| blob | 9f558e26c80d944f88b5761c2f598ca86784a8cb |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2018 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /*@@ This file should be rewritten to use an arbitrary precision
21 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
22 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
23 @@ The routines that translate from the ap rep should
24 @@ warn if precision et. al. is lost.
25 @@ This would also make life easier when this technology is used
26 @@ for cross-compilers. */
28 /* The entry points in this file are fold, size_int_wide and size_binop.
30 fold takes a tree as argument and returns a simplified tree.
32 size_binop takes a tree code for an arithmetic operation
33 and two operands that are trees, and produces a tree for the
34 result, assuming the type comes from `sizetype'.
36 size_int takes an integer value, and creates a tree constant
37 with type from `sizetype'.
39 Note: Since the folders get called on non-gimple code as well as
40 gimple code, we need to handle GIMPLE tuples as well as their
41 corresponding tree equivalents. */
87 /* Nonzero if we are folding constants inside an initializer; zero
88 otherwise. */
91 /* The following constants represent a bit based encoding of GCC's
92 comparison operators. This encoding simplifies transformations
93 on relational comparison operators, such as AND and OR. */
111 };
144 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
145 Otherwise, return LOC. */
147 static location_t
149 {
152 }
154 /* Similar to protected_set_expr_location, but never modify x in place,
155 if location can and needs to be set, unshare it. */
159 {
165 {
168 }
170 }
171 \f
172 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
173 division and returns the quotient. Otherwise returns
174 NULL_TREE. */
176 tree
178 {
179 widest_int quo;
186 }
187 \f
188 /* This is nonzero if we should defer warnings about undefined
189 overflow. This facility exists because these warnings are a
190 special case. The code to estimate loop iterations does not want
191 to issue any warnings, since it works with expressions which do not
192 occur in user code. Various bits of cleanup code call fold(), but
193 only use the result if it has certain characteristics (e.g., is a
194 constant); that code only wants to issue a warning if the result is
195 used. */
199 /* If a warning about undefined overflow is deferred, this is the
200 warning. Note that this may cause us to turn two warnings into
201 one, but that is fine since it is sufficient to only give one
202 warning per expression. */
206 /* If a warning about undefined overflow is deferred, this is the
207 level at which the warning should be emitted. */
211 /* Start deferring overflow warnings. We could use a stack here to
212 permit nested calls, but at present it is not necessary. */
214 void
216 {
218 }
220 /* Stop deferring overflow warnings. If there is a pending warning,
221 and ISSUE is true, then issue the warning if appropriate. STMT is
222 the statement with which the warning should be associated (used for
223 location information); STMT may be NULL. CODE is the level of the
224 warning--a warn_strict_overflow_code value. This function will use
225 the smaller of CODE and the deferred code when deciding whether to
226 issue the warning. CODE may be zero to mean to always use the
227 deferred code. */
229 void
231 {
233 location_t locus;
238 {
244 }
255 /* Use the smallest code level when deciding to issue the
256 warning. */
265 else
268 }
270 /* Stop deferring overflow warnings, ignoring any deferred
271 warnings. */
273 void
275 {
277 }
279 /* Whether we are deferring overflow warnings. */
281 bool
283 {
285 }
287 /* This is called when we fold something based on the fact that signed
288 overflow is undefined. */
290 void
292 {
294 {
297 {
300 }
301 }
304 }
305 \f
306 /* Return true if the built-in mathematical function specified by CODE
307 is odd, i.e. -f(x) == f(-x). */
309 bool
311 {
313 {
314 CASE_CFN_ASIN:
315 CASE_CFN_ASINH:
316 CASE_CFN_ATAN:
317 CASE_CFN_ATANH:
318 CASE_CFN_CASIN:
319 CASE_CFN_CASINH:
320 CASE_CFN_CATAN:
321 CASE_CFN_CATANH:
322 CASE_CFN_CBRT:
323 CASE_CFN_CPROJ:
324 CASE_CFN_CSIN:
325 CASE_CFN_CSINH:
326 CASE_CFN_CTAN:
327 CASE_CFN_CTANH:
328 CASE_CFN_ERF:
329 CASE_CFN_LLROUND:
330 CASE_CFN_LROUND:
331 CASE_CFN_ROUND:
332 CASE_CFN_SIN:
333 CASE_CFN_SINH:
334 CASE_CFN_TAN:
335 CASE_CFN_TANH:
336 CASE_CFN_TRUNC:
339 CASE_CFN_LLRINT:
340 CASE_CFN_LRINT:
341 CASE_CFN_NEARBYINT:
342 CASE_CFN_RINT:
347 }
349 }
351 /* Check whether we may negate an integer constant T without causing
352 overflow. */
354 bool
356 {
357 tree type;
366 }
368 /* Determine whether an expression T can be cheaply negated using
369 the function negate_expr without introducing undefined overflow. */
371 static bool
373 {
374 tree type;
383 {
388 /* Check that -CST will not overflow type. */
401 /* We want to canonicalize to positive real constants. Pretend
402 that only negative ones can be easily negated. */
410 {
414 /* Steps don't prevent negation. */
421 }
436 /* -(A + B) -> (-B) - A. */
439 /* -(A + B) -> (-A) - B. */
443 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
452 /* INT_MIN/n * n doesn't overflow while negating one operand it does
453 if n is a (negative) power of two. */
464 /* Fall through. */
479 /* In general we can't negate B in A / B, because if A is INT_MIN and
480 B is 1, we may turn this into INT_MIN / -1 which is undefined
481 and actually traps on some architectures. */
490 /* Negate -((double)float) as (double)(-float). */
492 {
496 }
500 /* Negate -f(x) as f(-x). */
506 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
508 {
512 }
517 }
519 }
521 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
522 simplification is possible.
523 If negate_expr_p would return true for T, NULL_TREE will never be
524 returned. */
526 static tree
528 {
530 tree tem;
533 {
534 /* Convert - (~A) to A + 1. */
558 {
563 }
567 {
568 tree_vector_builder elts;
572 {
577 }
580 }
603 {
604 /* -(A + B) -> (-B) - A. */
606 {
610 }
612 /* -(A + B) -> (-A) - B. */
614 {
618 }
619 }
623 /* - (A - B) -> B - A */
634 /* Fall through. */
638 {
647 }
659 /* In general we can't negate B in A / B, because if A is INT_MIN and
660 B is 1, we may turn this into INT_MIN / -1 which is undefined
661 and actually traps on some architectures. */
673 /* Convert -((double)float) into (double)(-float). */
675 {
679 }
683 /* Negate -f(x) as f(-x). */
686 {
692 }
696 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
698 {
701 {
708 }
709 }
714 }
717 }
719 /* A wrapper for fold_negate_expr_1. */
721 static tree
723 {
730 }
732 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
733 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
734 return NULL_TREE. */
736 static tree
738 {
740 location_t loc;
753 }
754 \f
755 /* Split a tree IN into a constant, literal and variable parts that could be
756 combined with CODE to make IN. "constant" means an expression with
757 TREE_CONSTANT but that isn't an actual constant. CODE must be a
758 commutative arithmetic operation. Store the constant part into *CONP,
759 the literal in *LITP and return the variable part. If a part isn't
760 present, set it to null. If the tree does not decompose in this way,
761 return the entire tree as the variable part and the other parts as null.
763 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
764 case, we negate an operand that was subtracted. Except if it is a
765 literal for which we use *MINUS_LITP instead.
767 If NEGATE_P is true, we are negating all of IN, again except a literal
768 for which we use *MINUS_LITP instead. If a variable part is of pointer
769 type, it is negated after converting to TYPE. This prevents us from
770 generating illegal MINUS pointer expression. LOC is the location of
771 the converted variable part.
773 If IN is itself a literal or constant, return it as appropriate.
775 Note that we do not guarantee that any of the three values will be the
776 same type as IN, but they will have the same signedness and mode. */
778 static tree
782 {
790 /* Strip any conversions that don't change the machine mode or signedness. */
799 /* We can associate addition and subtraction together (even
800 though the C standard doesn't say so) for integers because
801 the value is not affected. For reals, the value might be
802 affected, so we can't. */
808 {
814 /* First see if either of the operands is a literal, then a constant. */
827 /* If we haven't dealt with either operand, this is not a case we can
828 decompose. Otherwise, VAR is either of the ones remaining, if any. */
833 else
836 /* Now do any needed negations. */
843 }
848 {
849 /* -1 - X is folded to ~X, undo that here. Do _not_ do this
850 when IN is constant. */
853 }
854 else
858 {
871 }
881 }
883 /* Re-associate trees split by the above function. T1 and T2 are
884 either expressions to associate or null. Return the new
885 expression, if any. LOC is the location of the new expression. If
886 we build an operation, do it in TYPE and with CODE. */
888 static tree
890 {
892 {
895 }
899 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
900 try to fold this since we will have infinite recursion. But do
901 deal with any NEGATE_EXPRs. */
905 {
907 {
920 }
922 {
925 }
929 }
933 }
934 \f
935 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
936 for use in int_const_binop, size_binop and size_diffop. */
938 static bool
940 {
947 {
956 }
961 }
963 /* Subroutine of int_const_binop_1 that handles two INTEGER_CSTs. */
965 static tree
968 {
969 wide_int res;
970 tree t;
979 {
995 {
999 else
1001 }
1004 /* It's unclear from the C standard whether shifts can overflow.
1005 The following code ignores overflow; perhaps a C standard
1006 interpretation ruling is needed. */
1008 else
1015 {
1019 else
1021 }
1025 else
1104 }
1112 }
1114 /* Combine two integer constants PARG1 and PARG2 under operation CODE
1115 to produce a new constant. Return NULL_TREE if we don't know how
1116 to evaluate CODE at compile-time. */
1118 static tree
1121 {
1128 {
1129 poly_wide_int res;
1134 {
1152 else
1159 else
1172 }
1177 }
1180 }
1182 tree
1184 {
1186 }
1188 /* Return true if binary operation OP distributes over addition in operand
1189 OPNO, with the other operand being held constant. OPNO counts from 1. */
1191 static bool
1193 {
1195 {
1206 }
1207 }
1209 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1210 constant. We assume ARG1 and ARG2 have the same data type, or at least
1211 are the same kind of constant and the same machine mode. Return zero if
1212 combining the constants is not allowed in the current operating mode. */
1214 static tree
1216 {
1217 /* Sanity check for the recursive cases. */
1225 {
1231 }
1234 {
1235 machine_mode mode;
1236 REAL_VALUE_TYPE d1;
1237 REAL_VALUE_TYPE d2;
1238 REAL_VALUE_TYPE value;
1239 REAL_VALUE_TYPE result;
1243 /* The following codes are handled by real_arithmetic. */
1245 {
1256 }
1264 /* Don't perform operation if we honor signaling NaNs and
1265 either operand is a signaling NaN. */
1271 /* Don't perform operation if it would raise a division
1272 by zero exception. */
1278 /* If either operand is a NaN, just return it. Otherwise, set up
1279 for floating-point trap; we return an overflow. */
1281 {
1282 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1283 is off. */
1287 }
1289 {
1290 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1291 is off. */
1295 }
1300 /* Don't constant fold this floating point operation if
1301 the result has overflowed and flag_trapping_math. */
1309 /* Don't constant fold this floating point operation if the
1310 result may dependent upon the run-time rounding mode and
1311 flag_rounding_math is set, or if GCC's software emulation
1312 is unable to accurately represent the result. */
1322 }
1325 {
1326 FIXED_VALUE_TYPE f1;
1327 FIXED_VALUE_TYPE f2;
1328 FIXED_VALUE_TYPE result;
1333 /* The following codes are handled by fixed_arithmetic. */
1335 {
1347 {
1354 }
1359 }
1366 /* Propagate overflow flags. */
1370 }
1373 {
1382 {
1393 mpc_mul);
1407 mpc_div);
1408 /* Fallthru. */
1414 {
1415 /* Keep this algorithm in sync with
1416 tree-complex.c:expand_complex_div_straight().
1418 Expand complex division to scalars, straightforward algorithm.
1419 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1420 t = br*br + bi*bi
1421 */
1422 tree magsquared
1426 tree t1
1430 tree t2
1437 }
1438 else
1439 {
1440 /* Keep this algorithm in sync with
1441 tree-complex.c:expand_complex_div_wide().
1443 Expand complex division to scalars, modified algorithm to minimize
1444 overflow with wide input ranges. */
1450 {
1451 /* In the TRUE branch, we compute
1452 ratio = br/bi;
1453 div = (br * ratio) + bi;
1454 tr = (ar * ratio) + ai;
1455 ti = (ai * ratio) - ar;
1456 tr = tr / div;
1457 ti = ti / div; */
1468 }
1469 else
1470 {
1471 /* In the FALSE branch, we compute
1472 ratio = d/c;
1473 divisor = (d * ratio) + c;
1474 tr = (b * ratio) + a;
1475 ti = b - (a * ratio);
1476 tr = tr / div;
1477 ti = ti / div; */
1489 }
1490 }
1495 }
1499 }
1505 {
1510 /* We can operate directly on the encoding if:
1512 a3 - a2 == a2 - a1 && b3 - b2 == b2 - b1
1513 implies
1514 (a3 op b3) - (a2 op b2) == (a2 op b2) - (a1 op b1)
1516 Addition and subtraction are the supported operators
1517 for which this is true. */
1520 /* We can operate directly on stepped encodings if:
1522 a3 - a2 == a2 - a1
1523 implies:
1524 (a3 op c) - (a2 op c) == (a2 op c) - (a1 op c)
1526 which is true if (x -> x op c) distributes over addition. */
1528 else
1529 /* Similarly in reverse. */
1531 tree_vector_builder elts;
1536 {
1542 /* It is possible that const_binop cannot handle the given
1543 code and return NULL_TREE */
1547 }
1550 }
1552 /* Shifts allow a scalar offset for a vector. */
1555 {
1558 tree_vector_builder elts;
1563 {
1568 /* It is possible that const_binop cannot handle the given
1569 code and return NULL_TREE. */
1573 }
1576 }
1578 }
1580 /* Overload that adds a TYPE parameter to be able to dispatch
1581 to fold_relational_const. */
1583 tree
1585 {
1589 /* ??? Until we make the const_binop worker take the type of the
1590 result as argument put those cases that need it here. */
1592 {
1609 {
1614 }
1619 {
1633 {
1643 }
1646 }
1652 {
1674 {
1687 }
1690 }
1693 }
1698 /* Make sure type and arg0 have the same saturating flag. */
1703 }
1705 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1706 Return zero if computing the constants is not possible. */
1708 tree
1710 {
1711 /* Don't perform the operation, other than NEGATE and ABS, if
1712 flag_signaling_nans is on and the operand is a signaling NaN. */
1721 {
1722 CASE_CONVERT:
1729 /* If the source address is 0, and the source address space
1730 cannot have a valid object at 0, fold to dest type null. */
1741 {
1742 /* Can't call fold_negate_const directly here as that doesn't
1743 handle all cases and we might not be able to negate some
1744 constants. */
1749 }
1758 {
1762 }
1770 /* Perform BIT_NOT_EXPR on each element individually. */
1772 {
1773 tree elem;
1775 /* This can cope with stepped encodings because ~x == -1 - x. */
1776 tree_vector_builder elements;
1780 {
1786 }
1789 }
1811 {
1829 else
1834 {
1840 }
1843 }
1852 }
1855 }
1857 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1858 indicates which particular sizetype to create. */
1860 tree
1862 {
1864 }
1865 \f
1866 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1867 is a tree code. The type of the result is taken from the operands.
1868 Both must be equivalent integer types, ala int_binop_types_match_p.
1869 If the operands are constant, so is the result. */
1871 tree
1873 {
1882 /* Handle the special case of two poly_int constants faster. */
1884 {
1885 /* And some specific cases even faster than that. */
1887 {
1892 }
1894 {
1897 }
1899 {
1902 }
1904 /* Handle general case of two integer constants. For sizetype
1905 constant calculations we always want to know about overflow,
1906 even in the unsigned case. */
1910 }
1913 }
1915 /* Given two values, either both of sizetype or both of bitsizetype,
1916 compute the difference between the two values. Return the value
1917 in signed type corresponding to the type of the operands. */
1919 tree
1921 {
1923 tree ctype;
1928 /* If the type is already signed, just do the simple thing. */
1936 else
1939 /* If either operand is not a constant, do the conversions to the signed
1940 type and subtract. The hardware will do the right thing with any
1941 overflow in the subtraction. */
1947 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1948 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1949 overflow) and negate (which can't either). Special-case a result
1950 of zero while we're here. */
1956 else
1960 MINUS_EXPR,
1962 }
1963 \f
1964 /* A subroutine of fold_convert_const handling conversions of an
1965 INTEGER_CST to another integer type. */
1967 static tree
1969 {
1970 /* Given an integer constant, make new constant with new type,
1971 appropriately sign-extended or truncated. Use widest_int
1972 so that any extension is done according ARG1's type. */
1976 }
1978 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1979 to an integer type. */
1981 static tree
1983 {
1985 tree t;
1987 /* The following code implements the floating point to integer
1988 conversion rules required by the Java Language Specification,
1989 that IEEE NaNs are mapped to zero and values that overflow
1990 the target precision saturate, i.e. values greater than
1991 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
1992 are mapped to INT_MIN. These semantics are allowed by the
1993 C and C++ standards that simply state that the behavior of
1994 FP-to-integer conversion is unspecified upon overflow. */
1996 wide_int val;
1997 REAL_VALUE_TYPE r;
2001 {
2008 }
2010 /* If R is NaN, return zero and show we have an overflow. */
2012 {
2015 }
2017 /* See if R is less than the lower bound or greater than the
2018 upper bound. */
2021 {
2025 {
2028 }
2029 }
2032 {
2035 {
2038 {
2041 }
2042 }
2043 }
2050 }
2052 /* A subroutine of fold_convert_const handling conversions of a
2053 FIXED_CST to an integer type. */
2055 static tree
2057 {
2058 tree t;
2060 scalar_mode mode;
2062 /* Right shift FIXED_CST to temp by fbit. */
2066 {
2068 HOST_BITS_PER_DOUBLE_INT,
2071 /* Left shift temp to temp_trunc by fbit. */
2073 HOST_BITS_PER_DOUBLE_INT,
2075 }
2076 else
2077 {
2080 }
2082 /* If FIXED_CST is negative, we need to round the value toward 0.
2083 By checking if the fractional bits are not zero to add 1 to temp. */
2089 /* Given a fixed-point constant, make new constant with new type,
2090 appropriately sign-extended or truncated. */
2098 }
2100 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2101 to another floating point type. */
2103 static tree
2105 {
2106 REAL_VALUE_TYPE value;
2107 tree t;
2109 /* Don't perform the operation if flag_signaling_nans is on
2110 and the operand is a signaling NaN. */
2118 /* If converting an infinity or NAN to a representation that doesn't
2119 have one, set the overflow bit so that we can produce some kind of
2120 error message at the appropriate point if necessary. It's not the
2121 most user-friendly message, but it's better than nothing. */
2128 /* Regular overflow, conversion produced an infinity in a mode that
2129 can't represent them. */
2134 else
2137 }
2139 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2140 to a floating point type. */
2142 static tree
2144 {
2145 REAL_VALUE_TYPE value;
2146 tree t;
2154 }
2156 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2157 to another fixed-point type. */
2159 static tree
2161 {
2162 FIXED_VALUE_TYPE value;
2163 tree t;
2170 /* Propagate overflow flags. */
2174 }
2176 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2177 to a fixed-point type. */
2179 static tree
2181 {
2182 FIXED_VALUE_TYPE value;
2183 tree t;
2185 double_int di;
2192 else
2200 /* Propagate overflow flags. */
2204 }
2206 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2207 to a fixed-point type. */
2209 static tree
2211 {
2212 FIXED_VALUE_TYPE value;
2213 tree t;
2221 /* Propagate overflow flags. */
2225 }
2227 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2228 type TYPE. If no simplification can be done return NULL_TREE. */
2230 static tree
2232 {
2237 /* We can't widen types, since the runtime value could overflow the
2238 original type before being extended to the new type. */
2249 {
2256 }
2258 {
2265 }
2267 {
2274 }
2276 {
2279 {
2282 /* We can't handle steps directly when extending, since the
2283 values need to wrap at the original precision first. */
2284 bool step_ok_p
2288 tree_vector_builder v;
2293 {
2299 }
2301 }
2302 }
2304 }
2306 /* Construct a vector of zero elements of vector type TYPE. */
2308 static tree
2310 {
2311 tree t;
2315 }
2317 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2319 bool
2321 {
2336 {
2351 }
2352 }
2354 /* Convert expression ARG to type TYPE. Used by the middle-end for
2355 simple conversions in preference to calling the front-end's convert. */
2357 tree
2359 {
2361 tree tem;
2372 {
2375 /* Handle conversions between pointers to different address spaces. */
2380 /* fall through */
2385 {
2389 }
2403 {
2407 }
2409 {
2413 }
2415 {
2419 }
2422 {
2440 }
2445 {
2449 }
2452 {
2466 }
2470 {
2479 integer_zero_node));
2481 {
2485 {
2491 }
2499 }
2503 }
2521 }
2522 fold_convert_exit:
2525 }
2526 \f
2527 /* Return false if expr can be assumed not to be an lvalue, true
2528 otherwise. */
2530 static bool
2532 {
2533 /* We only need to wrap lvalue tree codes. */
2535 {
2566 /* Assume the worst for front-end tree codes. */
2570 }
2573 }
2575 /* Return an expr equal to X but certainly not valid as an lvalue. */
2577 tree
2579 {
2580 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2581 us. */
2588 }
2590 /* When pedantic, return an expr equal to X but certainly not valid as a
2591 pedantic lvalue. Otherwise, return X. */
2593 static tree
2595 {
2597 }
2598 \f
2599 /* Given a tree comparison code, return the code that is the logical inverse.
2600 It is generally not safe to do this for floating-point comparisons, except
2601 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2602 ERROR_MARK in this case. */
2604 enum tree_code
2606 {
2612 {
2643 }
2644 }
2646 /* Similar, but return the comparison that results if the operands are
2647 swapped. This is safe for floating-point. */
2649 enum tree_code
2651 {
2653 {
2679 }
2680 }
2683 /* Convert a comparison tree code from an enum tree_code representation
2684 into a compcode bit-based encoding. This function is the inverse of
2685 compcode_to_comparison. */
2687 static enum comparison_code
2689 {
2691 {
2722 }
2723 }
2725 /* Convert a compcode bit-based encoding of a comparison operator back
2726 to GCC's enum tree_code representation. This function is the
2727 inverse of comparison_to_compcode. */
2729 static enum tree_code
2731 {
2733 {
2764 }
2765 }
2767 /* Return a tree for the comparison which is the combination of
2768 doing the AND or OR (depending on CODE) of the two operations LCODE
2769 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2770 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2771 if this makes the transformation invalid. */
2773 tree
2778 {
2785 {
2796 }
2799 {
2800 /* Eliminate unordered comparisons, as well as LTGT and ORD
2801 which are not used unless the mode has NaNs. */
2807 }
2809 {
2810 /* Check that the original operation and the optimized ones will trap
2811 under the same condition. */
2822 /* In a short-circuited boolean expression the LHS might be
2823 such that the RHS, if evaluated, will never trap. For
2824 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2825 if neither x nor y is NaN. (This is a mixed blessing: for
2826 example, the expression above will never trap, hence
2827 optimizing it to x < y would be invalid). */
2832 /* If the comparison was short-circuited, and only the RHS
2833 trapped, we may now generate a spurious trap. */
2838 /* If we changed the conditions that cause a trap, we lose. */
2841 }
2847 else
2848 {
2853 }
2854 }
2855 \f
2856 /* Return nonzero if two operands (typically of the same tree node)
2857 are necessarily equal. FLAGS modifies behavior as follows:
2859 If OEP_ONLY_CONST is set, only return nonzero for constants.
2860 This function tests whether the operands are indistinguishable;
2861 it does not test whether they are equal using C's == operation.
2862 The distinction is important for IEEE floating point, because
2863 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2864 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2866 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2867 even though it may hold multiple values during a function.
2868 This is because a GCC tree node guarantees that nothing else is
2869 executed between the evaluation of its "operands" (which may often
2870 be evaluated in arbitrary order). Hence if the operands themselves
2871 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2872 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2873 unset means assuming isochronic (or instantaneous) tree equivalence.
2874 Unless comparing arbitrary expression trees, such as from different
2875 statements, this flag can usually be left unset.
2877 If OEP_PURE_SAME is set, then pure functions with identical arguments
2878 are considered the same. It is used when the caller has other ways
2879 to ensure that global memory is unchanged in between.
2881 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2882 not values of expressions.
2884 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
2885 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
2887 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2888 any operand with side effect. This is unnecesarily conservative in the
2889 case we know that arg0 and arg1 are in disjoint code paths (such as in
2890 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2891 addresses with TREE_CONSTANT flag set so we know that &var == &var
2892 even if var is volatile. */
2894 int
2896 {
2897 /* When checking, verify at the outermost operand_equal_p call that
2898 if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
2899 hash value. */
2901 {
2903 {
2905 {
2912 }
2914 }
2915 else
2917 }
2919 /* If either is ERROR_MARK, they aren't equal. */
2925 /* Similar, if either does not have a type (like a released SSA name),
2926 they aren't equal. */
2930 /* We cannot consider pointers to different address space equal. */
2937 /* Check equality of integer constants before bailing out due to
2938 precision differences. */
2940 {
2941 /* Address of INTEGER_CST is not defined; check that we did not forget
2942 to drop the OEP_ADDRESS_OF flags. */
2945 }
2948 {
2949 /* If both types don't have the same signedness, then we can't consider
2950 them equal. We must check this before the STRIP_NOPS calls
2951 because they may change the signedness of the arguments. As pointers
2952 strictly don't have a signedness, require either two pointers or
2953 two non-pointers as well. */
2959 /* If both types don't have the same precision, then it is not safe
2960 to strip NOPs. */
2967 }
2968 #if 0
2969 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
2970 sanity check once the issue is solved. */
2971 else
2972 /* Addresses of conversions and SSA_NAMEs (and many other things)
2973 are not defined. Check that we did not forget to drop the
2974 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
2977 #endif
2979 /* In case both args are comparisons but with different comparison
2980 code, try to swap the comparison operands of one arg to produce
2981 a match and compare that variant. */
2985 {
2993 }
2996 {
2997 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
2999 ;
3001 {
3002 /* If we are interested in comparing addresses ignore
3003 MEM_REF wrappings of the base that can appear just for
3004 TBAA reasons. */
3018 }
3019 else
3021 }
3023 /* When not checking adddresses, this is needed for conversions and for
3024 COMPONENT_REF. Might as well play it safe and always test this. */
3031 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3032 We don't care about side effects in that case because the SAVE_EXPR
3033 takes care of that for us. In all other cases, two expressions are
3034 equal if they have no side effects. If we have two identical
3035 expressions with side effects that should be treated the same due
3036 to the only side effects being identical SAVE_EXPR's, that will
3037 be detected in the recursive calls below.
3038 If we are taking an invariant address of two identical objects
3039 they are necessarily equal as well. */
3046 /* Next handle constant cases, those for which we can return 1 even
3047 if ONLY_CONST is set. */
3050 {
3064 {
3065 /* If we do not distinguish between signed and unsigned zero,
3066 consider them equal. */
3069 }
3073 {
3088 }
3092 flags)
3094 flags));
3105 flags | OEP_ADDRESS_OF
3108 /* In GIMPLE empty constructors are allowed in initializers of
3109 aggregates. */
3113 }
3118 /* Define macros to test an operand from arg0 and arg1 for equality and a
3119 variant that allows null and views null as being different from any
3120 non-null value. In the latter case, if either is null, the both
3121 must be; otherwise, do the normal comparison. */
3122 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3123 TREE_OPERAND (arg1, N), flags)
3125 #define OP_SAME_WITH_NULL(N) \
3126 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3127 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3130 {
3132 /* Two conversions are equal only if signedness and modes match. */
3134 {
3135 CASE_CONVERT:
3143 }
3153 /* For commutative ops, allow the other order. */
3161 /* If either of the pointer (or reference) expressions we are
3162 dereferencing contain a side effect, these cannot be equal,
3163 but their addresses can be. */
3170 {
3180 /* Require the same offset. */
3186 /* Fallthru. */
3194 {
3195 /* Require equal access sizes */
3201 flags)))
3203 /* Verify that access happens in similar types. */
3206 /* Verify that accesses are TBAA compatible. */
3215 /* Verify that alignment is compatible. */
3219 }
3222 /* TARGET_MEM_REF require equal extra operands. */
3233 /* Compare the array index by value if it is constant first as we
3234 may have different types but same value here. */
3240 /* Compare low bound and element size as with OEP_ADDRESS_OF
3241 we have to account for the offset of the ref. */
3246 array_ref_low_bound
3250 array_ref_element_size
3252 flags))));
3255 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3256 may be NULL when we're called to compare MEM_EXPRs. */
3271 }
3275 {
3277 /* Be sure we pass right ADDRESS_OF flag. */
3295 /* The multiplcation operands are commutative. */
3296 /* FALLTHRU */
3304 /* Otherwise take into account this is a commutative operation. */
3317 /* BIT_INSERT_EXPR has an implict operand as the type precision
3318 of op1. Need to check to make sure they are the same. */
3324 /* FALLTHRU */
3349 }
3353 {
3357 /* If not both CALL_EXPRs are either internal or normal function
3358 functions, then they are not equal. */
3361 {
3362 /* If the CALL_EXPRs call different internal functions, then they
3363 are not equal. */
3366 }
3367 else
3368 {
3369 /* If the CALL_EXPRs call different functions, then they are not
3370 equal. */
3372 flags))
3374 }
3376 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3377 {
3381 else
3385 }
3387 /* Now see if all the arguments are the same. */
3388 {
3399 /* If we get here and both argument lists are exhausted
3400 then the CALL_EXPRs are equal. */
3402 }
3405 }
3408 /* Consider __builtin_sqrt equal to sqrt. */
3416 {
3417 /* In GIMPLE constructors are used only to build vectors from
3418 elements. Individual elements in the constructor must be
3419 indexed in increasing order and form an initial sequence.
3421 We make no effort to compare constructors in generic.
3422 (see sem_variable::equals in ipa-icf which can do so for
3423 constants). */
3428 /* Be sure that vectors constructed have the same representation.
3429 We only tested element precision and modes to match.
3430 Vectors may be BLKmode and thus also check that the number of
3431 parts match. */
3444 {
3449 /* In GIMPLE the indexes can be either NULL or matching i.
3450 Double check this so we won't get false
3451 positives for GENERIC. */
3459 }
3461 }
3464 {
3465 /* Compare the STATEMENT_LISTs. */
3471 {
3472 /* The lists don't have the same number of statements. */
3478 OEP_LEXICOGRAPHIC))
3480 }
3481 }
3486 {
3493 }
3497 }
3499 #undef OP_SAME
3500 #undef OP_SAME_WITH_NULL
3501 }
3502 \f
3503 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
3504 with a different signedness or a narrower precision. */
3506 static bool
3508 {
3516 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3517 and see if the inner values are the same. This removes any
3518 signedness comparison, which doesn't matter here. */
3526 /* Discard a single widening conversion from ARG1 and see if the inner
3527 value is the same as ARG0. */
3536 }
3537 \f
3538 /* See if ARG is an expression that is either a comparison or is performing
3539 arithmetic on comparisons. The comparisons must only be comparing
3540 two different values, which will be stored in *CVAL1 and *CVAL2; if
3541 they are nonzero it means that some operands have already been found.
3542 No variables may be used anywhere else in the expression except in the
3543 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3544 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3546 If this is true, return 1. Otherwise, return zero. */
3548 static int
3550 {
3554 /* We can handle some of the tcc_expression cases here. */
3564 {
3565 /* If we've already found a CVAL1 or CVAL2, this expression is
3566 two complex to handle. */
3572 }
3575 {
3598 /* First see if we can handle the first operand, then the second. For
3599 the second operand, we know *CVAL1 can't be zero. It must be that
3600 one side of the comparison is each of the values; test for the
3601 case where this isn't true by failing if the two operands
3602 are the same. */
3611 ;
3615 ;
3616 else
3620 ;
3624 ;
3625 else
3632 }
3633 }
3634 \f
3635 /* ARG is a tree that is known to contain just arithmetic operations and
3636 comparisons. Evaluate the operations in the tree substituting NEW0 for
3637 any occurrence of OLD0 as an operand of a comparison and likewise for
3638 NEW1 and OLD1. */
3640 static tree
3643 {
3648 /* We can handle some of the tcc_expression cases here. */
3656 {
3671 {
3690 }
3691 /* Fall through - ??? */
3694 {
3698 /* We need to check both for exact equality and tree equality. The
3699 former will be true if the operand has a side-effect. In that
3700 case, we know the operand occurred exactly once. */
3713 }
3717 }
3718 }
3719 \f
3720 /* Return a tree for the case when the result of an expression is RESULT
3721 converted to TYPE and OMITTED was previously an operand of the expression
3722 but is now not needed (e.g., we folded OMITTED * 0).
3724 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3725 the conversion of RESULT to TYPE. */
3727 tree
3729 {
3732 /* If the resulting operand is an empty statement, just return the omitted
3733 statement casted to void. */
3743 }
3745 /* Return a tree for the case when the result of an expression is RESULT
3746 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3747 of the expression but are now not needed.
3749 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3750 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3751 evaluated before OMITTED2. Otherwise, if neither has side effects,
3752 just do the conversion of RESULT to TYPE. */
3754 tree
3757 {
3766 }
3768 \f
3769 /* Return a simplified tree node for the truth-negation of ARG. This
3770 never alters ARG itself. We assume that ARG is an operation that
3771 returns a truth value (0 or 1).
3773 FIXME: one would think we would fold the result, but it causes
3774 problems with the dominator optimizer. */
3776 static tree
3778 {
3783 /* If this is a comparison, we can simply invert it, except for
3784 floating-point non-equality comparisons, in which case we just
3785 enclose a TRUTH_NOT_EXPR around what we have. */
3788 {
3791 && flag_trapping_math
3805 }
3808 {
3827 /* Here we can invert either operand. We invert the first operand
3828 unless the second operand is a TRUTH_NOT_EXPR in which case our
3829 result is the XOR of the first operand with the inside of the
3830 negation of the second operand. */
3835 else
3858 {
3865 /* A COND_EXPR may have a throw as one operand, which
3866 then has void type. Just leave void operands
3867 as they are. */
3873 }
3885 CASE_CONVERT:
3889 /* fall through */
3911 }
3912 }
3914 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3915 assume that ARG is an operation that returns a truth value (0 or 1
3916 for scalars, 0 or -1 for vectors). Return the folded expression if
3917 folding is successful. Otherwise, return NULL_TREE. */
3919 static tree
3921 {
3924 ? BIT_NOT_EXPR
3927 }
3929 /* Return a simplified tree node for the truth-negation of ARG. This
3930 never alters ARG itself. We assume that ARG is an operation that
3931 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3933 tree
3935 {
3941 ? BIT_NOT_EXPR
3944 }
3945 \f
3946 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3947 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
3948 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
3949 is the original memory reference used to preserve the alias set of
3950 the access. */
3952 static tree
3956 {
3959 /* Attempt not to lose the access path if possible. */
3961 {
3963 machine_mode nmode;
3965 tree noffset;
3973 && !reversep
3974 && !nreversep
3976 {
3979 }
3980 }
3989 {
3996 }
4011 }
4013 /* Optimize a bit-field compare.
4015 There are two cases: First is a compare against a constant and the
4016 second is a comparison of two items where the fields are at the same
4017 bit position relative to the start of a chunk (byte, halfword, word)
4018 large enough to contain it. In these cases we can avoid the shift
4019 implicit in bitfield extractions.
4021 For constants, we emit a compare of the shifted constant with the
4022 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4023 compared. For two fields at the same position, we do the ANDs with the
4024 similar mask and compare the result of the ANDs.
4026 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4027 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4028 are the left and right operands of the comparison, respectively.
4030 If the optimization described above can be done, we return the resulting
4031 tree. Otherwise we return zero. */
4033 static tree
4036 {
4040 tree unsigned_type;
4043 scalar_int_mode nmode;
4048 tree mask;
4049 tree offset;
4051 /* Get all the information about the extractions being done. If the bit size
4052 is the same as the size of the underlying object, we aren't doing an
4053 extraction at all and so can do nothing. We also don't want to
4054 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4055 then will no longer be able to replace it. */
4070 else
4071 {
4072 /* If this is not a constant, we can only do something if bit positions,
4073 sizes, signedness and storage order are the same. */
4074 rinner
4087 }
4089 /* Honor the C++ memory model and mimic what RTL expansion does. */
4093 {
4097 }
4099 /* See if we can find a mode to refer to this field. We should be able to,
4100 but fail if we can't. */
4108 /* Set signed and unsigned types of the precision of this mode for the
4109 shifts below. */
4112 /* Compute the bit position and size for the new reference and our offset
4113 within it. If the new reference is the same size as the original, we
4114 won't optimize anything, so return zero. */
4124 /* Make the mask to be used against the extracted field. */
4131 {
4135 /* If not comparing with constant, just rework the comparison
4136 and return. */
4144 }
4146 /* Otherwise, we are handling the constant case. See if the constant is too
4147 big for the field. Warn and return a tree for 0 (false) if so. We do
4148 this not only for its own sake, but to avoid having to test for this
4149 error case below. If we didn't, we might generate wrong code.
4151 For unsigned fields, the constant shifted right by the field length should
4152 be all zero. For signed fields, the high-order bits should agree with
4153 the sign bit. */
4156 {
4158 {
4162 }
4163 }
4164 else
4165 {
4168 {
4172 }
4173 }
4178 /* Single-bit compares should always be against zero. */
4180 {
4183 }
4185 /* Make a new bitfield reference, shift the constant over the
4186 appropriate number of bits and mask it with the computed mask
4187 (in case this was a signed field). If we changed it, make a new one. */
4195 mask);
4200 }
4201 \f
4202 /* Subroutine for fold_truth_andor_1: decode a field reference.
4204 If EXP is a comparison reference, we return the innermost reference.
4206 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4207 set to the starting bit number.
4209 If the innermost field can be completely contained in a mode-sized
4210 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4212 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4213 otherwise it is not changed.
4215 *PUNSIGNEDP is set to the signedness of the field.
4217 *PREVERSEP is set to the storage order of the field.
4219 *PMASK is set to the mask used. This is either contained in a
4220 BIT_AND_EXPR or derived from the width of the field.
4222 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4224 Return 0 if this is not a component reference or is one that we can't
4225 do anything with. */
4227 static tree
4232 {
4237 tree unsigned_type;
4240 /* All the optimizations using this function assume integer fields.
4241 There are problems with FP fields since the type_for_size call
4242 below can fail for, e.g., XFmode. */
4246 /* We are interested in the bare arrangement of bits, so strip everything
4247 that doesn't affect the machine mode. However, record the type of the
4248 outermost expression if it may matter below. */
4255 {
4261 }
4272 /* Reject out-of-bound accesses (PR79731). */
4280 /* If the number of bits in the reference is the same as the bitsize of
4281 the outer type, then the outer type gives the signedness. Otherwise
4282 (in case of a small bitfield) the signedness is unchanged. */
4286 /* Compute the mask to access the bitfield. */
4295 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4303 }
4305 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4306 bit positions and MASK is SIGNED. */
4308 static int
4310 {
4314 /* If this function returns true when the type of the mask is
4315 UNSIGNED, then there will be errors. In particular see
4316 gcc.c-torture/execute/990326-1.c. There does not appear to be
4317 any documentation paper trail as to why this is so. But the pre
4318 wide-int worked with that restriction and it has been preserved
4319 here. */
4324 }
4326 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4327 represents the sign bit of EXP's type. If EXP represents a sign
4328 or zero extension, also test VAL against the unextended type.
4329 The return value is the (sub)expression whose sign bit is VAL,
4330 or NULL_TREE otherwise. */
4332 tree
4334 {
4336 tree t;
4338 /* Tree EXP must have an integral type. */
4343 /* Tree VAL must be an integer constant. */
4352 /* Handle extension from a narrower type. */
4358 }
4360 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4361 to be evaluated unconditionally. */
4363 static int
4365 {
4366 /* Strip any conversions that don't change the machine mode. */
4375 /* Don't regard global variables as simple. They may be
4376 allocated in ways unknown to the compiler (shared memory,
4377 #pragma weak, etc). */
4380 /* Weakrefs are not safe to be read, since they can be NULL.
4381 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4382 have DECL_WEAK flag set. */
4384 /* Loading a static variable is unduly expensive, but global
4385 registers aren't expensive. */
4387 }
4389 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4390 to be evaluated unconditionally.
4391 I addition to simple_operand_p, we assume that comparisons, conversions,
4392 and logic-not operations are simple, if their operands are simple, too. */
4394 static bool
4396 {
4416 }
4418 \f
4419 /* The following functions are subroutines to fold_range_test and allow it to
4420 try to change a logical combination of comparisons into a range test.
4422 For example, both
4423 X == 2 || X == 3 || X == 4 || X == 5
4424 and
4425 X >= 2 && X <= 5
4426 are converted to
4427 (unsigned) (X - 2) <= 3
4429 We describe each set of comparisons as being either inside or outside
4430 a range, using a variable named like IN_P, and then describe the
4431 range with a lower and upper bound. If one of the bounds is omitted,
4432 it represents either the highest or lowest value of the type.
4434 In the comments below, we represent a range by two numbers in brackets
4435 preceded by a "+" to designate being inside that range, or a "-" to
4436 designate being outside that range, so the condition can be inverted by
4437 flipping the prefix. An omitted bound is represented by a "-". For
4438 example, "- [-, 10]" means being outside the range starting at the lowest
4439 possible value and ending at 10, in other words, being greater than 10.
4440 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4441 always false.
4443 We set up things so that the missing bounds are handled in a consistent
4444 manner so neither a missing bound nor "true" and "false" need to be
4445 handled using a special case. */
4447 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4448 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4449 and UPPER1_P are nonzero if the respective argument is an upper bound
4450 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4451 must be specified for a comparison. ARG1 will be converted to ARG0's
4452 type if both are specified. */
4454 static tree
4457 {
4458 tree tem;
4462 /* If neither arg represents infinity, do the normal operation.
4463 Else, if not a comparison, return infinity. Else handle the special
4464 comparison rules. Note that most of the cases below won't occur, but
4465 are handled for consistency. */
4468 {
4473 }
4478 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4479 for neither. In real maths, we cannot assume open ended ranges are
4480 the same. But, this is computer arithmetic, where numbers are finite.
4481 We can therefore make the transformation of any unbounded range with
4482 the value Z, Z being greater than any representable number. This permits
4483 us to treat unbounded ranges as equal. */
4487 {
4508 }
4511 }
4512 \f
4513 /* Helper routine for make_range. Perform one step for it, return
4514 new expression if the loop should continue or NULL_TREE if it should
4515 stop. */
4517 tree
4521 {
4527 {
4529 /* We can only do something if the range is testing for zero. */
4538 /* We can only do something if the range is testing for zero
4539 and if the second operand is an integer constant. Note that
4540 saying something is "in" the range we make is done by
4541 complementing IN_P since it will set in the initial case of
4542 being not equal to zero; "out" is leaving it alone. */
4549 {
4570 }
4572 /* If this is an unsigned comparison, we also know that EXP is
4573 greater than or equal to zero. We base the range tests we make
4574 on that fact, so we record it here so we can parse existing
4575 range tests. We test arg0_type since often the return type
4576 of, e.g. EQ_EXPR, is boolean. */
4578 {
4582 NULL_TREE))
4587 /* If the high bound is missing, but we have a nonzero low
4588 bound, reverse the range so it goes from zero to the low bound
4589 minus 1. */
4591 {
4596 }
4597 }
4605 /* If flag_wrapv and ARG0_TYPE is signed, make sure
4606 low and high are non-NULL, then normalize will DTRT. */
4609 {
4614 }
4616 /* (-x) IN [a,b] -> x in [-b, -a] */
4628 /* ~ X -> -X - 1 */
4637 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4638 move a constant to the other side. */
4643 /* If EXP is signed, any overflow in the computation is undefined,
4644 so we don't worry about it so long as our computations on
4645 the bounds don't overflow. For unsigned, overflow is defined
4646 and this is exactly the right thing. */
4658 normalize:
4659 /* Check for an unsigned range which has wrapped around the maximum
4660 value thus making n_high < n_low, and normalize it. */
4662 {
4668 /* If the range is of the form +/- [ x+1, x ], we won't
4669 be able to normalize it. But then, it represents the
4670 whole range or the empty set, so make it
4671 +/- [ -, - ]. */
4675 else
4677 }
4678 else
4686 CASE_CONVERT:
4704 /* If we're converting arg0 from an unsigned type, to exp,
4705 a signed type, we will be doing the comparison as unsigned.
4706 The tests above have already verified that LOW and HIGH
4707 are both positive.
4709 So we have to ensure that we will handle large unsigned
4710 values the same way that the current signed bounds treat
4711 negative values. */
4714 {
4715 tree high_positive;
4716 tree equiv_type;
4717 /* For fixed-point modes, we need to pass the saturating flag
4718 as the 2nd parameter. */
4720 equiv_type
4723 else
4724 equiv_type
4727 /* A range without an upper bound is, naturally, unbounded.
4728 Since convert would have cropped a very large value, use
4729 the max value for the destination type. */
4730 high_positive
4737 high_positive),
4740 /* If the low bound is specified, "and" the range with the
4741 range for which the original unsigned value will be
4742 positive. */
4744 {
4747 integer_zero_node),
4748 high_positive))
4752 }
4753 else
4754 {
4755 /* Otherwise, "or" the range with the range of the input
4756 that will be interpreted as negative. */
4759 integer_zero_node),
4760 high_positive))
4764 }
4765 }
4774 }
4775 }
4777 /* Given EXP, a logical expression, set the range it is testing into
4778 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4779 actually being tested. *PLOW and *PHIGH will be made of the same
4780 type as the returned expression. If EXP is not a comparison, we
4781 will most likely not be returning a useful value and range. Set
4782 *STRICT_OVERFLOW_P to true if the return value is only valid
4783 because signed overflow is undefined; otherwise, do not change
4784 *STRICT_OVERFLOW_P. */
4786 tree
4789 {
4797 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4798 and see if we can refine the range. Some of the cases below may not
4799 happen, but it doesn't seem worth worrying about this. We "continue"
4800 the outer loop when we've changed something; otherwise we "break"
4801 the switch, which will "break" the while. */
4807 {
4813 {
4821 }
4830 }
4832 /* If EXP is a constant, we can evaluate whether this is true or false. */
4834 {
4841 }
4845 }
4847 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
4848 a bitwise check i.e. when
4849 LOW == 0xXX...X00...0
4850 HIGH == 0xXX...X11...1
4851 Return corresponding mask in MASK and stem in VALUE. */
4853 static bool
4856 {
4879 }
4880 \f
4881 /* Helper routine for build_range_check and match.pd. Return the type to
4882 perform the check or NULL if it shouldn't be optimized. */
4884 tree
4886 {
4887 /* First make sure that arithmetics in this type is valid, then make sure
4888 that it wraps around. */
4894 {
4897 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4898 for the type in question, as we rely on this here. */
4908 else
4910 }
4912 }
4914 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4915 type, TYPE, return an expression to test if EXP is in (or out of, depending
4916 on IN_P) the range. Return 0 if the test couldn't be created. */
4918 tree
4921 {
4924 /* Disable this optimization for function pointer expressions
4925 on targets that require function pointer canonicalization. */
4932 {
4938 }
4960 value);
4963 {
4965 {
4969 }
4971 }
4973 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4975 {
4979 {
4981 {
4984 etype
4986 else
4989 }
4992 }
4993 }
4995 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4996 This requires wrap-around arithmetics for the type of the expression. */
5016 }
5017 \f
5018 /* Return the predecessor of VAL in its type, handling the infinite case. */
5020 static tree
5022 {
5028 else
5031 }
5033 /* Return the successor of VAL in its type, handling the infinite case. */
5035 static tree
5037 {
5043 else
5046 }
5048 /* Given two ranges, see if we can merge them into one. Return 1 if we
5049 can, 0 if we can't. Set the output range into the specified parameters. */
5051 bool
5054 {
5058 tree tem;
5068 /* Make range 0 be the range that starts first, or ends last if they
5069 start at the same value. Swap them if it isn't. */
5072 || (lowequal
5075 {
5079 }
5081 /* Now flag two cases, whether the ranges are disjoint or whether the
5082 second range is totally subsumed in the first. Note that the tests
5083 below are simplified by the ones above. */
5089 /* We now have four cases, depending on whether we are including or
5090 excluding the two ranges. */
5092 {
5093 /* If they don't overlap, the result is false. If the second range
5094 is a subset it is the result. Otherwise, the range is from the start
5095 of the second to the end of the first. */
5100 else
5102 }
5105 {
5106 /* If they don't overlap, the result is the first range. If they are
5107 equal, the result is false. If the second range is a subset of the
5108 first, and the ranges begin at the same place, we go from just after
5109 the end of the second range to the end of the first. If the second
5110 range is not a subset of the first, or if it is a subset and both
5111 ranges end at the same place, the range starts at the start of the
5112 first range and ends just before the second range.
5113 Otherwise, we can't describe this as a single range. */
5119 {
5124 {
5125 /* We are in the weird situation where high0 > high1 but
5126 high1 has no successor. Punt. */
5128 }
5129 }
5131 {
5136 {
5137 /* low0 < low1 but low1 has no predecessor. Punt. */
5139 }
5140 }
5141 else
5143 }
5146 {
5147 /* If they don't overlap, the result is the second range. If the second
5148 is a subset of the first, the result is false. Otherwise,
5149 the range starts just after the first range and ends at the
5150 end of the second. */
5155 else
5156 {
5161 {
5162 /* high1 > high0 but high0 has no successor. Punt. */
5164 }
5165 }
5166 }
5168 else
5169 {
5170 /* The case where we are excluding both ranges. Here the complex case
5171 is if they don't overlap. In that case, the only time we have a
5172 range is if they are adjacent. If the second is a subset of the
5173 first, the result is the first. Otherwise, the range to exclude
5174 starts at the beginning of the first range and ends at the end of the
5175 second. */
5177 {
5182 else
5183 {
5184 /* Canonicalize - [min, x] into - [-, x]. */
5187 {
5192 /* FALLTHROUGH */
5205 }
5207 /* Canonicalize - [x, max] into - [x, -]. */
5210 {
5215 /* FALLTHROUGH */
5231 }
5233 /* The ranges might be also adjacent between the maximum and
5234 minimum values of the given type. For
5235 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5236 return + [x + 1, y - 1]. */
5238 {
5245 }
5246 else
5248 }
5249 }
5252 else
5254 }
5258 }
5259 \f
5261 /* Subroutine of fold, looking inside expressions of the form
5262 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5263 of the COND_EXPR. This function is being used also to optimize
5264 A op B ? C : A, by reversing the comparison first.
5266 Return a folded expression whose code is not a COND_EXPR
5267 anymore, or NULL_TREE if no folding opportunity is found. */
5269 static tree
5272 {
5277 tree tem;
5282 /* If we have A op 0 ? A : -A, consider applying the following
5283 transformations:
5285 A == 0? A : -A same as -A
5286 A != 0? A : -A same as A
5287 A >= 0? A : -A same as abs (A)
5288 A > 0? A : -A same as abs (A)
5289 A <= 0? A : -A same as -abs (A)
5290 A < 0? A : -A same as -abs (A)
5292 None of these transformations work for modes with signed
5293 zeros. If A is +/-0, the first two transformations will
5294 change the sign of the result (from +0 to -0, or vice
5295 versa). The last four will fix the sign of the result,
5296 even though the original expressions could be positive or
5297 negative, depending on the sign of A.
5299 Note that all these transformations are correct if A is
5300 NaN, since the two alternatives (A and -A) are also NaNs. */
5307 /* In the case that A is of the form X-Y, '-A' (arg2) may
5308 have already been folded to Y-X, check for that. */
5316 {
5328 /* Fall through. */
5339 /* FALLTHRU */
5349 }
5351 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5352 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5353 both transformations are correct when A is NaN: A != 0
5354 is then true, and A == 0 is false. */
5358 {
5363 }
5365 /* Try some transformations of A op B ? A : B.
5367 A == B? A : B same as B
5368 A != B? A : B same as A
5369 A >= B? A : B same as max (A, B)
5370 A > B? A : B same as max (B, A)
5371 A <= B? A : B same as min (A, B)
5372 A < B? A : B same as min (B, A)
5374 As above, these transformations don't work in the presence
5375 of signed zeros. For example, if A and B are zeros of
5376 opposite sign, the first two transformations will change
5377 the sign of the result. In the last four, the original
5378 expressions give different results for (A=+0, B=-0) and
5379 (A=-0, B=+0), but the transformed expressions do not.
5381 The first two transformations are correct if either A or B
5382 is a NaN. In the first transformation, the condition will
5383 be false, and B will indeed be chosen. In the case of the
5384 second transformation, the condition A != B will be true,
5385 and A will be chosen.
5387 The conversions to max() and min() are not correct if B is
5388 a number and A is not. The conditions in the original
5389 expressions will be false, so all four give B. The min()
5390 and max() versions would give a NaN instead. */
5393 /* Avoid these transformations if the COND_EXPR may be used
5394 as an lvalue in the C++ front-end. PR c++/19199. */
5395 && (in_gimple_form
5401 {
5407 {
5416 /* In C++ a ?: expression can be an lvalue, so put the
5417 operand which will be used if they are equal first
5418 so that we can convert this back to the
5419 corresponding COND_EXPR. */
5421 {
5429 }
5436 {
5444 }
5457 }
5458 }
5461 }
5464 \f
5465 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5466 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5467 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5468 false) >= 2)
5469 #endif
5471 /* EXP is some logical combination of boolean tests. See if we can
5472 merge it into some range test. Return the new tree if so. */
5474 static tree
5477 {
5493 /* If this is an OR operation, invert both sides; we will invert
5494 again at the end. */
5498 /* If both expressions are the same, if we can merge the ranges, and we
5499 can build the range test, return it or it inverted. If one of the
5500 ranges is always true or always false, consider it to be the same
5501 expression as the other. */
5509 {
5513 }
5515 /* On machines where the branch cost is expensive, if this is a
5516 short-circuited branch and the underlying object on both sides
5517 is the same, make a non-short-circuit operation. */
5519 && !flag_sanitize_coverage
5524 {
5525 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5526 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5527 which cases we can't do this. */
5535 {
5544 {
5547 WARN_STRICT_OVERFLOW_COMPARISON);
5551 }
5552 }
5553 }
5556 }
5557 \f
5558 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
5559 bit value. Arrange things so the extra bits will be set to zero if and
5560 only if C is signed-extended to its full width. If MASK is nonzero,
5561 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5563 static tree
5565 {
5568 tree temp;
5573 /* We work by getting just the sign bit into the low-order bit, then
5574 into the high-order bit, then sign-extend. We then XOR that value
5575 with C. */
5579 /* We must use a signed type in order to get an arithmetic right shift.
5580 However, we must also avoid introducing accidental overflows, so that
5581 a subsequent call to integer_zerop will work. Hence we must
5582 do the type conversion here. At this point, the constant is either
5583 zero or one, and the conversion to a signed type can never overflow.
5584 We could get an overflow if this conversion is done anywhere else. */
5593 /* If necessary, convert the type back to match the type of C. */
5598 }
5599 \f
5600 /* For an expression that has the form
5601 (A && B) || ~B
5602 or
5603 (A || B) && ~B,
5604 we can drop one of the inner expressions and simplify to
5605 A || ~B
5606 or
5607 A && ~B
5608 LOC is the location of the resulting expression. OP is the inner
5609 logical operation; the left-hand side in the examples above, while CMPOP
5610 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5611 removing a condition that guards another, as in
5612 (A != NULL && A->...) || A == NULL
5613 which we must not transform. If RHS_ONLY is true, only eliminate the
5614 right-most operand of the inner logical operation. */
5616 static tree
5619 {
5637 {
5640 {
5643 }
5644 }
5646 {
5649 {
5652 }
5653 }
5668 }
5670 /* Find ways of folding logical expressions of LHS and RHS:
5671 Try to merge two comparisons to the same innermost item.
5672 Look for range tests like "ch >= '0' && ch <= '9'".
5673 Look for combinations of simple terms on machines with expensive branches
5674 and evaluate the RHS unconditionally.
5676 For example, if we have p->a == 2 && p->b == 4 and we can make an
5677 object large enough to span both A and B, we can do this with a comparison
5678 against the object ANDed with the a mask.
5680 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5681 operations to do this with one comparison.
5683 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5684 function and the one above.
5686 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5687 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5689 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5690 two operands.
5692 We return the simplified tree or 0 if no optimization is possible. */
5694 static tree
5697 {
5698 /* If this is the "or" of two comparisons, we can do something if
5699 the comparisons are NE_EXPR. If this is the "and", we can do something
5700 if the comparisons are EQ_EXPR. I.e.,
5701 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5703 WANTED_CODE is this operation code. For single bit fields, we can
5704 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5705 comparison for one-bit fields. */
5726 /* Start by getting the comparison codes. Fail if anything is volatile.
5727 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5728 it were surrounded with a NE_EXPR. */
5737 {
5741 }
5744 {
5748 }
5759 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5762 {
5765 {
5770 }
5773 {
5779 }
5780 }
5785 /* If the RHS can be evaluated unconditionally and its operands are
5786 simple, it wins to evaluate the RHS unconditionally on machines
5787 with expensive branches. In this case, this isn't a comparison
5788 that can be merged. */
5795 {
5796 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5807 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5817 }
5819 /* See if the comparisons can be merged. Then get all the parameters for
5820 each side. */
5845 /* It must be true that the inner operation on the lhs of each
5846 comparison must be the same if we are to be able to do anything.
5847 Then see if we have constants. If not, the same must be true for
5848 the rhs's. */
5857 {
5860 }
5865 else
5868 /* If either comparison code is not correct for our logical operation,
5869 fail. However, we can convert a one-bit comparison against zero into
5870 the opposite comparison against that bit being set in the field. */
5874 {
5876 {
5877 /* Make the left operand unsigned, since we are only interested
5878 in the value of one bit. Otherwise we are doing the wrong
5879 thing below. */
5882 }
5883 else
5885 }
5887 /* This is analogous to the code for l_const above. */
5889 {
5891 {
5894 }
5895 else
5897 }
5899 /* See if we can find a mode that contains both fields being compared on
5900 the left. If we can't, fail. Otherwise, update all constants and masks
5901 to be relative to a field of that size. */
5915 {
5918 }
5926 {
5933 {
5937 }
5938 }
5940 {
5947 {
5951 }
5952 }
5954 /* If the right sides are not constant, do the same for it. Also,
5955 disallow this optimization if a size or signedness mismatch occurs
5956 between the left and right sides. */
5958 {
5961 /* Make sure the two fields on the right
5962 correspond to the left without being swapped. */
5979 {
5982 }
5991 /* Make a mask that corresponds to both fields being compared.
5992 Do this for both items being compared. If the operands are the
5993 same size and the bits being compared are in the same position
5994 then we can do this by masking both and comparing the masked
5995 results. */
6002 {
6016 }
6018 /* There is still another way we can do something: If both pairs of
6019 fields being compared are adjacent, we may be able to make a wider
6020 field containing them both.
6022 Note that we still must mask the lhs/rhs expressions. Furthermore,
6023 the mask must be shifted to account for the shift done by
6024 make_bit_field_ref. */
6033 {
6034 tree type;
6050 /* Convert to the smaller type before masking out unwanted bits. */
6053 {
6055 {
6059 }
6061 {
6065 }
6066 }
6075 }
6078 }
6080 /* Handle the case of comparisons with constants. If there is something in
6081 common between the masks, those bits of the constants must be the same.
6082 If not, the condition is always false. Test for this to avoid generating
6083 incorrect code below. */
6088 {
6090 {
6093 }
6094 else
6095 {
6098 }
6099 }
6104 /* Construct the expression we will return. First get the component
6105 reference we will make. Unless the mask is all ones the width of
6106 that field, perform the mask operation. Then compare with the
6107 merged constant. */
6118 }
6119 \f
6120 /* T is an integer expression that is being multiplied, divided, or taken a
6121 modulus (CODE says which and what kind of divide or modulus) by a
6122 constant C. See if we can eliminate that operation by folding it with
6123 other operations already in T. WIDE_TYPE, if non-null, is a type that
6124 should be used for the computation if wider than our type.
6126 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6127 (X * 2) + (Y * 4). We must, however, be assured that either the original
6128 expression would not overflow or that overflow is undefined for the type
6129 in the language in question.
6131 If we return a non-null expression, it is an equivalent form of the
6132 original computation, but need not be in the original type.
6134 We set *STRICT_OVERFLOW_P to true if the return values depends on
6135 signed overflow being undefined. Otherwise we do not change
6136 *STRICT_OVERFLOW_P. */
6138 static tree
6141 {
6142 /* To avoid exponential search depth, refuse to allow recursion past
6143 three levels. Beyond that (1) it's highly unlikely that we'll find
6144 something interesting and (2) we've probably processed it before
6145 when we built the inner expression. */
6148 tree ret;
6153 depth++;
6155 depth--;
6158 }
6160 static tree
6163 {
6175 /* Don't deal with constants of zero here; they confuse the code below. */
6185 /* Note that we need not handle conditional operations here since fold
6186 already handles those cases. So just do arithmetic here. */
6188 {
6190 /* For a constant, we can always simplify if we are a multiply
6191 or (for divide and modulus) if it is a multiple of our constant. */
6195 {
6198 /* If the multiplication overflowed, we lost information on it.
6199 See PR68142 and PR69845. */
6203 }
6207 /* If op0 is an expression ... */
6213 /* ... and has wrapping overflow, and its type is smaller
6214 than ctype, then we cannot pass through as widening. */
6219 /* ... or this is a truncation (t is narrower than op0),
6220 then we cannot pass through this narrowing. */
6223 /* ... or signedness changes for division or modulus,
6224 then we cannot pass through this conversion. */
6228 /* ... or has undefined overflow while the converted to
6229 type has not, we cannot do the operation in the inner type
6230 as that would introduce undefined overflow. */
6236 /* Pass the constant down and see if we can make a simplification. If
6237 we can, replace this expression with the inner simplification for
6238 possible later conversion to our or some other type. */
6249 /* If widening the type changes it from signed to unsigned, then we
6250 must avoid building ABS_EXPR itself as unsigned. */
6252 {
6256 {
6259 }
6261 }
6262 /* If the constant is negative, we cannot simplify this. */
6265 /* FALLTHROUGH */
6267 /* For division and modulus, type can't be unsigned, as e.g.
6268 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6269 For signed types, even with wrapping overflow, this is fine. */
6278 /* If widening the type changes the signedness, then we can't perform
6279 this optimization as that changes the result. */
6283 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6289 {
6296 }
6300 /* If the second operand is constant, this is a multiplication
6301 or floor division, by a power of two, so we can treat it that
6302 way unless the multiplier or divisor overflows. Signed
6303 left-shift overflow is implementation-defined rather than
6304 undefined in C90, so do not convert signed left shift into
6305 multiplication. */
6308 /* const_binop may not detect overflow correctly,
6309 so check for it explicitly here. */
6318 ctype,
6320 t1),
6325 /* See if we can eliminate the operation on both sides. If we can, we
6326 can return a new PLUS or MINUS. If we can't, the only remaining
6327 cases where we can do anything are if the second operand is a
6328 constant. */
6335 /* If not multiplication, we can only do this if both operands
6336 are divisible by c. */
6339 {
6344 }
6346 /* If this was a subtraction, negate OP1 and set it to be an addition.
6347 This simplifies the logic below. */
6349 {
6351 /* If OP1 was not easily negatable, the constant may be OP0. */
6353 {
6356 }
6357 }
6362 /* If either OP1 or C are negative, this optimization is not safe for
6363 some of the division and remainder types while for others we need
6364 to change the code. */
6366 {
6374 }
6376 /* If it's a multiply or a division/modulus operation of a multiple
6377 of our constant, do the operation and verify it doesn't overflow. */
6381 {
6384 /* We allow the constant to overflow with wrapping semantics. */
6388 }
6389 else
6392 /* If we have an unsigned type, we cannot widen the operation since it
6393 will change the result if the original computation overflowed. */
6397 /* The last case is if we are a multiply. In that case, we can
6398 apply the distributive law to commute the multiply and addition
6399 if the multiplication of the constants doesn't overflow
6400 and overflow is defined. With undefined overflow
6401 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
6407 op1);
6412 /* We have a special case here if we are doing something like
6413 (C * 8) % 4 since we know that's zero. */
6416 /* If the multiplication can overflow we cannot optimize this. */
6421 {
6424 }
6426 /* ... fall through ... */
6430 /* If we can extract our operation from the LHS, do so and return a
6431 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6432 do something only if the second operand is a constant. */
6448 /* If these are the same operation types, we can associate them
6449 assuming no overflow. */
6451 {
6466 }
6468 /* If these operations "cancel" each other, we have the main
6469 optimizations of this pass, which occur when either constant is a
6470 multiple of the other, in which case we replace this with either an
6471 operation or CODE or TCODE.
6473 If we have an unsigned type, we cannot do this since it will change
6474 the result if the original computation overflowed. */
6481 {
6484 {
6491 }
6494 {
6501 }
6502 }
6507 }
6510 }
6511 \f
6512 /* Return a node which has the indicated constant VALUE (either 0 or
6513 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6514 and is of the indicated TYPE. */
6516 tree
6518 {
6527 else
6529 }
6532 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6533 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6534 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6535 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6536 COND is the first argument to CODE; otherwise (as in the example
6537 given here), it is the second argument. TYPE is the type of the
6538 original expression. Return NULL_TREE if no simplification is
6539 possible. */
6541 static tree
6546 {
6556 {
6560 /* If this operand throws an expression, then it does not make
6561 sense to try to perform a logical or arithmetic operation
6562 involving it. */
6567 }
6570 {
6575 }
6576 else
6577 /* Detect the case of mixing vector and scalar types - bail out. */
6583 /* This transformation is only worthwhile if we don't have to wrap ARG
6584 in a SAVE_EXPR and the operation can be simplified without recursing
6585 on at least one of the branches once its pushed inside the COND_EXPR. */
6594 {
6598 else
6600 }
6602 {
6606 else
6608 }
6610 /* Check that we have simplified at least one of the branches. */
6615 }
6617 \f
6618 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6620 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6621 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6622 ADDEND is the same as X.
6624 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6625 and finite. The problematic cases are when X is zero, and its mode
6626 has signed zeros. In the case of rounding towards -infinity,
6627 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6628 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6630 bool
6632 {
6636 /* Don't allow the fold with -fsignaling-nans. */
6640 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6644 /* In a vector or complex, we would need to check the sign of all zeros. */
6648 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6652 /* The mode has signed zeros, and we have to honor their sign.
6653 In this situation, there is only one case we can return true for.
6654 X - 0 is the same as X unless rounding towards -infinity is
6655 supported. */
6657 }
6659 /* Subroutine of match.pd that optimizes comparisons of a division by
6660 a nonzero integer constant against an integer constant, i.e.
6661 X/C1 op C2.
6663 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6664 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
6666 enum tree_code
6669 {
6674 /* We have to do this the hard way to detect unsigned overflow.
6675 prod = int_const_binop (MULT_EXPR, c1, c2); */
6681 {
6685 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6688 }
6690 {
6693 {
6712 }
6713 }
6714 else
6715 {
6716 /* A negative divisor reverses the relational operators. */
6721 {
6740 }
6741 }
6754 }
6757 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6758 equality/inequality test, then return a simplified form of the test
6759 using a sign testing. Otherwise return NULL. TYPE is the desired
6760 result type. */
6762 static tree
6765 tree result_type)
6766 {
6767 /* If this is testing a single bit, we can optimize the test. */
6771 {
6772 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6773 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6777 /* This is only a win if casting to a signed type is cheap,
6778 i.e. when arg00's type is not a partial mode. */
6780 {
6783 result_type,
6786 }
6787 }
6790 }
6792 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6793 equality/inequality test, then return a simplified form of
6794 the test using shifts and logical operations. Otherwise return
6795 NULL. TYPE is the desired result type. */
6797 tree
6800 {
6801 /* If this is testing a single bit, we can optimize the test. */
6805 {
6814 /* First, see if we can fold the single bit test into a sign-bit
6815 test. */
6817 result_type);
6821 /* Otherwise we have (A & C) != 0 where C is a single bit,
6822 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6823 Similarly for (A & C) == 0. */
6825 /* If INNER is a right shift of a constant and it plus BITNUM does
6826 not overflow, adjust BITNUM and INNER. */
6832 {
6835 }
6837 /* If we are going to be able to omit the AND below, we must do our
6838 operations as unsigned. If we must use the AND, we have a choice.
6839 Normally unsigned is faster, but for some machines signed is. */
6857 /* Put the AND last so it can combine with more things. */
6860 /* Make sure to return the proper type. */
6864 }
6866 }
6868 /* Test whether it is preferable two swap two operands, ARG0 and
6869 ARG1, for example because ARG0 is an integer constant and ARG1
6870 isn't. */
6872 bool
6874 {
6888 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6889 for commutative and comparison operators. Ensuring a canonical
6890 form allows the optimizers to find additional redundancies without
6891 having to explicitly check for both orderings. */
6897 /* Put SSA_NAMEs last. */
6903 /* Put variables last. */
6910 }
6913 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6914 means A >= Y && A != MAX, but in this case we know that
6915 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6917 static tree
6919 {
6926 else
6935 {
6938 }
6940 {
6943 }
6944 else
6951 {
6952 /* Convert the pointer types into integer before taking the difference. */
6956 }
6957 else
6964 }
6966 /* Fold a sum or difference of at least one multiplication.
6967 Returns the folded tree or NULL if no simplification could be made. */
6969 static tree
6972 {
6976 /* (A * C) +- (B * C) -> (A+-B) * C.
6977 (A * C) +- A -> A * (C+-1).
6978 We are most concerned about the case where C is a constant,
6979 but other combinations show up during loop reduction. Since
6980 it is not difficult, try all four possibilities. */
6983 {
6986 }
6988 {
6991 }
6992 else
6993 {
6994 /* We cannot generate constant 1 for fract. */
6999 }
7001 {
7004 }
7006 {
7008 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7009 the purpose of this canonicalization. */
7013 {
7016 }
7017 else
7019 }
7020 else
7021 {
7022 /* We cannot generate constant 1 for fract. */
7027 }
7030 /* Prefer factoring a common non-constant. */
7040 /* No identical multiplicands; see if we can find a common
7041 power-of-two factor in non-power-of-two multiplies. This
7042 can help in multi-dimensional array access. */
7045 {
7048 tree maybe_same;
7052 /* Move min of absolute values to int11. */
7054 {
7059 }
7060 else
7064 /* The remainder should not be a constant, otherwise we
7065 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7066 increased the number of multiplications necessary. */
7068 {
7076 }
7077 }
7084 /* We are neither factoring zero nor minus one. */
7092 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7093 same may be minus one and thus the multiplication may overflow. Perform
7094 the operations in an unsigned type. */
7099 /* If the sum evaluated to a constant that is not -INF the multiplication
7100 cannot overflow. */
7110 }
7112 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7113 specified by EXPR into the buffer PTR of length LEN bytes.
7114 Return the number of bytes placed in the buffer, or zero
7115 upon failure. */
7117 static int
7119 {
7131 /* Dry run. */
7137 {
7139 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7140 number of bytes. */
7144 {
7151 else
7153 }
7154 else
7158 }
7160 }
7163 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7164 specified by EXPR into the buffer PTR of length LEN bytes.
7165 Return the number of bytes placed in the buffer, or zero
7166 upon failure. */
7168 static int
7170 {
7174 FIXED_VALUE_TYPE value;
7189 }
7192 /* Subroutine of native_encode_expr. Encode the REAL_CST
7193 specified by EXPR into the buffer PTR of length LEN bytes.
7194 Return the number of bytes placed in the buffer, or zero
7195 upon failure. */
7197 static int
7199 {
7205 /* There are always 32 bits in each long, no matter the size of
7206 the hosts long. We handle floating point representations with
7207 up to 192 bits. */
7216 /* Dry run. */
7225 {
7230 {
7237 else
7239 }
7240 else
7241 {
7244 {
7245 /* Reverse bytes within each long, or within the entire float
7246 if it's smaller than a long (for HFmode). */
7249 }
7250 }
7255 }
7257 }
7259 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7260 specified by EXPR into the buffer PTR of length LEN bytes.
7261 Return the number of bytes placed in the buffer, or zero
7262 upon failure. */
7264 static int
7266 {
7268 tree part;
7282 }
7285 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7286 specified by EXPR into the buffer PTR of length LEN bytes.
7287 Return the number of bytes placed in the buffer, or zero
7288 upon failure. */
7290 static int
7292 {
7302 {
7304 {
7307 }
7318 }
7320 }
7323 /* Subroutine of native_encode_expr. Encode the STRING_CST
7324 specified by EXPR into the buffer PTR of length LEN bytes.
7325 Return the number of bytes placed in the buffer, or zero
7326 upon failure. */
7328 static int
7330 {
7333 /* Wide-char strings are encoded in target byte-order so native
7334 encoding them is trivial. */
7349 {
7352 {
7355 }
7358 }
7359 else
7362 }
7365 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7366 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7367 buffer PTR of length LEN bytes. If PTR is NULL, don't actually store
7368 anything, just do a dry run. If OFF is not -1 then start
7369 the encoding at byte offset OFF and encode at most LEN bytes.
7370 Return the number of bytes placed in the buffer, or zero upon failure. */
7372 int
7374 {
7375 /* We don't support starting at negative offset and -1 is special. */
7380 {
7401 }
7402 }
7405 /* Subroutine of native_interpret_expr. Interpret the contents of
7406 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7407 If the buffer cannot be interpreted, return NULL_TREE. */
7409 static tree
7411 {
7421 }
7424 /* Subroutine of native_interpret_expr. Interpret the contents of
7425 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7426 If the buffer cannot be interpreted, return NULL_TREE. */
7428 static tree
7430 {
7433 double_int result;
7434 FIXED_VALUE_TYPE fixed_value;
7444 }
7447 /* Subroutine of native_interpret_expr. Interpret the contents of
7448 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7449 If the buffer cannot be interpreted, return NULL_TREE. */
7451 static tree
7453 {
7457 /* There are always 32 bits in each long, no matter the size of
7458 the hosts long. We handle floating point representations with
7459 up to 192 bits. */
7460 REAL_VALUE_TYPE r;
7470 {
7471 /* Both OFFSET and BYTE index within a long;
7472 bitpos indexes the whole float. */
7475 {
7482 else
7484 }
7485 else
7486 {
7489 {
7490 /* Reverse bytes within each long, or within the entire float
7491 if it's smaller than a long (for HFmode). */
7494 }
7495 }
7499 }
7503 }
7506 /* Subroutine of native_interpret_expr. Interpret the contents of
7507 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7508 If the buffer cannot be interpreted, return NULL_TREE. */
7510 static tree
7512 {
7527 }
7530 /* Subroutine of native_interpret_expr. Interpret the contents of
7531 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7532 If the buffer cannot be interpreted, return NULL_TREE. */
7534 static tree
7536 {
7548 {
7553 }
7555 }
7558 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7559 the buffer PTR of length LEN as a constant of type TYPE. For
7560 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7561 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7562 return NULL_TREE. */
7564 tree
7566 {
7568 {
7590 }
7591 }
7593 /* Returns true if we can interpret the contents of a native encoding
7594 as TYPE. */
7596 static bool
7598 {
7600 {
7613 }
7614 }
7617 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7618 TYPE at compile-time. If we're unable to perform the conversion
7619 return NULL_TREE. */
7621 static tree
7623 {
7624 /* We support up to 512-bit values (for V8DFmode). */
7628 /* Check that the host and target are sane. */
7637 }
7639 /* Build an expression for the address of T. Folds away INDIRECT_REF
7640 to avoid confusing the gimplify process. */
7642 tree
7644 {
7645 /* The size of the object is not relevant when talking about its address. */
7650 {
7655 }
7665 {
7670 }
7671 else
7675 }
7677 /* Build an expression for the address of T. */
7679 tree
7681 {
7685 }
7687 /* Fold a unary expression of code CODE and type TYPE with operand
7688 OP0. Return the folded expression if folding is successful.
7689 Otherwise, return NULL_TREE. */
7691 tree
7693 {
7694 tree tem;
7695 tree arg0;
7703 {
7706 {
7707 /* Don't use STRIP_NOPS, because signedness of argument type
7708 matters. */
7710 }
7711 else
7712 {
7713 /* Strip any conversions that don't change the mode. This
7714 is safe for every expression, except for a comparison
7715 expression because its signedness is derived from its
7716 operands.
7718 Note that this is done as an internal manipulation within
7719 the constant folder, in order to find the simplest
7720 representation of the arguments so that their form can be
7721 studied. In any cases, the appropriate type conversions
7722 should be put back in the tree that will get out of the
7723 constant folder. */
7725 }
7728 {
7731 {
7735 }
7736 }
7737 }
7744 {
7751 {
7765 /* If this was a conversion, and all we did was to move into
7766 inside the COND_EXPR, bring it back out. But leave it if
7767 it is a conversion from integer to integer and the
7768 result precision is no wider than a word since such a
7769 conversion is cheap and may be optimized away by combine,
7770 while it couldn't if it were outside the COND_EXPR. Then return
7771 so we don't get into an infinite recursion loop taking the
7772 conversion out and then back in. */
7784 && (INTEGRAL_TYPE_P
7797 }
7798 }
7801 {
7807 CASE_CONVERT:
7811 {
7812 /* If we have (type) (a CMP b) and type is an integral type, return
7813 new expression involving the new type. Canonicalize
7814 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7815 non-integral type.
7816 Do not fold the result as that would not simplify further, also
7817 folding again results in recursions. */
7827 }
7829 /* Handle (T *)&A.B.C for A being of type T and B and C
7830 living at offset zero. This occurs frequently in
7831 C++ upcasting and then accessing the base. */
7835 {
7837 tree offset;
7838 machine_mode mode;
7840 tree base
7844 /* If the reference was to a (constant) zero offset, we can use
7845 the address of the base if it has the same base type
7846 as the result type and the pointer type is unqualified. */
7854 }
7858 /* Detect assigning a bitfield. */
7860 && DECL_BIT_FIELD
7862 {
7863 /* Don't leave an assignment inside a conversion
7864 unless assigning a bitfield. */
7866 /* First do the assignment, then return converted constant. */
7871 }
7873 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7874 constants (if x has signed type, the sign bit cannot be set
7875 in c). This folds extension into the BIT_AND_EXPR.
7876 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7877 very likely don't have maximal range for their precision and this
7878 transformation effectively doesn't preserve non-maximal ranges. */
7882 {
7893 <= HOST_BITS_PER_WIDE_INT
7895 {
7899 cst &= HOST_WIDE_INT_M1U
7903 && !flag_syntax_only
7906 {
7910 }
7911 }
7913 {
7918 }
7919 }
7921 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
7922 cast (T1)X will fold away. We assume that this happens when X itself
7923 is a cast. */
7927 {
7931 return fold_build_pointer_plus_loc
7933 }
7935 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7936 of the same precision, and X is an integer type not narrower than
7937 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7943 {
7949 }
7951 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7952 type of X and Y (integer types only). */
7957 {
7958 /* Be careful not to introduce new overflows. */
7959 tree mult_type;
7962 else
7966 {
7973 }
7974 }
7980 {
7987 }
7998 /* Convert fabs((double)float) into (double)fabsf(float). */
8001 {
8007 targ0));
8008 }
8012 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8031 /* Note that the operand of this must be an int
8032 and its values must be 0 or 1.
8033 ("true" is a fixed value perhaps depending on the language,
8034 but we don't handle values other than 1 correctly yet.) */
8041 /* Fold *&X to X if X is an lvalue. */
8043 {
8050 }
8056 }
8059 /* If the operation was a conversion do _not_ mark a resulting constant
8060 with TREE_OVERFLOW if the original constant was not. These conversions
8061 have implementation defined behavior and retaining the TREE_OVERFLOW
8062 flag here would confuse later passes such as VRP. */
8063 tree
8066 {
8075 }
8077 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
8078 operands OP0 and OP1. LOC is the location of the resulting expression.
8079 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
8080 Return the folded expression if folding is successful. Otherwise,
8081 return NULL_TREE. */
8082 static tree
8085 {
8086 tree tem;
8088 /* We only do these simplifications if we are optimizing. */
8092 /* Check for things like (A || B) && (A || C). We can convert this
8093 to A || (B && C). Note that either operator can be any of the four
8094 truth and/or operations and the transformation will still be
8095 valid. Also note that we only care about order for the
8096 ANDIF and ORIF operators. If B contains side effects, this
8097 might change the truth-value of A. */
8104 {
8124 /* This case if tricky because we must either have commutative
8125 operators or else A10 must not have side-effects. */
8131 a01);
8132 }
8134 /* See if we can build a range comparison. */
8140 {
8144 }
8148 {
8152 }
8154 /* Check for the possibility of merging component references. If our
8155 lhs is another similar operation, try to merge its rhs with our
8156 rhs. Then try to merge our lhs and rhs. */
8166 && !flag_sanitize_coverage
8171 {
8178 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8179 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8180 We don't want to pack more than two leafs to a non-IF AND/OR
8181 expression.
8182 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8183 equal to IF-CODE, then we don't want to add right-hand operand.
8184 If the inner right-hand side of left-hand operand has
8185 side-effects, or isn't simple, then we can't add to it,
8186 as otherwise we might destroy if-sequence. */
8189 /* Needed for sequence points to handle trappings, and
8190 side-effects. */
8192 {
8194 arg1);
8196 tem);
8197 }
8198 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8199 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8202 /* Needed for sequence points to handle trappings, and
8203 side-effects. */
8205 {
8210 }
8211 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8212 into (A OR B).
8213 For sequence point consistancy, we need to check for trapping,
8214 and side-effects. */
8218 }
8221 }
8223 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8224 by changing CODE to reduce the magnitude of constants involved in
8225 ARG0 of the comparison.
8226 Returns a canonicalized comparison tree if a simplification was
8227 possible, otherwise returns NULL_TREE.
8228 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8229 valid if signed overflow is undefined. */
8231 static tree
8235 {
8240 /* Match A +- CST code arg1. We can change this only if overflow
8241 is undefined. */
8244 /* In principle pointers also have undefined overflow behavior,
8245 but that causes problems elsewhere. */
8252 /* Identify the constant in arg0 and its sign. */
8256 /* Overflowed constants and zero will cause problems. */
8261 /* See if we can reduce the magnitude of the constant in
8262 arg0 by changing the comparison code. */
8263 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8267 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8271 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8275 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8279 else
8283 /* Now build the constant reduced in magnitude. But not if that
8284 would produce one outside of its types range. */
8300 }
8302 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8303 overflow further. Try to decrease the magnitude of constants involved
8304 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8305 and put sole constants at the second argument position.
8306 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8308 static tree
8311 {
8312 tree t;
8317 /* Try canonicalization by simplifying arg0. */
8322 {
8326 }
8328 /* Try canonicalization by simplifying arg1 using the swapped
8329 comparison. */
8337 }
8339 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8340 space. This is used to avoid issuing overflow warnings for
8341 expressions like &p->x which can not wrap. */
8343 static bool
8345 {
8352 poly_wide_int wi_offset;
8358 else
8363 precision);
8378 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8379 array. */
8388 }
8390 /* Return a positive integer when the symbol DECL is known to have
8391 a nonzero address, zero when it's known not to (e.g., it's a weak
8392 symbol), and a negative integer when the symbol is not yet in the
8393 symbol table and so whether or not its address is zero is unknown.
8394 For function local objects always return positive integer. */
8395 static int
8397 {
8402 /* Function local objects are never NULL. */
8410 }
8412 /* Subroutine of fold_binary. This routine performs all of the
8413 transformations that are common to the equality/inequality
8414 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8415 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8416 fold_binary should call fold_binary. Fold a comparison with
8417 tree code CODE and type TYPE with operands OP0 and OP1. Return
8418 the folded comparison or NULL_TREE. */
8420 static tree
8423 {
8433 /* For comparisons of pointers we can decompose it to a compile time
8434 comparison of the base objects and the offsets into the object.
8435 This requires at least one operand being an ADDR_EXPR or a
8436 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8442 {
8445 machine_mode mode;
8449 /* Get base and offset for the access. Strip ADDR_EXPR for
8450 get_inner_reference, but put it back by stripping INDIRECT_REF
8451 off the base object if possible. indirect_baseN will be true
8452 if baseN is not an address but refers to the object itself. */
8455 {
8456 base0
8462 else
8464 }
8466 {
8470 {
8471 base0
8477 else
8479 }
8482 else
8486 {
8493 }
8494 }
8498 {
8499 base1
8505 else
8507 }
8509 {
8513 {
8514 base1
8520 else
8522 }
8525 else
8529 {
8536 }
8537 }
8539 /* If we have equivalent bases we might be able to simplify. */
8543 {
8544 /* We can fold this expression to a constant if the non-constant
8545 offset parts are equal. */
8549 {
8555 "occur when comparing P +- C1 with "
8557 WARN_STRICT_OVERFLOW_CONDITIONAL);
8560 {
8598 }
8599 }
8600 /* We can simplify the comparison to a comparison of the variable
8601 offset parts if the constant offset parts are equal.
8602 Be careful to use signed sizetype here because otherwise we
8603 mess with array offsets in the wrong way. This is possible
8604 because pointer arithmetic is restricted to retain within an
8605 object and overflow on pointer differences is undefined as of
8606 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8608 {
8609 /* By converting to signed sizetype we cover middle-end pointer
8610 arithmetic which operates on unsigned pointer types of size
8611 type size and ARRAY_REF offsets which are properly sign or
8612 zero extended from their type in case it is narrower than
8613 sizetype. */
8616 else
8620 else
8627 "occur when comparing P +- C1 with "
8629 WARN_STRICT_OVERFLOW_COMPARISON);
8632 }
8633 }
8634 /* For equal offsets we can simplify to a comparison of the
8635 base addresses. */
8637 && (indirect_base0
8639 && (indirect_base1
8644 {
8650 }
8651 /* Comparison between an ordinary (non-weak) symbol and a null
8652 pointer can be eliminated since such symbols must have a non
8653 null address. In C, relational expressions between pointers
8654 to objects and null pointers are undefined. The results
8655 below follow the C++ rules with the additional property that
8656 every object pointer compares greater than a null pointer.
8657 */
8660 /* Avoid folding references to struct members at offset 0 to
8661 prevent tests like '&ptr->firstmember == 0' from getting
8662 eliminated. When ptr is null, although the -> expression
8663 is strictly speaking invalid, GCC retains it as a matter
8664 of QoI. See PR c/44555. */
8667 && indirect_base0
8668 /* The caller guarantees that when one of the arguments is
8669 constant (i.e., null in this case) it is second. */
8671 {
8673 {
8684 }
8685 }
8686 }
8688 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8689 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8690 the resulting offset is smaller in absolute value than the
8691 original one and has the same sign. */
8700 {
8705 tree cst;
8707 "occur when combining constants around "
8710 /* Put the constant on the side where it doesn't overflow and is
8711 of lower absolute value and of same sign than before. */
8718 {
8721 variable1,
8725 }
8733 {
8739 variable2);
8740 }
8741 }
8747 /* If we are comparing an expression that just has comparisons
8748 of two integer values, arithmetic expressions of those comparisons,
8749 and constants, we can simplify it. There are only three cases
8750 to check: the two values can either be equal, the first can be
8751 greater, or the second can be greater. Fold the expression for
8752 those three values. Since each value must be 0 or 1, we have
8753 eight possibilities, each of which corresponds to the constant 0
8754 or 1 or one of the six possible comparisons.
8756 This handles common cases like (a > b) == 0 but also handles
8757 expressions like ((x > y) - (y > x)) > 0, which supposedly
8758 occur in macroized code. */
8761 {
8766 /* Don't handle degenerate cases here; they should already
8767 have been handled anyway. */
8776 {
8780 /* We can't just pass T to eval_subst in case cval1 or cval2
8781 was the same as ARG1. */
8783 tree high_result
8787 arg1);
8788 tree equal_result
8792 arg1);
8793 tree low_result
8797 arg1);
8799 /* All three of these results should be 0 or 1. Confirm they are.
8800 Then use those values to select the proper code to use. */
8805 {
8806 /* Make a 3-bit mask with the high-order bit being the
8807 value for `>', the next for '=', and the low for '<'. */
8811 {
8813 /* Always false. */
8834 /* Always true. */
8836 }
8839 {
8843 }
8845 }
8846 }
8847 }
8850 }
8853 /* Subroutine of fold_binary. Optimize complex multiplications of the
8854 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
8855 argument EXPR represents the expression "z" of type TYPE. */
8857 static tree
8859 {
8864 {
8867 }
8869 {
8872 }
8873 else
8874 {
8878 }
8887 }
8890 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
8891 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
8892 true if successful. */
8894 static bool
8896 {
8900 {
8903 }
8905 {
8911 else
8913 }
8914 else
8920 }
8922 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
8923 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
8924 NULL_TREE otherwise. */
8926 static tree
8928 {
8949 {
8950 HOST_WIDE_INT index;
8956 }
8959 {
8965 }
8966 else
8968 }
8970 /* Try to fold a pointer difference of type TYPE two address expressions of
8971 array references AREF0 and AREF1 using location LOC. Return a
8972 simplified expression for the difference or NULL_TREE. */
8974 static tree
8978 {
8983 /* If the bases are array references as well, recurse. If the bases
8984 are pointer indirections compute the difference of the pointers.
8985 If the bases are equal, we are set. */
8988 && (base_offset
8990 use_pointer_diff)))
8993 && (base_offset
8994 = use_pointer_diff
9004 {
9010 base_offset,
9013 }
9015 }
9017 /* If the real or vector real constant CST of type TYPE has an exact
9018 inverse, return it, else return NULL. */
9020 tree
9022 {
9023 REAL_VALUE_TYPE r;
9024 tree unit_type;
9025 machine_mode mode;
9028 {
9038 {
9042 tree_vector_builder elts;
9047 {
9052 }
9055 }
9059 }
9060 }
9062 /* Mask out the tz least significant bits of X of type TYPE where
9063 tz is the number of trailing zeroes in Y. */
9064 static wide_int
9066 {
9071 }
9073 /* Return true when T is an address and is known to be nonzero.
9074 For floating point we further ensure that T is not denormal.
9075 Similar logic is present in nonzero_address in rtlanal.h.
9077 If the return value is based on the assumption that signed overflow
9078 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
9079 change *STRICT_OVERFLOW_P. */
9081 static bool
9083 {
9087 /* Doing something useful for floating point would need more work. */
9093 {
9096 strict_overflow_p);
9102 strict_overflow_p);
9110 }
9113 {
9116 strict_overflow_p);
9124 strict_overflow_p);
9139 strict_overflow_p);
9143 strict_overflow_p);
9146 {
9158 }
9162 }
9164 }
9166 /* Return true when T is an address and is known to be nonzero.
9167 Handle warnings about undefined signed overflow. */
9169 bool
9171 {
9178 "determining that expression is always "
9180 WARN_STRICT_OVERFLOW_MISC);
9182 }
9184 /* Return true if T is known not to be equal to an integer W. */
9186 bool
9188 {
9190 value_range_type rtype;
9192 {
9201 {
9206 }
9211 /* If T has some known zero bits and W has any of those bits set,
9212 then T is known not to be equal to W. */
9220 }
9221 }
9223 /* Fold a binary expression of code CODE and type TYPE with operands
9224 OP0 and OP1. LOC is the location of the resulting expression.
9225 Return the folded expression if folding is successful. Otherwise,
9226 return NULL_TREE. */
9228 tree
9231 {
9246 /* Strip any conversions that don't change the mode. This is
9247 safe for every expression, except for a comparison expression
9248 because its signedness is derived from its operands. So, in
9249 the latter case, only strip conversions that don't change the
9250 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9251 preserved.
9253 Note that this is done as an internal manipulation within the
9254 constant folder, in order to find the simplest representation
9255 of the arguments so that their form can be studied. In any
9256 cases, the appropriate type conversions should be put back in
9257 the tree that will get out of the constant folder. */
9260 {
9263 }
9264 else
9265 {
9268 }
9270 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9271 constant but we can't do arithmetic on them. */
9273 {
9276 {
9280 }
9281 }
9283 /* If this is a commutative operation, and ARG0 is a constant, move it
9284 to ARG1 to reduce the number of tests below. */
9289 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9290 to ARG1 to reduce the number of tests below. */
9299 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9301 First check for cases where an arithmetic operation is applied to a
9302 compound, conditional, or comparison operation. Push the arithmetic
9303 operation inside the compound or conditional to see if any folding
9304 can then be done. Convert comparison to conditional for this purpose.
9305 The also optimizes non-constant cases that used to be done in
9306 expand_expr.
9308 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9309 one of the operands is a comparison and the other is a comparison, a
9310 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9311 code below would make the expression more complex. Change it to a
9312 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9313 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9326 {
9330 boolean_type_node,
9338 }
9342 {
9344 {
9349 tem);
9350 }
9352 {
9357 tem);
9358 }
9363 {
9369 }
9374 {
9380 }
9381 }
9384 {
9386 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9389 {
9395 }
9397 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9400 {
9401 tree base;
9402 poly_int64 coffset;
9411 }
9416 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9422 arg1),
9424 arg0)));
9430 {
9431 /* X + (X / CST) * -CST is X % CST. */
9436 {
9445 cst0));
9446 }
9447 }
9449 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9450 one. Make sure the type is not saturating and has the signedness of
9451 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9452 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9459 {
9463 }
9466 {
9467 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9468 (plus (plus (mult) (mult)) (foo)) so that we can
9469 take advantage of the factoring cases below. */
9478 {
9484 else
9497 parg0),
9499 marg)),
9503 return
9509 parg1)));
9510 }
9511 }
9512 else
9513 {
9514 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9515 to __complex__ ( x, y ). This is not the same for SNaNs or
9516 if signed zeros are involved. */
9520 {
9527 {
9531 {
9537 }
9539 {
9545 }
9546 }
9547 }
9549 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9550 We associate floats only if the user has specified
9551 -fassociative-math. */
9555 {
9560 {
9561 tree tree0;
9564 }
9565 }
9566 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9567 We associate floats only if the user has specified
9568 -fassociative-math. */
9572 {
9577 {
9578 tree tree0;
9581 }
9582 }
9583 }
9585 bit_rotate:
9586 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9587 is a rotate of A by C1 bits. */
9588 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9589 is a rotate of A by B bits.
9590 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
9591 though in this case CODE must be | and not + or ^, otherwise
9592 it doesn't return A when B is 0. */
9593 {
9595 tree rtype;
9604 /* Only create rotates in complete modes. Other cases are not
9605 expanded properly. */
9608 {
9621 {
9626 }
9631 {
9634 code0 == LSHIFT_EXPR
9637 }
9639 {
9649 {
9653 orig_tree01);
9655 }
9656 }
9660 {
9671 {
9675 orig_tree01);
9677 }
9678 }
9679 }
9680 }
9682 associate:
9683 /* In most languages, can't associate operations on floats through
9684 parentheses. Rather than remember where the parentheses were, we
9685 don't associate floats at all, unless the user has specified
9686 -fassociative-math.
9687 And, we need to make sure type is not saturating. */
9691 {
9697 /* Split both trees into variables, constants, and literals. Then
9698 associate each group together, the constants with literals,
9699 then the result with variables. This increases the chances of
9700 literals being recombined later and of generating relocatable
9701 expressions for the sum of a constant and literal. */
9709 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9713 /* With undefined overflow prefer doing association in a type
9714 which wraps on overflow, if that is one of the operand types. */
9717 {
9725 }
9727 /* With undefined overflow we can only associate constants with one
9728 variable, and constants whose association doesn't overflow. */
9731 {
9733 {
9734 /* ??? If split_tree would handle NEGATE_EXPR we could
9735 simply reject these cases and the allowed cases would
9736 be the var0/minus_var1 ones. */
9742 {
9745 }
9752 {
9755 }
9761 /* The only case we can still associate with two variables
9762 is if they cancel out. */
9766 }
9772 }
9774 /* Only do something if we found more than two objects. Otherwise,
9775 nothing has changed and we risk infinite recursion. */
9783 {
9795 {
9799 }
9801 {
9805 }
9807 /* Preserve the MINUS_EXPR if the negative part of the literal is
9808 greater than the positive part. Otherwise, the multiplicative
9809 folding code (i.e extract_muldiv) may be fooled in case
9810 unsigned constants are subtracted, like in the following
9811 example: ((X*2 + 4) - 8U)/2. */
9813 {
9817 /* But avoid ending up with only negated parts. */
9819 {
9823 }
9824 else
9825 {
9829 }
9830 }
9832 /* Don't introduce overflows through reassociation. */
9837 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
9844 /* Eliminate minus_con0. */
9846 {
9853 else
9856 }
9858 /* Eliminate minus_var0. */
9860 {
9864 else
9867 }
9869 return
9872 }
9873 }
9879 /* Fold &a[i] - &a[j] to i-j. */
9884 {
9888 code
9892 }
9894 /* Further transformations are not for pointers. */
9898 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9901 /* If arg0 is e.g. unsigned int and type is int, then this could
9902 introduce UB, because if A is INT_MIN at runtime, the original
9903 expression can be well defined while the latter is not.
9904 See PR83269. */
9913 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
9914 __complex__ ( x, -y ). This is not the same for SNaNs or if
9915 signed zeros are involved. */
9919 {
9926 {
9930 {
9932 arg1r ? arg1r
9937 }
9939 {
9943 arg1i ? arg1i
9946 }
9947 }
9948 }
9950 /* A - B -> A + (-B) if B is easily negatable. */
9954 /* Avoid this transformation if B is a positive REAL_CST. */
9962 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
9963 one. Make sure the type is not saturating and has the signedness of
9964 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9965 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9972 {
9976 }
9982 {
9983 /* Transform x * -C into -x * C if x is easily negatable. */
9998 {
10001 "occur when simplifying "
10003 WARN_STRICT_OVERFLOW_MISC);
10005 }
10007 /* Optimize z * conj(z) for integer complex numbers. */
10014 }
10015 else
10016 {
10017 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10018 This is not the same for NaNs or if signed zeros are
10019 involved. */
10025 {
10028 return
10034 return
10039 }
10041 /* Optimize z * conj(z) for floating point complex numbers.
10042 Guarded by flag_unsafe_math_optimizations as non-finite
10043 imaginary components don't produce scalar results. */
10052 }
10056 /* Canonicalize (X & C1) | C2. */
10060 {
10065 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10073 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10075 {
10078 }
10080 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10081 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10082 mode which allows further optimizations. */
10087 {
10092 {
10095 }
10096 }
10099 {
10104 }
10105 }
10107 /* See if this can be simplified into a rotate first. If that
10108 is unsuccessful continue in the association code. */
10112 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10120 /* See if this can be simplified into a rotate first. If that
10121 is unsuccessful continue in the association code. */
10125 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10130 {
10131 tree tem2;
10138 }
10139 /* Fold ~X & 1 as (X & 1) == 0. */
10143 {
10144 tree tem2;
10151 }
10152 /* Fold !X & 1 as X == 0. */
10155 {
10159 }
10161 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
10162 multiple of 1 << CST. */
10164 {
10171 }
10173 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
10174 bits from CST2. */
10178 {
10180 wide_int masked
10187 {
10188 /* Avoid the transform if arg1 is a mask of some
10189 mode which allows further optimizations. */
10196 }
10197 }
10199 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
10200 ((A & N) + B) & M -> (A + B) & M
10201 Similarly if (N & M) == 0,
10202 ((A | N) + B) & M -> (A + B) & M
10203 and for - instead of + (or unary - instead of +)
10204 and/or ^ instead of |.
10205 If B is constant and (B & M) == 0, fold into A & M. */
10207 {
10216 {
10219 wide_int cst0;
10221 /* Now we know that arg0 is (C + D) or (C - D) or
10222 -C and arg1 (M) is == (1LL << cst) - 1.
10223 Store C into PMOP[0] and D into PMOP[1]. */
10227 {
10230 }
10237 {
10246 {
10249 }
10252 /* If C or D is of the form (A & N) where
10253 (N & M) == M, or of the form (A | N) or
10254 (A ^ N) where (N & M) == 0, replace it with A. */
10258 /* If C or D is a N where (N & M) == 0, it can be
10259 omitted (assumed 0). */
10267 }
10269 /* Only build anything new if we optimized one or both arguments
10270 above. */
10274 {
10277 {
10278 /* Perform the operations in a type that has defined
10279 overflow behavior. */
10285 }
10290 {
10298 else
10300 }
10303 else
10306 /* TEM is now the new binary +, - or unary - replacement. */
10310 }
10311 }
10312 }
10314 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10317 {
10322 return
10324 }
10329 /* Don't touch a floating-point divide by zero unless the mode
10330 of the constant can represent infinity. */
10336 /* (-A) / (-B) -> A / B */
10348 /* Fall through */
10351 /* Simplify A / (B << N) where A and B are positive and B is
10352 a power of 2, to A >> (N + log2(B)). */
10357 {
10360 {
10368 WARN_STRICT_OVERFLOW_MISC);
10374 }
10375 }
10377 /* Fall through */
10385 /* Convert -A / -B to A / B when the type is signed and overflow is
10386 undefined. */
10390 {
10393 "when distributing negation across "
10395 WARN_STRICT_OVERFLOW_MISC);
10400 }
10404 {
10407 "when distributing negation across "
10409 WARN_STRICT_OVERFLOW_MISC);
10414 }
10416 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
10417 operation, EXACT_DIV_EXPR.
10419 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
10420 At one time others generated faster code, it's not clear if they do
10421 after the last round to changes to the DIV code in expmed.c. */
10432 {
10436 WARN_STRICT_OVERFLOW_MISC);
10438 }
10450 {
10454 WARN_STRICT_OVERFLOW_MISC);
10456 }
10464 /* Since negative shift count is not well-defined,
10465 don't try to compute it in the compiler. */
10471 /* If we have a rotate of a bit operation with the rotate count and
10472 the second operand of the bit operation both constant,
10473 permute the two operations. */
10479 {
10487 }
10489 /* Two consecutive rotates adding up to the some integer
10490 multiple of the precision of the type can be ignored. */
10506 /* Note that the operands of this must be ints
10507 and their values must be 0 or 1.
10508 ("true" is a fixed value perhaps depending on the language.) */
10509 /* If first arg is constant zero, return it. */
10512 /* FALLTHRU */
10514 /* If either arg is constant true, drop it. */
10518 /* Preserve sequence points. */
10521 /* If second arg is constant zero, result is zero, but first arg
10522 must be evaluated. */
10525 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
10526 case will be handled here. */
10530 /* !X && X is always false. */
10534 /* X && !X is always false. */
10539 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
10540 means A >= Y && A != MAX, but in this case we know that
10541 A < X <= MAX. */
10545 {
10553 }
10562 /* Note that the operands of this must be ints
10563 and their values must be 0 or true.
10564 ("true" is a fixed value perhaps depending on the language.) */
10565 /* If first arg is constant true, return it. */
10568 /* FALLTHRU */
10570 /* If either arg is constant zero, drop it. */
10574 /* Preserve sequence points. */
10577 /* If second arg is constant true, result is true, but we must
10578 evaluate first arg. */
10581 /* Likewise for first arg, but note this only occurs here for
10582 TRUTH_OR_EXPR. */
10586 /* !X || X is always true. */
10590 /* X || !X is always true. */
10595 /* (X && !Y) || (!X && Y) is X ^ Y */
10598 {
10615 }
10624 /* If the second arg is constant zero, drop it. */
10627 /* If the second arg is constant true, this is a logical inversion. */
10629 {
10632 }
10633 /* Identical arguments cancel to zero. */
10637 /* !X ^ X is always true. */
10642 /* X ^ !X is always true. */
10658 /* bool_var != 1 becomes !bool_var. */
10665 /* bool_var == 0 becomes !bool_var. */
10672 /* !exp != 0 becomes !exp */
10677 /* If this is an EQ or NE comparison with zero and ARG0 is
10678 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
10679 two operations, but the latter can be done in one less insn
10680 on machines that have only two-operand insns or on which a
10681 constant cannot be the first operand. */
10684 {
10689 {
10696 arg1);
10697 }
10700 {
10707 arg1);
10708 }
10709 }
10711 /* If this is an NE or EQ comparison of zero against the result of a
10712 signed MOD operation whose second operand is a power of 2, make
10713 the MOD operation unsigned since it is simpler and equivalent. */
10721 {
10731 }
10733 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
10734 C1 is a valid shift constant, and C2 is a power of two, i.e.
10735 a single bit. */
10739 == INTEGER_CST
10742 {
10747 /* Check for a valid shift count. */
10749 {
10753 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
10754 can be rewritten as (X & (C2 << C1)) != 0. */
10756 {
10761 }
10762 /* Otherwise, for signed (arithmetic) shifts,
10763 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
10764 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
10768 /* Otherwise, of unsigned (logical) shifts,
10769 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
10770 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
10771 else
10775 arg000);
10776 }
10777 }
10779 /* If this is a comparison of a field, we may be able to simplify it. */
10782 /* Handle the constant case even without -O
10783 to make sure the warnings are given. */
10785 {
10789 }
10791 /* Optimize comparisons of strlen vs zero to a compare of the
10792 first character of the string vs zero. To wit,
10793 strlen(ptr) == 0 => *ptr == 0
10794 strlen(ptr) != 0 => *ptr != 0
10795 Other cases should reduce to one of these two (or a constant)
10796 due to the return value of strlen being unsigned. */
10799 {
10807 {
10812 }
10813 }
10815 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
10816 of X. Similarly fold (X >> C) == 0 into X >= 0. */
10820 {
10825 {
10827 {
10830 }
10833 }
10834 }
10836 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
10837 (X & C) == 0 when C is a single bit. */
10842 {
10849 arg1));
10850 }
10852 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
10853 constant C is a power of two, i.e. a single bit. */
10860 {
10864 }
10866 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
10867 when is C is a power of two, i.e. a single bit. */
10874 {
10880 }
10884 {
10887 }
10889 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
10892 {
10900 {
10906 }
10908 {
10914 }
10916 {
10922 }
10924 {
10930 }
10931 }
10935 {
10942 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
10943 operand_equal_p guarantees no side-effects so we don't need
10944 to use omit_one_operand on Z. */
10948 arg10));
10952 arg11));
10956 arg10));
10960 arg11));
10962 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
10965 {
10971 }
10972 }
10974 /* Attempt to simplify equality/inequality comparisons of complex
10975 values. Only lower the comparison if the result is known or
10976 can be simplified to a single scalar comparison. */
10981 {
10986 {
10989 }
10990 else
10991 {
10994 }
10997 {
11000 }
11001 else
11002 {
11005 }
11009 {
11011 {
11016 }
11017 else
11018 {
11023 }
11024 }
11028 {
11030 {
11035 }
11036 else
11037 {
11042 }
11043 }
11044 }
11056 /* Transform comparisons of the form X +- C CMP X. */
11061 {
11066 /* (X - c) > X becomes false. */
11072 /* Likewise (X + c) < X becomes false. */
11078 /* Convert (X - c) <= X to true. */
11085 /* Convert (X + c) >= X to true. */
11091 }
11093 /* If we are comparing an ABS_EXPR with a constant, we can
11094 convert all the cases into explicit comparisons, but they may
11095 well not be faster than doing the ABS and one comparison.
11096 But ABS (X) <= C is a range comparison, which becomes a subtraction
11097 and a comparison, and is probably faster. */
11111 /* Convert ABS_EXPR<x> >= 0 to true. */
11118 {
11121 "when simplifying comparison of "
11123 WARN_STRICT_OVERFLOW_CONDITIONAL);
11126 arg0);
11127 }
11129 /* Convert ABS_EXPR<x> < 0 to false. */
11134 {
11137 "when simplifying comparison of "
11139 WARN_STRICT_OVERFLOW_CONDITIONAL);
11142 arg0);
11143 }
11145 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
11146 and similarly for >= into !=. */
11156 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
11157 otherwise Y might be >= # of bits in X's type and thus e.g.
11158 (unsigned char) (1 << Y) for Y 15 might be 0.
11159 If the cast is widening, then 1 << Y should have unsigned type,
11160 otherwise if Y is number of bits in the signed shift type minus 1,
11161 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
11162 31 might be 0xffffffff80000000. */
11173 {
11179 }
11191 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
11192 {
11204 }
11209 /* When pedantic, a compound expression can be neither an lvalue
11210 nor an integer constant expression. */
11213 /* Don't let (0, 0) be null pointer constant. */
11219 /* An ASSERT_EXPR should never be passed to fold_binary. */
11225 }
11227 /* Used by contains_label_[p1]. */
11229 struct contains_label_data
11230 {
11233 };
11235 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
11236 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
11237 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
11239 static tree
11241 {
11244 {
11255 {
11263 }
11272 }
11273 }
11275 /* Return whether the sub-tree ST contains a label which is accessible from
11276 outside the sub-tree. */
11278 static bool
11280 {
11284 }
11286 /* Fold a ternary expression of code CODE and type TYPE with operands
11287 OP0, OP1, and OP2. Return the folded expression if folding is
11288 successful. Otherwise, return NULL_TREE. */
11290 tree
11293 {
11294 tree tem;
11301 /* If this is a commutative operation, and OP0 is a constant, move it
11302 to OP1 to reduce the number of tests below. */
11311 /* Strip any conversions that don't change the mode. This is safe
11312 for every expression, except for a comparison expression because
11313 its signedness is derived from its operands. So, in the latter
11314 case, only strip conversions that don't change the signedness.
11316 Note that this is done as an internal manipulation within the
11317 constant folder, in order to find the simplest representation of
11318 the arguments so that their form can be studied. In any cases,
11319 the appropriate type conversions should be put back in the tree
11320 that will get out of the constant folder. */
11322 {
11325 }
11328 {
11331 }
11334 {
11337 }
11340 {
11344 {
11350 }
11355 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
11356 so all simple results must be passed through pedantic_non_lvalue. */
11358 {
11361 /* Only optimize constant conditions when the selected branch
11362 has the same type as the COND_EXPR. This avoids optimizing
11363 away "c ? x : throw", where the throw has a void type.
11364 Avoid throwing away that operand which contains label. */
11371 }
11373 {
11378 {
11383 {
11391 }
11396 }
11397 }
11399 /* If we have A op B ? A : C, we may be able to convert this to a
11400 simpler expression, depending on the operation and the values
11401 of B and C. Signed zeros prevent all of these transformations,
11402 for reasons given above each one.
11404 Also try swapping the arguments and inverting the conditional. */
11408 {
11412 }
11417 {
11421 {
11425 }
11426 }
11428 /* If the second operand is simpler than the third, swap them
11429 since that produces better jump optimization results. */
11432 {
11434 /* See if this can be inverted. If it can't, possibly because
11435 it was a floating-point inequality comparison, don't do
11436 anything. */
11440 }
11442 /* Convert A ? 1 : 0 to simply A. */
11447 /* If we try to convert OP0 to our type, the
11448 call to fold will try to move the conversion inside
11449 a COND, which will recurse. In that case, the COND_EXPR
11450 is probably the best choice, so leave it alone. */
11454 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
11455 over COND_EXPR in cases such as floating point comparisons. */
11464 arg0)));
11466 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
11471 {
11472 /* sign_bit_p looks through both zero and sign extensions,
11473 but for this optimization only sign extensions are
11474 usable. */
11477 {
11480 {
11483 }
11485 }
11486 /* sign_bit_p only checks ARG1 bits within A's precision.
11487 If <sign bit of A> has wider type than A, bits outside
11488 of A's precision in <sign bit of A> need to be checked.
11489 If they are all 0, this optimization needs to be done
11490 in unsigned A's type, if they are all 1 in signed A's type,
11491 otherwise this can't be done. */
11497 {
11499 tree tem_type;
11512 {
11515 }
11517 {
11520 }
11521 else
11523 }
11526 return
11532 arg1)));
11533 }
11535 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
11536 already handled above. */
11541 {
11551 op1);
11552 }
11554 /* A & N ? N : 0 is simply A & N if N is a power of two. This
11555 is probably obsolete because the first operand should be a
11556 truth value (that's why we have the two cases above), but let's
11557 leave it in until we can confirm this for all front-ends. */
11569 /* Disable the transformations below for vectors, since
11570 fold_binary_op_with_conditional_arg may undo them immediately,
11571 yielding an infinite loop. */
11575 /* Convert A ? B : 0 into A && B if A and B are truth values. */
11584 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
11589 {
11591 /* Only perform transformation if ARG0 is easily inverted. */
11595 ? BIT_IOR_EXPR
11598 op1);
11599 }
11601 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
11606 {
11608 /* Only perform transformation if ARG0 is easily inverted. */
11614 op2);
11615 }
11617 /* Convert A ? 1 : B into A || B if A and B are truth values. */
11629 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
11630 of fold_ternary on them. */
11638 {
11648 {
11653 {
11661 }
11662 }
11663 }
11665 /* On constants we can use native encode/interpret to constant
11666 fold (nearly) all BIT_FIELD_REFs. */
11672 {
11675 /* Limit us to a reasonable amount of work. To relax the
11676 other limitations we need bit-shifting of the buffer
11677 and rounding up the size. */
11681 {
11683 unsigned HOST_WIDE_INT len
11688 {
11693 }
11694 }
11695 }
11700 /* For integers we can decompose the FMA if possible. */
11712 {
11713 /* Build a vector of integers from the tree mask. */
11714 vec_perm_builder builder;
11718 /* Create a vec_perm_indices for the integer vector. */
11723 /* Check for cases that fold to OP0 or OP1 in their original
11724 element order. */
11731 {
11735 {
11738 }
11739 }
11745 {
11749 }
11753 /* Generate a canonical form of the selector. */
11755 {
11756 /* Some targets are deficient and fail to expand a single
11757 argument permutation while still allowing an equivalent
11758 2-argument version. */
11762 else
11763 {
11767 else
11768 /* Not directly supported with either encoding,
11769 so use the preferred form. */
11771 }
11773 }
11777 }
11781 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
11784 {
11790 wide_int tem2
11794 }
11799 {
11801 unsigned HOST_WIDE_INT elsize
11804 {
11808 else
11809 {
11816 }
11817 }
11818 }
11824 }
11826 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
11827 of an array (or vector). */
11829 tree
11831 {
11836 {
11839 {
11840 /* Static constructors for variably sized objects makes no sense. */
11844 }
11845 }
11856 offset_int max_index;
11861 {
11862 /* Array constructor might explicitly set index, or specify a range,
11863 or leave index NULL meaning that it is next index after previous
11864 one. */
11866 {
11869 else
11870 {
11874 }
11875 }
11876 else
11877 {
11883 }
11885 /* Do we have match? */
11889 }
11891 }
11893 /* Perform constant folding and related simplification of EXPR.
11894 The related simplifications include x*1 => x, x*0 => 0, etc.,
11895 and application of the associative law.
11896 NOP_EXPR conversions may be removed freely (as long as we
11897 are careful not to change the type of the overall expression).
11898 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
11899 but we can constant-fold them if they have constant operands. */
11901 #ifdef ENABLE_FOLD_CHECKING
11902 # define fold(x) fold_1 (x)
11904 static
11905 #endif
11906 tree
11908 {
11912 tree tem;
11915 /* Return right away if a constant. */
11919 /* CALL_EXPR-like objects with variable numbers of operands are
11920 treated specially. */
11922 {
11924 {
11927 }
11929 }
11932 {
11937 {
11955 }
11956 }
11959 {
11961 {
11968 {
11973 }
11976 }
11978 /* Return a VECTOR_CST if possible. */
11980 {
11986 tree val;
11992 }
12000 }
12002 #ifdef ENABLE_FOLD_CHECKING
12003 #undef fold
12010 /* When --enable-checking=fold, compute a digest of expr before
12011 and after actual fold call to see if fold did not accidentally
12012 change original expr. */
12014 tree
12016 {
12017 tree ret;
12037 }
12039 void
12041 {
12052 }
12054 static void
12056 {
12058 }
12060 static void
12063 {
12069 recursive_label:
12079 {
12080 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
12085 }
12093 {
12094 /* Allow these fields to be modified. */
12095 tree tmp;
12104 {
12107 }
12108 }
12119 {
12122 {
12138 }
12142 {
12155 }
12172 {
12178 }
12181 {
12183 {
12186 }
12188 }
12199 {
12202 }
12212 }
12213 }
12215 /* Helper function for outputting the checksum of a tree T. When
12216 debugging with gdb, you can "define mynext" to be "next" followed
12217 by "call debug_fold_checksum (op0)", then just trace down till the
12218 outputs differ. */
12220 DEBUG_FUNCTION void
12222 {
12237 }
12239 #endif
12241 /* Fold a unary tree expression with code CODE of type TYPE with an
12242 operand OP0. LOC is the location of the resulting expression.
12243 Return a folded expression if successful. Otherwise, return a tree
12244 expression with code CODE of type TYPE with an operand OP0. */
12246 tree
12249 {
12250 tree tem;
12251 #ifdef ENABLE_FOLD_CHECKING
12260 #endif
12266 #ifdef ENABLE_FOLD_CHECKING
12273 #endif
12275 }
12277 /* Fold a binary tree expression with code CODE of type TYPE with
12278 operands OP0 and OP1. LOC is the location of the resulting
12279 expression. Return a folded expression if successful. Otherwise,
12280 return a tree expression with code CODE of type TYPE with operands
12281 OP0 and OP1. */
12283 tree
12286 MEM_STAT_DECL)
12287 {
12288 tree tem;
12289 #ifdef ENABLE_FOLD_CHECKING
12306 #endif
12312 #ifdef ENABLE_FOLD_CHECKING
12327 #endif
12329 }
12331 /* Fold a ternary tree expression with code CODE of type TYPE with
12332 operands OP0, OP1, and OP2. Return a folded expression if
12333 successful. Otherwise, return a tree expression with code CODE of
12334 type TYPE with operands OP0, OP1, and OP2. */
12336 tree
12339 {
12340 tree tem;
12341 #ifdef ENABLE_FOLD_CHECKING
12365 #endif
12372 #ifdef ENABLE_FOLD_CHECKING
12395 #endif
12397 }
12399 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
12400 arguments in ARGARRAY, and a null static chain.
12401 Return a folded expression if successful. Otherwise, return a CALL_EXPR
12402 of type TYPE from the given operands as constructed by build_call_array. */
12404 tree
12407 {
12408 tree tem;
12409 #ifdef ENABLE_FOLD_CHECKING
12428 #endif
12434 #ifdef ENABLE_FOLD_CHECKING
12450 #endif
12452 }
12454 /* Perform constant folding and related simplification of initializer
12455 expression EXPR. These behave identically to "fold_buildN" but ignore
12456 potential run-time traps and exceptions that fold must preserve. */
12458 #define START_FOLD_INIT \
12459 int saved_signaling_nans = flag_signaling_nans;\
12460 int saved_trapping_math = flag_trapping_math;\
12461 int saved_rounding_math = flag_rounding_math;\
12462 int saved_trapv = flag_trapv;\
12463 int saved_folding_initializer = folding_initializer;\
12464 flag_signaling_nans = 0;\
12465 flag_trapping_math = 0;\
12466 flag_rounding_math = 0;\
12467 flag_trapv = 0;\
12468 folding_initializer = 1;
12470 #define END_FOLD_INIT \
12471 flag_signaling_nans = saved_signaling_nans;\
12472 flag_trapping_math = saved_trapping_math;\
12473 flag_rounding_math = saved_rounding_math;\
12474 flag_trapv = saved_trapv;\
12475 folding_initializer = saved_folding_initializer;
12477 tree
12480 {
12481 tree result;
12482 START_FOLD_INIT;
12486 END_FOLD_INIT;
12488 }
12490 tree
12493 {
12494 tree result;
12495 START_FOLD_INIT;
12499 END_FOLD_INIT;
12501 }
12503 tree
12506 {
12507 tree result;
12508 START_FOLD_INIT;
12512 END_FOLD_INIT;
12514 }
12516 #undef START_FOLD_INIT
12517 #undef END_FOLD_INIT
12519 /* Determine if first argument is a multiple of second argument. Return 0 if
12520 it is not, or we cannot easily determined it to be.
12522 An example of the sort of thing we care about (at this point; this routine
12523 could surely be made more general, and expanded to do what the *_DIV_EXPR's
12524 fold cases do now) is discovering that
12526 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12528 is a multiple of
12530 SAVE_EXPR (J * 8)
12532 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
12534 This code also handles discovering that
12536 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12538 is a multiple of 8 so we don't have to worry about dealing with a
12539 possible remainder.
12541 Note that we *look* inside a SAVE_EXPR only to determine how it was
12542 calculated; it is not safe for fold to do much of anything else with the
12543 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
12544 at run time. For example, the latter example above *cannot* be implemented
12545 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
12546 evaluation time of the original SAVE_EXPR is not necessarily the same at
12547 the time the new expression is evaluated. The only optimization of this
12548 sort that would be valid is changing
12550 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
12552 divided by 8 to
12554 SAVE_EXPR (I) * SAVE_EXPR (J)
12556 (where the same SAVE_EXPR (J) is used in the original and the
12557 transformed version). */
12559 int
12561 {
12572 {
12574 /* Bitwise and provides a power of two multiple. If the mask is
12575 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
12578 /* FALLTHRU */
12585 /* It is impossible to prove if op0 - op1 is multiple of bottom
12586 precisely, so be conservative here checking if both op0 and op1
12587 are multiple of bottom. Note we check the second operand first
12588 since it's usually simpler. */
12593 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
12594 as op0 - 3 if the expression has unsigned type. For example,
12595 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
12605 {
12607 /* const_binop may not detect overflow correctly,
12608 so check for it explicitly here. */
12616 }
12620 /* Can't handle conversions from non-integral or wider integral type. */
12626 /* fall through */
12643 SIGNED);
12649 {
12652 /* Check for special cases to see if top is defined as multiple
12653 of bottom:
12655 top = (X & ~(bottom - 1) ; bottom is power of 2
12657 or
12659 Y = X % bottom
12660 top = X - Y. */
12679 }
12681 /* fall through */
12689 }
12690 }
12692 #define tree_expr_nonnegative_warnv_p(X, Y) \
12695 #define RECURSE(X) \
12696 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
12698 /* Return true if CODE or TYPE is known to be non-negative. */
12700 static bool
12702 {
12705 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
12706 have a signed:1 type (where the value is -1 and 0). */
12709 }
12711 /* Return true if (CODE OP0) is known to be non-negative. If the return
12712 value is based on the assumption that signed overflow is undefined,
12713 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12714 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12716 bool
12719 {
12724 {
12726 /* We can't return 1 if flag_wrapv is set because
12727 ABS_EXPR<INT_MIN> = INT_MIN. */
12731 {
12734 }
12742 CASE_CONVERT:
12743 {
12748 {
12752 {
12756 }
12757 }
12759 {
12765 }
12766 }
12771 }
12773 /* We don't know sign of `t', so be conservative and return false. */
12775 }
12777 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
12778 value is based on the assumption that signed overflow is undefined,
12779 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12780 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12782 bool
12786 {
12791 {
12797 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
12798 both unsigned and at least 2 bits shorter than the result. */
12802 {
12807 {
12811 }
12812 }
12817 {
12818 /* x * x is always non-negative for floating point x
12819 or without overflow. */
12822 {
12827 }
12828 }
12830 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
12831 both unsigned and their total bits is shorter than the result. */
12835 {
12854 {
12864 }
12865 }
12892 }
12894 /* We don't know sign of `t', so be conservative and return false. */
12896 }
12898 /* Return true if T is known to be non-negative. If the return
12899 value is based on the assumption that signed overflow is undefined,
12900 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12901 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12903 bool
12905 {
12910 {
12924 /* Limit the depth of recursion to avoid quadratic behavior.
12925 This is expected to catch almost all occurrences in practice.
12926 If this code misses important cases that unbounded recursion
12927 would not, passes that need this information could be revised
12928 to provide it through dataflow propagation. */
12936 }
12937 }
12939 /* Return true if T is known to be non-negative. If the return
12940 value is based on the assumption that signed overflow is undefined,
12941 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12942 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12944 bool
12947 {
12949 {
12950 CASE_CFN_ACOS:
12951 CASE_CFN_ACOSH:
12952 CASE_CFN_CABS:
12953 CASE_CFN_COSH:
12954 CASE_CFN_ERFC:
12955 CASE_CFN_EXP:
12956 CASE_CFN_EXP10:
12957 CASE_CFN_EXP2:
12958 CASE_CFN_FABS:
12959 CASE_CFN_FDIM:
12960 CASE_CFN_HYPOT:
12961 CASE_CFN_POW10:
12962 CASE_CFN_FFS:
12963 CASE_CFN_PARITY:
12964 CASE_CFN_POPCOUNT:
12965 CASE_CFN_CLZ:
12966 CASE_CFN_CLRSB:
12969 /* Always true. */
12972 CASE_CFN_SQRT:
12973 CASE_CFN_SQRT_FN:
12974 /* sqrt(-0.0) is -0.0. */
12979 CASE_CFN_ASINH:
12980 CASE_CFN_ATAN:
12981 CASE_CFN_ATANH:
12982 CASE_CFN_CBRT:
12983 CASE_CFN_CEIL:
12984 CASE_CFN_CEIL_FN:
12985 CASE_CFN_ERF:
12986 CASE_CFN_EXPM1:
12987 CASE_CFN_FLOOR:
12988 CASE_CFN_FLOOR_FN:
12989 CASE_CFN_FMOD:
12990 CASE_CFN_FREXP:
12991 CASE_CFN_ICEIL:
12992 CASE_CFN_IFLOOR:
12993 CASE_CFN_IRINT:
12994 CASE_CFN_IROUND:
12995 CASE_CFN_LCEIL:
12996 CASE_CFN_LDEXP:
12997 CASE_CFN_LFLOOR:
12998 CASE_CFN_LLCEIL:
12999 CASE_CFN_LLFLOOR:
13000 CASE_CFN_LLRINT:
13001 CASE_CFN_LLROUND:
13002 CASE_CFN_LRINT:
13003 CASE_CFN_LROUND:
13004 CASE_CFN_MODF:
13005 CASE_CFN_NEARBYINT:
13006 CASE_CFN_NEARBYINT_FN:
13007 CASE_CFN_RINT:
13008 CASE_CFN_RINT_FN:
13009 CASE_CFN_ROUND:
13010 CASE_CFN_ROUND_FN:
13011 CASE_CFN_SCALB:
13012 CASE_CFN_SCALBLN:
13013 CASE_CFN_SCALBN:
13014 CASE_CFN_SIGNBIT:
13015 CASE_CFN_SIGNIFICAND:
13016 CASE_CFN_SINH:
13017 CASE_CFN_TANH:
13018 CASE_CFN_TRUNC:
13019 CASE_CFN_TRUNC_FN:
13020 /* True if the 1st argument is nonnegative. */
13023 CASE_CFN_FMAX:
13024 CASE_CFN_FMAX_FN:
13025 /* True if the 1st OR 2nd arguments are nonnegative. */
13028 CASE_CFN_FMIN:
13029 CASE_CFN_FMIN_FN:
13030 /* True if the 1st AND 2nd arguments are nonnegative. */
13033 CASE_CFN_COPYSIGN:
13034 CASE_CFN_COPYSIGN_FN:
13035 /* True if the 2nd argument is nonnegative. */
13038 CASE_CFN_POWI:
13039 /* True if the 1st argument is nonnegative or the second
13040 argument is an even integer. */
13046 CASE_CFN_POW:
13047 /* True if the 1st argument is nonnegative or the second
13048 argument is an even integer valued real. */
13050 {
13051 REAL_VALUE_TYPE c;
13052 HOST_WIDE_INT n;
13057 {
13058 REAL_VALUE_TYPE cint;
13062 }
13063 }
13068 }
13070 }
13072 /* Return true if T is known to be non-negative. If the return
13073 value is based on the assumption that signed overflow is undefined,
13074 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13075 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13077 static bool
13079 {
13085 {
13087 {
13091 /* If the initializer is non-void, then it's a normal expression
13092 that will be assigned to the slot. */
13096 /* Otherwise, the initializer sets the slot in some way. One common
13097 way is an assignment statement at the end of the initializer. */
13099 {
13107 else
13109 }
13115 }
13118 {
13124 arg0,
13125 arg1,
13127 }
13140 }
13141 }
13143 #undef RECURSE
13144 #undef tree_expr_nonnegative_warnv_p
13146 /* Return true if T is known to be non-negative. If the return
13147 value is based on the assumption that signed overflow is undefined,
13148 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13149 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13151 bool
13153 {
13160 {
13182 }
13185 {
13211 }
13212 }
13214 /* Return true if `t' is known to be non-negative. Handle warnings
13215 about undefined signed overflow. */
13217 bool
13219 {
13226 "determining that expression is always "
13228 WARN_STRICT_OVERFLOW_MISC);
13230 }
13233 /* Return true when (CODE OP0) is an address and is known to be nonzero.
13234 For floating point we further ensure that T is not denormal.
13235 Similar logic is present in nonzero_address in rtlanal.h.
13237 If the return value is based on the assumption that signed overflow
13238 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13239 change *STRICT_OVERFLOW_P. */
13241 bool
13244 {
13246 {
13249 strict_overflow_p);
13252 {
13258 strict_overflow_p));
13259 }
13264 strict_overflow_p);
13268 }
13271 }
13273 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
13274 For floating point we further ensure that T is not denormal.
13275 Similar logic is present in nonzero_address in rtlanal.h.
13277 If the return value is based on the assumption that signed overflow
13278 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13279 change *STRICT_OVERFLOW_P. */
13281 bool
13283 tree type,
13284 tree op0,
13286 {
13289 {
13293 {
13294 /* With the presence of negative values it is hard
13295 to say something. */
13302 /* One of operands must be positive and the other non-negative. */
13303 /* We don't set *STRICT_OVERFLOW_P here: even if this value
13304 overflows, on a twos-complement machine the sum of two
13305 nonnegative numbers can never be zero. */
13307 strict_overflow_p)
13309 strict_overflow_p));
13310 }
13315 {
13317 strict_overflow_p)
13319 strict_overflow_p))
13320 {
13323 }
13324 }
13333 {
13336 }
13343 {
13347 /* When both operands are nonzero, then MAX must be too. */
13349 strict_overflow_p))
13352 /* MAX where operand 0 is positive is positive. */
13354 strict_overflow_p);
13355 }
13356 /* MAX where operand 1 is positive is positive. */
13361 {
13365 }
13370 strict_overflow_p)
13372 strict_overflow_p));
13376 }
13379 }
13381 /* Return true when T is an address and is known to be nonzero.
13382 For floating point we further ensure that T is not denormal.
13383 Similar logic is present in nonzero_address in rtlanal.h.
13385 If the return value is based on the assumption that signed overflow
13386 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13387 change *STRICT_OVERFLOW_P. */
13389 bool
13391 {
13394 {
13399 {
13411 /* For objects in symbol table check if we know they are non-zero.
13412 Don't do anything for variables and functions before symtab is built;
13413 it is quite possible that they will be declared weak later. */
13418 /* Constants are never weak. */
13423 }
13431 {
13435 }
13445 }
13447 }
13449 #define integer_valued_real_p(X) \
13452 #define RECURSE(X) \
13453 ((integer_valued_real_p) (X, depth + 1))
13455 /* Return true if the floating point result of (CODE OP0) has an
13456 integer value. We also allow +Inf, -Inf and NaN to be considered
13457 integer values. Return false for signaling NaN.
13459 DEPTH is the current nesting depth of the query. */
13461 bool
13463 {
13465 {
13472 CASE_CONVERT:
13473 {
13480 }
13484 }
13486 }
13488 /* Return true if the floating point result of (CODE OP0 OP1) has an
13489 integer value. We also allow +Inf, -Inf and NaN to be considered
13490 integer values. Return false for signaling NaN.
13492 DEPTH is the current nesting depth of the query. */
13494 bool
13496 {
13498 {
13508 }
13510 }
13512 /* Return true if the floating point result of calling FNDECL with arguments
13513 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
13514 considered integer values. Return false for signaling NaN. If FNDECL
13515 takes fewer than 2 arguments, the remaining ARGn are null.
13517 DEPTH is the current nesting depth of the query. */
13519 bool
13521 {
13523 {
13524 CASE_CFN_CEIL:
13525 CASE_CFN_CEIL_FN:
13526 CASE_CFN_FLOOR:
13527 CASE_CFN_FLOOR_FN:
13528 CASE_CFN_NEARBYINT:
13529 CASE_CFN_NEARBYINT_FN:
13530 CASE_CFN_RINT:
13531 CASE_CFN_RINT_FN:
13532 CASE_CFN_ROUND:
13533 CASE_CFN_ROUND_FN:
13534 CASE_CFN_TRUNC:
13535 CASE_CFN_TRUNC_FN:
13538 CASE_CFN_FMIN:
13539 CASE_CFN_FMIN_FN:
13540 CASE_CFN_FMAX:
13541 CASE_CFN_FMAX_FN:
13546 }
13548 }
13550 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
13551 has an integer value. We also allow +Inf, -Inf and NaN to be
13552 considered integer values. Return false for signaling NaN.
13554 DEPTH is the current nesting depth of the query. */
13556 bool
13558 {
13560 {
13568 /* Limit the depth of recursion to avoid quadratic behavior.
13569 This is expected to catch almost all occurrences in practice.
13570 If this code misses important cases that unbounded recursion
13571 would not, passes that need this information could be revised
13572 to provide it through dataflow propagation. */
13576 depth));
13580 }
13582 }
13584 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
13585 has an integer value. We also allow +Inf, -Inf and NaN to be
13586 considered integer values. Return false for signaling NaN.
13588 DEPTH is the current nesting depth of the query. */
13590 static bool
13592 {
13594 {
13605 }
13607 }
13609 #undef RECURSE
13610 #undef integer_valued_real_p
13612 /* Return true if the floating point expression T has an integer value.
13613 We also allow +Inf, -Inf and NaN to be considered integer values.
13614 Return false for signaling NaN.
13616 DEPTH is the current nesting depth of the query. */
13618 bool
13620 {
13626 {
13642 }
13645 {
13651 {
13660 }
13664 }
13665 }
13667 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
13668 attempt to fold the expression to a constant without modifying TYPE,
13669 OP0 or OP1.
13671 If the expression could be simplified to a constant, then return
13672 the constant. If the expression would not be simplified to a
13673 constant, then return NULL_TREE. */
13675 tree
13677 {
13680 }
13682 /* Given the components of a unary expression CODE, TYPE and OP0,
13683 attempt to fold the expression to a constant without modifying
13684 TYPE or OP0.
13686 If the expression could be simplified to a constant, then return
13687 the constant. If the expression would not be simplified to a
13688 constant, then return NULL_TREE. */
13690 tree
13692 {
13695 }
13697 /* If EXP represents referencing an element in a constant string
13698 (either via pointer arithmetic or array indexing), return the
13699 tree representing the value accessed, otherwise return NULL. */
13701 tree
13703 {
13707 {
13709 tree index;
13710 tree string;
13715 else
13716 {
13720 /* Optimize the special-case of a zero lower bound.
13722 We convert the low_bound to sizetype to avoid some problems
13723 with constant folding. (E.g. suppose the lower bound is 1,
13724 and its mode is QI. Without the conversion,l (ARRAY
13725 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
13726 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
13732 }
13734 scalar_int_mode char_mode;
13746 }
13748 }
13750 /* Return the tree for neg (ARG0) when ARG0 is known to be either
13751 an integer constant, real, or fixed-point constant.
13753 TYPE is the type of the result. */
13755 static tree
13757 {
13761 {
13767 {
13768 FIXED_VALUE_TYPE f;
13773 /* Propagate overflow flags. */
13777 }
13781 {
13788 }
13791 }
13794 }
13796 /* Return the tree for abs (ARG0) when ARG0 is known to be either
13797 an integer constant or real constant.
13799 TYPE is the type of the result. */
13801 tree
13803 {
13807 {
13809 {
13810 /* If the value is unsigned or non-negative, then the absolute value
13811 is the same as the ordinary value. */
13815 /* If the value is negative, then the absolute value is
13816 its negation. */
13817 else
13818 {
13823 }
13824 }
13830 else
13836 }
13839 }
13841 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
13842 constant. TYPE is the type of the result. */
13844 static tree
13846 {
13850 }
13852 /* Given CODE, a relational operator, the target type, TYPE and two
13853 constant operands OP0 and OP1, return the result of the
13854 relational operation. If the result is not a compile time
13855 constant, then return NULL_TREE. */
13857 static tree
13859 {
13862 /* From here on, the only cases we handle are when the result is
13863 known to be a constant. */
13866 {
13870 /* Handle the cases where either operand is a NaN. */
13872 {
13874 {
13902 }
13905 }
13908 }
13911 {
13915 }
13917 /* Handle equality/inequality of complex constants. */
13919 {
13930 else
13932 }
13935 {
13937 {
13938 /* Have vector comparison with scalar boolean result. */
13942 {
13950 }
13952 }
13953 tree_vector_builder elts;
13958 {
13971 }
13974 }
13976 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
13978 To compute GT, swap the arguments and do LT.
13979 To compute GE, do LT and invert the result.
13980 To compute LE, swap the arguments, do LT and invert the result.
13981 To compute NE, do EQ and invert the result.
13983 Therefore, the code below must handle only EQ and LT. */
13986 {
13989 }
13991 /* Note that it is safe to invert for real values here because we
13992 have already handled the one case that it matters. */
13996 {
13999 }
14001 /* Compute a result for LT or EQ if args permit;
14002 Otherwise return T. */
14004 {
14007 else
14009 }
14010 else
14016 }
14018 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
14019 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
14020 itself. */
14022 tree
14024 {
14025 /* If the expression does not have side effects then we don't have to wrap
14026 it with a cleanup point expression. */
14030 /* If the expression is a return, check to see if the expression inside the
14031 return has no side effects or the right hand side of the modify expression
14032 inside the return. If either don't have side effects set we don't need to
14033 wrap the expression in a cleanup point expression. Note we don't check the
14034 left hand side of the modify because it should always be a return decl. */
14036 {
14043 }
14046 }
14048 /* Given a pointer value OP0 and a type TYPE, return a simplified version
14049 of an indirection through OP0, or NULL_TREE if no simplification is
14050 possible. */
14052 tree
14054 {
14056 tree subtype;
14057 poly_uint64 const_op01;
14066 {
14069 /* *&CONST_DECL -> to the value of the const decl. */
14072 /* *&p => p; make sure to handle *&"str"[cst] here. */
14074 {
14078 else
14080 }
14081 /* *(foo *)&fooarray => fooarray[0] */
14084 && (!in_gimple_form
14086 {
14096 }
14097 /* *(foo *)&complexfoo => __real__ complexfoo */
14101 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14104 {
14108 }
14109 }
14113 {
14119 {
14120 tree op00type;
14124 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
14127 {
14129 poly_uint64 max_offset
14133 {
14138 }
14139 }
14140 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
14143 {
14145 const_op01))
14147 }
14148 /* ((foo *)&fooarray)[1] => fooarray[1] */
14151 {
14158 offset_int remainder;
14161 {
14166 }
14167 }
14168 }
14169 }
14171 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
14174 && (!in_gimple_form
14176 {
14177 tree type_domain;
14187 NULL_TREE);
14188 }
14191 }
14193 /* Builds an expression for an indirection through T, simplifying some
14194 cases. */
14196 tree
14198 {
14206 }
14208 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14210 tree
14212 {
14217 else
14219 }
14221 /* Strip non-trapping, non-side-effecting tree nodes from an expression
14222 whose result is ignored. The type of the returned tree need not be
14223 the same as the original expression. */
14225 tree
14227 {
14233 {
14244 else
14250 {
14266 }
14271 }
14272 }
14274 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
14276 tree
14278 {
14284 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14285 have to do anything. Only do this when we are not given a const,
14286 because in that case, this check is more expensive than just
14287 doing it. */
14289 {
14294 }
14296 /* If divisor is a power of two, simplify this to bit manipulation. */
14298 {
14300 {
14314 }
14315 else
14316 {
14317 tree t;
14323 }
14324 }
14325 else
14326 {
14331 }
14334 }
14336 /* Likewise, but round down. */
14338 tree
14340 {
14347 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14348 have to do anything. Only do this when we are not given a const,
14349 because in that case, this check is more expensive than just
14350 doing it. */
14352 {
14357 }
14359 /* If divisor is a power of two, simplify this to bit manipulation. */
14361 {
14362 tree t;
14366 }
14367 else
14368 {
14373 }
14376 }
14378 /* Returns the pointer to the base of the object addressed by EXP and
14379 extracts the information about the offset of the access, storing it
14380 to PBITPOS and POFFSET. */
14382 static tree
14385 {
14386 tree core;
14387 machine_mode mode;
14389 poly_int64 bitsize;
14393 {
14398 }
14400 {
14406 {
14407 poly_offset_int tem
14413 }
14414 }
14415 else
14416 {
14420 }
14423 }
14425 /* Returns true if addresses of E1 and E2 differ by a constant, false
14426 otherwise. If they do, E1 - E2 is stored in *DIFF. */
14428 bool
14430 {
14445 {
14455 }
14457 {
14458 /* If only one of the offsets is non-constant, the difference cannot
14459 be a constant. */
14461 }
14462 else
14467 }
14469 /* Return OFF converted to a pointer offset type suitable as offset for
14470 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
14471 tree
14473 {
14475 }
14477 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14478 tree
14480 {
14483 }
14485 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14486 tree
14488 {
14491 }
14493 /* Return a char pointer for a C string if it is a string constant
14494 or sum of string constant and integer constant. We only support
14495 string constants properly terminated with '\0' character.
14496 If STRLEN is a valid pointer, length (including terminating character)
14497 of returned string is stored to the argument. */
14501 {
14502 tree offset_node;
14513 {
14516 else
14518 }
14523 /* Support only properly null-terminated strings. */
14532 }
14534 #if CHECKING_P
14538 /* Helper functions for writing tests of folding trees. */
14540 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
14542 static void
14544 tree constant)
14545 {
14547 }
14549 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
14550 wrapping WRAPPED_EXPR. */
14552 static void
14554 tree wrapped_expr)
14555 {
14560 }
14562 /* Verify that various arithmetic binary operations are folded
14563 correctly. */
14565 static void
14567 {
14573 /* Addition. */
14574 /* 1 <-- (0 + 1) */
14576 one);
14578 one);
14580 /* (nonlvalue)x <-- (x + 0) */
14582 x);
14584 /* Subtraction. */
14585 /* 0 <-- (x - x) */
14587 zero);
14589 x);
14591 /* Multiplication. */
14592 /* 0 <-- (x * 0) */
14594 zero);
14596 /* (nonlvalue)x <-- (x * 1) */
14598 x);
14599 }
14601 /* Verify that various binary operations on vectors are folded
14602 correctly. */
14604 static void
14606 {
14612 /* Verify equality tests that return a scalar boolean result. */
14618 }
14620 /* Verify folding of VEC_DUPLICATE_EXPRs. */
14622 static void
14624 {
14627 /* This will be 1 if VEC_MODE isn't a vector mode. */
14634 }
14636 /* Run all of the selftests within this file. */
14638 void
14640 {
14644 }