verify that the access types are compatible. */
3232 }
3237 /* Require the same offset. */
3243 /* Fallthru. */
3251 {
3252 /* Require equal access sizes */
3258 flags)))
3260 /* Verify that access happens in similar types. */
3263 /* Verify that accesses are TBAA compatible. */
3272 /* Verify that alignment is compatible. */
3276 }
3279 /* TARGET_MEM_REF require equal extra operands. */
3290 /* Compare the array index by value if it is constant first as we
3291 may have different types but same value here. */
3297 /* Compare low bound and element size as with OEP_ADDRESS_OF
3298 we have to account for the offset of the ref. */
3303 array_ref_low_bound
3307 array_ref_element_size
3309 flags))));
3312 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3313 may be NULL when we're called to compare MEM_EXPRs. */
3328 }
3332 {
3334 /* Be sure we pass right ADDRESS_OF flag. */
3351 /* The multiplcation operands are commutative. */
3352 /* FALLTHRU */
3360 /* Otherwise take into account this is a commutative operation. */
3373 /* BIT_INSERT_EXPR has an implict operand as the type precision
3374 of op1. Need to check to make sure they are the same. */
3380 /* FALLTHRU */
3406 }
3410 {
3414 /* If not both CALL_EXPRs are either internal or normal function
3415 functions, then they are not equal. */
3418 {
3419 /* If the CALL_EXPRs call different internal functions, then they
3420 are not equal. */
3423 }
3424 else
3425 {
3426 /* If the CALL_EXPRs call different functions, then they are not
3427 equal. */
3429 flags))
3431 }
3433 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3434 {
3438 else
3442 }
3444 /* Now see if all the arguments are the same. */
3445 {
3456 /* If we get here and both argument lists are exhausted
3457 then the CALL_EXPRs are equal. */
3459 }
3462 }
3465 /* Consider __builtin_sqrt equal to sqrt. */
3473 {
3474 /* In GIMPLE constructors are used only to build vectors from
3475 elements. Individual elements in the constructor must be
3476 indexed in increasing order and form an initial sequence.
3478 We make no effort to compare constructors in generic.
3479 (see sem_variable::equals in ipa-icf which can do so for
3480 constants). */
3485 /* Be sure that vectors constructed have the same representation.
3486 We only tested element precision and modes to match.
3487 Vectors may be BLKmode and thus also check that the number of
3488 parts match. */
3501 {
3506 /* In GIMPLE the indexes can be either NULL or matching i.
3507 Double check this so we won't get false
3508 positives for GENERIC. */
3516 }
3518 }
3521 {
3522 /* Compare the STATEMENT_LISTs. */
3528 {
3529 /* The lists don't have the same number of statements. */
3535 flags & (OEP_LEXICOGRAPHIC
3538 }
3539 }
3544 {
3555 }
3559 }
3561 #undef OP_SAME
3562 #undef OP_SAME_WITH_NULL
3563 }
3564 \f
3565 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
3566 with a different signedness or a narrower precision. */
3568 static bool
3570 {
3578 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3579 and see if the inner values are the same. This removes any
3580 signedness comparison, which doesn't matter here. */
3588 /* Discard a single widening conversion from ARG1 and see if the inner
3589 value is the same as ARG0. */
3598 }
3599 \f
3600 /* See if ARG is an expression that is either a comparison or is performing
3601 arithmetic on comparisons. The comparisons must only be comparing
3602 two different values, which will be stored in *CVAL1 and *CVAL2; if
3603 they are nonzero it means that some operands have already been found.
3604 No variables may be used anywhere else in the expression except in the
3605 comparisons.
3607 If this is true, return 1. Otherwise, return zero. */
3609 static int
3611 {
3615 /* We can handle some of the tcc_expression cases here. */
3624 {
3643 /* First see if we can handle the first operand, then the second. For
3644 the second operand, we know *CVAL1 can't be zero. It must be that
3645 one side of the comparison is each of the values; test for the
3646 case where this isn't true by failing if the two operands
3647 are the same. */
3656 ;
3660 ;
3661 else
3665 ;
3669 ;
3670 else
3677 }
3678 }
3679 \f
3680 /* ARG is a tree that is known to contain just arithmetic operations and
3681 comparisons. Evaluate the operations in the tree substituting NEW0 for
3682 any occurrence of OLD0 as an operand of a comparison and likewise for
3683 NEW1 and OLD1. */
3685 static tree
3688 {
3693 /* We can handle some of the tcc_expression cases here. */
3701 {
3716 {
3735 }
3736 /* Fall through - ??? */
3739 {
3743 /* We need to check both for exact equality and tree equality. The
3744 former will be true if the operand has a side-effect. In that
3745 case, we know the operand occurred exactly once. */
3758 }
3762 }
3763 }
3764 \f
3765 /* Return a tree for the case when the result of an expression is RESULT
3766 converted to TYPE and OMITTED was previously an operand of the expression
3767 but is now not needed (e.g., we folded OMITTED * 0).
3769 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3770 the conversion of RESULT to TYPE. */
3772 tree
3774 {
3777 /* If the resulting operand is an empty statement, just return the omitted
3778 statement casted to void. */
3788 }
3790 /* Return a tree for the case when the result of an expression is RESULT
3791 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3792 of the expression but are now not needed.
3794 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3795 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3796 evaluated before OMITTED2. Otherwise, if neither has side effects,
3797 just do the conversion of RESULT to TYPE. */
3799 tree
3802 {
3811 }
3813 \f
3814 /* Return a simplified tree node for the truth-negation of ARG. This
3815 never alters ARG itself. We assume that ARG is an operation that
3816 returns a truth value (0 or 1).
3818 FIXME: one would think we would fold the result, but it causes
3819 problems with the dominator optimizer. */
3821 static tree
3823 {
3828 /* If this is a comparison, we can simply invert it, except for
3829 floating-point non-equality comparisons, in which case we just
3830 enclose a TRUTH_NOT_EXPR around what we have. */
3833 {
3836 && flag_trapping_math
3850 }
3853 {
3872 /* Here we can invert either operand. We invert the first operand
3873 unless the second operand is a TRUTH_NOT_EXPR in which case our
3874 result is the XOR of the first operand with the inside of the
3875 negation of the second operand. */
3880 else
3903 {
3910 /* A COND_EXPR may have a throw as one operand, which
3911 then has void type. Just leave void operands
3912 as they are. */
3918 }
3930 CASE_CONVERT:
3934 /* fall through */
3956 }
3957 }
3959 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3960 assume that ARG is an operation that returns a truth value (0 or 1
3961 for scalars, 0 or -1 for vectors). Return the folded expression if
3962 folding is successful. Otherwise, return NULL_TREE. */
3964 static tree
3966 {
3969 ? BIT_NOT_EXPR
3972 }
3974 /* Return a simplified tree node for the truth-negation of ARG. This
3975 never alters ARG itself. We assume that ARG is an operation that
3976 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3978 tree
3980 {
3986 ? BIT_NOT_EXPR
3989 }
3990 \f
3991 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3992 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
3993 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
3994 is the original memory reference used to preserve the alias set of
3995 the access. */
3997 static tree
4001 {
4004 /* Attempt not to lose the access path if possible. */
4006 {
4008 machine_mode nmode;
4010 tree noffset;
4018 && !reversep
4019 && !nreversep
4021 {
4024 }
4025 }
4034 {
4041 }
4056 }
4058 /* Optimize a bit-field compare.
4060 There are two cases: First is a compare against a constant and the
4061 second is a comparison of two items where the fields are at the same
4062 bit position relative to the start of a chunk (byte, halfword, word)
4063 large enough to contain it. In these cases we can avoid the shift
4064 implicit in bitfield extractions.
4066 For constants, we emit a compare of the shifted constant with the
4067 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4068 compared. For two fields at the same position, we do the ANDs with the
4069 similar mask and compare the result of the ANDs.
4071 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4072 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4073 are the left and right operands of the comparison, respectively.
4075 If the optimization described above can be done, we return the resulting
4076 tree. Otherwise we return zero. */
4078 static tree
4081 {
4085 tree unsigned_type;
4088 scalar_int_mode nmode;
4093 tree mask;
4094 tree offset;
4096 /* Get all the information about the extractions being done. If the bit size
4097 is the same as the size of the underlying object, we aren't doing an
4098 extraction at all and so can do nothing. We also don't want to
4099 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4100 then will no longer be able to replace it. */
4115 else
4116 {
4117 /* If this is not a constant, we can only do something if bit positions,
4118 sizes, signedness and storage order are the same. */
4119 rinner
4132 }
4134 /* Honor the C++ memory model and mimic what RTL expansion does. */
4138 {
4142 }
4144 /* See if we can find a mode to refer to this field. We should be able to,
4145 but fail if we can't. */
4153 /* Set signed and unsigned types of the precision of this mode for the
4154 shifts below. */
4157 /* Compute the bit position and size for the new reference and our offset
4158 within it. If the new reference is the same size as the original, we
4159 won't optimize anything, so return zero. */
4169 /* Make the mask to be used against the extracted field. */
4176 {
4180 /* If not comparing with constant, just rework the comparison
4181 and return. */
4189 }
4191 /* Otherwise, we are handling the constant case. See if the constant is too
4192 big for the field. Warn and return a tree for 0 (false) if so. We do
4193 this not only for its own sake, but to avoid having to test for this
4194 error case below. If we didn't, we might generate wrong code.
4196 For unsigned fields, the constant shifted right by the field length should
4197 be all zero. For signed fields, the high-order bits should agree with
4198 the sign bit. */
4201 {
4203 {
4207 }
4208 }
4209 else
4210 {
4213 {
4217 }
4218 }
4223 /* Single-bit compares should always be against zero. */
4225 {
4228 }
4230 /* Make a new bitfield reference, shift the constant over the
4231 appropriate number of bits and mask it with the computed mask
4232 (in case this was a signed field). If we changed it, make a new one. */
4240 mask);
4245 }
4246 \f
4247 /* Subroutine for fold_truth_andor_1: decode a field reference.
4249 If EXP is a comparison reference, we return the innermost reference.
4251 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4252 set to the starting bit number.
4254 If the innermost field can be completely contained in a mode-sized
4255 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4257 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4258 otherwise it is not changed.
4260 *PUNSIGNEDP is set to the signedness of the field.
4262 *PREVERSEP is set to the storage order of the field.
4264 *PMASK is set to the mask used. This is either contained in a
4265 BIT_AND_EXPR or derived from the width of the field.
4267 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4269 Return 0 if this is not a component reference or is one that we can't
4270 do anything with. */
4272 static tree
4277 {
4282 tree unsigned_type;
4285 /* All the optimizations using this function assume integer fields.
4286 There are problems with FP fields since the type_for_size call
4287 below can fail for, e.g., XFmode. */
4291 /* We are interested in the bare arrangement of bits, so strip everything
4292 that doesn't affect the machine mode. However, record the type of the
4293 outermost expression if it may matter below. */
4300 {
4306 }
4317 /* Reject out-of-bound accesses (PR79731). */
4329 /* If the number of bits in the reference is the same as the bitsize of
4330 the outer type, then the outer type gives the signedness. Otherwise
4331 (in case of a small bitfield) the signedness is unchanged. */
4335 /* Compute the mask to access the bitfield. */
4343 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4351 }
4353 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4354 bit positions and MASK is SIGNED. */
4356 static int
4358 {
4362 /* If this function returns true when the type of the mask is
4363 UNSIGNED, then there will be errors. In particular see
4364 gcc.c-torture/execute/990326-1.c. There does not appear to be
4365 any documentation paper trail as to why this is so. But the pre
4366 wide-int worked with that restriction and it has been preserved
4367 here. */
4372 }
4374 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4375 represents the sign bit of EXP's type. If EXP represents a sign
4376 or zero extension, also test VAL against the unextended type.
4377 The return value is the (sub)expression whose sign bit is VAL,
4378 or NULL_TREE otherwise. */
4380 tree
4382 {
4384 tree t;
4386 /* Tree EXP must have an integral type. */
4391 /* Tree VAL must be an integer constant. */
4400 /* Handle extension from a narrower type. */
4406 }
4408 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4409 to be evaluated unconditionally. */
4411 static int
4413 {
4414 /* Strip any conversions that don't change the machine mode. */
4423 /* Don't regard global variables as simple. They may be
4424 allocated in ways unknown to the compiler (shared memory,
4425 #pragma weak, etc). */
4428 /* Weakrefs are not safe to be read, since they can be NULL.
4429 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4430 have DECL_WEAK flag set. */
4432 /* Loading a static variable is unduly expensive, but global
4433 registers aren't expensive. */
4435 }
4437 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4438 to be evaluated unconditionally.
4439 I addition to simple_operand_p, we assume that comparisons, conversions,
4440 and logic-not operations are simple, if their operands are simple, too. */
4442 static bool
4444 {
4464 }
4466 \f
4467 /* The following functions are subroutines to fold_range_test and allow it to
4468 try to change a logical combination of comparisons into a range test.
4470 For example, both
4471 X == 2 || X == 3 || X == 4 || X == 5
4472 and
4473 X >= 2 && X <= 5
4474 are converted to
4475 (unsigned) (X - 2) <= 3
4477 We describe each set of comparisons as being either inside or outside
4478 a range, using a variable named like IN_P, and then describe the
4479 range with a lower and upper bound. If one of the bounds is omitted,
4480 it represents either the highest or lowest value of the type.
4482 In the comments below, we represent a range by two numbers in brackets
4483 preceded by a "+" to designate being inside that range, or a "-" to
4484 designate being outside that range, so the condition can be inverted by
4485 flipping the prefix. An omitted bound is represented by a "-". For
4486 example, "- [-, 10]" means being outside the range starting at the lowest
4487 possible value and ending at 10, in other words, being greater than 10.
4488 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4489 always false.
4491 We set up things so that the missing bounds are handled in a consistent
4492 manner so neither a missing bound nor "true" and "false" need to be
4493 handled using a special case. */
4495 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4496 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4497 and UPPER1_P are nonzero if the respective argument is an upper bound
4498 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4499 must be specified for a comparison. ARG1 will be converted to ARG0's
4500 type if both are specified. */
4502 static tree
4505 {
4506 tree tem;
4510 /* If neither arg represents infinity, do the normal operation.
4511 Else, if not a comparison, return infinity. Else handle the special
4512 comparison rules. Note that most of the cases below won't occur, but
4513 are handled for consistency. */
4516 {
4521 }
4526 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4527 for neither. In real maths, we cannot assume open ended ranges are
4528 the same. But, this is computer arithmetic, where numbers are finite.
4529 We can therefore make the transformation of any unbounded range with
4530 the value Z, Z being greater than any representable number. This permits
4531 us to treat unbounded ranges as equal. */
4535 {
4556 }
4559 }
4560 \f
4561 /* Helper routine for make_range. Perform one step for it, return
4562 new expression if the loop should continue or NULL_TREE if it should
4563 stop. */
4565 tree
4569 {
4575 {
4577 /* We can only do something if the range is testing for zero. */
4586 /* We can only do something if the range is testing for zero
4587 and if the second operand is an integer constant. Note that
4588 saying something is "in" the range we make is done by
4589 complementing IN_P since it will set in the initial case of
4590 being not equal to zero; "out" is leaving it alone. */
4597 {
4618 }
4620 /* If this is an unsigned comparison, we also know that EXP is
4621 greater than or equal to zero. We base the range tests we make
4622 on that fact, so we record it here so we can parse existing
4623 range tests. We test arg0_type since often the return type
4624 of, e.g. EQ_EXPR, is boolean. */
4626 {
4630 NULL_TREE))
4635 /* If the high bound is missing, but we have a nonzero low
4636 bound, reverse the range so it goes from zero to the low bound
4637 minus 1. */
4639 {
4644 }
4645 }
4653 /* If flag_wrapv and ARG0_TYPE is signed, make sure
4654 low and high are non-NULL, then normalize will DTRT. */
4657 {
4662 }
4664 /* (-x) IN [a,b] -> x in [-b, -a] */
4676 /* ~ X -> -X - 1 */
4685 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4686 move a constant to the other side. */
4691 /* If EXP is signed, any overflow in the computation is undefined,
4692 so we don't worry about it so long as our computations on
4693 the bounds don't overflow. For unsigned, overflow is defined
4694 and this is exactly the right thing. */
4706 normalize:
4707 /* Check for an unsigned range which has wrapped around the maximum
4708 value thus making n_high < n_low, and normalize it. */
4710 {
4716 /* If the range is of the form +/- [ x+1, x ], we won't
4717 be able to normalize it. But then, it represents the
4718 whole range or the empty set, so make it
4719 +/- [ -, - ]. */
4723 else
4725 }
4726 else
4734 CASE_CONVERT:
4752 /* If we're converting arg0 from an unsigned type, to exp,
4753 a signed type, we will be doing the comparison as unsigned.
4754 The tests above have already verified that LOW and HIGH
4755 are both positive.
4757 So we have to ensure that we will handle large unsigned
4758 values the same way that the current signed bounds treat
4759 negative values. */
4762 {
4763 tree high_positive;
4764 tree equiv_type;
4765 /* For fixed-point modes, we need to pass the saturating flag
4766 as the 2nd parameter. */
4768 equiv_type
4771 else
4772 equiv_type
4775 /* A range without an upper bound is, naturally, unbounded.
4776 Since convert would have cropped a very large value, use
4777 the max value for the destination type. */
4778 high_positive
4785 high_positive),
4788 /* If the low bound is specified, "and" the range with the
4789 range for which the original unsigned value will be
4790 positive. */
4792 {
4795 integer_zero_node),
4796 high_positive))
4800 }
4801 else
4802 {
4803 /* Otherwise, "or" the range with the range of the input
4804 that will be interpreted as negative. */
4807 integer_zero_node),
4808 high_positive))
4812 }
4813 }
4822 }
4823 }
4825 /* Given EXP, a logical expression, set the range it is testing into
4826 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4827 actually being tested. *PLOW and *PHIGH will be made of the same
4828 type as the returned expression. If EXP is not a comparison, we
4829 will most likely not be returning a useful value and range. Set
4830 *STRICT_OVERFLOW_P to true if the return value is only valid
4831 because signed overflow is undefined; otherwise, do not change
4832 *STRICT_OVERFLOW_P. */
4834 tree
4837 {
4845 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4846 and see if we can refine the range. Some of the cases below may not
4847 happen, but it doesn't seem worth worrying about this. We "continue"
4848 the outer loop when we've changed something; otherwise we "break"
4849 the switch, which will "break" the while. */
4855 {
4861 {
4869 }
4878 }
4880 /* If EXP is a constant, we can evaluate whether this is true or false. */
4882 {
4889 }
4893 }
4895 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
4896 a bitwise check i.e. when
4897 LOW == 0xXX...X00...0
4898 HIGH == 0xXX...X11...1
4899 Return corresponding mask in MASK and stem in VALUE. */
4901 static bool
4904 {
4927 }
4928 \f
4929 /* Helper routine for build_range_check and match.pd. Return the type to
4930 perform the check or NULL if it shouldn't be optimized. */
4932 tree
4934 {
4935 /* First make sure that arithmetics in this type is valid, then make sure
4936 that it wraps around. */
4942 {
4945 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4946 for the type in question, as we rely on this here. */
4956 else
4958 }
4960 }
4962 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4963 type, TYPE, return an expression to test if EXP is in (or out of, depending
4964 on IN_P) the range. Return 0 if the test couldn't be created. */
4966 tree
4969 {
4972 /* Disable this optimization for function pointer expressions
4973 on targets that require function pointer canonicalization. */
4980 {
4986 }
5008 value);
5011 {
5013 {
5017 }
5019 }
5021 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
5023 {
5027 {
5029 {
5032 etype
5034 else
5037 }
5040 }
5041 }
5043 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
5044 This requires wrap-around arithmetics for the type of the expression. */
5064 }
5065 \f
5066 /* Return the predecessor of VAL in its type, handling the infinite case. */
5068 static tree
5070 {
5076 else
5079 }
5081 /* Return the successor of VAL in its type, handling the infinite case. */
5083 static tree
5085 {
5091 else
5094 }
5096 /* Given two ranges, see if we can merge them into one. Return 1 if we
5097 can, 0 if we can't. Set the output range into the specified parameters. */
5099 bool
5102 {
5106 tree tem;
5116 /* Make range 0 be the range that starts first, or ends last if they
5117 start at the same value. Swap them if it isn't. */
5120 || (lowequal
5123 {
5127 }
5129 /* If the second range is != high1 where high1 is the type maximum of
5130 the type, try first merging with < high1 range. */
5132 && high1
5139 {
5144 /* Similarly for the second range != low1 where low1 is the type minimum
5145 of the type, try first merging with > low1 range. */
5150 }
5152 /* Now flag two cases, whether the ranges are disjoint or whether the
5153 second range is totally subsumed in the first. Note that the tests
5154 below are simplified by the ones above. */
5160 /* We now have four cases, depending on whether we are including or
5161 excluding the two ranges. */
5163 {
5164 /* If they don't overlap, the result is false. If the second range
5165 is a subset it is the result. Otherwise, the range is from the start
5166 of the second to the end of the first. */
5171 else
5173 }
5176 {
5177 /* If they don't overlap, the result is the first range. If they are
5178 equal, the result is false. If the second range is a subset of the
5179 first, and the ranges begin at the same place, we go from just after
5180 the end of the second range to the end of the first. If the second
5181 range is not a subset of the first, or if it is a subset and both
5182 ranges end at the same place, the range starts at the start of the
5183 first range and ends just before the second range.
5184 Otherwise, we can't describe this as a single range. */
5190 {
5195 {
5196 /* We are in the weird situation where high0 > high1 but
5197 high1 has no successor. Punt. */
5199 }
5200 }
5202 {
5207 {
5208 /* low0 < low1 but low1 has no predecessor. Punt. */
5210 }
5211 }
5212 else
5214 }
5217 {
5218 /* If they don't overlap, the result is the second range. If the second
5219 is a subset of the first, the result is false. Otherwise,
5220 the range starts just after the first range and ends at the
5221 end of the second. */
5226 else
5227 {
5232 {
5233 /* high1 > high0 but high0 has no successor. Punt. */
5235 }
5236 }
5237 }
5239 else
5240 {
5241 /* The case where we are excluding both ranges. Here the complex case
5242 is if they don't overlap. In that case, the only time we have a
5243 range is if they are adjacent. If the second is a subset of the
5244 first, the result is the first. Otherwise, the range to exclude
5245 starts at the beginning of the first range and ends at the end of the
5246 second. */
5248 {
5253 else
5254 {
5255 /* Canonicalize - [min, x] into - [-, x]. */
5258 {
5261 GET_MODE_BITSIZE
5264 /* FALLTHROUGH */
5277 }
5279 /* Canonicalize - [x, max] into - [x, -]. */
5282 {
5285 GET_MODE_BITSIZE
5288 /* FALLTHROUGH */
5304 }
5306 /* The ranges might be also adjacent between the maximum and
5307 minimum values of the given type. For
5308 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5309 return + [x + 1, y - 1]. */
5311 {
5318 }
5319 else
5321 }
5322 }
5325 else
5327 }
5331 }
5332 \f
5334 /* Subroutine of fold, looking inside expressions of the form
5335 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5336 of the COND_EXPR. This function is being used also to optimize
5337 A op B ? C : A, by reversing the comparison first.
5339 Return a folded expression whose code is not a COND_EXPR
5340 anymore, or NULL_TREE if no folding opportunity is found. */
5342 static tree
5345 {
5350 tree tem;
5355 /* If we have A op 0 ? A : -A, consider applying the following
5356 transformations:
5358 A == 0? A : -A same as -A
5359 A != 0? A : -A same as A
5360 A >= 0? A : -A same as abs (A)
5361 A > 0? A : -A same as abs (A)
5362 A <= 0? A : -A same as -abs (A)
5363 A < 0? A : -A same as -abs (A)
5365 None of these transformations work for modes with signed
5366 zeros. If A is +/-0, the first two transformations will
5367 change the sign of the result (from +0 to -0, or vice
5368 versa). The last four will fix the sign of the result,
5369 even though the original expressions could be positive or
5370 negative, depending on the sign of A.
5372 Note that all these transformations are correct if A is
5373 NaN, since the two alternatives (A and -A) are also NaNs. */
5380 /* In the case that A is of the form X-Y, '-A' (arg2) may
5381 have already been folded to Y-X, check for that. */
5389 {
5401 /* Fall through. */
5412 /* FALLTHRU */
5422 }
5424 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5425 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5426 both transformations are correct when A is NaN: A != 0
5427 is then true, and A == 0 is false. */
5431 {
5436 }
5438 /* Try some transformations of A op B ? A : B.
5440 A == B? A : B same as B
5441 A != B? A : B same as A
5442 A >= B? A : B same as max (A, B)
5443 A > B? A : B same as max (B, A)
5444 A <= B? A : B same as min (A, B)
5445 A < B? A : B same as min (B, A)
5447 As above, these transformations don't work in the presence
5448 of signed zeros. For example, if A and B are zeros of
5449 opposite sign, the first two transformations will change
5450 the sign of the result. In the last four, the original
5451 expressions give different results for (A=+0, B=-0) and
5452 (A=-0, B=+0), but the transformed expressions do not.
5454 The first two transformations are correct if either A or B
5455 is a NaN. In the first transformation, the condition will
5456 be false, and B will indeed be chosen. In the case of the
5457 second transformation, the condition A != B will be true,
5458 and A will be chosen.
5460 The conversions to max() and min() are not correct if B is
5461 a number and A is not. The conditions in the original
5462 expressions will be false, so all four give B. The min()
5463 and max() versions would give a NaN instead. */
5466 /* Avoid these transformations if the COND_EXPR may be used
5467 as an lvalue in the C++ front-end. PR c++/19199. */
5468 && (in_gimple_form
5474 {
5480 {
5489 /* In C++ a ?: expression can be an lvalue, so put the
5490 operand which will be used if they are equal first
5491 so that we can convert this back to the
5492 corresponding COND_EXPR. */
5494 {
5502 }
5509 {
5517 }
5530 }
5531 }
5534 }
5537 \f
5538 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5539 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5540 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5541 false) >= 2)
5542 #endif
5544 /* EXP is some logical combination of boolean tests. See if we can
5545 merge it into some range test. Return the new tree if so. */
5547 static tree
5550 {
5566 /* If this is an OR operation, invert both sides; we will invert
5567 again at the end. */
5571 /* If both expressions are the same, if we can merge the ranges, and we
5572 can build the range test, return it or it inverted. If one of the
5573 ranges is always true or always false, consider it to be the same
5574 expression as the other. */
5582 {
5586 }
5588 /* On machines where the branch cost is expensive, if this is a
5589 short-circuited branch and the underlying object on both sides
5590 is the same, make a non-short-circuit operation. */
5593 logical_op_non_short_circuit
5596 && !flag_sanitize_coverage
5600 {
5601 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5602 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5603 which cases we can't do this. */
5611 {
5620 {
5623 WARN_STRICT_OVERFLOW_COMPARISON);
5627 }
5628 }
5629 }
5632 }
5633 \f
5634 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
5635 bit value. Arrange things so the extra bits will be set to zero if and
5636 only if C is signed-extended to its full width. If MASK is nonzero,
5637 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5639 static tree
5641 {
5644 tree temp;
5649 /* We work by getting just the sign bit into the low-order bit, then
5650 into the high-order bit, then sign-extend. We then XOR that value
5651 with C. */
5655 /* We must use a signed type in order to get an arithmetic right shift.
5656 However, we must also avoid introducing accidental overflows, so that
5657 a subsequent call to integer_zerop will work. Hence we must
5658 do the type conversion here. At this point, the constant is either
5659 zero or one, and the conversion to a signed type can never overflow.
5660 We could get an overflow if this conversion is done anywhere else. */
5669 /* If necessary, convert the type back to match the type of C. */
5674 }
5675 \f
5676 /* For an expression that has the form
5677 (A && B) || ~B
5678 or
5679 (A || B) && ~B,
5680 we can drop one of the inner expressions and simplify to
5681 A || ~B
5682 or
5683 A && ~B
5684 LOC is the location of the resulting expression. OP is the inner
5685 logical operation; the left-hand side in the examples above, while CMPOP
5686 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5687 removing a condition that guards another, as in
5688 (A != NULL && A->...) || A == NULL
5689 which we must not transform. If RHS_ONLY is true, only eliminate the
5690 right-most operand of the inner logical operation. */
5692 static tree
5695 {
5713 {
5716 {
5719 }
5720 }
5722 {
5725 {
5728 }
5729 }
5744 }
5746 /* Find ways of folding logical expressions of LHS and RHS:
5747 Try to merge two comparisons to the same innermost item.
5748 Look for range tests like "ch >= '0' && ch <= '9'".
5749 Look for combinations of simple terms on machines with expensive branches
5750 and evaluate the RHS unconditionally.
5752 For example, if we have p->a == 2 && p->b == 4 and we can make an
5753 object large enough to span both A and B, we can do this with a comparison
5754 against the object ANDed with the a mask.
5756 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5757 operations to do this with one comparison.
5759 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5760 function and the one above.
5762 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5763 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5765 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5766 two operands.
5768 We return the simplified tree or 0 if no optimization is possible. */
5770 static tree
5773 {
5774 /* If this is the "or" of two comparisons, we can do something if
5775 the comparisons are NE_EXPR. If this is the "and", we can do something
5776 if the comparisons are EQ_EXPR. I.e.,
5777 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5779 WANTED_CODE is this operation code. For single bit fields, we can
5780 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5781 comparison for one-bit fields. */
5802 /* Start by getting the comparison codes. Fail if anything is volatile.
5803 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5804 it were surrounded with a NE_EXPR. */
5813 {
5817 }
5820 {
5824 }
5835 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5838 {
5841 {
5846 }
5849 {
5855 }
5856 }
5861 /* If the RHS can be evaluated unconditionally and its operands are
5862 simple, it wins to evaluate the RHS unconditionally on machines
5863 with expensive branches. In this case, this isn't a comparison
5864 that can be merged. */
5871 {
5872 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5883 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5893 }
5895 /* See if the comparisons can be merged. Then get all the parameters for
5896 each side. */
5921 /* It must be true that the inner operation on the lhs of each
5922 comparison must be the same if we are to be able to do anything.
5923 Then see if we have constants. If not, the same must be true for
5924 the rhs's. */
5933 {
5936 }
5941 else
5944 /* If either comparison code is not correct for our logical operation,
5945 fail. However, we can convert a one-bit comparison against zero into
5946 the opposite comparison against that bit being set in the field. */
5950 {
5952 {
5953 /* Make the left operand unsigned, since we are only interested
5954 in the value of one bit. Otherwise we are doing the wrong
5955 thing below. */
5958 }
5959 else
5961 }
5963 /* This is analogous to the code for l_const above. */
5965 {
5967 {
5970 }
5971 else
5973 }
5975 /* See if we can find a mode that contains both fields being compared on
5976 the left. If we can't, fail. Otherwise, update all constants and masks
5977 to be relative to a field of that size. */
5991 {
5994 }
6002 {
6009 {
6013 }
6014 }
6016 {
6023 {
6027 }
6028 }
6030 /* If the right sides are not constant, do the same for it. Also,
6031 disallow this optimization if a size, signedness or storage order
6032 mismatch occurs between the left and right sides. */
6034 {
6038 /* Make sure the two fields on the right
6039 correspond to the left without being swapped. */
6056 {
6059 }
6068 /* Make a mask that corresponds to both fields being compared.
6069 Do this for both items being compared. If the operands are the
6070 same size and the bits being compared are in the same position
6071 then we can do this by masking both and comparing the masked
6072 results. */
6079 {
6093 }
6095 /* There is still another way we can do something: If both pairs of
6096 fields being compared are adjacent, we may be able to make a wider
6097 field containing them both.
6099 Note that we still must mask the lhs/rhs expressions. Furthermore,
6100 the mask must be shifted to account for the shift done by
6101 make_bit_field_ref. */
6110 {
6111 tree type;
6127 /* Convert to the smaller type before masking out unwanted bits. */
6130 {
6132 {
6136 }
6138 {
6142 }
6143 }
6152 }
6155 }
6157 /* Handle the case of comparisons with constants. If there is something in
6158 common between the masks, those bits of the constants must be the same.
6159 If not, the condition is always false. Test for this to avoid generating
6160 incorrect code below. */
6165 {
6167 {
6170 }
6171 else
6172 {
6175 }
6176 }
6181 /* Construct the expression we will return. First get the component
6182 reference we will make. Unless the mask is all ones the width of
6183 that field, perform the mask operation. Then compare with the
6184 merged constant. */
6195 }
6196 \f
6197 /* T is an integer expression that is being multiplied, divided, or taken a
6198 modulus (CODE says which and what kind of divide or modulus) by a
6199 constant C. See if we can eliminate that operation by folding it with
6200 other operations already in T. WIDE_TYPE, if non-null, is a type that
6201 should be used for the computation if wider than our type.
6203 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6204 (X * 2) + (Y * 4). We must, however, be assured that either the original
6205 expression would not overflow or that overflow is undefined for the type
6206 in the language in question.
6208 If we return a non-null expression, it is an equivalent form of the
6209 original computation, but need not be in the original type.
6211 We set *STRICT_OVERFLOW_P to true if the return values depends on
6212 signed overflow being undefined. Otherwise we do not change
6213 *STRICT_OVERFLOW_P. */
6215 static tree
6218 {
6219 /* To avoid exponential search depth, refuse to allow recursion past
6220 three levels. Beyond that (1) it's highly unlikely that we'll find
6221 something interesting and (2) we've probably processed it before
6222 when we built the inner expression. */
6225 tree ret;
6230 depth++;
6232 depth--;
6235 }
6237 static tree
6240 {
6252 /* Don't deal with constants of zero here; they confuse the code below. */
6262 /* Note that we need not handle conditional operations here since fold
6263 already handles those cases. So just do arithmetic here. */
6265 {
6267 /* For a constant, we can always simplify if we are a multiply
6268 or (for divide and modulus) if it is a multiple of our constant. */
6272 {
6275 /* If the multiplication overflowed, we lost information on it.
6276 See PR68142 and PR69845. */
6280 }
6284 /* If op0 is an expression ... */
6290 /* ... and has wrapping overflow, and its type is smaller
6291 than ctype, then we cannot pass through as widening. */
6296 /* ... or this is a truncation (t is narrower than op0),
6297 then we cannot pass through this narrowing. */
6300 /* ... or signedness changes for division or modulus,
6301 then we cannot pass through this conversion. */
6305 /* ... or has undefined overflow while the converted to
6306 type has not, we cannot do the operation in the inner type
6307 as that would introduce undefined overflow. */
6313 /* Pass the constant down and see if we can make a simplification. If
6314 we can, replace this expression with the inner simplification for
6315 possible later conversion to our or some other type. */
6326 /* If widening the type changes it from signed to unsigned, then we
6327 must avoid building ABS_EXPR itself as unsigned. */
6329 {
6333 {
6336 }
6338 }
6339 /* If the constant is negative, we cannot simplify this. */
6342 /* FALLTHROUGH */
6344 /* For division and modulus, type can't be unsigned, as e.g.
6345 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6346 For signed types, even with wrapping overflow, this is fine. */
6355 /* If widening the type changes the signedness, then we can't perform
6356 this optimization as that changes the result. */
6360 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6366 {
6373 }
6377 /* If the second operand is constant, this is a multiplication
6378 or floor division, by a power of two, so we can treat it that
6379 way unless the multiplier or divisor overflows. Signed
6380 left-shift overflow is implementation-defined rather than
6381 undefined in C90, so do not convert signed left shift into
6382 multiplication. */
6385 /* const_binop may not detect overflow correctly,
6386 so check for it explicitly here. */
6395 ctype,
6397 t1),
6402 /* See if we can eliminate the operation on both sides. If we can, we
6403 can return a new PLUS or MINUS. If we can't, the only remaining
6404 cases where we can do anything are if the second operand is a
6405 constant. */
6412 /* If not multiplication, we can only do this if both operands
6413 are divisible by c. */
6416 {
6421 }
6423 /* If this was a subtraction, negate OP1 and set it to be an addition.
6424 This simplifies the logic below. */
6426 {
6428 /* If OP1 was not easily negatable, the constant may be OP0. */
6430 {
6433 }
6434 }
6439 /* If either OP1 or C are negative, this optimization is not safe for
6440 some of the division and remainder types while for others we need
6441 to change the code. */
6443 {
6451 }
6453 /* If it's a multiply or a division/modulus operation of a multiple
6454 of our constant, do the operation and verify it doesn't overflow. */
6458 {
6461 /* We allow the constant to overflow with wrapping semantics. */
6465 }
6466 else
6469 /* If we have an unsigned type, we cannot widen the operation since it
6470 will change the result if the original computation overflowed. */
6474 /* The last case is if we are a multiply. In that case, we can
6475 apply the distributive law to commute the multiply and addition
6476 if the multiplication of the constants doesn't overflow
6477 and overflow is defined. With undefined overflow
6478 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
6484 op1);
6489 /* We have a special case here if we are doing something like
6490 (C * 8) % 4 since we know that's zero. */
6493 /* If the multiplication can overflow we cannot optimize this. */
6498 {
6501 }
6503 /* ... fall through ... */
6507 /* If we can extract our operation from the LHS, do so and return a
6508 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6509 do something only if the second operand is a constant. */
6525 /* If these are the same operation types, we can associate them
6526 assuming no overflow. */
6528 {
6543 }
6545 /* If these operations "cancel" each other, we have the main
6546 optimizations of this pass, which occur when either constant is a
6547 multiple of the other, in which case we replace this with either an
6548 operation or CODE or TCODE.
6550 If we have an unsigned type, we cannot do this since it will change
6551 the result if the original computation overflowed. */
6558 {
6561 {
6568 }
6571 {
6578 }
6579 }
6584 }
6587 }
6588 \f
6589 /* Return a node which has the indicated constant VALUE (either 0 or
6590 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6591 and is of the indicated TYPE. */
6593 tree
6595 {
6604 else
6606 }
6609 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6610 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6611 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6612 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6613 COND is the first argument to CODE; otherwise (as in the example
6614 given here), it is the second argument. TYPE is the type of the
6615 original expression. Return NULL_TREE if no simplification is
6616 possible. */
6618 static tree
6623 {
6631 /* Do not move possibly trapping operations into the conditional as this
6632 pessimizes code and causes gimplification issues when applied late. */
6640 {
6644 /* If this operand throws an expression, then it does not make
6645 sense to try to perform a logical or arithmetic operation
6646 involving it. */
6651 }
6654 {
6659 }
6660 else
6661 /* Detect the case of mixing vector and scalar types - bail out. */
6667 /* This transformation is only worthwhile if we don't have to wrap ARG
6668 in a SAVE_EXPR and the operation can be simplified without recursing
6669 on at least one of the branches once its pushed inside the COND_EXPR. */
6678 {
6682 else
6684 }
6686 {
6690 else
6692 }
6694 /* Check that we have simplified at least one of the branches. */
6699 }
6701 \f
6702 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6704 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6705 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6706 ADDEND is the same as X.
6708 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6709 and finite. The problematic cases are when X is zero, and its mode
6710 has signed zeros. In the case of rounding towards -infinity,
6711 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6712 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6714 bool
6716 {
6720 /* Don't allow the fold with -fsignaling-nans. */
6724 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6728 /* In a vector or complex, we would need to check the sign of all zeros. */
6732 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6736 /* The mode has signed zeros, and we have to honor their sign.
6737 In this situation, there is only one case we can return true for.
6738 X - 0 is the same as X unless rounding towards -infinity is
6739 supported. */
6741 }
6743 /* Subroutine of match.pd that optimizes comparisons of a division by
6744 a nonzero integer constant against an integer constant, i.e.
6745 X/C1 op C2.
6747 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6748 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
6750 enum tree_code
6753 {
6758 /* We have to do this the hard way to detect unsigned overflow.
6759 prod = int_const_binop (MULT_EXPR, c1, c2); */
6765 {
6769 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6772 }
6774 {
6777 {
6796 }
6797 }
6798 else
6799 {
6800 /* A negative divisor reverses the relational operators. */
6805 {
6824 }
6825 }
6838 }
6841 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6842 equality/inequality test, then return a simplified form of the test
6843 using a sign testing. Otherwise return NULL. TYPE is the desired
6844 result type. */
6846 static tree
6849 tree result_type)
6850 {
6851 /* If this is testing a single bit, we can optimize the test. */
6855 {
6856 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6857 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6861 /* This is only a win if casting to a signed type is cheap,
6862 i.e. when arg00's type is not a partial mode. */
6864 {
6867 result_type,
6870 }
6871 }
6874 }
6876 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6877 equality/inequality test, then return a simplified form of
6878 the test using shifts and logical operations. Otherwise return
6879 NULL. TYPE is the desired result type. */
6881 tree
6884 {
6885 /* If this is testing a single bit, we can optimize the test. */
6889 {
6898 /* First, see if we can fold the single bit test into a sign-bit
6899 test. */
6901 result_type);
6905 /* Otherwise we have (A & C) != 0 where C is a single bit,
6906 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6907 Similarly for (A & C) == 0. */
6909 /* If INNER is a right shift of a constant and it plus BITNUM does
6910 not overflow, adjust BITNUM and INNER. */
6916 {
6919 }
6921 /* If we are going to be able to omit the AND below, we must do our
6922 operations as unsigned. If we must use the AND, we have a choice.
6923 Normally unsigned is faster, but for some machines signed is. */
6941 /* Put the AND last so it can combine with more things. */
6944 /* Make sure to return the proper type. */
6948 }
6950 }
6952 /* Test whether it is preferable two swap two operands, ARG0 and
6953 ARG1, for example because ARG0 is an integer constant and ARG1
6954 isn't. */
6956 bool
6958 {
6972 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6973 for commutative and comparison operators. Ensuring a canonical
6974 form allows the optimizers to find additional redundancies without
6975 having to explicitly check for both orderings. */
6981 /* Put SSA_NAMEs last. */
6987 /* Put variables last. */
6994 }
6997 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6998 means A >= Y && A != MAX, but in this case we know that
6999 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7001 static tree
7003 {
7010 else
7019 {
7022 }
7024 {
7027 }
7028 else
7035 {
7036 /* Convert the pointer types into integer before taking the difference. */
7040 }
7041 else
7048 }
7050 /* Fold a sum or difference of at least one multiplication.
7051 Returns the folded tree or NULL if no simplification could be made. */
7053 static tree
7056 {
7060 /* (A * C) +- (B * C) -> (A+-B) * C.
7061 (A * C) +- A -> A * (C+-1).
7062 We are most concerned about the case where C is a constant,
7063 but other combinations show up during loop reduction. Since
7064 it is not difficult, try all four possibilities. */
7067 {
7070 }
7072 {
7075 }
7076 else
7077 {
7078 /* We cannot generate constant 1 for fract. */
7083 }
7085 {
7088 }
7090 {
7092 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7093 the purpose of this canonicalization. */
7097 {
7100 }
7101 else
7103 }
7104 else
7105 {
7106 /* We cannot generate constant 1 for fract. */
7111 }
7114 /* Prefer factoring a common non-constant. */
7124 /* No identical multiplicands; see if we can find a common
7125 power-of-two factor in non-power-of-two multiplies. This
7126 can help in multi-dimensional array access. */
7129 {
7132 tree maybe_same;
7136 /* Move min of absolute values to int11. */
7138 {
7143 }
7144 else
7148 /* The remainder should not be a constant, otherwise we
7149 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7150 increased the number of multiplications necessary. */
7152 {
7160 }
7161 }
7168 /* We are neither factoring zero nor minus one. */
7176 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7177 same may be minus one and thus the multiplication may overflow. Perform
7178 the sum operation in an unsigned type. */
7183 /* If the sum evaluated to a constant that is not -INF the multiplication
7184 cannot overflow. */
7191 /* Do not resort to unsigned multiplication because
7192 we lose the no-overflow property of the expression. */
7194 }
7196 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7197 specified by EXPR into the buffer PTR of length LEN bytes.
7198 Return the number of bytes placed in the buffer, or zero
7199 upon failure. */
7201 static int
7203 {
7215 /* Dry run. */
7221 {
7223 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7224 number of bytes. */
7228 {
7235 else
7237 }
7238 else
7242 }
7244 }
7247 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7248 specified by EXPR into the buffer PTR of length LEN bytes.
7249 Return the number of bytes placed in the buffer, or zero
7250 upon failure. */
7252 static int
7254 {
7258 FIXED_VALUE_TYPE value;
7273 }
7276 /* Subroutine of native_encode_expr. Encode the REAL_CST
7277 specified by EXPR into the buffer PTR of length LEN bytes.
7278 Return the number of bytes placed in the buffer, or zero
7279 upon failure. */
7281 static int
7283 {
7289 /* There are always 32 bits in each long, no matter the size of
7290 the hosts long. We handle floating point representations with
7291 up to 192 bits. */
7300 /* Dry run. */
7309 {
7314 {
7321 else
7323 }
7324 else
7325 {
7328 {
7329 /* Reverse bytes within each long, or within the entire float
7330 if it's smaller than a long (for HFmode). */
7333 }
7334 }
7339 }
7341 }
7343 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7344 specified by EXPR into the buffer PTR of length LEN bytes.
7345 Return the number of bytes placed in the buffer, or zero
7346 upon failure. */
7348 static int
7350 {
7352 tree part;
7366 }
7369 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7370 specified by EXPR into the buffer PTR of length LEN bytes.
7371 Return the number of bytes placed in the buffer, or zero
7372 upon failure. */
7374 static int
7376 {
7387 {
7389 {
7392 }
7403 }
7405 }
7408 /* Subroutine of native_encode_expr. Encode the STRING_CST
7409 specified by EXPR into the buffer PTR of length LEN bytes.
7410 Return the number of bytes placed in the buffer, or zero
7411 upon failure. */
7413 static int
7415 {
7418 /* Wide-char strings are encoded in target byte-order so native
7419 encoding them is trivial. */
7434 {
7437 {
7440 }
7443 }
7444 else
7447 }
7450 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7451 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7452 buffer PTR of length LEN bytes. If PTR is NULL, don't actually store
7453 anything, just do a dry run. If OFF is not -1 then start
7454 the encoding at byte offset OFF and encode at most LEN bytes.
7455 Return the number of bytes placed in the buffer, or zero upon failure. */
7457 int
7459 {
7460 /* We don't support starting at negative offset and -1 is special. */
7465 {
7486 }
7487 }
7490 /* Subroutine of native_interpret_expr. Interpret the contents of
7491 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7492 If the buffer cannot be interpreted, return NULL_TREE. */
7494 static tree
7496 {
7506 }
7509 /* Subroutine of native_interpret_expr. Interpret the contents of
7510 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7511 If the buffer cannot be interpreted, return NULL_TREE. */
7513 static tree
7515 {
7518 double_int result;
7519 FIXED_VALUE_TYPE fixed_value;
7529 }
7532 /* Subroutine of native_interpret_expr. Interpret the contents of
7533 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7534 If the buffer cannot be interpreted, return NULL_TREE. */
7536 static tree
7538 {
7542 /* There are always 32 bits in each long, no matter the size of
7543 the hosts long. We handle floating point representations with
7544 up to 192 bits. */
7545 REAL_VALUE_TYPE r;
7555 {
7556 /* Both OFFSET and BYTE index within a long;
7557 bitpos indexes the whole float. */
7560 {
7567 else
7569 }
7570 else
7571 {
7574 {
7575 /* Reverse bytes within each long, or within the entire float
7576 if it's smaller than a long (for HFmode). */
7579 }
7580 }
7584 }
7588 }
7591 /* Subroutine of native_interpret_expr. Interpret the contents of
7592 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7593 If the buffer cannot be interpreted, return NULL_TREE. */
7595 static tree
7597 {
7612 }
7615 /* Subroutine of native_interpret_expr. Interpret the contents of
7616 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7617 If the buffer cannot be interpreted, return NULL_TREE. */
7619 static tree
7621 {
7634 {
7639 }
7641 }
7644 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7645 the buffer PTR of length LEN as a constant of type TYPE. For
7646 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7647 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7648 return NULL_TREE. */
7650 tree
7652 {
7654 {
7676 }
7677 }
7679 /* Returns true if we can interpret the contents of a native encoding
7680 as TYPE. */
7682 static bool
7684 {
7686 {
7699 }
7700 }
7703 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7704 TYPE at compile-time. If we're unable to perform the conversion
7705 return NULL_TREE. */
7707 static tree
7709 {
7710 /* We support up to 512-bit values (for V8DFmode). */
7714 /* Check that the host and target are sane. */
7723 }
7725 /* Build an expression for the address of T. Folds away INDIRECT_REF
7726 to avoid confusing the gimplify process. */
7728 tree
7730 {
7731 /* The size of the object is not relevant when talking about its address. */
7736 {
7741 }
7751 {
7756 }
7757 else
7761 }
7763 /* Build an expression for the address of T. */
7765 tree
7767 {
7771 }
7773 /* Fold a unary expression of code CODE and type TYPE with operand
7774 OP0. Return the folded expression if folding is successful.
7775 Otherwise, return NULL_TREE. */
7777 tree
7779 {
7780 tree tem;
7781 tree arg0;
7789 {
7792 {
7793 /* Don't use STRIP_NOPS, because signedness of argument type
7794 matters. */
7796 }
7797 else
7798 {
7799 /* Strip any conversions that don't change the mode. This
7800 is safe for every expression, except for a comparison
7801 expression because its signedness is derived from its
7802 operands.
7804 Note that this is done as an internal manipulation within
7805 the constant folder, in order to find the simplest
7806 representation of the arguments so that their form can be
7807 studied. In any cases, the appropriate type conversions
7808 should be put back in the tree that will get out of the
7809 constant folder. */
7811 }
7814 {
7817 {
7821 }
7822 }
7823 }
7830 {
7837 {
7851 /* If this was a conversion, and all we did was to move into
7852 inside the COND_EXPR, bring it back out. But leave it if
7853 it is a conversion from integer to integer and the
7854 result precision is no wider than a word since such a
7855 conversion is cheap and may be optimized away by combine,
7856 while it couldn't if it were outside the COND_EXPR. Then return
7857 so we don't get into an infinite recursion loop taking the
7858 conversion out and then back in. */
7870 && (INTEGRAL_TYPE_P
7883 }
7884 }
7887 {
7893 CASE_CONVERT:
7897 {
7898 /* If we have (type) (a CMP b) and type is an integral type, return
7899 new expression involving the new type. Canonicalize
7900 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7901 non-integral type.
7902 Do not fold the result as that would not simplify further, also
7903 folding again results in recursions. */
7913 }
7915 /* Handle (T *)&A.B.C for A being of type T and B and C
7916 living at offset zero. This occurs frequently in
7917 C++ upcasting and then accessing the base. */
7921 {
7923 tree offset;
7924 machine_mode mode;
7926 tree base
7930 /* If the reference was to a (constant) zero offset, we can use
7931 the address of the base if it has the same base type
7932 as the result type and the pointer type is unqualified. */
7940 }
7944 /* Detect assigning a bitfield. */
7946 && DECL_BIT_FIELD
7948 {
7949 /* Don't leave an assignment inside a conversion
7950 unless assigning a bitfield. */
7952 /* First do the assignment, then return converted constant. */
7957 }
7959 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7960 constants (if x has signed type, the sign bit cannot be set
7961 in c). This folds extension into the BIT_AND_EXPR.
7962 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7963 very likely don't have maximal range for their precision and this
7964 transformation effectively doesn't preserve non-maximal ranges. */
7968 {
7979 <= HOST_BITS_PER_WIDE_INT
7981 {
7985 cst &= HOST_WIDE_INT_M1U
7989 && !flag_syntax_only
7992 {
7996 }
7997 }
7999 {
8004 }
8005 }
8007 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
8008 cast (T1)X will fold away. We assume that this happens when X itself
8009 is a cast. */
8013 {
8017 return fold_build_pointer_plus_loc
8019 }
8021 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
8022 of the same precision, and X is an integer type not narrower than
8023 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
8029 {
8035 }
8037 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
8038 type of X and Y (integer types only). */
8043 {
8044 /* Be careful not to introduce new overflows. */
8045 tree mult_type;
8048 else
8052 {
8059 }
8060 }
8066 {
8073 }
8084 /* Convert fabs((double)float) into (double)fabsf(float). */
8087 {
8093 targ0));
8094 }
8098 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8117 /* Note that the operand of this must be an int
8118 and its values must be 0 or 1.
8119 ("true" is a fixed value perhaps depending on the language,
8120 but we don't handle values other than 1 correctly yet.) */
8127 /* Fold *&X to X if X is an lvalue. */
8129 {
8136 }
8142 }
8145 /* If the operation was a conversion do _not_ mark a resulting constant
8146 with TREE_OVERFLOW if the original constant was not. These conversions
8147 have implementation defined behavior and retaining the TREE_OVERFLOW
8148 flag here would confuse later passes such as VRP. */
8149 tree
8152 {
8161 }
8163 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
8164 operands OP0 and OP1. LOC is the location of the resulting expression.
8165 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
8166 Return the folded expression if folding is successful. Otherwise,
8167 return NULL_TREE. */
8168 static tree
8171 {
8172 tree tem;
8174 /* We only do these simplifications if we are optimizing. */
8178 /* Check for things like (A || B) && (A || C). We can convert this
8179 to A || (B && C). Note that either operator can be any of the four
8180 truth and/or operations and the transformation will still be
8181 valid. Also note that we only care about order for the
8182 ANDIF and ORIF operators. If B contains side effects, this
8183 might change the truth-value of A. */
8190 {
8210 /* This case if tricky because we must either have commutative
8211 operators or else A10 must not have side-effects. */
8217 a01);
8218 }
8220 /* See if we can build a range comparison. */
8226 {
8230 }
8234 {
8238 }
8240 /* Check for the possibility of merging component references. If our
8241 lhs is another similar operation, try to merge its rhs with our
8242 rhs. Then try to merge our lhs and rhs. */
8253 logical_op_non_short_circuit
8256 && !flag_sanitize_coverage
8261 {
8268 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8269 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8270 We don't want to pack more than two leafs to a non-IF AND/OR
8271 expression.
8272 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8273 equal to IF-CODE, then we don't want to add right-hand operand.
8274 If the inner right-hand side of left-hand operand has
8275 side-effects, or isn't simple, then we can't add to it,
8276 as otherwise we might destroy if-sequence. */
8279 /* Needed for sequence points to handle trappings, and
8280 side-effects. */
8282 {
8284 arg1);
8286 tem);
8287 }
8288 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8289 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8292 /* Needed for sequence points to handle trappings, and
8293 side-effects. */
8295 {
8300 }
8301 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8302 into (A OR B).
8303 For sequence point consistancy, we need to check for trapping,
8304 and side-effects. */
8308 }
8311 }
8313 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8314 by changing CODE to reduce the magnitude of constants involved in
8315 ARG0 of the comparison.
8316 Returns a canonicalized comparison tree if a simplification was
8317 possible, otherwise returns NULL_TREE.
8318 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8319 valid if signed overflow is undefined. */
8321 static tree
8325 {
8330 /* Match A +- CST code arg1. We can change this only if overflow
8331 is undefined. */
8334 /* In principle pointers also have undefined overflow behavior,
8335 but that causes problems elsewhere. */
8342 /* Identify the constant in arg0 and its sign. */
8346 /* Overflowed constants and zero will cause problems. */
8351 /* See if we can reduce the magnitude of the constant in
8352 arg0 by changing the comparison code. */
8353 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8357 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8361 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8365 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8369 else
8373 /* Now build the constant reduced in magnitude. But not if that
8374 would produce one outside of its types range. */
8390 }
8392 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8393 overflow further. Try to decrease the magnitude of constants involved
8394 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8395 and put sole constants at the second argument position.
8396 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8398 static tree
8401 {
8402 tree t;
8407 /* Try canonicalization by simplifying arg0. */
8412 {
8416 }
8418 /* Try canonicalization by simplifying arg1 using the swapped
8419 comparison. */
8427 }
8429 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8430 space. This is used to avoid issuing overflow warnings for
8431 expressions like &p->x which cannot wrap. */
8433 static bool
8435 {
8442 poly_wide_int wi_offset;
8448 else
8453 precision);
8468 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8469 array. */
8478 }
8480 /* Return a positive integer when the symbol DECL is known to have
8481 a nonzero address, zero when it's known not to (e.g., it's a weak
8482 symbol), and a negative integer when the symbol is not yet in the
8483 symbol table and so whether or not its address is zero is unknown.
8484 For function local objects always return positive integer. */
8485 static int
8487 {
8492 /* Function local objects are never NULL. */
8500 }
8502 /* Subroutine of fold_binary. This routine performs all of the
8503 transformations that are common to the equality/inequality
8504 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8505 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8506 fold_binary should call fold_binary. Fold a comparison with
8507 tree code CODE and type TYPE with operands OP0 and OP1. Return
8508 the folded comparison or NULL_TREE. */
8510 static tree
8513 {
8523 /* For comparisons of pointers we can decompose it to a compile time
8524 comparison of the base objects and the offsets into the object.
8525 This requires at least one operand being an ADDR_EXPR or a
8526 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8532 {
8535 machine_mode mode;
8539 /* Get base and offset for the access. Strip ADDR_EXPR for
8540 get_inner_reference, but put it back by stripping INDIRECT_REF
8541 off the base object if possible. indirect_baseN will be true
8542 if baseN is not an address but refers to the object itself. */
8545 {
8546 base0
8552 else
8554 }
8556 {
8560 {
8561 base0
8567 else
8569 }
8572 else
8576 {
8583 }
8584 }
8588 {
8589 base1
8595 else
8597 }
8599 {
8603 {
8604 base1
8610 else
8612 }
8615 else
8619 {
8626 }
8627 }
8629 /* If we have equivalent bases we might be able to simplify. */
8633 {
8634 /* We can fold this expression to a constant if the non-constant
8635 offset parts are equal. */
8639 && (equality_code
8640 || (indirect_base0
8643 {
8649 "occur when comparing P +- C1 with "
8651 WARN_STRICT_OVERFLOW_CONDITIONAL);
8654 {
8692 }
8693 }
8694 /* We can simplify the comparison to a comparison of the variable
8695 offset parts if the constant offset parts are equal.
8696 Be careful to use signed sizetype here because otherwise we
8697 mess with array offsets in the wrong way. This is possible
8698 because pointer arithmetic is restricted to retain within an
8699 object and overflow on pointer differences is undefined as of
8700 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8702 && (equality_code
8703 || (indirect_base0
8706 {
8707 /* By converting to signed sizetype we cover middle-end pointer
8708 arithmetic which operates on unsigned pointer types of size
8709 type size and ARRAY_REF offsets which are properly sign or
8710 zero extended from their type in case it is narrower than
8711 sizetype. */
8714 else
8718 else
8725 "occur when comparing P +- C1 with "
8727 WARN_STRICT_OVERFLOW_COMPARISON);
8730 }
8731 }
8732 /* For equal offsets we can simplify to a comparison of the
8733 base addresses. */
8735 && (indirect_base0
8737 && (indirect_base1
8742 {
8748 }
8749 /* Comparison between an ordinary (non-weak) symbol and a null
8750 pointer can be eliminated since such symbols must have a non
8751 null address. In C, relational expressions between pointers
8752 to objects and null pointers are undefined. The results
8753 below follow the C++ rules with the additional property that
8754 every object pointer compares greater than a null pointer.
8755 */
8758 /* Avoid folding references to struct members at offset 0 to
8759 prevent tests like '&ptr->firstmember == 0' from getting
8760 eliminated. When ptr is null, although the -> expression
8761 is strictly speaking invalid, GCC retains it as a matter
8762 of QoI. See PR c/44555. */
8765 && indirect_base0
8766 /* The caller guarantees that when one of the arguments is
8767 constant (i.e., null in this case) it is second. */
8769 {
8771 {
8782 }
8783 }
8784 }
8786 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8787 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8788 the resulting offset is smaller in absolute value than the
8789 original one and has the same sign. */
8798 {
8803 tree cst;
8805 "occur when combining constants around "
8808 /* Put the constant on the side where it doesn't overflow and is
8809 of lower absolute value and of same sign than before. */
8816 {
8819 variable1,
8823 }
8831 {
8837 variable2);
8838 }
8839 }
8845 /* If we are comparing an expression that just has comparisons
8846 of two integer values, arithmetic expressions of those comparisons,
8847 and constants, we can simplify it. There are only three cases
8848 to check: the two values can either be equal, the first can be
8849 greater, or the second can be greater. Fold the expression for
8850 those three values. Since each value must be 0 or 1, we have
8851 eight possibilities, each of which corresponds to the constant 0
8852 or 1 or one of the six possible comparisons.
8854 This handles common cases like (a > b) == 0 but also handles
8855 expressions like ((x > y) - (y > x)) > 0, which supposedly
8856 occur in macroized code. */
8859 {
8863 /* Don't handle degenerate cases here; they should already
8864 have been handled anyway. */
8873 {
8877 /* We can't just pass T to eval_subst in case cval1 or cval2
8878 was the same as ARG1. */
8880 tree high_result
8884 arg1);
8885 tree equal_result
8889 arg1);
8890 tree low_result
8894 arg1);
8896 /* All three of these results should be 0 or 1. Confirm they are.
8897 Then use those values to select the proper code to use. */
8902 {
8903 /* Make a 3-bit mask with the high-order bit being the
8904 value for `>', the next for '=', and the low for '<'. */
8908 {
8910 /* Always false. */
8931 /* Always true. */
8933 }
8936 }
8937 }
8938 }
8941 }
8944 /* Subroutine of fold_binary. Optimize complex multiplications of the
8945 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
8946 argument EXPR represents the expression "z" of type TYPE. */
8948 static tree
8950 {
8955 {
8958 }
8960 {
8963 }
8964 else
8965 {
8969 }
8978 }
8981 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
8982 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
8983 true if successful. */
8985 static bool
8987 {
8992 {
8995 }
8997 {
9003 else
9005 }
9006 else
9012 }
9014 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
9015 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
9016 NULL_TREE otherwise. */
9018 static tree
9020 {
9041 {
9042 HOST_WIDE_INT index;
9048 }
9051 {
9057 }
9058 else
9060 }
9062 /* Try to fold a pointer difference of type TYPE two address expressions of
9063 array references AREF0 and AREF1 using location LOC. Return a
9064 simplified expression for the difference or NULL_TREE. */
9066 static tree
9070 {
9075 /* If the bases are array references as well, recurse. If the bases
9076 are pointer indirections compute the difference of the pointers.
9077 If the bases are equal, we are set. */
9080 && (base_offset
9082 use_pointer_diff)))
9085 && (base_offset
9086 = use_pointer_diff
9096 {
9102 base_offset,
9105 }
9107 }
9109 /* If the real or vector real constant CST of type TYPE has an exact
9110 inverse, return it, else return NULL. */
9112 tree
9114 {
9115 REAL_VALUE_TYPE r;
9116 tree unit_type;
9117 machine_mode mode;
9120 {
9130 {
9134 tree_vector_builder elts;
9139 {
9144 }
9147 }
9151 }
9152 }
9154 /* Mask out the tz least significant bits of X of type TYPE where
9155 tz is the number of trailing zeroes in Y. */
9156 static wide_int
9158 {
9163 }
9165 /* Return true when T is an address and is known to be nonzero.
9166 For floating point we further ensure that T is not denormal.
9167 Similar logic is present in nonzero_address in rtlanal.h.
9169 If the return value is based on the assumption that signed overflow
9170 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
9171 change *STRICT_OVERFLOW_P. */
9173 static bool
9175 {
9179 /* Doing something useful for floating point would need more work. */
9185 {
9188 strict_overflow_p);
9194 strict_overflow_p);
9202 }
9205 {
9208 strict_overflow_p);
9216 strict_overflow_p);
9231 strict_overflow_p);
9235 strict_overflow_p);
9238 {
9250 }
9254 }
9256 }
9258 /* Return true when T is an address and is known to be nonzero.
9259 Handle warnings about undefined signed overflow. */
9261 bool
9263 {
9270 "determining that expression is always "
9272 WARN_STRICT_OVERFLOW_MISC);
9274 }
9276 /* Return true if T is known not to be equal to an integer W. */
9278 bool
9280 {
9282 value_range_kind rtype;
9284 {
9293 {
9298 }
9303 /* If T has some known zero bits and W has any of those bits set,
9304 then T is known not to be equal to W. */
9312 }
9313 }
9315 /* Fold a binary expression of code CODE and type TYPE with operands
9316 OP0 and OP1. LOC is the location of the resulting expression.
9317 Return the folded expression if folding is successful. Otherwise,
9318 return NULL_TREE. */
9320 tree
9323 {
9338 /* Strip any conversions that don't change the mode. This is
9339 safe for every expression, except for a comparison expression
9340 because its signedness is derived from its operands. So, in
9341 the latter case, only strip conversions that don't change the
9342 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9343 preserved.
9345 Note that this is done as an internal manipulation within the
9346 constant folder, in order to find the simplest representation
9347 of the arguments so that their form can be studied. In any
9348 cases, the appropriate type conversions should be put back in
9349 the tree that will get out of the constant folder. */
9352 {
9355 }
9356 else
9357 {
9360 }
9362 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9363 constant but we can't do arithmetic on them. */
9365 {
9368 {
9372 }
9373 }
9375 /* If this is a commutative operation, and ARG0 is a constant, move it
9376 to ARG1 to reduce the number of tests below. */
9381 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9382 to ARG1 to reduce the number of tests below. */
9391 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9393 First check for cases where an arithmetic operation is applied to a
9394 compound, conditional, or comparison operation. Push the arithmetic
9395 operation inside the compound or conditional to see if any folding
9396 can then be done. Convert comparison to conditional for this purpose.
9397 The also optimizes non-constant cases that used to be done in
9398 expand_expr.
9400 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9401 one of the operands is a comparison and the other is a comparison, a
9402 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9403 code below would make the expression more complex. Change it to a
9404 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9405 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9418 {
9422 boolean_type_node,
9430 }
9434 {
9436 {
9441 tem);
9442 }
9444 {
9449 tem);
9450 }
9455 {
9461 }
9466 {
9472 }
9473 }
9476 {
9478 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9481 {
9487 }
9489 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9492 {
9493 tree base;
9494 poly_int64 coffset;
9503 }
9508 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9514 arg1),
9516 arg0)));
9522 {
9523 /* X + (X / CST) * -CST is X % CST. */
9528 {
9537 cst0));
9538 }
9539 }
9541 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9542 one. Make sure the type is not saturating and has the signedness of
9543 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9544 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9551 {
9555 }
9558 {
9559 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9560 (plus (plus (mult) (mult)) (foo)) so that we can
9561 take advantage of the factoring cases below. */
9570 {
9576 else
9589 parg0),
9591 marg)),
9595 return
9601 parg1)));
9602 }
9603 }
9604 else
9605 {
9606 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9607 to __complex__ ( x, y ). This is not the same for SNaNs or
9608 if signed zeros are involved. */
9612 {
9619 {
9623 {
9629 }
9631 {
9637 }
9638 }
9639 }
9641 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9642 We associate floats only if the user has specified
9643 -fassociative-math. */
9647 {
9652 {
9653 tree tree0;
9656 }
9657 }
9658 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9659 We associate floats only if the user has specified
9660 -fassociative-math. */
9664 {
9669 {
9670 tree tree0;
9673 }
9674 }
9675 }
9677 bit_rotate:
9678 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9679 is a rotate of A by C1 bits. */
9680 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9681 is a rotate of A by B bits.
9682 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
9683 though in this case CODE must be | and not + or ^, otherwise
9684 it doesn't return A when B is 0. */
9685 {
9687 tree rtype;
9696 /* Only create rotates in complete modes. Other cases are not
9697 expanded properly. */
9700 {
9713 {
9718 }
9723 {
9726 code0 == LSHIFT_EXPR
9729 }
9731 {
9741 {
9745 orig_tree01);
9747 }
9748 }
9752 {
9763 {
9767 orig_tree01);
9769 }
9770 }
9771 }
9772 }
9774 associate:
9775 /* In most languages, can't associate operations on floats through
9776 parentheses. Rather than remember where the parentheses were, we
9777 don't associate floats at all, unless the user has specified
9778 -fassociative-math.
9779 And, we need to make sure type is not saturating. */
9783 {
9789 /* Split both trees into variables, constants, and literals. Then
9790 associate each group together, the constants with literals,
9791 then the result with variables. This increases the chances of
9792 literals being recombined later and of generating relocatable
9793 expressions for the sum of a constant and literal. */
9801 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9805 /* With undefined overflow prefer doing association in a type
9806 which wraps on overflow, if that is one of the operand types. */
9809 {
9817 }
9819 /* With undefined overflow we can only associate constants with one
9820 variable, and constants whose association doesn't overflow. */
9823 {
9825 {
9826 /* ??? If split_tree would handle NEGATE_EXPR we could
9827 simply reject these cases and the allowed cases would
9828 be the var0/minus_var1 ones. */
9834 {
9837 }
9844 {
9847 }
9853 /* The only case we can still associate with two variables
9854 is if they cancel out. */
9858 }
9864 }
9866 /* Only do something if we found more than two objects. Otherwise,
9867 nothing has changed and we risk infinite recursion. */
9875 {
9887 {
9891 }
9893 {
9897 }
9899 /* Preserve the MINUS_EXPR if the negative part of the literal is
9900 greater than the positive part. Otherwise, the multiplicative
9901 folding code (i.e extract_muldiv) may be fooled in case
9902 unsigned constants are subtracted, like in the following
9903 example: ((X*2 + 4) - 8U)/2. */
9905 {
9909 /* But avoid ending up with only negated parts. */
9911 {
9915 }
9916 else
9917 {
9921 }
9922 }
9924 /* Don't introduce overflows through reassociation. */
9929 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
9936 /* Eliminate minus_con0. */
9938 {
9945 else
9948 }
9950 /* Eliminate minus_var0. */
9952 {
9956 else
9959 }
9961 return
9964 }
9965 }
9971 /* Fold &a[i] - &a[j] to i-j. */
9976 {
9980 code
9984 }
9986 /* Further transformations are not for pointers. */
9990 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9993 /* If arg0 is e.g. unsigned int and type is int, then this could
9994 introduce UB, because if A is INT_MIN at runtime, the original
9995 expression can be well defined while the latter is not.
9996 See PR83269. */
10005 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
10006 __complex__ ( x, -y ). This is not the same for SNaNs or if
10007 signed zeros are involved. */
10011 {
10018 {
10022 {
10024 arg1r ? arg1r
10029 }
10031 {
10035 arg1i ? arg1i
10038 }
10039 }
10040 }
10042 /* A - B -> A + (-B) if B is easily negatable. */
10046 /* Avoid this transformation if B is a positive REAL_CST. */
10054 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
10055 one. Make sure the type is not saturating and has the signedness of
10056 the stripped operands, as fold_plusminus_mult_expr will re-associate.
10057 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
10064 {
10068 }
10074 {
10075 /* Transform x * -C into -x * C if x is easily negatable. */
10090 {
10093 "occur when simplifying "
10095 WARN_STRICT_OVERFLOW_MISC);
10097 }
10099 /* Optimize z * conj(z) for integer complex numbers. */
10106 }
10107 else
10108 {
10109 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10110 This is not the same for NaNs or if signed zeros are
10111 involved. */
10117 {
10120 return
10126 return
10131 }
10133 /* Optimize z * conj(z) for floating point complex numbers.
10134 Guarded by flag_unsafe_math_optimizations as non-finite
10135 imaginary components don't produce scalar results. */
10144 }
10148 /* Canonicalize (X & C1) | C2. */
10152 {
10157 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10165 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10167 {
10170 }
10172 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10173 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10174 mode which allows further optimizations. */
10179 {
10184 {
10187 }
10188 }
10191 {
10196 }
10197 }
10199 /* See if this can be simplified into a rotate first. If that
10200 is unsuccessful continue in the association code. */
10204 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10212 /* See if this can be simplified into a rotate first. If that
10213 is unsuccessful continue in the association code. */
10217 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10222 {
10223 tree tem2;
10230 }
10231 /* Fold ~X & 1 as (X & 1) == 0. */
10235 {
10236 tree tem2;
10243 }
10244 /* Fold !X & 1 as X == 0. */
10247 {
10251 }
10253 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
10254 multiple of 1 << CST. */
10256 {
10263 }
10265 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
10266 bits from CST2. */
10270 {
10272 wide_int masked
10279 {
10280 /* Avoid the transform if arg1 is a mask of some
10281 mode which allows further optimizations. */
10288 }
10289 }
10291 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10294 {
10299 return
10301 }
10306 /* Don't touch a floating-point divide by zero unless the mode
10307 of the constant can represent infinity. */
10313 /* (-A) / (-B) -> A / B */
10325 /* Fall through */
10328 /* Simplify A / (B << N) where A and B are positive and B is
10329 a power of 2, to A >> (N + log2(B)). */
10334 {
10337 {
10345 WARN_STRICT_OVERFLOW_MISC);
10351 }
10352 }
10354 /* Fall through */
10362 /* Convert -A / -B to A / B when the type is signed and overflow is
10363 undefined. */
10367 {
10370 "when distributing negation across "
10372 WARN_STRICT_OVERFLOW_MISC);
10377 }
10381 {
10384 "when distributing negation across "
10386 WARN_STRICT_OVERFLOW_MISC);
10391 }
10393 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
10394 operation, EXACT_DIV_EXPR.
10396 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
10397 At one time others generated faster code, it's not clear if they do
10398 after the last round to changes to the DIV code in expmed.c. */
10409 {
10413 WARN_STRICT_OVERFLOW_MISC);
10415 }
10427 {
10431 WARN_STRICT_OVERFLOW_MISC);
10433 }
10441 /* Since negative shift count is not well-defined,
10442 don't try to compute it in the compiler. */
10448 /* If we have a rotate of a bit operation with the rotate count and
10449 the second operand of the bit operation both constant,
10450 permute the two operations. */
10456 {
10464 }
10466 /* Two consecutive rotates adding up to the some integer
10467 multiple of the precision of the type can be ignored. */
10483 /* Note that the operands of this must be ints
10484 and their values must be 0 or 1.
10485 ("true" is a fixed value perhaps depending on the language.) */
10486 /* If first arg is constant zero, return it. */
10489 /* FALLTHRU */
10491 /* If either arg is constant true, drop it. */
10495 /* Preserve sequence points. */
10498 /* If second arg is constant zero, result is zero, but first arg
10499 must be evaluated. */
10502 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
10503 case will be handled here. */
10507 /* !X && X is always false. */
10511 /* X && !X is always false. */
10516 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
10517 means A >= Y && A != MAX, but in this case we know that
10518 A < X <= MAX. */
10522 {
10530 }
10539 /* Note that the operands of this must be ints
10540 and their values must be 0 or true.
10541 ("true" is a fixed value perhaps depending on the language.) */
10542 /* If first arg is constant true, return it. */
10545 /* FALLTHRU */
10547 /* If either arg is constant zero, drop it. */
10551 /* Preserve sequence points. */
10554 /* If second arg is constant true, result is true, but we must
10555 evaluate first arg. */
10558 /* Likewise for first arg, but note this only occurs here for
10559 TRUTH_OR_EXPR. */
10563 /* !X || X is always true. */
10567 /* X || !X is always true. */
10572 /* (X && !Y) || (!X && Y) is X ^ Y */
10575 {
10592 }
10601 /* If the second arg is constant zero, drop it. */
10604 /* If the second arg is constant true, this is a logical inversion. */
10606 {
10609 }
10610 /* Identical arguments cancel to zero. */
10614 /* !X ^ X is always true. */
10619 /* X ^ !X is always true. */
10635 /* bool_var != 1 becomes !bool_var. */
10642 /* bool_var == 0 becomes !bool_var. */
10649 /* !exp != 0 becomes !exp */
10654 /* If this is an EQ or NE comparison with zero and ARG0 is
10655 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
10656 two operations, but the latter can be done in one less insn
10657 on machines that have only two-operand insns or on which a
10658 constant cannot be the first operand. */
10661 {
10666 {
10673 arg1);
10674 }
10677 {
10684 arg1);
10685 }
10686 }
10688 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
10689 C1 is a valid shift constant, and C2 is a power of two, i.e.
10690 a single bit. */
10694 == INTEGER_CST
10697 {
10702 /* Check for a valid shift count. */
10704 {
10708 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
10709 can be rewritten as (X & (C2 << C1)) != 0. */
10711 {
10716 }
10717 /* Otherwise, for signed (arithmetic) shifts,
10718 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
10719 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
10723 /* Otherwise, of unsigned (logical) shifts,
10724 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
10725 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
10726 else
10730 arg000);
10731 }
10732 }
10734 /* If this is a comparison of a field, we may be able to simplify it. */
10737 /* Handle the constant case even without -O
10738 to make sure the warnings are given. */
10740 {
10744 }
10746 /* Optimize comparisons of strlen vs zero to a compare of the
10747 first character of the string vs zero. To wit,
10748 strlen(ptr) == 0 => *ptr == 0
10749 strlen(ptr) != 0 => *ptr != 0
10750 Other cases should reduce to one of these two (or a constant)
10751 due to the return value of strlen being unsigned. */
10753 {
10761 {
10762 tree ptrtype
10764 TYPE_QUAL_CONST));
10770 }
10771 }
10773 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
10774 of X. Similarly fold (X >> C) == 0 into X >= 0. */
10778 {
10783 {
10785 {
10788 }
10791 }
10792 }
10794 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
10795 (X & C) == 0 when C is a single bit. */
10800 {
10807 arg1));
10808 }
10810 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
10811 constant C is a power of two, i.e. a single bit. */
10818 {
10822 }
10824 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
10825 when is C is a power of two, i.e. a single bit. */
10832 {
10838 }
10842 {
10845 }
10847 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
10850 {
10858 {
10864 }
10866 {
10872 }
10874 {
10880 }
10882 {
10888 }
10889 }
10893 {
10900 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
10901 operand_equal_p guarantees no side-effects so we don't need
10902 to use omit_one_operand on Z. */
10906 arg10));
10910 arg11));
10914 arg10));
10918 arg11));
10920 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
10923 {
10929 }
10930 }
10932 /* Attempt to simplify equality/inequality comparisons of complex
10933 values. Only lower the comparison if the result is known or
10934 can be simplified to a single scalar comparison. */
10939 {
10944 {
10947 }
10948 else
10949 {
10952 }
10955 {
10958 }
10959 else
10960 {
10963 }
10967 {
10969 {
10974 }
10975 else
10976 {
10981 }
10982 }
10986 {
10988 {
10993 }
10994 else
10995 {
11000 }
11001 }
11002 }
11014 /* Transform comparisons of the form X +- C CMP X. */
11019 {
11024 /* (X - c) > X becomes false. */
11030 /* Likewise (X + c) < X becomes false. */
11036 /* Convert (X - c) <= X to true. */
11043 /* Convert (X + c) >= X to true. */
11049 }
11051 /* If we are comparing an ABS_EXPR with a constant, we can
11052 convert all the cases into explicit comparisons, but they may
11053 well not be faster than doing the ABS and one comparison.
11054 But ABS (X) <= C is a range comparison, which becomes a subtraction
11055 and a comparison, and is probably faster. */
11069 /* Convert ABS_EXPR<x> >= 0 to true. */
11076 {
11079 "when simplifying comparison of "
11081 WARN_STRICT_OVERFLOW_CONDITIONAL);
11084 arg0);
11085 }
11087 /* Convert ABS_EXPR<x> < 0 to false. */
11092 {
11095 "when simplifying comparison of "
11097 WARN_STRICT_OVERFLOW_CONDITIONAL);
11100 arg0);
11101 }
11103 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
11104 and similarly for >= into !=. */
11114 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
11115 otherwise Y might be >= # of bits in X's type and thus e.g.
11116 (unsigned char) (1 << Y) for Y 15 might be 0.
11117 If the cast is widening, then 1 << Y should have unsigned type,
11118 otherwise if Y is number of bits in the signed shift type minus 1,
11119 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
11120 31 might be 0xffffffff80000000. */
11131 {
11137 }
11149 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
11150 {
11162 }
11167 /* When pedantic, a compound expression can be neither an lvalue
11168 nor an integer constant expression. */
11171 /* Don't let (0, 0) be null pointer constant. */
11177 /* An ASSERT_EXPR should never be passed to fold_binary. */
11183 }
11185 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
11186 ((A & N) + B) & M -> (A + B) & M
11187 Similarly if (N & M) == 0,
11188 ((A | N) + B) & M -> (A + B) & M
11189 and for - instead of + (or unary - instead of +)
11190 and/or ^ instead of |.
11191 If B is constant and (B & M) == 0, fold into A & M.
11193 This function is a helper for match.pd patterns. Return non-NULL
11194 type in which the simplified operation should be performed only
11195 if any optimization is possible.
11197 ARG1 is M above, ARG00 is left operand of +/-, if CODE00 is BIT_*_EXPR,
11198 then ARG00{0,1} are operands of that bitop, otherwise CODE00 is ERROR_MARK.
11199 Similarly for ARG01, CODE01 and ARG01{0,1}, just for the right operand of
11200 +/-. */
11201 tree
11206 {
11221 wide_int cst0;
11223 /* Now we know that arg0 is (C + D) or (C - D) or -C and
11224 arg1 (M) is == (1LL << cst) - 1.
11225 Store C into PMOP[0] and D into PMOP[1]. */
11232 {
11239 {
11242 }
11245 /* If C or D is of the form (A & N) where
11246 (N & M) == M, or of the form (A | N) or
11247 (A ^ N) where (N & M) == 0, replace it with A. */
11253 /* If C or D is a N where (N & M) == 0, it can be
11254 omitted (replaced with 0). */
11259 /* Similarly, with C - N where (-N & M) == 0. */
11267 }
11269 /* Only build anything new if we optimized one or both arguments above. */
11275 else
11277 }
11279 /* Used by contains_label_[p1]. */
11281 struct contains_label_data
11282 {
11285 };
11287 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
11288 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
11289 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
11291 static tree
11293 {
11296 {
11307 {
11315 }
11324 }
11325 }
11327 /* Return whether the sub-tree ST contains a label which is accessible from
11328 outside the sub-tree. */
11330 static bool
11332 {
11336 }
11338 /* Fold a ternary expression of code CODE and type TYPE with operands
11339 OP0, OP1, and OP2. Return the folded expression if folding is
11340 successful. Otherwise, return NULL_TREE. */
11342 tree
11345 {
11346 tree tem;
11353 /* If this is a commutative operation, and OP0 is a constant, move it
11354 to OP1 to reduce the number of tests below. */
11363 /* Strip any conversions that don't change the mode. This is safe
11364 for every expression, except for a comparison expression because
11365 its signedness is derived from its operands. So, in the latter
11366 case, only strip conversions that don't change the signedness.
11368 Note that this is done as an internal manipulation within the
11369 constant folder, in order to find the simplest representation of
11370 the arguments so that their form can be studied. In any cases,
11371 the appropriate type conversions should be put back in the tree
11372 that will get out of the constant folder. */
11374 {
11377 }
11380 {
11383 }
11386 {
11389 }
11392 {
11396 {
11402 }
11407 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
11408 so all simple results must be passed through pedantic_non_lvalue. */
11410 {
11413 /* Only optimize constant conditions when the selected branch
11414 has the same type as the COND_EXPR. This avoids optimizing
11415 away "c ? x : throw", where the throw has a void type.
11416 Avoid throwing away that operand which contains label. */
11423 }
11425 {
11432 {
11435 {
11443 }
11448 }
11449 }
11451 /* If we have A op B ? A : C, we may be able to convert this to a
11452 simpler expression, depending on the operation and the values
11453 of B and C. Signed zeros prevent all of these transformations,
11454 for reasons given above each one.
11456 Also try swapping the arguments and inverting the conditional. */
11460 {
11464 }
11469 {
11473 {
11477 }
11478 }
11480 /* If the second operand is simpler than the third, swap them
11481 since that produces better jump optimization results. */
11484 {
11486 /* See if this can be inverted. If it can't, possibly because
11487 it was a floating-point inequality comparison, don't do
11488 anything. */
11492 }
11494 /* Convert A ? 1 : 0 to simply A. */
11499 /* If we try to convert OP0 to our type, the
11500 call to fold will try to move the conversion inside
11501 a COND, which will recurse. In that case, the COND_EXPR
11502 is probably the best choice, so leave it alone. */
11506 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
11507 over COND_EXPR in cases such as floating point comparisons. */
11516 arg0)));
11518 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
11523 {
11524 /* sign_bit_p looks through both zero and sign extensions,
11525 but for this optimization only sign extensions are
11526 usable. */
11529 {
11532 {
11535 }
11537 }
11538 /* sign_bit_p only checks ARG1 bits within A's precision.
11539 If <sign bit of A> has wider type than A, bits outside
11540 of A's precision in <sign bit of A> need to be checked.
11541 If they are all 0, this optimization needs to be done
11542 in unsigned A's type, if they are all 1 in signed A's type,
11543 otherwise this can't be done. */
11549 {
11551 tree tem_type;
11564 {
11567 }
11569 {
11572 }
11573 else
11575 }
11578 return
11584 arg1)));
11585 }
11587 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
11588 already handled above. */
11593 {
11603 op1);
11604 }
11606 /* A & N ? N : 0 is simply A & N if N is a power of two. This
11607 is probably obsolete because the first operand should be a
11608 truth value (that's why we have the two cases above), but let's
11609 leave it in until we can confirm this for all front-ends. */
11617 /* operand_equal_p compares just value, not precision, so e.g.
11618 arg1 could be 8-bit -128 and be power of two, but BIT_AND_EXPR
11619 second operand 32-bit -128, which is not a power of two (or vice
11620 versa. */
11627 /* Disable the transformations below for vectors, since
11628 fold_binary_op_with_conditional_arg may undo them immediately,
11629 yielding an infinite loop. */
11633 /* Convert A ? B : 0 into A && B if A and B are truth values. */
11642 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
11647 {
11649 /* Only perform transformation if ARG0 is easily inverted. */
11653 ? BIT_IOR_EXPR
11656 op1);
11657 }
11659 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
11664 {
11666 /* Only perform transformation if ARG0 is easily inverted. */
11672 op2);
11673 }
11675 /* Convert A ? 1 : B into A || B if A and B are truth values. */
11687 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
11688 of fold_ternary on them. */
11698 {
11709 {
11714 {
11716 {
11721 }
11727 }
11728 }
11729 }
11731 /* On constants we can use native encode/interpret to constant
11732 fold (nearly) all BIT_FIELD_REFs. */
11738 {
11741 /* Limit us to a reasonable amount of work. To relax the
11742 other limitations we need bit-shifting of the buffer
11743 and rounding up the size. */
11747 {
11749 unsigned HOST_WIDE_INT len
11754 {
11759 }
11760 }
11761 }
11767 {
11768 /* Build a vector of integers from the tree mask. */
11769 vec_perm_builder builder;
11773 /* Create a vec_perm_indices for the integer vector. */
11778 /* Check for cases that fold to OP0 or OP1 in their original
11779 element order. */
11786 {
11790 {
11793 }
11794 }
11800 {
11804 }
11808 /* Generate a canonical form of the selector. */
11810 {
11811 /* Some targets are deficient and fail to expand a single
11812 argument permutation while still allowing an equivalent
11813 2-argument version. */
11817 else
11818 {
11822 else
11823 /* Not directly supported with either encoding,
11824 so use the preferred form. */
11826 }
11828 }
11832 }
11836 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
11839 {
11845 wide_int tem2
11849 }
11854 {
11856 unsigned HOST_WIDE_INT elsize
11859 {
11865 {
11871 }
11872 }
11873 }
11879 }
11881 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
11882 of an array (or vector). */
11884 tree
11886 {
11891 {
11894 {
11895 /* Static constructors for variably sized objects makes no sense. */
11899 }
11900 }
11911 offset_int max_index;
11916 {
11917 /* Array constructor might explicitly set index, or specify a range,
11918 or leave index NULL meaning that it is next index after previous
11919 one. */
11921 {
11924 else
11925 {
11929 }
11930 }
11931 else
11932 {
11938 }
11940 /* Do we have match? */
11944 }
11946 }
11948 /* Perform constant folding and related simplification of EXPR.
11949 The related simplifications include x*1 => x, x*0 => 0, etc.,
11950 and application of the associative law.
11951 NOP_EXPR conversions may be removed freely (as long as we
11952 are careful not to change the type of the overall expression).
11953 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
11954 but we can constant-fold them if they have constant operands. */
11956 #ifdef ENABLE_FOLD_CHECKING
11957 # define fold(x) fold_1 (x)
11959 static
11960 #endif
11961 tree
11963 {
11967 tree tem;
11970 /* Return right away if a constant. */
11974 /* CALL_EXPR-like objects with variable numbers of operands are
11975 treated specially. */
11977 {
11979 {
11982 }
11984 }
11987 {
11992 {
12010 }
12011 }
12014 {
12016 {
12023 {
12028 }
12031 }
12033 /* Return a VECTOR_CST if possible. */
12035 {
12041 tree val;
12047 }
12055 }
12057 #ifdef ENABLE_FOLD_CHECKING
12058 #undef fold
12065 /* When --enable-checking=fold, compute a digest of expr before
12066 and after actual fold call to see if fold did not accidentally
12067 change original expr. */
12069 tree
12071 {
12072 tree ret;
12092 }
12094 void
12096 {
12107 }
12109 static void
12111 {
12113 }
12115 static void
12118 {
12124 recursive_label:
12134 {
12135 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
12143 }
12151 {
12152 /* Allow these fields to be modified. */
12153 tree tmp;
12164 {
12167 }
12168 }
12170 {
12171 /* Allow TREE_NO_WARNING to be set. Perhaps we shouldn't allow that
12172 and change builtins.c etc. instead - see PR89543. */
12178 }
12189 {
12192 {
12208 }
12212 {
12225 }
12242 {
12248 }
12251 {
12253 {
12256 }
12258 }
12269 {
12272 }
12282 }
12283 }
12285 /* Helper function for outputting the checksum of a tree T. When
12286 debugging with gdb, you can "define mynext" to be "next" followed
12287 by "call debug_fold_checksum (op0)", then just trace down till the
12288 outputs differ. */
12290 DEBUG_FUNCTION void
12292 {
12307 }
12309 #endif
12311 /* Fold a unary tree expression with code CODE of type TYPE with an
12312 operand OP0. LOC is the location of the resulting expression.
12313 Return a folded expression if successful. Otherwise, return a tree
12314 expression with code CODE of type TYPE with an operand OP0. */
12316 tree
12319 {
12320 tree tem;
12321 #ifdef ENABLE_FOLD_CHECKING
12330 #endif
12336 #ifdef ENABLE_FOLD_CHECKING
12343 #endif
12345 }
12347 /* Fold a binary tree expression with code CODE of type TYPE with
12348 operands OP0 and OP1. LOC is the location of the resulting
12349 expression. Return a folded expression if successful. Otherwise,
12350 return a tree expression with code CODE of type TYPE with operands
12351 OP0 and OP1. */
12353 tree
12356 MEM_STAT_DECL)
12357 {
12358 tree tem;
12359 #ifdef ENABLE_FOLD_CHECKING
12376 #endif
12382 #ifdef ENABLE_FOLD_CHECKING
12397 #endif
12399 }
12401 /* Fold a ternary tree expression with code CODE of type TYPE with
12402 operands OP0, OP1, and OP2. Return a folded expression if
12403 successful. Otherwise, return a tree expression with code CODE of
12404 type TYPE with operands OP0, OP1, and OP2. */
12406 tree
12409 {
12410 tree tem;
12411 #ifdef ENABLE_FOLD_CHECKING
12435 #endif
12442 #ifdef ENABLE_FOLD_CHECKING
12465 #endif
12467 }
12469 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
12470 arguments in ARGARRAY, and a null static chain.
12471 Return a folded expression if successful. Otherwise, return a CALL_EXPR
12472 of type TYPE from the given operands as constructed by build_call_array. */
12474 tree
12477 {
12478 tree tem;
12479 #ifdef ENABLE_FOLD_CHECKING
12498 #endif
12504 #ifdef ENABLE_FOLD_CHECKING
12520 #endif
12522 }
12524 /* Perform constant folding and related simplification of initializer
12525 expression EXPR. These behave identically to "fold_buildN" but ignore
12526 potential run-time traps and exceptions that fold must preserve. */
12528 #define START_FOLD_INIT \
12529 int saved_signaling_nans = flag_signaling_nans;\
12530 int saved_trapping_math = flag_trapping_math;\
12531 int saved_rounding_math = flag_rounding_math;\
12532 int saved_trapv = flag_trapv;\
12533 int saved_folding_initializer = folding_initializer;\
12534 flag_signaling_nans = 0;\
12535 flag_trapping_math = 0;\
12536 flag_rounding_math = 0;\
12537 flag_trapv = 0;\
12538 folding_initializer = 1;
12540 #define END_FOLD_INIT \
12541 flag_signaling_nans = saved_signaling_nans;\
12542 flag_trapping_math = saved_trapping_math;\
12543 flag_rounding_math = saved_rounding_math;\
12544 flag_trapv = saved_trapv;\
12545 folding_initializer = saved_folding_initializer;
12547 tree
12550 {
12551 tree result;
12552 START_FOLD_INIT;
12556 END_FOLD_INIT;
12558 }
12560 tree
12563 {
12564 tree result;
12565 START_FOLD_INIT;
12569 END_FOLD_INIT;
12571 }
12573 tree
12576 {
12577 tree result;
12578 START_FOLD_INIT;
12582 END_FOLD_INIT;
12584 }
12586 #undef START_FOLD_INIT
12587 #undef END_FOLD_INIT
12589 /* Determine if first argument is a multiple of second argument. Return 0 if
12590 it is not, or we cannot easily determined it to be.
12592 An example of the sort of thing we care about (at this point; this routine
12593 could surely be made more general, and expanded to do what the *_DIV_EXPR's
12594 fold cases do now) is discovering that
12596 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12598 is a multiple of
12600 SAVE_EXPR (J * 8)
12602 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
12604 This code also handles discovering that
12606 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12608 is a multiple of 8 so we don't have to worry about dealing with a
12609 possible remainder.
12611 Note that we *look* inside a SAVE_EXPR only to determine how it was
12612 calculated; it is not safe for fold to do much of anything else with the
12613 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
12614 at run time. For example, the latter example above *cannot* be implemented
12615 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
12616 evaluation time of the original SAVE_EXPR is not necessarily the same at
12617 the time the new expression is evaluated. The only optimization of this
12618 sort that would be valid is changing
12620 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
12622 divided by 8 to
12624 SAVE_EXPR (I) * SAVE_EXPR (J)
12626 (where the same SAVE_EXPR (J) is used in the original and the
12627 transformed version). */
12629 int
12631 {
12642 {
12644 /* Bitwise and provides a power of two multiple. If the mask is
12645 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
12653 {
12659 {
12662 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
12664 {
12668 {
12671 }
12672 }
12674 }
12675 }
12680 /* It is impossible to prove if op0 - op1 is multiple of bottom
12681 precisely, so be conservative here checking if both op0 and op1
12682 are multiple of bottom. Note we check the second operand first
12683 since it's usually simpler. */
12688 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
12689 as op0 - 3 if the expression has unsigned type. For example,
12690 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
12700 {
12702 /* const_binop may not detect overflow correctly,
12703 so check for it explicitly here. */
12711 }
12715 /* Can't handle conversions from non-integral or wider integral type. */
12721 /* fall through */
12738 SIGNED);
12744 {
12747 /* Check for special cases to see if top is defined as multiple
12748 of bottom:
12750 top = (X & ~(bottom - 1) ; bottom is power of 2
12752 or
12754 Y = X % bottom
12755 top = X - Y. */
12774 }
12776 /* fall through */
12784 }
12785 }
12787 #define tree_expr_nonnegative_warnv_p(X, Y) \
12790 #define RECURSE(X) \
12791 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
12793 /* Return true if CODE or TYPE is known to be non-negative. */
12795 static bool
12797 {
12800 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
12801 have a signed:1 type (where the value is -1 and 0). */
12804 }
12806 /* Return true if (CODE OP0) is known to be non-negative. If the return
12807 value is based on the assumption that signed overflow is undefined,
12808 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12809 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12811 bool
12814 {
12819 {
12821 /* We can't return 1 if flag_wrapv is set because
12822 ABS_EXPR<INT_MIN> = INT_MIN. */
12826 {
12829 }
12837 CASE_CONVERT:
12838 {
12843 {
12847 {
12851 }
12852 }
12854 {
12860 }
12861 }
12866 }
12868 /* We don't know sign of `t', so be conservative and return false. */
12870 }
12872 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
12873 value is based on the assumption that signed overflow is undefined,
12874 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12875 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12877 bool
12881 {
12886 {
12892 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
12893 both unsigned and at least 2 bits shorter than the result. */
12897 {
12902 {
12906 }
12907 }
12912 {
12913 /* x * x is always non-negative for floating point x
12914 or without overflow. */
12917 {
12922 }
12923 }
12925 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
12926 both unsigned and their total bits is shorter than the result. */
12930 {
12949 {
12959 }
12960 }
12987 }
12989 /* We don't know sign of `t', so be conservative and return false. */
12991 }
12993 /* Return true if T is known to be non-negative. If the return
12994 value is based on the assumption that signed overflow is undefined,
12995 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12996 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12998 bool
13000 {
13005 {
13019 /* Limit the depth of recursion to avoid quadratic behavior.
13020 This is expected to catch almost all occurrences in practice.
13021 If this code misses important cases that unbounded recursion
13022 would not, passes that need this information could be revised
13023 to provide it through dataflow propagation. */
13031 }
13032 }
13034 /* Return true if T is known to be non-negative. If the return
13035 value is based on the assumption that signed overflow is undefined,
13036 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13037 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13039 bool
13042 {
13044 {
13045 CASE_CFN_ACOS:
13046 CASE_CFN_ACOSH:
13047 CASE_CFN_CABS:
13048 CASE_CFN_COSH:
13049 CASE_CFN_ERFC:
13050 CASE_CFN_EXP:
13051 CASE_CFN_EXP10:
13052 CASE_CFN_EXP2:
13053 CASE_CFN_FABS:
13054 CASE_CFN_FDIM:
13055 CASE_CFN_HYPOT:
13056 CASE_CFN_POW10:
13057 CASE_CFN_FFS:
13058 CASE_CFN_PARITY:
13059 CASE_CFN_POPCOUNT:
13060 CASE_CFN_CLZ:
13061 CASE_CFN_CLRSB:
13064 /* Always true. */
13067 CASE_CFN_SQRT:
13068 CASE_CFN_SQRT_FN:
13069 /* sqrt(-0.0) is -0.0. */
13074 CASE_CFN_ASINH:
13075 CASE_CFN_ATAN:
13076 CASE_CFN_ATANH:
13077 CASE_CFN_CBRT:
13078 CASE_CFN_CEIL:
13079 CASE_CFN_CEIL_FN:
13080 CASE_CFN_ERF:
13081 CASE_CFN_EXPM1:
13082 CASE_CFN_FLOOR:
13083 CASE_CFN_FLOOR_FN:
13084 CASE_CFN_FMOD:
13085 CASE_CFN_FREXP:
13086 CASE_CFN_ICEIL:
13087 CASE_CFN_IFLOOR:
13088 CASE_CFN_IRINT:
13089 CASE_CFN_IROUND:
13090 CASE_CFN_LCEIL:
13091 CASE_CFN_LDEXP:
13092 CASE_CFN_LFLOOR:
13093 CASE_CFN_LLCEIL:
13094 CASE_CFN_LLFLOOR:
13095 CASE_CFN_LLRINT:
13096 CASE_CFN_LLROUND:
13097 CASE_CFN_LRINT:
13098 CASE_CFN_LROUND:
13099 CASE_CFN_MODF:
13100 CASE_CFN_NEARBYINT:
13101 CASE_CFN_NEARBYINT_FN:
13102 CASE_CFN_RINT:
13103 CASE_CFN_RINT_FN:
13104 CASE_CFN_ROUND:
13105 CASE_CFN_ROUND_FN:
13106 CASE_CFN_SCALB:
13107 CASE_CFN_SCALBLN:
13108 CASE_CFN_SCALBN:
13109 CASE_CFN_SIGNBIT:
13110 CASE_CFN_SIGNIFICAND:
13111 CASE_CFN_SINH:
13112 CASE_CFN_TANH:
13113 CASE_CFN_TRUNC:
13114 CASE_CFN_TRUNC_FN:
13115 /* True if the 1st argument is nonnegative. */
13118 CASE_CFN_FMAX:
13119 CASE_CFN_FMAX_FN:
13120 /* True if the 1st OR 2nd arguments are nonnegative. */
13123 CASE_CFN_FMIN:
13124 CASE_CFN_FMIN_FN:
13125 /* True if the 1st AND 2nd arguments are nonnegative. */
13128 CASE_CFN_COPYSIGN:
13129 CASE_CFN_COPYSIGN_FN:
13130 /* True if the 2nd argument is nonnegative. */
13133 CASE_CFN_POWI:
13134 /* True if the 1st argument is nonnegative or the second
13135 argument is an even integer. */
13141 CASE_CFN_POW:
13142 /* True if the 1st argument is nonnegative or the second
13143 argument is an even integer valued real. */
13145 {
13146 REAL_VALUE_TYPE c;
13147 HOST_WIDE_INT n;
13152 {
13153 REAL_VALUE_TYPE cint;
13157 }
13158 }
13163 }
13165 }
13167 /* Return true if T is known to be non-negative. If the return
13168 value is based on the assumption that signed overflow is undefined,
13169 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13170 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13172 static bool
13174 {
13180 {
13182 {
13186 /* If the initializer is non-void, then it's a normal expression
13187 that will be assigned to the slot. */
13191 /* Otherwise, the initializer sets the slot in some way. One common
13192 way is an assignment statement at the end of the initializer. */
13194 {
13202 else
13204 }
13210 }
13213 {
13219 arg0,
13220 arg1,
13222 }
13235 }
13236 }
13238 #undef RECURSE
13239 #undef tree_expr_nonnegative_warnv_p
13241 /* Return true if T is known to be non-negative. If the return
13242 value is based on the assumption that signed overflow is undefined,
13243 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13244 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13246 bool
13248 {
13255 {
13277 }
13280 {
13306 }
13307 }
13309 /* Return true if `t' is known to be non-negative. Handle warnings
13310 about undefined signed overflow. */
13312 bool
13314 {
13321 "determining that expression is always "
13323 WARN_STRICT_OVERFLOW_MISC);
13325 }
13328 /* Return true when (CODE OP0) is an address and is known to be nonzero.
13329 For floating point we further ensure that T is not denormal.
13330 Similar logic is present in nonzero_address in rtlanal.h.
13332 If the return value is based on the assumption that signed overflow
13333 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13334 change *STRICT_OVERFLOW_P. */
13336 bool
13339 {
13341 {
13344 strict_overflow_p);
13347 {
13353 strict_overflow_p));
13354 }
13359 strict_overflow_p);
13363 }
13366 }
13368 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
13369 For floating point we further ensure that T is not denormal.
13370 Similar logic is present in nonzero_address in rtlanal.h.
13372 If the return value is based on the assumption that signed overflow
13373 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13374 change *STRICT_OVERFLOW_P. */
13376 bool
13378 tree type,
13379 tree op0,
13381 {
13384 {
13388 {
13389 /* With the presence of negative values it is hard
13390 to say something. */
13397 /* One of operands must be positive and the other non-negative. */
13398 /* We don't set *STRICT_OVERFLOW_P here: even if this value
13399 overflows, on a twos-complement machine the sum of two
13400 nonnegative numbers can never be zero. */
13402 strict_overflow_p)
13404 strict_overflow_p));
13405 }
13410 {
13412 strict_overflow_p)
13414 strict_overflow_p))
13415 {
13418 }
13419 }
13428 {
13431 }
13438 {
13442 /* When both operands are nonzero, then MAX must be too. */
13444 strict_overflow_p))
13447 /* MAX where operand 0 is positive is positive. */
13449 strict_overflow_p);
13450 }
13451 /* MAX where operand 1 is positive is positive. */
13456 {
13460 }
13465 strict_overflow_p)
13467 strict_overflow_p));
13471 }
13474 }
13476 /* Return true when T is an address and is known to be nonzero.
13477 For floating point we further ensure that T is not denormal.
13478 Similar logic is present in nonzero_address in rtlanal.h.
13480 If the return value is based on the assumption that signed overflow
13481 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13482 change *STRICT_OVERFLOW_P. */
13484 bool
13486 {
13489 {
13494 {
13506 /* For objects in symbol table check if we know they are non-zero.
13507 Don't do anything for variables and functions before symtab is built;
13508 it is quite possible that they will be declared weak later. */
13513 /* Constants are never weak. */
13518 }
13526 {
13530 }
13540 }
13542 }
13544 #define integer_valued_real_p(X) \
13547 #define RECURSE(X) \
13548 ((integer_valued_real_p) (X, depth + 1))
13550 /* Return true if the floating point result of (CODE OP0) has an
13551 integer value. We also allow +Inf, -Inf and NaN to be considered
13552 integer values. Return false for signaling NaN.
13554 DEPTH is the current nesting depth of the query. */
13556 bool
13558 {
13560 {
13567 CASE_CONVERT:
13568 {
13575 }
13579 }
13581 }
13583 /* Return true if the floating point result of (CODE OP0 OP1) has an
13584 integer value. We also allow +Inf, -Inf and NaN to be considered
13585 integer values. Return false for signaling NaN.
13587 DEPTH is the current nesting depth of the query. */
13589 bool
13591 {
13593 {
13603 }
13605 }
13607 /* Return true if the floating point result of calling FNDECL with arguments
13608 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
13609 considered integer values. Return false for signaling NaN. If FNDECL
13610 takes fewer than 2 arguments, the remaining ARGn are null.
13612 DEPTH is the current nesting depth of the query. */
13614 bool
13616 {
13618 {
13619 CASE_CFN_CEIL:
13620 CASE_CFN_CEIL_FN:
13621 CASE_CFN_FLOOR:
13622 CASE_CFN_FLOOR_FN:
13623 CASE_CFN_NEARBYINT:
13624 CASE_CFN_NEARBYINT_FN:
13625 CASE_CFN_RINT:
13626 CASE_CFN_RINT_FN:
13627 CASE_CFN_ROUND:
13628 CASE_CFN_ROUND_FN:
13629 CASE_CFN_TRUNC:
13630 CASE_CFN_TRUNC_FN:
13633 CASE_CFN_FMIN:
13634 CASE_CFN_FMIN_FN:
13635 CASE_CFN_FMAX:
13636 CASE_CFN_FMAX_FN:
13641 }
13643 }
13645 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
13646 has an integer value. We also allow +Inf, -Inf and NaN to be
13647 considered integer values. Return false for signaling NaN.
13649 DEPTH is the current nesting depth of the query. */
13651 bool
13653 {
13655 {
13663 /* Limit the depth of recursion to avoid quadratic behavior.
13664 This is expected to catch almost all occurrences in practice.
13665 If this code misses important cases that unbounded recursion
13666 would not, passes that need this information could be revised
13667 to provide it through dataflow propagation. */
13671 depth));
13675 }
13677 }
13679 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
13680 has an integer value. We also allow +Inf, -Inf and NaN to be
13681 considered integer values. Return false for signaling NaN.
13683 DEPTH is the current nesting depth of the query. */
13685 static bool
13687 {
13689 {
13700 }
13702 }
13704 #undef RECURSE
13705 #undef integer_valued_real_p
13707 /* Return true if the floating point expression T has an integer value.
13708 We also allow +Inf, -Inf and NaN to be considered integer values.
13709 Return false for signaling NaN.
13711 DEPTH is the current nesting depth of the query. */
13713 bool
13715 {
13723 {
13739 }
13742 {
13748 {
13757 }
13761 }
13762 }
13764 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
13765 attempt to fold the expression to a constant without modifying TYPE,
13766 OP0 or OP1.
13768 If the expression could be simplified to a constant, then return
13769 the constant. If the expression would not be simplified to a
13770 constant, then return NULL_TREE. */
13772 tree
13774 {
13777 }
13779 /* Given the components of a unary expression CODE, TYPE and OP0,
13780 attempt to fold the expression to a constant without modifying
13781 TYPE or OP0.
13783 If the expression could be simplified to a constant, then return
13784 the constant. If the expression would not be simplified to a
13785 constant, then return NULL_TREE. */
13787 tree
13789 {
13792 }
13794 /* If EXP represents referencing an element in a constant string
13795 (either via pointer arithmetic or array indexing), return the
13796 tree representing the value accessed, otherwise return NULL. */
13798 tree
13800 {
13804 {
13806 tree index;
13807 tree string;
13812 else
13813 {
13817 /* Optimize the special-case of a zero lower bound.
13819 We convert the low_bound to sizetype to avoid some problems
13820 with constant folding. (E.g. suppose the lower bound is 1,
13821 and its mode is QI. Without the conversion,l (ARRAY
13822 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
13823 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
13829 }
13831 scalar_int_mode char_mode;
13843 }
13845 }
13847 /* Return the tree for neg (ARG0) when ARG0 is known to be either
13848 an integer constant, real, or fixed-point constant.
13850 TYPE is the type of the result. */
13852 static tree
13854 {
13858 {
13864 {
13865 FIXED_VALUE_TYPE f;
13870 /* Propagate overflow flags. */
13874 }
13878 {
13885 }
13888 }
13891 }
13893 /* Return the tree for abs (ARG0) when ARG0 is known to be either
13894 an integer constant or real constant.
13896 TYPE is the type of the result. */
13898 tree
13900 {
13904 {
13906 {
13907 /* If the value is unsigned or non-negative, then the absolute value
13908 is the same as the ordinary value. */
13912 ;
13914 /* If the value is negative, then the absolute value is
13915 its negation. */
13916 else
13919 /* Force to the destination type, set TREE_OVERFLOW for signed
13920 TYPE only. */
13922 }
13928 else
13934 }
13937 }
13939 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
13940 constant. TYPE is the type of the result. */
13942 static tree
13944 {
13948 }
13950 /* Given CODE, a relational operator, the target type, TYPE and two
13951 constant operands OP0 and OP1, return the result of the
13952 relational operation. If the result is not a compile time
13953 constant, then return NULL_TREE. */
13955 static tree
13957 {
13960 /* From here on, the only cases we handle are when the result is
13961 known to be a constant. */
13964 {
13968 /* Handle the cases where either operand is a NaN. */
13970 {
13972 {
14000 }
14003 }
14006 }
14009 {
14013 }
14015 /* Handle equality/inequality of complex constants. */
14017 {
14028 else
14030 }
14033 {
14035 {
14036 /* Have vector comparison with scalar boolean result. */
14044 {
14052 }
14054 }
14055 tree_vector_builder elts;
14060 {
14073 }
14076 }
14078 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
14080 To compute GT, swap the arguments and do LT.
14081 To compute GE, do LT and invert the result.
14082 To compute LE, swap the arguments, do LT and invert the result.
14083 To compute NE, do EQ and invert the result.
14085 Therefore, the code below must handle only EQ and LT. */
14088 {
14091 }
14093 /* Note that it is safe to invert for real values here because we
14094 have already handled the one case that it matters. */
14098 {
14101 }
14103 /* Compute a result for LT or EQ if args permit;
14104 Otherwise return T. */
14106 {
14109 else
14111 }
14112 else
14118 }
14120 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
14121 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
14122 itself. */
14124 tree
14126 {
14127 /* If the expression does not have side effects then we don't have to wrap
14128 it with a cleanup point expression. */
14132 /* If the expression is a return, check to see if the expression inside the
14133 return has no side effects or the right hand side of the modify expression
14134 inside the return. If either don't have side effects set we don't need to
14135 wrap the expression in a cleanup point expression. Note we don't check the
14136 left hand side of the modify because it should always be a return decl. */
14138 {
14145 }
14148 }
14150 /* Given a pointer value OP0 and a type TYPE, return a simplified version
14151 of an indirection through OP0, or NULL_TREE if no simplification is
14152 possible. */
14154 tree
14156 {
14158 tree subtype;
14159 poly_uint64 const_op01;
14168 {
14172 /* *&CONST_DECL -> to the value of the const decl. */
14175 /* *&p => p; make sure to handle *&"str"[cst] here. */
14177 {
14181 else
14183 }
14184 /* *(foo *)&fooarray => fooarray[0] */
14187 && (!in_gimple_form
14189 {
14199 }
14200 /* *(foo *)&complexfoo => __real__ complexfoo */
14204 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14207 {
14211 index);
14212 }
14213 }
14217 {
14223 {
14224 tree op00type;
14228 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
14231 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
14232 but we want to treat offsets with MSB set as negative.
14233 For the code below negative offsets are invalid and
14234 TYPE_SIZE of the element is something unsigned, so
14235 check whether op01 fits into poly_int64, which implies
14236 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
14237 then just use poly_uint64 because we want to treat the
14238 value as unsigned. */
14240 {
14242 poly_uint64 max_offset
14246 {
14251 }
14252 }
14253 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
14256 {
14258 const_op01))
14260 }
14261 /* ((foo *)&fooarray)[1] => fooarray[1] */
14264 {
14273 {
14278 }
14279 }
14280 }
14281 }
14283 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
14286 && (!in_gimple_form
14288 {
14289 tree type_domain;
14299 NULL_TREE);
14300 }
14303 }
14305 /* Builds an expression for an indirection through T, simplifying some
14306 cases. */
14308 tree
14310 {
14318 }
14320 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14322 tree
14324 {
14329 else
14331 }
14333 /* Strip non-trapping, non-side-effecting tree nodes from an expression
14334 whose result is ignored. The type of the returned tree need not be
14335 the same as the original expression. */
14337 tree
14339 {
14345 {
14356 else
14362 {
14378 }
14383 }
14384 }
14386 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
14388 tree
14390 {
14396 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14397 have to do anything. Only do this when we are not given a const,
14398 because in that case, this check is more expensive than just
14399 doing it. */
14401 {
14406 }
14408 /* If divisor is a power of two, simplify this to bit manipulation. */
14410 {
14412 {
14426 }
14427 else
14428 {
14429 tree t;
14435 }
14436 }
14437 else
14438 {
14443 }
14446 }
14448 /* Likewise, but round down. */
14450 tree
14452 {
14459 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14460 have to do anything. Only do this when we are not given a const,
14461 because in that case, this check is more expensive than just
14462 doing it. */
14464 {
14469 }
14471 /* If divisor is a power of two, simplify this to bit manipulation. */
14473 {
14474 tree t;
14478 }
14479 else
14480 {
14485 }
14488 }
14490 /* Returns the pointer to the base of the object addressed by EXP and
14491 extracts the information about the offset of the access, storing it
14492 to PBITPOS and POFFSET. */
14494 static tree
14497 {
14498 tree core;
14499 machine_mode mode;
14501 poly_int64 bitsize;
14505 {
14510 }
14512 {
14518 {
14519 poly_offset_int tem
14525 }
14526 }
14527 else
14528 {
14532 }
14535 }
14537 /* Returns true if addresses of E1 and E2 differ by a constant, false
14538 otherwise. If they do, E1 - E2 is stored in *DIFF. */
14540 bool
14542 {
14557 {
14567 }
14569 {
14570 /* If only one of the offsets is non-constant, the difference cannot
14571 be a constant. */
14573 }
14574 else
14579 }
14581 /* Return OFF converted to a pointer offset type suitable as offset for
14582 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
14583 tree
14585 {
14587 }
14589 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14590 tree
14592 {
14595 }
14597 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14598 tree
14600 {
14603 }
14605 /* Return a pointer P to a NUL-terminated string representing the sequence
14606 of constant characters referred to by SRC (or a subsequence of such
14607 characters within it if SRC is a reference to a string plus some
14608 constant offset). If STRLEN is non-null, store the number of bytes
14609 in the string constant including the terminating NUL char. *STRLEN is
14610 typically strlen(P) + 1 in the absence of embedded NUL characters. */
14614 {
14615 tree offset_node;
14616 tree mem_size;
14627 {
14630 else
14632 }
14637 /* STRING_LENGTH is the size of the string literal, including any
14638 embedded NULs. STRING_SIZE is the size of the array the string
14639 literal is stored in. */
14643 /* Ideally this would turn into a gcc_checking_assert over time. */
14649 /* Ideally this would turn into a gcc_checking_assert over time. */
14658 {
14659 /* Compute and store the length of the substring at OFFSET.
14660 All offsets past the initial length refer to null strings. */
14663 else
14665 }
14666 else
14667 {
14669 /* Support only properly NUL-terminated single byte strings. */
14674 }
14677 }
14679 /* Given a tree T, compute which bits in T may be nonzero. */
14681 wide_int
14683 {
14685 {
14703 CASE_CONVERT:
14709 {
14714 }
14718 {
14726 }
14730 {
14738 }
14742 }
14745 }
14747 #if CHECKING_P
14751 /* Helper functions for writing tests of folding trees. */
14753 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
14755 static void
14757 tree constant)
14758 {
14760 }
14762 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
14763 wrapping WRAPPED_EXPR. */
14765 static void
14767 tree wrapped_expr)
14768 {
14773 }
14775 /* Verify that various arithmetic binary operations are folded
14776 correctly. */
14778 static void
14780 {
14786 /* Addition. */
14787 /* 1 <-- (0 + 1) */
14789 one);
14791 one);
14793 /* (nonlvalue)x <-- (x + 0) */
14795 x);
14797 /* Subtraction. */
14798 /* 0 <-- (x - x) */
14800 zero);
14802 x);
14804 /* Multiplication. */
14805 /* 0 <-- (x * 0) */
14807 zero);
14809 /* (nonlvalue)x <-- (x * 1) */
14811 x);
14812 }
14814 /* Verify that various binary operations on vectors are folded
14815 correctly. */
14817 static void
14819 {
14825 /* Verify equality tests that return a scalar boolean result. */
14831 }
14833 /* Verify folding of VEC_DUPLICATE_EXPRs. */
14835 static void
14837 {
14840 /* This will be 1 if VEC_MODE isn't a vector mode. */
14847 }
14849 /* Run all of the selftests within this file. */
14851 void
14853 {
14857 }