| blob | 4c48d7076e796b89188d1fb6a66fa5527a18f2fb |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2021 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_ROUNDEVEN:
333 CASE_CFN_ROUNDEVEN_FN:
334 CASE_CFN_SIN:
335 CASE_CFN_SINH:
336 CASE_CFN_TAN:
337 CASE_CFN_TANH:
338 CASE_CFN_TRUNC:
341 CASE_CFN_LLRINT:
342 CASE_CFN_LRINT:
343 CASE_CFN_NEARBYINT:
344 CASE_CFN_RINT:
349 }
351 }
353 /* Check whether we may negate an integer constant T without causing
354 overflow. */
356 bool
358 {
359 tree type;
368 }
370 /* Determine whether an expression T can be cheaply negated using
371 the function negate_expr without introducing undefined overflow. */
373 static bool
375 {
376 tree type;
385 {
390 /* Check that -CST will not overflow type. */
403 /* We want to canonicalize to positive real constants. Pretend
404 that only negative ones can be easily negated. */
412 {
416 /* Steps don't prevent negation. */
423 }
438 /* -(A + B) -> (-B) - A. */
441 /* -(A + B) -> (-A) - B. */
445 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
454 /* INT_MIN/n * n doesn't overflow while negating one operand it does
455 if n is a (negative) power of two. */
466 /* Fall through. */
479 /* In general we can't negate A in A / B, because if A is INT_MIN and
480 B is not 1 we change the sign of the result. */
484 /* In general we can't negate B in A / B, because if A is INT_MIN and
485 B is 1, we may turn this into INT_MIN / -1 which is undefined
486 and actually traps on some architectures. */
495 /* Negate -((double)float) as (double)(-float). */
497 {
501 }
505 /* Negate -f(x) as f(-x). */
511 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
513 {
517 }
522 }
524 }
526 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
527 simplification is possible.
528 If negate_expr_p would return true for T, NULL_TREE will never be
529 returned. */
531 static tree
533 {
535 tree tem;
538 {
539 /* Convert - (~A) to A + 1. */
563 {
568 }
572 {
573 tree_vector_builder elts;
577 {
582 }
585 }
608 {
609 /* -(A + B) -> (-B) - A. */
611 {
615 }
617 /* -(A + B) -> (-A) - B. */
619 {
623 }
624 }
628 /* - (A - B) -> B - A */
639 /* Fall through. */
643 {
652 }
660 /* In general we can't negate A in A / B, because if A is INT_MIN and
661 B is not 1 we change the sign of the result. */
667 /* In general we can't negate B in A / B, because if A is INT_MIN and
668 B is 1, we may turn this into INT_MIN / -1 which is undefined
669 and actually traps on some architectures. */
681 /* Convert -((double)float) into (double)(-float). */
683 {
687 }
691 /* Negate -f(x) as f(-x). */
694 {
700 }
704 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
706 {
709 {
716 }
717 }
722 }
725 }
727 /* A wrapper for fold_negate_expr_1. */
729 static tree
731 {
738 }
740 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T cannot be
741 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
742 return NULL_TREE. */
744 static tree
746 {
748 location_t loc;
761 }
762 \f
763 /* Split a tree IN into a constant, literal and variable parts that could be
764 combined with CODE to make IN. "constant" means an expression with
765 TREE_CONSTANT but that isn't an actual constant. CODE must be a
766 commutative arithmetic operation. Store the constant part into *CONP,
767 the literal in *LITP and return the variable part. If a part isn't
768 present, set it to null. If the tree does not decompose in this way,
769 return the entire tree as the variable part and the other parts as null.
771 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
772 case, we negate an operand that was subtracted. Except if it is a
773 literal for which we use *MINUS_LITP instead.
775 If NEGATE_P is true, we are negating all of IN, again except a literal
776 for which we use *MINUS_LITP instead. If a variable part is of pointer
777 type, it is negated after converting to TYPE. This prevents us from
778 generating illegal MINUS pointer expression. LOC is the location of
779 the converted variable part.
781 If IN is itself a literal or constant, return it as appropriate.
783 Note that we do not guarantee that any of the three values will be the
784 same type as IN, but they will have the same signedness and mode. */
786 static tree
790 {
798 /* Strip any conversions that don't change the machine mode or signedness. */
807 /* We can associate addition and subtraction together (even
808 though the C standard doesn't say so) for integers because
809 the value is not affected. For reals, the value might be
810 affected, so we can't. */
816 {
822 /* First see if either of the operands is a literal, then a constant. */
835 /* If we haven't dealt with either operand, this is not a case we can
836 decompose. Otherwise, VAR is either of the ones remaining, if any. */
841 else
844 /* Now do any needed negations. */
851 }
856 {
857 /* -1 - X is folded to ~X, undo that here. Do _not_ do this
858 when IN is constant. */
861 }
862 else
866 {
879 }
889 }
891 /* Re-associate trees split by the above function. T1 and T2 are
892 either expressions to associate or null. Return the new
893 expression, if any. LOC is the location of the new expression. If
894 we build an operation, do it in TYPE and with CODE. */
896 static tree
898 {
900 {
903 }
907 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
908 try to fold this since we will have infinite recursion. But do
909 deal with any NEGATE_EXPRs. */
913 {
915 {
928 }
930 {
933 }
937 }
941 }
942 \f
943 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
944 for use in int_const_binop, size_binop and size_diffop. */
946 static bool
948 {
955 {
964 }
969 }
971 /* Combine two wide ints ARG1 and ARG2 under operation CODE to produce
972 a new constant in RES. Return FALSE if we don't know how to
973 evaluate CODE at compile-time. */
975 bool
979 {
980 wide_int tmp;
983 {
1005 /* It's unclear from the C standard whether shifts can overflow.
1006 The following code ignores overflow; perhaps a C standard
1007 interpretation ruling is needed. */
1014 {
1018 else
1020 }
1021 else
1026 else
1105 }
1107 }
1109 /* Combine two poly int's ARG1 and ARG2 under operation CODE to
1110 produce a new constant in RES. Return FALSE if we don't know how
1111 to evaluate CODE at compile-time. */
1113 static bool
1117 {
1121 {
1139 else
1146 else
1159 }
1161 }
1163 /* Combine two integer constants ARG1 and ARG2 under operation CODE to
1164 produce a new constant. Return NULL_TREE if we don't know how to
1165 evaluate CODE at compile-time. */
1167 tree
1170 {
1171 poly_wide_int poly_res;
1177 {
1183 }
1192 }
1194 /* Return true if binary operation OP distributes over addition in operand
1195 OPNO, with the other operand being held constant. OPNO counts from 1. */
1197 static bool
1199 {
1201 {
1212 }
1213 }
1215 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1216 constant. We assume ARG1 and ARG2 have the same data type, or at least
1217 are the same kind of constant and the same machine mode. Return zero if
1218 combining the constants is not allowed in the current operating mode. */
1220 static tree
1222 {
1223 /* Sanity check for the recursive cases. */
1231 {
1237 }
1240 {
1241 machine_mode mode;
1242 REAL_VALUE_TYPE d1;
1243 REAL_VALUE_TYPE d2;
1244 REAL_VALUE_TYPE value;
1245 REAL_VALUE_TYPE result;
1249 /* The following codes are handled by real_arithmetic. */
1251 {
1262 }
1270 /* Don't perform operation if we honor signaling NaNs and
1271 either operand is a signaling NaN. */
1277 /* Don't perform operation if it would raise a division
1278 by zero exception. */
1284 /* If either operand is a NaN, just return it. Otherwise, set up
1285 for floating-point trap; we return an overflow. */
1287 {
1288 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1289 is off. */
1293 }
1295 {
1296 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1297 is off. */
1301 }
1306 /* Don't constant fold this floating point operation if
1307 the result has overflowed and flag_trapping_math. */
1315 /* Don't constant fold this floating point operation if the
1316 result may dependent upon the run-time rounding mode and
1317 flag_rounding_math is set, or if GCC's software emulation
1318 is unable to accurately represent the result. */
1328 }
1331 {
1332 FIXED_VALUE_TYPE f1;
1333 FIXED_VALUE_TYPE f2;
1334 FIXED_VALUE_TYPE result;
1339 /* The following codes are handled by fixed_arithmetic. */
1341 {
1353 {
1360 }
1365 }
1372 /* Propagate overflow flags. */
1376 }
1379 {
1388 {
1399 mpc_mul);
1413 mpc_div);
1414 /* Fallthru. */
1420 {
1421 /* Keep this algorithm in sync with
1422 tree-complex.c:expand_complex_div_straight().
1424 Expand complex division to scalars, straightforward algorithm.
1425 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1426 t = br*br + bi*bi
1427 */
1428 tree magsquared
1432 tree t1
1436 tree t2
1443 }
1444 else
1445 {
1446 /* Keep this algorithm in sync with
1447 tree-complex.c:expand_complex_div_wide().
1449 Expand complex division to scalars, modified algorithm to minimize
1450 overflow with wide input ranges. */
1456 {
1457 /* In the TRUE branch, we compute
1458 ratio = br/bi;
1459 div = (br * ratio) + bi;
1460 tr = (ar * ratio) + ai;
1461 ti = (ai * ratio) - ar;
1462 tr = tr / div;
1463 ti = ti / div; */
1474 }
1475 else
1476 {
1477 /* In the FALSE branch, we compute
1478 ratio = d/c;
1479 divisor = (d * ratio) + c;
1480 tr = (b * ratio) + a;
1481 ti = b - (a * ratio);
1482 tr = tr / div;
1483 ti = ti / div; */
1495 }
1496 }
1501 }
1505 }
1511 {
1516 /* We can operate directly on the encoding if:
1518 a3 - a2 == a2 - a1 && b3 - b2 == b2 - b1
1519 implies
1520 (a3 op b3) - (a2 op b2) == (a2 op b2) - (a1 op b1)
1522 Addition and subtraction are the supported operators
1523 for which this is true. */
1526 /* We can operate directly on stepped encodings if:
1528 a3 - a2 == a2 - a1
1529 implies:
1530 (a3 op c) - (a2 op c) == (a2 op c) - (a1 op c)
1532 which is true if (x -> x op c) distributes over addition. */
1534 else
1535 /* Similarly in reverse. */
1537 tree_vector_builder elts;
1542 {
1548 /* It is possible that const_binop cannot handle the given
1549 code and return NULL_TREE */
1553 }
1556 }
1558 /* Shifts allow a scalar offset for a vector. */
1561 {
1564 tree_vector_builder elts;
1569 {
1574 /* It is possible that const_binop cannot handle the given
1575 code and return NULL_TREE. */
1579 }
1582 }
1584 }
1586 /* Overload that adds a TYPE parameter to be able to dispatch
1587 to fold_relational_const. */
1589 tree
1591 {
1595 /* ??? Until we make the const_binop worker take the type of the
1596 result as argument put those cases that need it here. */
1598 {
1615 {
1620 }
1626 {
1642 {
1647 ? NOP_EXPR
1654 }
1657 }
1663 {
1686 {
1699 }
1702 }
1705 }
1710 /* Make sure type and arg0 have the same saturating flag. */
1715 }
1717 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1718 Return zero if computing the constants is not possible. */
1720 tree
1722 {
1723 /* Don't perform the operation, other than NEGATE and ABS, if
1724 flag_signaling_nans is on and the operand is a signaling NaN. */
1734 {
1735 CASE_CONVERT:
1742 /* If the source address is 0, and the source address space
1743 cannot have a valid object at 0, fold to dest type null. */
1754 {
1755 /* Can't call fold_negate_const directly here as that doesn't
1756 handle all cases and we might not be able to negate some
1757 constants. */
1762 }
1772 {
1776 }
1784 /* Perform BIT_NOT_EXPR on each element individually. */
1786 {
1787 tree elem;
1789 /* This can cope with stepped encodings because ~x == -1 - x. */
1790 tree_vector_builder elements;
1794 {
1800 }
1803 }
1827 {
1850 else
1855 {
1861 }
1864 }
1873 }
1876 }
1878 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1879 indicates which particular sizetype to create. */
1881 tree
1883 {
1885 }
1886 \f
1887 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1888 is a tree code. The type of the result is taken from the operands.
1889 Both must be equivalent integer types, ala int_binop_types_match_p.
1890 If the operands are constant, so is the result. */
1892 tree
1894 {
1903 /* Handle the special case of two poly_int constants faster. */
1905 {
1906 /* And some specific cases even faster than that. */
1908 {
1915 }
1917 {
1921 }
1923 {
1927 }
1929 /* Handle general case of two integer constants. For sizetype
1930 constant calculations we always want to know about overflow,
1931 even in the unsigned case. */
1935 }
1938 }
1940 /* Given two values, either both of sizetype or both of bitsizetype,
1941 compute the difference between the two values. Return the value
1942 in signed type corresponding to the type of the operands. */
1944 tree
1946 {
1948 tree ctype;
1953 /* If the type is already signed, just do the simple thing. */
1961 else
1964 /* If either operand is not a constant, do the conversions to the signed
1965 type and subtract. The hardware will do the right thing with any
1966 overflow in the subtraction. */
1972 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1973 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1974 overflow) and negate (which can't either). Special-case a result
1975 of zero while we're here. */
1981 else
1985 MINUS_EXPR,
1987 }
1988 \f
1989 /* A subroutine of fold_convert_const handling conversions of an
1990 INTEGER_CST to another integer type. */
1992 static tree
1994 {
1995 /* Given an integer constant, make new constant with new type,
1996 appropriately sign-extended or truncated. Use widest_int
1997 so that any extension is done according ARG1's type. */
2001 }
2003 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2004 to an integer type. */
2006 static tree
2008 {
2010 tree t;
2012 /* The following code implements the floating point to integer
2013 conversion rules required by the Java Language Specification,
2014 that IEEE NaNs are mapped to zero and values that overflow
2015 the target precision saturate, i.e. values greater than
2016 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2017 are mapped to INT_MIN. These semantics are allowed by the
2018 C and C++ standards that simply state that the behavior of
2019 FP-to-integer conversion is unspecified upon overflow. */
2021 wide_int val;
2022 REAL_VALUE_TYPE r;
2026 {
2033 }
2035 /* If R is NaN, return zero and show we have an overflow. */
2037 {
2040 }
2042 /* See if R is less than the lower bound or greater than the
2043 upper bound. */
2046 {
2050 {
2053 }
2054 }
2057 {
2060 {
2063 {
2066 }
2067 }
2068 }
2075 }
2077 /* A subroutine of fold_convert_const handling conversions of a
2078 FIXED_CST to an integer type. */
2080 static tree
2082 {
2083 tree t;
2085 scalar_mode mode;
2087 /* Right shift FIXED_CST to temp by fbit. */
2091 {
2093 HOST_BITS_PER_DOUBLE_INT,
2096 /* Left shift temp to temp_trunc by fbit. */
2098 HOST_BITS_PER_DOUBLE_INT,
2100 }
2101 else
2102 {
2105 }
2107 /* If FIXED_CST is negative, we need to round the value toward 0.
2108 By checking if the fractional bits are not zero to add 1 to temp. */
2114 /* Given a fixed-point constant, make new constant with new type,
2115 appropriately sign-extended or truncated. */
2123 }
2125 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2126 to another floating point type. */
2128 static tree
2130 {
2131 REAL_VALUE_TYPE value;
2132 tree t;
2134 /* Don't perform the operation if flag_signaling_nans is on
2135 and the operand is a signaling NaN. */
2143 /* If converting an infinity or NAN to a representation that doesn't
2144 have one, set the overflow bit so that we can produce some kind of
2145 error message at the appropriate point if necessary. It's not the
2146 most user-friendly message, but it's better than nothing. */
2153 /* Regular overflow, conversion produced an infinity in a mode that
2154 can't represent them. */
2159 else
2162 }
2164 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2165 to a floating point type. */
2167 static tree
2169 {
2170 REAL_VALUE_TYPE value;
2171 tree t;
2179 }
2181 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2182 to another fixed-point type. */
2184 static tree
2186 {
2187 FIXED_VALUE_TYPE value;
2188 tree t;
2195 /* Propagate overflow flags. */
2199 }
2201 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2202 to a fixed-point type. */
2204 static tree
2206 {
2207 FIXED_VALUE_TYPE value;
2208 tree t;
2210 double_int di;
2217 else
2225 /* Propagate overflow flags. */
2229 }
2231 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2232 to a fixed-point type. */
2234 static tree
2236 {
2237 FIXED_VALUE_TYPE value;
2238 tree t;
2246 /* Propagate overflow flags. */
2250 }
2252 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2253 type TYPE. If no simplification can be done return NULL_TREE. */
2255 static tree
2257 {
2262 /* We can't widen types, since the runtime value could overflow the
2263 original type before being extended to the new type. */
2274 {
2281 }
2283 {
2290 }
2292 {
2299 }
2301 {
2304 {
2307 /* We can't handle steps directly when extending, since the
2308 values need to wrap at the original precision first. */
2309 bool step_ok_p
2313 tree_vector_builder v;
2318 {
2324 }
2326 }
2327 }
2329 }
2331 /* Construct a vector of zero elements of vector type TYPE. */
2333 static tree
2335 {
2336 tree t;
2340 }
2342 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2344 bool
2346 {
2361 {
2383 }
2384 }
2386 /* Convert expression ARG to type TYPE. Used by the middle-end for
2387 simple conversions in preference to calling the front-end's convert. */
2389 tree
2391 {
2393 tree tem;
2404 {
2407 /* Handle conversions between pointers to different address spaces. */
2412 /* fall through */
2417 {
2421 }
2435 {
2439 }
2441 {
2445 }
2447 {
2451 }
2454 {
2472 }
2477 {
2481 }
2484 {
2498 }
2502 {
2511 integer_zero_node));
2513 {
2517 {
2523 }
2531 }
2535 }
2553 }
2554 fold_convert_exit:
2557 }
2558 \f
2559 /* Return false if expr can be assumed not to be an lvalue, true
2560 otherwise. */
2562 static bool
2564 {
2565 /* We only need to wrap lvalue tree codes. */
2567 {
2599 /* Assume the worst for front-end tree codes. */
2603 }
2606 }
2608 /* Return an expr equal to X but certainly not valid as an lvalue. */
2610 tree
2612 {
2613 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2614 us. */
2621 }
2623 /* When pedantic, return an expr equal to X but certainly not valid as a
2624 pedantic lvalue. Otherwise, return X. */
2626 static tree
2628 {
2630 }
2631 \f
2632 /* Given a tree comparison code, return the code that is the logical inverse.
2633 It is generally not safe to do this for floating-point comparisons, except
2634 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2635 ERROR_MARK in this case. */
2637 enum tree_code
2639 {
2645 {
2676 }
2677 }
2679 /* Similar, but return the comparison that results if the operands are
2680 swapped. This is safe for floating-point. */
2682 enum tree_code
2684 {
2686 {
2712 }
2713 }
2716 /* Convert a comparison tree code from an enum tree_code representation
2717 into a compcode bit-based encoding. This function is the inverse of
2718 compcode_to_comparison. */
2720 static enum comparison_code
2722 {
2724 {
2755 }
2756 }
2758 /* Convert a compcode bit-based encoding of a comparison operator back
2759 to GCC's enum tree_code representation. This function is the
2760 inverse of comparison_to_compcode. */
2762 static enum tree_code
2764 {
2766 {
2797 }
2798 }
2800 /* Return true if COND1 tests the opposite condition of COND2. */
2802 bool
2804 {
2807 && (invert_tree_comparison
2814 }
2816 /* Return a tree for the comparison which is the combination of
2817 doing the AND or OR (depending on CODE) of the two operations LCODE
2818 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2819 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2820 if this makes the transformation invalid. */
2822 tree
2827 {
2834 {
2845 }
2848 {
2849 /* Eliminate unordered comparisons, as well as LTGT and ORD
2850 which are not used unless the mode has NaNs. */
2856 }
2858 {
2859 /* Check that the original operation and the optimized ones will trap
2860 under the same condition. */
2871 /* In a short-circuited boolean expression the LHS might be
2872 such that the RHS, if evaluated, will never trap. For
2873 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2874 if neither x nor y is NaN. (This is a mixed blessing: for
2875 example, the expression above will never trap, hence
2876 optimizing it to x < y would be invalid). */
2881 /* If the comparison was short-circuited, and only the RHS
2882 trapped, we may now generate a spurious trap. */
2887 /* If we changed the conditions that cause a trap, we lose. */
2890 }
2896 else
2897 {
2902 }
2903 }
2904 \f
2905 /* Return nonzero if two operands (typically of the same tree node)
2906 are necessarily equal. FLAGS modifies behavior as follows:
2908 If OEP_ONLY_CONST is set, only return nonzero for constants.
2909 This function tests whether the operands are indistinguishable;
2910 it does not test whether they are equal using C's == operation.
2911 The distinction is important for IEEE floating point, because
2912 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2913 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2915 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2916 even though it may hold multiple values during a function.
2917 This is because a GCC tree node guarantees that nothing else is
2918 executed between the evaluation of its "operands" (which may often
2919 be evaluated in arbitrary order). Hence if the operands themselves
2920 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2921 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2922 unset means assuming isochronic (or instantaneous) tree equivalence.
2923 Unless comparing arbitrary expression trees, such as from different
2924 statements, this flag can usually be left unset.
2926 If OEP_PURE_SAME is set, then pure functions with identical arguments
2927 are considered the same. It is used when the caller has other ways
2928 to ensure that global memory is unchanged in between.
2930 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2931 not values of expressions.
2933 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
2934 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
2936 If OEP_BITWISE is set, then require the values to be bitwise identical
2937 rather than simply numerically equal. Do not take advantage of things
2938 like math-related flags or undefined behavior; only return true for
2939 values that are provably bitwise identical in all circumstances.
2941 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2942 any operand with side effect. This is unnecesarily conservative in the
2943 case we know that arg0 and arg1 are in disjoint code paths (such as in
2944 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2945 addresses with TREE_CONSTANT flag set so we know that &var == &var
2946 even if var is volatile. */
2948 bool
2951 {
2959 /* If either is ERROR_MARK, they aren't equal. */
2965 /* Similar, if either does not have a type (like a template id),
2966 they aren't equal. */
2970 /* Bitwise identity makes no sense if the values have different layouts. */
2975 /* We cannot consider pointers to different address space equal. */
2982 /* Check equality of integer constants before bailing out due to
2983 precision differences. */
2985 {
2986 /* Address of INTEGER_CST is not defined; check that we did not forget
2987 to drop the OEP_ADDRESS_OF flags. */
2990 }
2993 {
2994 /* If both types don't have the same signedness, then we can't consider
2995 them equal. We must check this before the STRIP_NOPS calls
2996 because they may change the signedness of the arguments. As pointers
2997 strictly don't have a signedness, require either two pointers or
2998 two non-pointers as well. */
3004 /* If both types don't have the same precision, then it is not safe
3005 to strip NOPs. */
3012 }
3013 #if 0
3014 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
3015 sanity check once the issue is solved. */
3016 else
3017 /* Addresses of conversions and SSA_NAMEs (and many other things)
3018 are not defined. Check that we did not forget to drop the
3019 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
3022 #endif
3024 /* In case both args are comparisons but with different comparison
3025 code, try to swap the comparison operands of one arg to produce
3026 a match and compare that variant. */
3030 {
3038 }
3041 {
3042 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
3044 ;
3046 {
3047 /* If we are interested in comparing addresses ignore
3048 MEM_REF wrappings of the base that can appear just for
3049 TBAA reasons. */
3063 }
3064 else
3066 }
3068 /* When not checking adddresses, this is needed for conversions and for
3069 COMPONENT_REF. Might as well play it safe and always test this. */
3076 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3077 We don't care about side effects in that case because the SAVE_EXPR
3078 takes care of that for us. In all other cases, two expressions are
3079 equal if they have no side effects. If we have two identical
3080 expressions with side effects that should be treated the same due
3081 to the only side effects being identical SAVE_EXPR's, that will
3082 be detected in the recursive calls below.
3083 If we are taking an invariant address of two identical objects
3084 they are necessarily equal as well. */
3091 /* Next handle constant cases, those for which we can return 1 even
3092 if ONLY_CONST is set. */
3095 {
3108 {
3109 /* If we do not distinguish between signed and unsigned zero,
3110 consider them equal. */
3113 }
3117 {
3132 }
3136 flags)
3138 flags));
3149 flags | OEP_ADDRESS_OF
3152 /* In GIMPLE empty constructors are allowed in initializers of
3153 aggregates. */
3157 }
3159 /* Don't handle more cases for OEP_BITWISE, since we can't guarantee that
3160 two instances of undefined behavior will give identical results. */
3164 /* Define macros to test an operand from arg0 and arg1 for equality and a
3165 variant that allows null and views null as being different from any
3166 non-null value. In the latter case, if either is null, the both
3167 must be; otherwise, do the normal comparison. */
3168 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3169 TREE_OPERAND (arg1, N), flags)
3171 #define OP_SAME_WITH_NULL(N) \
3172 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3173 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3176 {
3178 /* Two conversions are equal only if signedness and modes match. */
3180 {
3181 CASE_CONVERT:
3189 }
3199 /* For commutative ops, allow the other order. */
3207 /* If either of the pointer (or reference) expressions we are
3208 dereferencing contain a side effect, these cannot be equal,
3209 but their addresses can be. */
3216 {
3219 {
3223 /* Verify that the access types are compatible. */
3227 }
3232 /* Require the same offset. */
3238 /* Fallthru. */
3246 {
3247 /* Require equal access sizes */
3253 flags)))
3255 /* Verify that access happens in similar types. */
3258 /* Verify that accesses are TBAA compatible. */
3267 /* Verify that alignment is compatible. */
3271 }
3274 /* TARGET_MEM_REF require equal extra operands. */
3285 /* Compare the array index by value if it is constant first as we
3286 may have different types but same value here. */
3292 /* Compare low bound and element size as with OEP_ADDRESS_OF
3293 we have to account for the offset of the ref. */
3298 array_ref_low_bound
3302 array_ref_element_size
3304 flags))));
3307 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3308 may be NULL when we're called to compare MEM_EXPRs. */
3311 {
3314 /* Most of time we only need to compare FIELD_DECLs for equality.
3315 However when determining address look into actual offsets.
3316 These may match for unions and unshared record types. */
3319 {
3322 {
3333 flags))
3335 }
3336 else
3338 }
3339 }
3350 }
3354 {
3356 /* Be sure we pass right ADDRESS_OF flag. */
3373 /* The multiplcation operands are commutative. */
3374 /* FALLTHRU */
3382 /* Otherwise take into account this is a commutative operation. */
3395 /* BIT_INSERT_EXPR has an implict operand as the type precision
3396 of op1. Need to check to make sure they are the same. */
3402 /* FALLTHRU */
3427 /* Virtual table reference. */
3439 {
3444 }
3449 }
3453 {
3457 /* If not both CALL_EXPRs are either internal or normal function
3458 functions, then they are not equal. */
3461 {
3462 /* If the CALL_EXPRs call different internal functions, then they
3463 are not equal. */
3466 }
3467 else
3468 {
3469 /* If the CALL_EXPRs call different functions, then they are not
3470 equal. */
3472 flags))
3474 }
3476 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3477 {
3481 else
3485 }
3487 /* Now see if all the arguments are the same. */
3488 {
3499 /* If we get here and both argument lists are exhausted
3500 then the CALL_EXPRs are equal. */
3502 }
3505 }
3508 /* Consider __builtin_sqrt equal to sqrt. */
3517 {
3521 /* In GIMPLE constructors are used only to build vectors from
3522 elements. Individual elements in the constructor must be
3523 indexed in increasing order and form an initial sequence.
3525 We make no effort to compare constructors in generic.
3526 (see sem_variable::equals in ipa-icf which can do so for
3527 constants). */
3532 /* Be sure that vectors constructed have the same representation.
3533 We only tested element precision and modes to match.
3534 Vectors may be BLKmode and thus also check that the number of
3535 parts match. */
3548 {
3553 /* In GIMPLE the indexes can be either NULL or matching i.
3554 Double check this so we won't get false
3555 positives for GENERIC. */
3563 }
3565 }
3568 {
3569 /* Compare the STATEMENT_LISTs. */
3575 {
3576 /* The lists don't have the same number of statements. */
3582 flags & (OEP_LEXICOGRAPHIC
3585 }
3586 }
3591 {
3602 }
3606 }
3608 #undef OP_SAME
3609 #undef OP_SAME_WITH_NULL
3610 }
3612 /* Generate a hash value for an expression. This can be used iteratively
3613 by passing a previous result as the HSTATE argument. */
3615 void
3618 {
3624 {
3627 }
3637 {
3638 /* Alas, constants aren't shared, so we can't rely on pointer
3639 identity. */
3649 {
3653 else
3657 }
3659 {
3663 }
3673 {
3680 }
3682 /* We can just compare by pointer. */
3686 /* The node itself doesn't matter. */
3690 /* Ignore. */
3693 /* A list of expressions, for a CALL_EXPR or as the elements of a
3694 VECTOR_CST. */
3699 {
3705 {
3706 /* In GIMPLE the indexes can be either NULL or matching i. */
3711 }
3713 }
3715 {
3716 tree_stmt_iterator i;
3721 }
3730 /* When referring to a built-in FUNCTION_DECL, use the __builtin__ form.
3731 Otherwise nodes that compare equal according to operand_equal_p might
3732 get different hash codes. However, don't do this for machine specific
3733 or front end builtins, since the function code is overloaded in those
3734 cases. */
3737 {
3740 }
3741 /* FALL THROUGH */
3744 {
3748 }
3752 {
3753 /* DECL's have a unique ID */
3755 }
3757 {
3758 /* For comparisons that can be swapped, use the lower
3759 tree code. */
3766 }
3768 {
3769 /* NOP_EXPR and CONVERT_EXPR are considered equal by
3770 operand_equal_p. */
3774 /* Don't hash the type, that can lead to having nodes which
3775 compare equal according to operand_equal_p, but which
3776 have different hash codes. Make sure to include signedness
3777 in the hash computation. */
3780 }
3781 /* For OEP_ADDRESS_OF, hash MEM_EXPR[&decl, 0] the same as decl. */
3789 /* Don't ICE on FE specific trees, or their arguments etc.
3790 during operand_equal_p hash verification. */
3793 else
3794 {
3800 {
3816 {
3821 else
3822 {
3828 }
3830 }
3844 {
3845 /* The multiplication operands are commutative. */
3852 }
3860 /* For TARGET_EXPR, just hash on the TARGET_EXPR_SLOT.
3861 Usually different TARGET_EXPRs just should use
3862 different temporaries in their slots. */
3867 /* Virtual table reference. */
3875 {
3877 /* We compute mangled names only when free_lang_data is run.
3878 In that case we can hash precisely. */
3881 hstate.add_object
3882 (IDENTIFIER_HASH_VALUE
3884 }
3888 }
3890 /* Don't hash the type, that can lead to having nodes which
3891 compare equal according to operand_equal_p, but which
3892 have different hash codes. */
3894 {
3895 /* Make sure to include signness in the hash computation. */
3898 }
3901 {
3902 /* It's a commutative expression. We want to hash it the same
3903 however it appears. We do this by first hashing both operands
3904 and then rehashing based on the order of their independent
3905 hashes. */
3910 }
3911 else
3915 }
3917 }
3918 }
3920 bool
3923 {
3924 /* When checking, verify at the outermost operand_equal_p call that
3925 if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
3926 hash value. */
3928 {
3930 {
3932 {
3939 }
3941 }
3942 else
3946 }
3949 }
3954 /* Conveinece wrapper around operand_compare class because usually we do
3955 not need to play with the valueizer. */
3957 bool
3959 {
3961 }
3963 namespace inchash
3964 {
3966 /* Generate a hash value for an expression. This can be used iteratively
3967 by passing a previous result as the HSTATE argument.
3969 This function is intended to produce the same hash for expressions which
3970 would compare equal using operand_equal_p. */
3971 void
3973 {
3975 }
3977 }
3978 \f
3979 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
3980 with a different signedness or a narrower precision. */
3982 static bool
3984 {
3992 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3993 and see if the inner values are the same. This removes any
3994 signedness comparison, which doesn't matter here. */
4002 /* Discard a single widening conversion from ARG1 and see if the inner
4003 value is the same as ARG0. */
4012 }
4013 \f
4014 /* See if ARG is an expression that is either a comparison or is performing
4015 arithmetic on comparisons. The comparisons must only be comparing
4016 two different values, which will be stored in *CVAL1 and *CVAL2; if
4017 they are nonzero it means that some operands have already been found.
4018 No variables may be used anywhere else in the expression except in the
4019 comparisons.
4021 If this is true, return 1. Otherwise, return zero. */
4023 static bool
4025 {
4029 /* We can handle some of the tcc_expression cases here. */
4038 {
4057 /* First see if we can handle the first operand, then the second. For
4058 the second operand, we know *CVAL1 can't be zero. It must be that
4059 one side of the comparison is each of the values; test for the
4060 case where this isn't true by failing if the two operands
4061 are the same. */
4070 ;
4074 ;
4075 else
4079 ;
4083 ;
4084 else
4091 }
4092 }
4093 \f
4094 /* ARG is a tree that is known to contain just arithmetic operations and
4095 comparisons. Evaluate the operations in the tree substituting NEW0 for
4096 any occurrence of OLD0 as an operand of a comparison and likewise for
4097 NEW1 and OLD1. */
4099 static tree
4102 {
4107 /* We can handle some of the tcc_expression cases here. */
4115 {
4130 {
4149 }
4150 /* Fall through - ??? */
4153 {
4157 /* We need to check both for exact equality and tree equality. The
4158 former will be true if the operand has a side-effect. In that
4159 case, we know the operand occurred exactly once. */
4172 }
4176 }
4177 }
4178 \f
4179 /* Return a tree for the case when the result of an expression is RESULT
4180 converted to TYPE and OMITTED was previously an operand of the expression
4181 but is now not needed (e.g., we folded OMITTED * 0).
4183 If OMITTED has side effects, we must evaluate it. Otherwise, just do
4184 the conversion of RESULT to TYPE. */
4186 tree
4188 {
4191 /* If the resulting operand is an empty statement, just return the omitted
4192 statement casted to void. */
4202 }
4204 /* Return a tree for the case when the result of an expression is RESULT
4205 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
4206 of the expression but are now not needed.
4208 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
4209 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
4210 evaluated before OMITTED2. Otherwise, if neither has side effects,
4211 just do the conversion of RESULT to TYPE. */
4213 tree
4216 {
4225 }
4227 \f
4228 /* Return a simplified tree node for the truth-negation of ARG. This
4229 never alters ARG itself. We assume that ARG is an operation that
4230 returns a truth value (0 or 1).
4232 FIXME: one would think we would fold the result, but it causes
4233 problems with the dominator optimizer. */
4235 static tree
4237 {
4242 /* If this is a comparison, we can simply invert it, except for
4243 floating-point non-equality comparisons, in which case we just
4244 enclose a TRUTH_NOT_EXPR around what we have. */
4247 {
4250 && flag_trapping_math
4264 }
4267 {
4286 /* Here we can invert either operand. We invert the first operand
4287 unless the second operand is a TRUTH_NOT_EXPR in which case our
4288 result is the XOR of the first operand with the inside of the
4289 negation of the second operand. */
4294 else
4317 {
4324 /* A COND_EXPR may have a throw as one operand, which
4325 then has void type. Just leave void operands
4326 as they are. */
4332 }
4344 CASE_CONVERT:
4348 /* fall through */
4370 }
4371 }
4373 /* Fold the truth-negation of ARG. This never alters ARG itself. We
4374 assume that ARG is an operation that returns a truth value (0 or 1
4375 for scalars, 0 or -1 for vectors). Return the folded expression if
4376 folding is successful. Otherwise, return NULL_TREE. */
4378 static tree
4380 {
4383 ? BIT_NOT_EXPR
4386 }
4388 /* Return a simplified tree node for the truth-negation of ARG. This
4389 never alters ARG itself. We assume that ARG is an operation that
4390 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
4392 tree
4394 {
4400 ? BIT_NOT_EXPR
4403 }
4404 \f
4405 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
4406 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
4407 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
4408 is the original memory reference used to preserve the alias set of
4409 the access. */
4411 static tree
4415 {
4418 /* Attempt not to lose the access path if possible. */
4420 {
4422 machine_mode nmode;
4424 tree noffset;
4432 && !reversep
4433 && !nreversep
4435 {
4438 }
4439 }
4448 {
4455 }
4470 }
4472 /* Optimize a bit-field compare.
4474 There are two cases: First is a compare against a constant and the
4475 second is a comparison of two items where the fields are at the same
4476 bit position relative to the start of a chunk (byte, halfword, word)
4477 large enough to contain it. In these cases we can avoid the shift
4478 implicit in bitfield extractions.
4480 For constants, we emit a compare of the shifted constant with the
4481 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4482 compared. For two fields at the same position, we do the ANDs with the
4483 similar mask and compare the result of the ANDs.
4485 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4486 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4487 are the left and right operands of the comparison, respectively.
4489 If the optimization described above can be done, we return the resulting
4490 tree. Otherwise we return zero. */
4492 static tree
4495 {
4499 tree unsigned_type;
4502 scalar_int_mode nmode;
4507 tree mask;
4508 tree offset;
4510 /* Get all the information about the extractions being done. If the bit size
4511 is the same as the size of the underlying object, we aren't doing an
4512 extraction at all and so can do nothing. We also don't want to
4513 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4514 then will no longer be able to replace it. */
4529 else
4530 {
4531 /* If this is not a constant, we can only do something if bit positions,
4532 sizes, signedness and storage order are the same. */
4533 rinner
4546 }
4548 /* Honor the C++ memory model and mimic what RTL expansion does. */
4552 {
4556 }
4558 /* See if we can find a mode to refer to this field. We should be able to,
4559 but fail if we can't. */
4567 /* Set signed and unsigned types of the precision of this mode for the
4568 shifts below. */
4571 /* Compute the bit position and size for the new reference and our offset
4572 within it. If the new reference is the same size as the original, we
4573 won't optimize anything, so return zero. */
4583 /* Make the mask to be used against the extracted field. */
4590 {
4594 /* If not comparing with constant, just rework the comparison
4595 and return. */
4603 }
4605 /* Otherwise, we are handling the constant case. See if the constant is too
4606 big for the field. Warn and return a tree for 0 (false) if so. We do
4607 this not only for its own sake, but to avoid having to test for this
4608 error case below. If we didn't, we might generate wrong code.
4610 For unsigned fields, the constant shifted right by the field length should
4611 be all zero. For signed fields, the high-order bits should agree with
4612 the sign bit. */
4615 {
4617 {
4621 }
4622 }
4623 else
4624 {
4627 {
4631 }
4632 }
4637 /* Single-bit compares should always be against zero. */
4639 {
4642 }
4644 /* Make a new bitfield reference, shift the constant over the
4645 appropriate number of bits and mask it with the computed mask
4646 (in case this was a signed field). If we changed it, make a new one. */
4654 mask);
4659 }
4660 \f
4661 /* Subroutine for fold_truth_andor_1: decode a field reference.
4663 If EXP is a comparison reference, we return the innermost reference.
4665 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4666 set to the starting bit number.
4668 If the innermost field can be completely contained in a mode-sized
4669 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4671 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4672 otherwise it is not changed.
4674 *PUNSIGNEDP is set to the signedness of the field.
4676 *PREVERSEP is set to the storage order of the field.
4678 *PMASK is set to the mask used. This is either contained in a
4679 BIT_AND_EXPR or derived from the width of the field.
4681 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4683 Return 0 if this is not a component reference or is one that we can't
4684 do anything with. */
4686 static tree
4691 {
4696 tree unsigned_type;
4699 /* All the optimizations using this function assume integer fields.
4700 There are problems with FP fields since the type_for_size call
4701 below can fail for, e.g., XFmode. */
4705 /* We are interested in the bare arrangement of bits, so strip everything
4706 that doesn't affect the machine mode. However, record the type of the
4707 outermost expression if it may matter below. */
4714 {
4720 }
4731 /* Reject out-of-bound accesses (PR79731). */
4743 /* If the number of bits in the reference is the same as the bitsize of
4744 the outer type, then the outer type gives the signedness. Otherwise
4745 (in case of a small bitfield) the signedness is unchanged. */
4749 /* Compute the mask to access the bitfield. */
4757 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4765 }
4767 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4768 bit positions and MASK is SIGNED. */
4770 static bool
4772 {
4776 /* If this function returns true when the type of the mask is
4777 UNSIGNED, then there will be errors. In particular see
4778 gcc.c-torture/execute/990326-1.c. There does not appear to be
4779 any documentation paper trail as to why this is so. But the pre
4780 wide-int worked with that restriction and it has been preserved
4781 here. */
4786 }
4788 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4789 represents the sign bit of EXP's type. If EXP represents a sign
4790 or zero extension, also test VAL against the unextended type.
4791 The return value is the (sub)expression whose sign bit is VAL,
4792 or NULL_TREE otherwise. */
4794 tree
4796 {
4798 tree t;
4800 /* Tree EXP must have an integral type. */
4805 /* Tree VAL must be an integer constant. */
4814 /* Handle extension from a narrower type. */
4820 }
4822 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4823 to be evaluated unconditionally. */
4825 static bool
4827 {
4828 /* Strip any conversions that don't change the machine mode. */
4837 /* Don't regard global variables as simple. They may be
4838 allocated in ways unknown to the compiler (shared memory,
4839 #pragma weak, etc). */
4842 /* Weakrefs are not safe to be read, since they can be NULL.
4843 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4844 have DECL_WEAK flag set. */
4846 /* Loading a static variable is unduly expensive, but global
4847 registers aren't expensive. */
4849 }
4851 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4852 to be evaluated unconditionally.
4853 I addition to simple_operand_p, we assume that comparisons, conversions,
4854 and logic-not operations are simple, if their operands are simple, too. */
4856 static bool
4858 {
4877 }
4879 \f
4880 /* The following functions are subroutines to fold_range_test and allow it to
4881 try to change a logical combination of comparisons into a range test.
4883 For example, both
4884 X == 2 || X == 3 || X == 4 || X == 5
4885 and
4886 X >= 2 && X <= 5
4887 are converted to
4888 (unsigned) (X - 2) <= 3
4890 We describe each set of comparisons as being either inside or outside
4891 a range, using a variable named like IN_P, and then describe the
4892 range with a lower and upper bound. If one of the bounds is omitted,
4893 it represents either the highest or lowest value of the type.
4895 In the comments below, we represent a range by two numbers in brackets
4896 preceded by a "+" to designate being inside that range, or a "-" to
4897 designate being outside that range, so the condition can be inverted by
4898 flipping the prefix. An omitted bound is represented by a "-". For
4899 example, "- [-, 10]" means being outside the range starting at the lowest
4900 possible value and ending at 10, in other words, being greater than 10.
4901 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4902 always false.
4904 We set up things so that the missing bounds are handled in a consistent
4905 manner so neither a missing bound nor "true" and "false" need to be
4906 handled using a special case. */
4908 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4909 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4910 and UPPER1_P are nonzero if the respective argument is an upper bound
4911 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4912 must be specified for a comparison. ARG1 will be converted to ARG0's
4913 type if both are specified. */
4915 static tree
4918 {
4919 tree tem;
4923 /* If neither arg represents infinity, do the normal operation.
4924 Else, if not a comparison, return infinity. Else handle the special
4925 comparison rules. Note that most of the cases below won't occur, but
4926 are handled for consistency. */
4929 {
4934 }
4939 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4940 for neither. In real maths, we cannot assume open ended ranges are
4941 the same. But, this is computer arithmetic, where numbers are finite.
4942 We can therefore make the transformation of any unbounded range with
4943 the value Z, Z being greater than any representable number. This permits
4944 us to treat unbounded ranges as equal. */
4948 {
4969 }
4972 }
4973 \f
4974 /* Helper routine for make_range. Perform one step for it, return
4975 new expression if the loop should continue or NULL_TREE if it should
4976 stop. */
4978 tree
4982 {
4988 {
4990 /* We can only do something if the range is testing for zero. */
4999 /* We can only do something if the range is testing for zero
5000 and if the second operand is an integer constant. Note that
5001 saying something is "in" the range we make is done by
5002 complementing IN_P since it will set in the initial case of
5003 being not equal to zero; "out" is leaving it alone. */
5010 {
5031 }
5033 /* If this is an unsigned comparison, we also know that EXP is
5034 greater than or equal to zero. We base the range tests we make
5035 on that fact, so we record it here so we can parse existing
5036 range tests. We test arg0_type since often the return type
5037 of, e.g. EQ_EXPR, is boolean. */
5039 {
5043 NULL_TREE))
5048 /* If the high bound is missing, but we have a nonzero low
5049 bound, reverse the range so it goes from zero to the low bound
5050 minus 1. */
5052 {
5057 }
5058 }
5066 /* If flag_wrapv and ARG0_TYPE is signed, make sure
5067 low and high are non-NULL, then normalize will DTRT. */
5070 {
5075 }
5077 /* (-x) IN [a,b] -> x in [-b, -a] */
5089 /* ~ X -> -X - 1 */
5098 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
5099 move a constant to the other side. */
5104 /* If EXP is signed, any overflow in the computation is undefined,
5105 so we don't worry about it so long as our computations on
5106 the bounds don't overflow. For unsigned, overflow is defined
5107 and this is exactly the right thing. */
5119 normalize:
5120 /* Check for an unsigned range which has wrapped around the maximum
5121 value thus making n_high < n_low, and normalize it. */
5123 {
5129 /* If the range is of the form +/- [ x+1, x ], we won't
5130 be able to normalize it. But then, it represents the
5131 whole range or the empty set, so make it
5132 +/- [ -, - ]. */
5136 else
5138 }
5139 else
5147 CASE_CONVERT:
5165 /* If we're converting arg0 from an unsigned type, to exp,
5166 a signed type, we will be doing the comparison as unsigned.
5167 The tests above have already verified that LOW and HIGH
5168 are both positive.
5170 So we have to ensure that we will handle large unsigned
5171 values the same way that the current signed bounds treat
5172 negative values. */
5175 {
5176 tree high_positive;
5177 tree equiv_type;
5178 /* For fixed-point modes, we need to pass the saturating flag
5179 as the 2nd parameter. */
5181 equiv_type
5184 else
5185 equiv_type
5188 /* A range without an upper bound is, naturally, unbounded.
5189 Since convert would have cropped a very large value, use
5190 the max value for the destination type. */
5191 high_positive
5198 high_positive),
5201 /* If the low bound is specified, "and" the range with the
5202 range for which the original unsigned value will be
5203 positive. */
5205 {
5208 integer_zero_node),
5209 high_positive))
5213 }
5214 else
5215 {
5216 /* Otherwise, "or" the range with the range of the input
5217 that will be interpreted as negative. */
5220 integer_zero_node),
5221 high_positive))
5225 }
5226 }
5235 }
5236 }
5238 /* Given EXP, a logical expression, set the range it is testing into
5239 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
5240 actually being tested. *PLOW and *PHIGH will be made of the same
5241 type as the returned expression. If EXP is not a comparison, we
5242 will most likely not be returning a useful value and range. Set
5243 *STRICT_OVERFLOW_P to true if the return value is only valid
5244 because signed overflow is undefined; otherwise, do not change
5245 *STRICT_OVERFLOW_P. */
5247 tree
5250 {
5258 /* Start with simply saying "EXP != 0" and then look at the code of EXP
5259 and see if we can refine the range. Some of the cases below may not
5260 happen, but it doesn't seem worth worrying about this. We "continue"
5261 the outer loop when we've changed something; otherwise we "break"
5262 the switch, which will "break" the while. */
5268 {
5274 {
5282 }
5291 }
5293 /* If EXP is a constant, we can evaluate whether this is true or false. */
5295 {
5302 }
5306 }
5308 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
5309 a bitwise check i.e. when
5310 LOW == 0xXX...X00...0
5311 HIGH == 0xXX...X11...1
5312 Return corresponding mask in MASK and stem in VALUE. */
5314 static bool
5317 {
5340 }
5341 \f
5342 /* Helper routine for build_range_check and match.pd. Return the type to
5343 perform the check or NULL if it shouldn't be optimized. */
5345 tree
5347 {
5348 /* First make sure that arithmetics in this type is valid, then make sure
5349 that it wraps around. */
5354 {
5357 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
5358 for the type in question, as we rely on this here. */
5368 else
5370 }
5374 }
5376 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
5377 type, TYPE, return an expression to test if EXP is in (or out of, depending
5378 on IN_P) the range. Return 0 if the test couldn't be created. */
5380 tree
5383 {
5386 /* Disable this optimization for function pointer expressions
5387 on targets that require function pointer canonicalization. */
5394 {
5400 }
5422 value);
5425 {
5427 {
5431 }
5433 }
5435 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
5437 {
5441 {
5443 {
5446 etype
5448 else
5451 }
5454 }
5455 }
5457 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
5458 This requires wrap-around arithmetics for the type of the expression. */
5475 }
5476 \f
5477 /* Return the predecessor of VAL in its type, handling the infinite case. */
5479 static tree
5481 {
5487 else
5490 }
5492 /* Return the successor of VAL in its type, handling the infinite case. */
5494 static tree
5496 {
5502 else
5505 }
5507 /* Given two ranges, see if we can merge them into one. Return 1 if we
5508 can, 0 if we can't. Set the output range into the specified parameters. */
5510 bool
5513 {
5517 tree tem;
5527 /* Make range 0 be the range that starts first, or ends last if they
5528 start at the same value. Swap them if it isn't. */
5531 || (lowequal
5534 {
5538 }
5540 /* If the second range is != high1 where high1 is the type maximum of
5541 the type, try first merging with < high1 range. */
5543 && high1
5550 {
5555 /* Similarly for the second range != low1 where low1 is the type minimum
5556 of the type, try first merging with > low1 range. */
5561 }
5563 /* Now flag two cases, whether the ranges are disjoint or whether the
5564 second range is totally subsumed in the first. Note that the tests
5565 below are simplified by the ones above. */
5571 /* We now have four cases, depending on whether we are including or
5572 excluding the two ranges. */
5574 {
5575 /* If they don't overlap, the result is false. If the second range
5576 is a subset it is the result. Otherwise, the range is from the start
5577 of the second to the end of the first. */
5582 else
5584 }
5587 {
5588 /* If they don't overlap, the result is the first range. If they are
5589 equal, the result is false. If the second range is a subset of the
5590 first, and the ranges begin at the same place, we go from just after
5591 the end of the second range to the end of the first. If the second
5592 range is not a subset of the first, or if it is a subset and both
5593 ranges end at the same place, the range starts at the start of the
5594 first range and ends just before the second range.
5595 Otherwise, we can't describe this as a single range. */
5601 {
5606 {
5607 /* We are in the weird situation where high0 > high1 but
5608 high1 has no successor. Punt. */
5610 }
5611 }
5613 {
5618 {
5619 /* low0 < low1 but low1 has no predecessor. Punt. */
5621 }
5622 }
5623 else
5625 }
5628 {
5629 /* If they don't overlap, the result is the second range. If the second
5630 is a subset of the first, the result is false. Otherwise,
5631 the range starts just after the first range and ends at the
5632 end of the second. */
5637 else
5638 {
5643 {
5644 /* high1 > high0 but high0 has no successor. Punt. */
5646 }
5647 }
5648 }
5650 else
5651 {
5652 /* The case where we are excluding both ranges. Here the complex case
5653 is if they don't overlap. In that case, the only time we have a
5654 range is if they are adjacent. If the second is a subset of the
5655 first, the result is the first. Otherwise, the range to exclude
5656 starts at the beginning of the first range and ends at the end of the
5657 second. */
5659 {
5664 else
5665 {
5666 /* Canonicalize - [min, x] into - [-, x]. */
5669 {
5672 GET_MODE_BITSIZE
5675 /* FALLTHROUGH */
5688 }
5690 /* Canonicalize - [x, max] into - [x, -]. */
5693 {
5696 GET_MODE_BITSIZE
5699 /* FALLTHROUGH */
5715 }
5717 /* The ranges might be also adjacent between the maximum and
5718 minimum values of the given type. For
5719 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5720 return + [x + 1, y - 1]. */
5722 {
5729 }
5730 else
5732 }
5733 }
5736 else
5738 }
5742 }
5743 \f
5745 /* Subroutine of fold, looking inside expressions of the form
5746 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5747 of the COND_EXPR. This function is being used also to optimize
5748 A op B ? C : A, by reversing the comparison first.
5750 Return a folded expression whose code is not a COND_EXPR
5751 anymore, or NULL_TREE if no folding opportunity is found. */
5753 static tree
5756 {
5761 tree tem;
5766 /* If we have A op 0 ? A : -A, consider applying the following
5767 transformations:
5769 A == 0? A : -A same as -A
5770 A != 0? A : -A same as A
5771 A >= 0? A : -A same as abs (A)
5772 A > 0? A : -A same as abs (A)
5773 A <= 0? A : -A same as -abs (A)
5774 A < 0? A : -A same as -abs (A)
5776 None of these transformations work for modes with signed
5777 zeros. If A is +/-0, the first two transformations will
5778 change the sign of the result (from +0 to -0, or vice
5779 versa). The last four will fix the sign of the result,
5780 even though the original expressions could be positive or
5781 negative, depending on the sign of A.
5783 Note that all these transformations are correct if A is
5784 NaN, since the two alternatives (A and -A) are also NaNs. */
5791 /* In the case that A is of the form X-Y, '-A' (arg2) may
5792 have already been folded to Y-X, check for that. */
5800 {
5812 /* Fall through. */
5823 /* FALLTHRU */
5830 {
5831 /* A <= 0 ? A : -A for A INT_MIN is valid, but -abs(INT_MIN)
5832 is not, invokes UB both in abs and in the negation of it.
5833 So, use ABSU_EXPR instead. */
5838 }
5839 else
5840 {
5843 }
5847 }
5849 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5850 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5851 both transformations are correct when A is NaN: A != 0
5852 is then true, and A == 0 is false. */
5856 {
5861 }
5863 /* Try some transformations of A op B ? A : B.
5865 A == B? A : B same as B
5866 A != B? A : B same as A
5867 A >= B? A : B same as max (A, B)
5868 A > B? A : B same as max (B, A)
5869 A <= B? A : B same as min (A, B)
5870 A < B? A : B same as min (B, A)
5872 As above, these transformations don't work in the presence
5873 of signed zeros. For example, if A and B are zeros of
5874 opposite sign, the first two transformations will change
5875 the sign of the result. In the last four, the original
5876 expressions give different results for (A=+0, B=-0) and
5877 (A=-0, B=+0), but the transformed expressions do not.
5879 The first two transformations are correct if either A or B
5880 is a NaN. In the first transformation, the condition will
5881 be false, and B will indeed be chosen. In the case of the
5882 second transformation, the condition A != B will be true,
5883 and A will be chosen.
5885 The conversions to max() and min() are not correct if B is
5886 a number and A is not. The conditions in the original
5887 expressions will be false, so all four give B. The min()
5888 and max() versions would give a NaN instead. */
5891 /* Avoid these transformations if the COND_EXPR may be used
5892 as an lvalue in the C++ front-end. PR c++/19199. */
5893 && (in_gimple_form
5899 {
5905 {
5914 /* In C++ a ?: expression can be an lvalue, so put the
5915 operand which will be used if they are equal first
5916 so that we can convert this back to the
5917 corresponding COND_EXPR. */
5919 {
5927 }
5934 {
5942 }
5955 }
5956 }
5959 }
5962 \f
5963 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5964 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5965 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5966 false) >= 2)
5967 #endif
5969 /* EXP is some logical combination of boolean tests. See if we can
5970 merge it into some range test. Return the new tree if so. */
5972 static tree
5975 {
5989 /* If op0 is known true or false and this is a short-circuiting
5990 operation we must not merge with op1 since that makes side-effects
5991 unconditional. So special-case this. */
5998 /* If this is an OR operation, invert both sides; we will invert
5999 again at the end. */
6003 /* If both expressions are the same, if we can merge the ranges, and we
6004 can build the range test, return it or it inverted. If one of the
6005 ranges is always true or always false, consider it to be the same
6006 expression as the other. */
6014 {
6018 }
6020 /* On machines where the branch cost is expensive, if this is a
6021 short-circuited branch and the underlying object on both sides
6022 is the same, make a non-short-circuit operation. */
6025 logical_op_non_short_circuit
6028 && !flag_sanitize_coverage
6032 {
6033 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
6034 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
6035 which cases we can't do this. */
6043 {
6052 {
6055 WARN_STRICT_OVERFLOW_COMPARISON);
6059 }
6060 }
6061 }
6064 }
6065 \f
6066 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
6067 bit value. Arrange things so the extra bits will be set to zero if and
6068 only if C is signed-extended to its full width. If MASK is nonzero,
6069 it is an INTEGER_CST that should be AND'ed with the extra bits. */
6071 static tree
6073 {
6076 tree temp;
6081 /* We work by getting just the sign bit into the low-order bit, then
6082 into the high-order bit, then sign-extend. We then XOR that value
6083 with C. */
6087 /* We must use a signed type in order to get an arithmetic right shift.
6088 However, we must also avoid introducing accidental overflows, so that
6089 a subsequent call to integer_zerop will work. Hence we must
6090 do the type conversion here. At this point, the constant is either
6091 zero or one, and the conversion to a signed type can never overflow.
6092 We could get an overflow if this conversion is done anywhere else. */
6101 /* If necessary, convert the type back to match the type of C. */
6106 }
6107 \f
6108 /* For an expression that has the form
6109 (A && B) || ~B
6110 or
6111 (A || B) && ~B,
6112 we can drop one of the inner expressions and simplify to
6113 A || ~B
6114 or
6115 A && ~B
6116 LOC is the location of the resulting expression. OP is the inner
6117 logical operation; the left-hand side in the examples above, while CMPOP
6118 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
6119 removing a condition that guards another, as in
6120 (A != NULL && A->...) || A == NULL
6121 which we must not transform. If RHS_ONLY is true, only eliminate the
6122 right-most operand of the inner logical operation. */
6124 static tree
6127 {
6145 {
6148 {
6151 }
6152 }
6154 {
6157 {
6160 }
6161 }
6176 }
6178 /* Find ways of folding logical expressions of LHS and RHS:
6179 Try to merge two comparisons to the same innermost item.
6180 Look for range tests like "ch >= '0' && ch <= '9'".
6181 Look for combinations of simple terms on machines with expensive branches
6182 and evaluate the RHS unconditionally.
6184 For example, if we have p->a == 2 && p->b == 4 and we can make an
6185 object large enough to span both A and B, we can do this with a comparison
6186 against the object ANDed with the a mask.
6188 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
6189 operations to do this with one comparison.
6191 We check for both normal comparisons and the BIT_AND_EXPRs made this by
6192 function and the one above.
6194 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
6195 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
6197 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
6198 two operands.
6200 We return the simplified tree or 0 if no optimization is possible. */
6202 static tree
6205 {
6206 /* If this is the "or" of two comparisons, we can do something if
6207 the comparisons are NE_EXPR. If this is the "and", we can do something
6208 if the comparisons are EQ_EXPR. I.e.,
6209 (a->b == 2 && a->c == 4) can become (a->new == NEW).
6211 WANTED_CODE is this operation code. For single bit fields, we can
6212 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
6213 comparison for one-bit fields. */
6234 /* Start by getting the comparison codes. Fail if anything is volatile.
6235 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
6236 it were surrounded with a NE_EXPR. */
6245 {
6249 }
6252 {
6256 }
6267 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
6270 {
6273 {
6278 }
6281 {
6287 }
6288 }
6293 /* If the RHS can be evaluated unconditionally and its operands are
6294 simple, it wins to evaluate the RHS unconditionally on machines
6295 with expensive branches. In this case, this isn't a comparison
6296 that can be merged. */
6303 {
6304 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
6315 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
6325 }
6327 /* See if the comparisons can be merged. Then get all the parameters for
6328 each side. */
6353 /* It must be true that the inner operation on the lhs of each
6354 comparison must be the same if we are to be able to do anything.
6355 Then see if we have constants. If not, the same must be true for
6356 the rhs's. */
6365 {
6368 }
6373 else
6376 /* If either comparison code is not correct for our logical operation,
6377 fail. However, we can convert a one-bit comparison against zero into
6378 the opposite comparison against that bit being set in the field. */
6382 {
6384 {
6385 /* Make the left operand unsigned, since we are only interested
6386 in the value of one bit. Otherwise we are doing the wrong
6387 thing below. */
6390 }
6391 else
6393 }
6395 /* This is analogous to the code for l_const above. */
6397 {
6399 {
6402 }
6403 else
6405 }
6407 /* See if we can find a mode that contains both fields being compared on
6408 the left. If we can't, fail. Otherwise, update all constants and masks
6409 to be relative to a field of that size. */
6423 {
6426 }
6434 {
6441 {
6445 }
6446 }
6448 {
6455 {
6459 }
6460 }
6462 /* If the right sides are not constant, do the same for it. Also,
6463 disallow this optimization if a size, signedness or storage order
6464 mismatch occurs between the left and right sides. */
6466 {
6470 /* Make sure the two fields on the right
6471 correspond to the left without being swapped. */
6488 {
6491 }
6500 /* Make a mask that corresponds to both fields being compared.
6501 Do this for both items being compared. If the operands are the
6502 same size and the bits being compared are in the same position
6503 then we can do this by masking both and comparing the masked
6504 results. */
6511 {
6525 }
6527 /* There is still another way we can do something: If both pairs of
6528 fields being compared are adjacent, we may be able to make a wider
6529 field containing them both.
6531 Note that we still must mask the lhs/rhs expressions. Furthermore,
6532 the mask must be shifted to account for the shift done by
6533 make_bit_field_ref. */
6542 {
6543 tree type;
6559 /* Convert to the smaller type before masking out unwanted bits. */
6562 {
6564 {
6568 }
6570 {
6574 }
6575 }
6584 }
6587 }
6589 /* Handle the case of comparisons with constants. If there is something in
6590 common between the masks, those bits of the constants must be the same.
6591 If not, the condition is always false. Test for this to avoid generating
6592 incorrect code below. */
6597 {
6599 {
6602 }
6603 else
6604 {
6607 }
6608 }
6613 /* Construct the expression we will return. First get the component
6614 reference we will make. Unless the mask is all ones the width of
6615 that field, perform the mask operation. Then compare with the
6616 merged constant. */
6627 }
6628 \f
6629 /* T is an integer expression that is being multiplied, divided, or taken a
6630 modulus (CODE says which and what kind of divide or modulus) by a
6631 constant C. See if we can eliminate that operation by folding it with
6632 other operations already in T. WIDE_TYPE, if non-null, is a type that
6633 should be used for the computation if wider than our type.
6635 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6636 (X * 2) + (Y * 4). We must, however, be assured that either the original
6637 expression would not overflow or that overflow is undefined for the type
6638 in the language in question.
6640 If we return a non-null expression, it is an equivalent form of the
6641 original computation, but need not be in the original type.
6643 We set *STRICT_OVERFLOW_P to true if the return values depends on
6644 signed overflow being undefined. Otherwise we do not change
6645 *STRICT_OVERFLOW_P. */
6647 static tree
6650 {
6651 /* To avoid exponential search depth, refuse to allow recursion past
6652 three levels. Beyond that (1) it's highly unlikely that we'll find
6653 something interesting and (2) we've probably processed it before
6654 when we built the inner expression. */
6657 tree ret;
6662 depth++;
6664 depth--;
6667 }
6669 static tree
6672 {
6684 /* Don't deal with constants of zero here; they confuse the code below. */
6694 /* Note that we need not handle conditional operations here since fold
6695 already handles those cases. So just do arithmetic here. */
6697 {
6699 /* For a constant, we can always simplify if we are a multiply
6700 or (for divide and modulus) if it is a multiple of our constant. */
6704 {
6707 /* If the multiplication overflowed, we lost information on it.
6708 See PR68142 and PR69845. */
6712 }
6716 /* If op0 is an expression ... */
6722 /* ... and has wrapping overflow, and its type is smaller
6723 than ctype, then we cannot pass through as widening. */
6728 /* ... or this is a truncation (t is narrower than op0),
6729 then we cannot pass through this narrowing. */
6732 /* ... or signedness changes for division or modulus,
6733 then we cannot pass through this conversion. */
6737 /* ... or has undefined overflow while the converted to
6738 type has not, we cannot do the operation in the inner type
6739 as that would introduce undefined overflow. */
6745 /* Pass the constant down and see if we can make a simplification. If
6746 we can, replace this expression with the inner simplification for
6747 possible later conversion to our or some other type. */
6758 /* If widening the type changes it from signed to unsigned, then we
6759 must avoid building ABS_EXPR itself as unsigned. */
6761 {
6765 {
6768 }
6770 }
6771 /* If the constant is negative, we cannot simplify this. */
6774 /* FALLTHROUGH */
6776 /* For division and modulus, type can't be unsigned, as e.g.
6777 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6778 For signed types, even with wrapping overflow, this is fine. */
6787 /* If widening the type changes the signedness, then we can't perform
6788 this optimization as that changes the result. */
6792 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6798 {
6805 }
6809 /* If the second operand is constant, this is a multiplication
6810 or floor division, by a power of two, so we can treat it that
6811 way unless the multiplier or divisor overflows. Signed
6812 left-shift overflow is implementation-defined rather than
6813 undefined in C90, so do not convert signed left shift into
6814 multiplication. */
6817 /* const_binop may not detect overflow correctly,
6818 so check for it explicitly here. */
6827 ctype,
6829 t1),
6834 /* See if we can eliminate the operation on both sides. If we can, we
6835 can return a new PLUS or MINUS. If we can't, the only remaining
6836 cases where we can do anything are if the second operand is a
6837 constant. */
6844 /* If not multiplication, we can only do this if both operands
6845 are divisible by c. */
6848 {
6853 }
6855 /* If this was a subtraction, negate OP1 and set it to be an addition.
6856 This simplifies the logic below. */
6858 {
6860 /* If OP1 was not easily negatable, the constant may be OP0. */
6862 {
6865 }
6866 }
6871 /* If either OP1 or C are negative, this optimization is not safe for
6872 some of the division and remainder types while for others we need
6873 to change the code. */
6875 {
6883 }
6885 /* If it's a multiply or a division/modulus operation of a multiple
6886 of our constant, do the operation and verify it doesn't overflow. */
6890 {
6893 /* We allow the constant to overflow with wrapping semantics. */
6897 }
6898 else
6901 /* If we have an unsigned type, we cannot widen the operation since it
6902 will change the result if the original computation overflowed. */
6906 /* The last case is if we are a multiply. In that case, we can
6907 apply the distributive law to commute the multiply and addition
6908 if the multiplication of the constants doesn't overflow
6909 and overflow is defined. With undefined overflow
6910 op0 * c might overflow, while (op0 + orig_op1) * c doesn't.
6911 But fold_plusminus_mult_expr would factor back any power-of-two
6912 value so do not distribute in the first place in this case. */
6920 op1);
6925 /* We have a special case here if we are doing something like
6926 (C * 8) % 4 since we know that's zero. */
6929 /* If the multiplication can overflow we cannot optimize this. */
6934 {
6937 }
6939 /* ... fall through ... */
6943 /* If we can extract our operation from the LHS, do so and return a
6944 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6945 do something only if the second operand is a constant. */
6961 /* If these are the same operation types, we can associate them
6962 assuming no overflow. */
6964 {
6979 }
6981 /* If these operations "cancel" each other, we have the main
6982 optimizations of this pass, which occur when either constant is a
6983 multiple of the other, in which case we replace this with either an
6984 operation or CODE or TCODE.
6986 If we have an unsigned type, we cannot do this since it will change
6987 the result if the original computation overflowed. */
6994 {
6997 {
7004 }
7007 {
7014 }
7015 }
7020 }
7023 }
7024 \f
7025 /* Return a node which has the indicated constant VALUE (either 0 or
7026 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
7027 and is of the indicated TYPE. */
7029 tree
7031 {
7040 else
7042 }
7045 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
7046 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
7047 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
7048 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
7049 COND is the first argument to CODE; otherwise (as in the example
7050 given here), it is the second argument. TYPE is the type of the
7051 original expression. Return NULL_TREE if no simplification is
7052 possible. */
7054 static tree
7059 {
7067 /* Do not move possibly trapping operations into the conditional as this
7068 pessimizes code and causes gimplification issues when applied late. */
7076 {
7080 /* If this operand throws an expression, then it does not make
7081 sense to try to perform a logical or arithmetic operation
7082 involving it. */
7087 }
7090 {
7095 }
7096 else
7097 /* Detect the case of mixing vector and scalar types - bail out. */
7103 /* This transformation is only worthwhile if we don't have to wrap ARG
7104 in a SAVE_EXPR and the operation can be simplified without recursing
7105 on at least one of the branches once its pushed inside the COND_EXPR. */
7114 {
7118 else
7120 }
7122 {
7126 else
7128 }
7130 /* Check that we have simplified at least one of the branches. */
7135 }
7137 \f
7138 /* Subroutine of fold() that checks for the addition of +/- 0.0.
7140 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
7141 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
7142 ADDEND is the same as X.
7144 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
7145 and finite. The problematic cases are when X is zero, and its mode
7146 has signed zeros. In the case of rounding towards -infinity,
7147 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
7148 modes, X + 0 is not the same as X because -0 + 0 is 0. */
7150 bool
7152 {
7156 /* Don't allow the fold with -fsignaling-nans. */
7160 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
7164 /* There is no case that is safe for all rounding modes. */
7168 /* In a vector or complex, we would need to check the sign of all zeros. */
7174 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
7178 /* The mode has signed zeros, and we have to honor their sign.
7179 In this situation, there is only one case we can return true for.
7180 X - 0 is the same as X with default rounding. */
7182 }
7184 /* Subroutine of match.pd that optimizes comparisons of a division by
7185 a nonzero integer constant against an integer constant, i.e.
7186 X/C1 op C2.
7188 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
7189 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
7191 enum tree_code
7194 {
7199 /* We have to do this the hard way to detect unsigned overflow.
7200 prod = int_const_binop (MULT_EXPR, c1, c2); */
7206 {
7210 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
7213 }
7215 {
7218 {
7237 }
7238 }
7239 else
7240 {
7241 /* A negative divisor reverses the relational operators. */
7246 {
7265 }
7266 }
7279 }
7282 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7283 equality/inequality test, then return a simplified form of the test
7284 using a sign testing. Otherwise return NULL. TYPE is the desired
7285 result type. */
7287 static tree
7290 tree result_type)
7291 {
7292 /* If this is testing a single bit, we can optimize the test. */
7296 {
7297 /* If we have (A & C) != 0 where C is the sign bit of A, convert
7298 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
7302 /* This is only a win if casting to a signed type is cheap,
7303 i.e. when arg00's type is not a partial mode. */
7305 {
7308 result_type,
7311 }
7312 }
7315 }
7317 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7318 equality/inequality test, then return a simplified form of
7319 the test using shifts and logical operations. Otherwise return
7320 NULL. TYPE is the desired result type. */
7322 tree
7325 {
7326 /* If this is testing a single bit, we can optimize the test. */
7330 {
7339 /* First, see if we can fold the single bit test into a sign-bit
7340 test. */
7342 result_type);
7346 /* Otherwise we have (A & C) != 0 where C is a single bit,
7347 convert that into ((A >> C2) & 1). Where C2 = log2(C).
7348 Similarly for (A & C) == 0. */
7350 /* If INNER is a right shift of a constant and it plus BITNUM does
7351 not overflow, adjust BITNUM and INNER. */
7357 {
7360 }
7362 /* If we are going to be able to omit the AND below, we must do our
7363 operations as unsigned. If we must use the AND, we have a choice.
7364 Normally unsigned is faster, but for some machines signed is. */
7382 /* Put the AND last so it can combine with more things. */
7385 /* Make sure to return the proper type. */
7389 }
7391 }
7393 /* Test whether it is preferable two swap two operands, ARG0 and
7394 ARG1, for example because ARG0 is an integer constant and ARG1
7395 isn't. */
7397 bool
7399 {
7413 /* It is preferable to swap two SSA_NAME to ensure a canonical form
7414 for commutative and comparison operators. Ensuring a canonical
7415 form allows the optimizers to find additional redundancies without
7416 having to explicitly check for both orderings. */
7422 /* Put SSA_NAMEs last. */
7428 /* Put variables last. */
7435 }
7438 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7439 means A >= Y && A != MAX, but in this case we know that
7440 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7442 static tree
7444 {
7451 else
7460 {
7463 }
7465 {
7468 }
7469 else
7476 {
7477 /* Convert the pointer types into integer before taking the difference. */
7481 }
7482 else
7489 }
7491 /* Fold a sum or difference of at least one multiplication.
7492 Returns the folded tree or NULL if no simplification could be made. */
7494 static tree
7497 {
7501 /* (A * C) +- (B * C) -> (A+-B) * C.
7502 (A * C) +- A -> A * (C+-1).
7503 We are most concerned about the case where C is a constant,
7504 but other combinations show up during loop reduction. Since
7505 it is not difficult, try all four possibilities. */
7508 {
7511 }
7513 {
7516 }
7517 else
7518 {
7519 /* We cannot generate constant 1 for fract. */
7524 }
7526 {
7529 }
7531 {
7533 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7534 the purpose of this canonicalization. */
7538 {
7541 }
7542 else
7544 }
7545 else
7546 {
7547 /* We cannot generate constant 1 for fract. */
7552 }
7555 /* Prefer factoring a common non-constant. */
7565 /* No identical multiplicands; see if we can find a common
7566 power-of-two factor in non-power-of-two multiplies. This
7567 can help in multi-dimensional array access. */
7569 {
7572 HOST_WIDE_INT tmp;
7574 tree maybe_same;
7576 /* Move min of absolute values to int11. */
7578 {
7583 }
7584 else
7591 /* The remainder should not be a constant, otherwise we
7592 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7593 increased the number of multiplications necessary. */
7595 {
7603 }
7604 }
7611 /* We are neither factoring zero nor minus one. */
7619 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7620 same may be minus one and thus the multiplication may overflow. Perform
7621 the sum operation in an unsigned type. */
7626 /* If the sum evaluated to a constant that is not -INF the multiplication
7627 cannot overflow. */
7634 /* Do not resort to unsigned multiplication because
7635 we lose the no-overflow property of the expression. */
7637 }
7639 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7640 specified by EXPR into the buffer PTR of length LEN bytes.
7641 Return the number of bytes placed in the buffer, or zero
7642 upon failure. */
7644 static int
7646 {
7658 /* Dry run. */
7664 {
7666 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7667 number of bytes. */
7671 {
7678 else
7680 }
7681 else
7685 }
7687 }
7690 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7691 specified by EXPR into the buffer PTR of length LEN bytes.
7692 Return the number of bytes placed in the buffer, or zero
7693 upon failure. */
7695 static int
7697 {
7701 FIXED_VALUE_TYPE value;
7716 }
7719 /* Subroutine of native_encode_expr. Encode the REAL_CST
7720 specified by EXPR into the buffer PTR of length LEN bytes.
7721 Return the number of bytes placed in the buffer, or zero
7722 upon failure. */
7724 static int
7726 {
7732 /* There are always 32 bits in each long, no matter the size of
7733 the hosts long. We handle floating point representations with
7734 up to 192 bits. */
7743 /* Dry run. */
7752 {
7757 {
7764 else
7766 }
7767 else
7768 {
7771 {
7772 /* Reverse bytes within each long, or within the entire float
7773 if it's smaller than a long (for HFmode). */
7776 }
7777 }
7782 }
7784 }
7786 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7787 specified by EXPR into the buffer PTR of length LEN bytes.
7788 Return the number of bytes placed in the buffer, or zero
7789 upon failure. */
7791 static int
7793 {
7795 tree part;
7809 }
7811 /* Like native_encode_vector, but only encode the first COUNT elements.
7812 The other arguments are as for native_encode_vector. */
7814 static int
7817 {
7821 {
7822 /* This is the only case in which elements can be smaller than a byte.
7823 Element 0 is always in the lsb of the containing byte. */
7832 /* Zero the buffer and then set bits later where necessary. */
7841 {
7847 {
7850 }
7851 }
7853 }
7858 {
7860 {
7863 }
7874 }
7876 }
7878 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7879 specified by EXPR into the buffer PTR of length LEN bytes.
7880 Return the number of bytes placed in the buffer, or zero
7881 upon failure. */
7883 static int
7885 {
7890 }
7893 /* Subroutine of native_encode_expr. Encode the STRING_CST
7894 specified by EXPR into the buffer PTR of length LEN bytes.
7895 Return the number of bytes placed in the buffer, or zero
7896 upon failure. */
7898 static int
7900 {
7903 /* Wide-char strings are encoded in target byte-order so native
7904 encoding them is trivial. */
7919 else
7920 {
7923 {
7926 }
7928 }
7930 }
7933 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST, REAL_CST,
7934 FIXED_CST, COMPLEX_CST, STRING_CST, or VECTOR_CST specified by EXPR into
7935 the buffer PTR of size LEN bytes. If PTR is NULL, don't actually store
7936 anything, just do a dry run. Fail either if OFF is -1 and LEN isn't
7937 sufficient to encode the entire EXPR, or if OFF is out of bounds.
7938 Otherwise, start at byte offset OFF and encode at most LEN bytes.
7939 Return the number of bytes placed in the buffer, or zero upon failure. */
7941 int
7943 {
7944 /* We don't support starting at negative offset and -1 is special. */
7949 {
7970 }
7971 }
7973 /* Try to find a type whose byte size is smaller or equal to LEN bytes larger
7974 or equal to FIELDSIZE bytes, with underlying mode precision/size multiple
7975 of BITS_PER_UNIT. As native_{interpret,encode}_int works in term of
7976 machine modes, we can't just use build_nonstandard_integer_type. */
7978 tree
7980 {
7981 machine_mode mode;
7983 {
7990 {
7994 }
7995 }
8001 {
8009 }
8012 }
8014 /* Similar to native_encode_expr, but also handle CONSTRUCTORs, VCEs,
8015 NON_LVALUE_EXPRs and nops. If MASK is non-NULL (then PTR has
8016 to be non-NULL and OFF zero), then in addition to filling the
8017 bytes pointed by PTR with the value also clear any bits pointed
8018 by MASK that are known to be initialized, keep them as is for
8019 e.g. uninitialized padding bits or uninitialized fields. */
8021 int
8024 {
8027 /* We don't support starting at negative offset and -1 is special. */
8035 {
8039 mask);
8054 {
8055 tree min_index;
8073 {
8078 {
8081 }
8086 else
8090 {
8094 offset_int wpos
8102 offset_int wcount
8109 }
8111 {
8114 offset_int wpos
8122 }
8125 {
8127 {
8138 }
8140 {
8144 }
8145 }
8149 do
8150 {
8155 {
8157 {
8160 fieldsize);
8163 }
8165 ptr
8168 fieldsize,
8171 mask
8175 else
8176 {
8179 }
8180 }
8183 {
8184 /* Partial overlap. */
8190 {
8194 fieldsize);
8195 }
8196 else
8197 {
8201 }
8204 }
8206 }
8208 }
8210 }
8213 {
8223 {
8229 {
8232 }
8235 {
8244 }
8248 else
8252 {
8253 tree fld;
8255 {
8268 }
8270 {
8274 }
8277 {
8278 cnt--;
8284 }
8285 }
8290 {
8303 {
8308 }
8309 }
8310 else
8311 {
8316 }
8321 {
8328 else
8334 }
8343 {
8344 /* FIXME: Handle PDP endian. */
8355 {
8358 }
8359 else
8360 {
8368 else
8369 {
8372 }
8373 }
8383 else
8396 /* If the bitfield does not start at byte boundary, handle
8397 the partial byte at the start. */
8400 {
8402 {
8407 {
8410 else
8412 }
8413 }
8414 else
8415 {
8420 {
8423 else
8427 }
8428 }
8429 }
8430 /* If the bitfield does not end at byte boundary, handle
8431 the partial byte at the end. */
8435 {
8437 {
8444 }
8445 else
8446 {
8453 }
8454 }
8458 {
8463 }
8464 else
8465 {
8466 /* Partial overlap. */
8470 {
8473 }
8477 }
8479 }
8484 {
8487 {
8490 {
8494 }
8497 }
8500 fldsize,
8510 }
8511 else
8512 {
8513 /* Partial overlap. */
8519 {
8523 fieldsize);
8524 }
8525 else
8526 {
8530 }
8533 }
8534 }
8536 }
8538 }
8539 }
8542 /* Subroutine of native_interpret_expr. Interpret the contents of
8543 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
8544 If the buffer cannot be interpreted, return NULL_TREE. */
8546 static tree
8548 {
8558 }
8561 /* Subroutine of native_interpret_expr. Interpret the contents of
8562 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
8563 If the buffer cannot be interpreted, return NULL_TREE. */
8565 static tree
8567 {
8570 double_int result;
8571 FIXED_VALUE_TYPE fixed_value;
8581 }
8584 /* Subroutine of native_interpret_expr. Interpret the contents of
8585 the buffer PTR of length LEN as a REAL_CST of type TYPE.
8586 If the buffer cannot be interpreted, return NULL_TREE. */
8588 static tree
8590 {
8594 /* There are always 32 bits in each long, no matter the size of
8595 the hosts long. We handle floating point representations with
8596 up to 192 bits. */
8597 REAL_VALUE_TYPE r;
8607 {
8608 /* Both OFFSET and BYTE index within a long;
8609 bitpos indexes the whole float. */
8612 {
8619 else
8621 }
8622 else
8623 {
8626 {
8627 /* Reverse bytes within each long, or within the entire float
8628 if it's smaller than a long (for HFmode). */
8631 }
8632 }
8636 }
8641 {
8642 /* For floating point values in composite modes, punt if this folding
8643 doesn't preserve bit representation. As the mode doesn't have fixed
8644 precision while GCC pretends it does, there could be valid values that
8645 GCC can't really represent accurately. See PR95450. */
8650 }
8652 }
8655 /* Subroutine of native_interpret_expr. Interpret the contents of
8656 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
8657 If the buffer cannot be interpreted, return NULL_TREE. */
8659 static tree
8661 {
8676 }
8678 /* Read a vector of type TYPE from the target memory image given by BYTES,
8679 which contains LEN bytes. The vector is known to be encodable using
8680 NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements each.
8682 Return the vector on success, otherwise return null. */
8684 static tree
8688 {
8692 {
8693 /* This is the only case in which elements can be smaller than a byte.
8694 Element 0 is always in the lsb of the containing byte. */
8701 {
8708 }
8710 }
8718 {
8724 }
8726 }
8728 /* Subroutine of native_interpret_expr. Interpret the contents of
8729 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
8730 If the buffer cannot be interpreted, return NULL_TREE. */
8732 static tree
8734 {
8735 tree etype;
8746 }
8749 /* Subroutine of fold_view_convert_expr. Interpret the contents of
8750 the buffer PTR of length LEN as a constant of type TYPE. For
8751 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
8752 we return a REAL_CST, etc... If the buffer cannot be interpreted,
8753 return NULL_TREE. */
8755 tree
8757 {
8759 {
8781 }
8782 }
8784 /* Returns true if we can interpret the contents of a native encoding
8785 as TYPE. */
8787 bool
8789 {
8791 {
8804 }
8805 }
8807 /* Attempt to interpret aggregate of TYPE from bytes encoded in target
8808 byte order at PTR + OFF with LEN bytes. Does not handle unions. */
8810 tree
8813 {
8816 {
8823 {
8827 }
8832 {
8837 {
8842 }
8846 eltsz);
8850 }
8852 }
8856 {
8864 {
8867 {
8868 poly_int64 bitoffset;
8873 else
8883 }
8884 else
8885 {
8903 HOST_WIDE_INT rpos;
8906 else
8907 {
8910 }
8919 }
8920 }
8923 {
8933 }
8937 {
8942 }
8949 {
8953 /* FIXME: Figure out how to handle PDP endian bitfields. */
8959 else
8963 }
8965 }
8967 }
8969 /* Routines for manipulation of native_encode_expr encoded data if the encoded
8970 or extracted constant positions and/or sizes aren't byte aligned. */
8972 /* Shift left the bytes in PTR of SZ elements by AMNT bits, carrying over the
8973 bits between adjacent elements. AMNT should be within
8974 [0, BITS_PER_UNIT).
8975 Example, AMNT = 2:
8976 00011111|11100000 << 2 = 01111111|10000000
8977 PTR[1] | PTR[0] PTR[1] | PTR[0]. */
8979 void
8982 {
8991 {
8997 {
9000 }
9001 }
9002 }
9004 /* Like shift_bytes_in_array_left but for big-endian.
9005 Shift right the bytes in PTR of SZ elements by AMNT bits, carrying over the
9006 bits between adjacent elements. AMNT should be within
9007 [0, BITS_PER_UNIT).
9008 Example, AMNT = 2:
9009 00011111|11100000 >> 2 = 00000111|11111000
9010 PTR[0] | PTR[1] PTR[0] | PTR[1]. */
9012 void
9015 {
9023 {
9030 }
9031 }
9033 /* Try to view-convert VECTOR_CST EXPR to VECTOR_TYPE TYPE by operating
9034 directly on the VECTOR_CST encoding, in a way that works for variable-
9035 length vectors. Return the resulting VECTOR_CST on success or null
9036 on failure. */
9038 static tree
9040 {
9052 /* We can only preserve the semantics of a stepped pattern if the new
9053 vector element is an integer of the same size. */
9058 /* The number of bits needed to encode one element from every pattern
9059 of the original vector. */
9060 unsigned int expr_sequence_bits
9063 /* The number of bits needed to encode one element from every pattern
9064 of the result. */
9065 unsigned int type_sequence_bits
9068 /* Don't try to read more bytes than are available, which can happen
9069 for constant-sized vectors if TYPE has larger elements than EXPR_TYPE.
9070 The general VIEW_CONVERT handling can cope with that case, so there's
9071 no point complicating things here. */
9074 BITS_PER_UNIT);
9079 /* Get enough bytes of EXPR to form the new encoding. */
9087 /* Reencode the bytes as TYPE. */
9091 }
9093 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
9094 TYPE at compile-time. If we're unable to perform the conversion
9095 return NULL_TREE. */
9097 static tree
9099 {
9100 /* We support up to 512-bit values (for V8DFmode). */
9104 /* Check that the host and target are sane. */
9117 }
9119 /* Build an expression for the address of T. Folds away INDIRECT_REF
9120 to avoid confusing the gimplify process. */
9122 tree
9124 {
9125 /* The size of the object is not relevant when talking about its address. */
9130 {
9135 }
9138 {
9143 }
9150 {
9155 }
9156 else
9160 }
9162 /* Build an expression for the address of T. */
9164 tree
9166 {
9170 }
9172 /* Fold a unary expression of code CODE and type TYPE with operand
9173 OP0. Return the folded expression if folding is successful.
9174 Otherwise, return NULL_TREE. */
9176 tree
9178 {
9179 tree tem;
9180 tree arg0;
9188 {
9191 {
9192 /* Don't use STRIP_NOPS, because signedness of argument type
9193 matters. */
9195 }
9196 else
9197 {
9198 /* Strip any conversions that don't change the mode. This
9199 is safe for every expression, except for a comparison
9200 expression because its signedness is derived from its
9201 operands.
9203 Note that this is done as an internal manipulation within
9204 the constant folder, in order to find the simplest
9205 representation of the arguments so that their form can be
9206 studied. In any cases, the appropriate type conversions
9207 should be put back in the tree that will get out of the
9208 constant folder. */
9210 }
9213 {
9216 {
9220 }
9221 }
9222 }
9229 {
9236 {
9250 /* If this was a conversion, and all we did was to move into
9251 inside the COND_EXPR, bring it back out. But leave it if
9252 it is a conversion from integer to integer and the
9253 result precision is no wider than a word since such a
9254 conversion is cheap and may be optimized away by combine,
9255 while it couldn't if it were outside the COND_EXPR. Then return
9256 so we don't get into an infinite recursion loop taking the
9257 conversion out and then back in. */
9269 && (INTEGRAL_TYPE_P
9282 }
9283 }
9286 {
9292 CASE_CONVERT:
9296 {
9297 /* If we have (type) (a CMP b) and type is an integral type, return
9298 new expression involving the new type. Canonicalize
9299 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
9300 non-integral type.
9301 Do not fold the result as that would not simplify further, also
9302 folding again results in recursions. */
9312 }
9314 /* Handle (T *)&A.B.C for A being of type T and B and C
9315 living at offset zero. This occurs frequently in
9316 C++ upcasting and then accessing the base. */
9320 {
9322 tree offset;
9323 machine_mode mode;
9325 tree base
9329 /* If the reference was to a (constant) zero offset, we can use
9330 the address of the base if it has the same base type
9331 as the result type and the pointer type is unqualified. */
9339 }
9343 /* Detect assigning a bitfield. */
9345 && DECL_BIT_FIELD
9347 {
9348 /* Don't leave an assignment inside a conversion
9349 unless assigning a bitfield. */
9351 /* First do the assignment, then return converted constant. */
9356 }
9358 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
9359 constants (if x has signed type, the sign bit cannot be set
9360 in c). This folds extension into the BIT_AND_EXPR.
9361 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
9362 very likely don't have maximal range for their precision and this
9363 transformation effectively doesn't preserve non-maximal ranges. */
9367 {
9378 <= HOST_BITS_PER_WIDE_INT
9380 {
9384 cst &= HOST_WIDE_INT_M1U
9388 && !flag_syntax_only
9391 {
9395 }
9396 }
9398 {
9403 }
9404 }
9406 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
9407 cast (T1)X will fold away. We assume that this happens when X itself
9408 is a cast. */
9412 {
9416 /* If -fsanitize=alignment, avoid this optimization in GENERIC
9417 when the pointed type needs higher alignment than
9418 the p+ first operand's pointed type. */
9427 }
9429 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
9430 of the same precision, and X is an integer type not narrower than
9431 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
9437 {
9443 }
9445 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
9446 type of X and Y (integer types only). */
9451 {
9452 /* Be careful not to introduce new overflows. */
9453 tree mult_type;
9456 else
9460 {
9467 }
9468 }
9474 {
9481 }
9492 /* Convert fabs((double)float) into (double)fabsf(float). */
9495 {
9501 targ0));
9502 }
9506 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
9525 /* Note that the operand of this must be an int
9526 and its values must be 0 or 1.
9527 ("true" is a fixed value perhaps depending on the language,
9528 but we don't handle values other than 1 correctly yet.) */
9535 /* Fold *&X to X if X is an lvalue. */
9537 {
9544 }
9550 }
9553 /* If the operation was a conversion do _not_ mark a resulting constant
9554 with TREE_OVERFLOW if the original constant was not. These conversions
9555 have implementation defined behavior and retaining the TREE_OVERFLOW
9556 flag here would confuse later passes such as VRP. */
9557 tree
9560 {
9569 }
9571 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
9572 operands OP0 and OP1. LOC is the location of the resulting expression.
9573 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
9574 Return the folded expression if folding is successful. Otherwise,
9575 return NULL_TREE. */
9576 static tree
9579 {
9580 tree tem;
9582 /* We only do these simplifications if we are optimizing. */
9586 /* Check for things like (A || B) && (A || C). We can convert this
9587 to A || (B && C). Note that either operator can be any of the four
9588 truth and/or operations and the transformation will still be
9589 valid. Also note that we only care about order for the
9590 ANDIF and ORIF operators. If B contains side effects, this
9591 might change the truth-value of A. */
9598 {
9618 /* This case if tricky because we must either have commutative
9619 operators or else A10 must not have side-effects. */
9625 a01);
9626 }
9628 /* See if we can build a range comparison. */
9634 {
9638 }
9642 {
9646 }
9648 /* Check for the possibility of merging component references. If our
9649 lhs is another similar operation, try to merge its rhs with our
9650 rhs. Then try to merge our lhs and rhs. */
9661 logical_op_non_short_circuit
9664 && !flag_sanitize_coverage
9669 {
9676 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
9677 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
9678 We don't want to pack more than two leafs to a non-IF AND/OR
9679 expression.
9680 If tree-code of left-hand operand isn't an AND/OR-IF code and not
9681 equal to IF-CODE, then we don't want to add right-hand operand.
9682 If the inner right-hand side of left-hand operand has
9683 side-effects, or isn't simple, then we can't add to it,
9684 as otherwise we might destroy if-sequence. */
9687 /* Needed for sequence points to handle trappings, and
9688 side-effects. */
9690 {
9692 arg1);
9694 tem);
9695 }
9696 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
9697 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
9700 /* Needed for sequence points to handle trappings, and
9701 side-effects. */
9703 {
9708 }
9709 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
9710 into (A OR B).
9711 For sequence point consistancy, we need to check for trapping,
9712 and side-effects. */
9716 }
9719 }
9721 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
9722 by changing CODE to reduce the magnitude of constants involved in
9723 ARG0 of the comparison.
9724 Returns a canonicalized comparison tree if a simplification was
9725 possible, otherwise returns NULL_TREE.
9726 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
9727 valid if signed overflow is undefined. */
9729 static tree
9733 {
9738 /* Match A +- CST code arg1. We can change this only if overflow
9739 is undefined. */
9742 /* In principle pointers also have undefined overflow behavior,
9743 but that causes problems elsewhere. */
9750 /* Identify the constant in arg0 and its sign. */
9754 /* Overflowed constants and zero will cause problems. */
9759 /* See if we can reduce the magnitude of the constant in
9760 arg0 by changing the comparison code. */
9761 /* A - CST < arg1 -> A - CST-1 <= arg1. */
9765 /* A + CST > arg1 -> A + CST-1 >= arg1. */
9769 /* A + CST <= arg1 -> A + CST-1 < arg1. */
9773 /* A - CST >= arg1 -> A - CST-1 > arg1. */
9777 else
9781 /* Now build the constant reduced in magnitude. But not if that
9782 would produce one outside of its types range. */
9798 }
9800 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
9801 overflow further. Try to decrease the magnitude of constants involved
9802 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
9803 and put sole constants at the second argument position.
9804 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
9806 static tree
9809 {
9810 tree t;
9815 /* Try canonicalization by simplifying arg0. */
9820 {
9824 }
9826 /* Try canonicalization by simplifying arg1 using the swapped
9827 comparison. */
9835 }
9837 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
9838 space. This is used to avoid issuing overflow warnings for
9839 expressions like &p->x which cannot wrap. */
9841 static bool
9843 {
9850 poly_wide_int wi_offset;
9856 else
9861 precision);
9876 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
9877 array. */
9886 }
9888 /* Return a positive integer when the symbol DECL is known to have
9889 a nonzero address, zero when it's known not to (e.g., it's a weak
9890 symbol), and a negative integer when the symbol is not yet in the
9891 symbol table and so whether or not its address is zero is unknown.
9892 For function local objects always return positive integer. */
9893 static int
9895 {
9900 /* Function local objects are never NULL. */
9908 }
9910 /* Subroutine of fold_binary. This routine performs all of the
9911 transformations that are common to the equality/inequality
9912 operators (EQ_EXPR and NE_EXPR) and the ordering operators
9913 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
9914 fold_binary should call fold_binary. Fold a comparison with
9915 tree code CODE and type TYPE with operands OP0 and OP1. Return
9916 the folded comparison or NULL_TREE. */
9918 static tree
9921 {
9931 /* For comparisons of pointers we can decompose it to a compile time
9932 comparison of the base objects and the offsets into the object.
9933 This requires at least one operand being an ADDR_EXPR or a
9934 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
9940 {
9943 machine_mode mode;
9947 /* Get base and offset for the access. Strip ADDR_EXPR for
9948 get_inner_reference, but put it back by stripping INDIRECT_REF
9949 off the base object if possible. indirect_baseN will be true
9950 if baseN is not an address but refers to the object itself. */
9953 {
9954 base0
9960 else
9962 }
9964 {
9968 {
9969 base0
9975 else
9977 }
9980 else
9984 {
9991 }
9992 }
9996 {
9997 base1
10003 else
10005 }
10007 {
10011 {
10012 base1
10018 else
10020 }
10023 else
10027 {
10034 }
10035 }
10037 /* If we have equivalent bases we might be able to simplify. */
10041 {
10042 /* We can fold this expression to a constant if the non-constant
10043 offset parts are equal. */
10047 && (equality_code
10048 || (indirect_base0
10051 {
10057 "occur when comparing P +- C1 with "
10059 WARN_STRICT_OVERFLOW_CONDITIONAL);
10062 {
10100 }
10101 }
10102 /* We can simplify the comparison to a comparison of the variable
10103 offset parts if the constant offset parts are equal.
10104 Be careful to use signed sizetype here because otherwise we
10105 mess with array offsets in the wrong way. This is possible
10106 because pointer arithmetic is restricted to retain within an
10107 object and overflow on pointer differences is undefined as of
10108 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
10110 && (equality_code
10111 || (indirect_base0
10114 {
10115 /* By converting to signed sizetype we cover middle-end pointer
10116 arithmetic which operates on unsigned pointer types of size
10117 type size and ARRAY_REF offsets which are properly sign or
10118 zero extended from their type in case it is narrower than
10119 sizetype. */
10122 else
10126 else
10133 "occur when comparing P +- C1 with "
10135 WARN_STRICT_OVERFLOW_COMPARISON);
10138 }
10139 }
10140 /* For equal offsets we can simplify to a comparison of the
10141 base addresses. */
10143 && (indirect_base0
10145 && (indirect_base1
10150 {
10156 }
10157 /* Comparison between an ordinary (non-weak) symbol and a null
10158 pointer can be eliminated since such symbols must have a non
10159 null address. In C, relational expressions between pointers
10160 to objects and null pointers are undefined. The results
10161 below follow the C++ rules with the additional property that
10162 every object pointer compares greater than a null pointer.
10163 */
10166 /* Avoid folding references to struct members at offset 0 to
10167 prevent tests like '&ptr->firstmember == 0' from getting
10168 eliminated. When ptr is null, although the -> expression
10169 is strictly speaking invalid, GCC retains it as a matter
10170 of QoI. See PR c/44555. */
10173 && indirect_base0
10174 /* The caller guarantees that when one of the arguments is
10175 constant (i.e., null in this case) it is second. */
10177 {
10179 {
10190 }
10191 }
10192 }
10194 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
10195 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
10196 the resulting offset is smaller in absolute value than the
10197 original one and has the same sign. */
10206 {
10211 tree cst;
10213 "occur when combining constants around "
10216 /* Put the constant on the side where it doesn't overflow and is
10217 of lower absolute value and of same sign than before. */
10224 {
10227 variable1,
10231 }
10239 {
10245 variable2);
10246 }
10247 }
10253 /* If we are comparing an expression that just has comparisons
10254 of two integer values, arithmetic expressions of those comparisons,
10255 and constants, we can simplify it. There are only three cases
10256 to check: the two values can either be equal, the first can be
10257 greater, or the second can be greater. Fold the expression for
10258 those three values. Since each value must be 0 or 1, we have
10259 eight possibilities, each of which corresponds to the constant 0
10260 or 1 or one of the six possible comparisons.
10262 This handles common cases like (a > b) == 0 but also handles
10263 expressions like ((x > y) - (y > x)) > 0, which supposedly
10264 occur in macroized code. */
10267 {
10271 /* Don't handle degenerate cases here; they should already
10272 have been handled anyway. */
10281 {
10285 /* We can't just pass T to eval_subst in case cval1 or cval2
10286 was the same as ARG1. */
10288 tree high_result
10292 arg1);
10293 tree equal_result
10297 arg1);
10298 tree low_result
10302 arg1);
10304 /* All three of these results should be 0 or 1. Confirm they are.
10305 Then use those values to select the proper code to use. */
10310 {
10311 /* Make a 3-bit mask with the high-order bit being the
10312 value for `>', the next for '=', and the low for '<'. */
10316 {
10318 /* Always false. */
10339 /* Always true. */
10341 }
10344 }
10345 }
10346 }
10349 }
10352 /* Subroutine of fold_binary. Optimize complex multiplications of the
10353 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
10354 argument EXPR represents the expression "z" of type TYPE. */
10356 static tree
10358 {
10363 {
10366 }
10368 {
10371 }
10372 else
10373 {
10377 }
10386 }
10389 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
10390 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
10391 true if successful. */
10393 static bool
10395 {
10400 {
10403 }
10405 {
10411 else
10413 }
10414 else
10420 }
10422 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
10423 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
10424 NULL_TREE otherwise. */
10426 tree
10428 {
10449 {
10450 HOST_WIDE_INT index;
10456 }
10459 {
10465 }
10466 else
10468 }
10470 /* Try to fold a pointer difference of type TYPE two address expressions of
10471 array references AREF0 and AREF1 using location LOC. Return a
10472 simplified expression for the difference or NULL_TREE. */
10474 static tree
10478 {
10483 /* If the bases are array references as well, recurse. If the bases
10484 are pointer indirections compute the difference of the pointers.
10485 If the bases are equal, we are set. */
10488 && (base_offset
10490 use_pointer_diff)))
10493 && (base_offset
10494 = use_pointer_diff
10504 {
10510 base_offset,
10513 }
10515 }
10517 /* If the real or vector real constant CST of type TYPE has an exact
10518 inverse, return it, else return NULL. */
10520 tree
10522 {
10523 REAL_VALUE_TYPE r;
10524 tree unit_type;
10525 machine_mode mode;
10528 {
10538 {
10542 tree_vector_builder elts;
10547 {
10552 }
10555 }
10559 }
10560 }
10562 /* Mask out the tz least significant bits of X of type TYPE where
10563 tz is the number of trailing zeroes in Y. */
10564 static wide_int
10566 {
10571 }
10573 /* Return true when T is an address and is known to be nonzero.
10574 For floating point we further ensure that T is not denormal.
10575 Similar logic is present in nonzero_address in rtlanal.h.
10577 If the return value is based on the assumption that signed overflow
10578 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
10579 change *STRICT_OVERFLOW_P. */
10581 static bool
10583 {
10587 /* Doing something useful for floating point would need more work. */
10593 {
10596 strict_overflow_p);
10602 strict_overflow_p);
10610 }
10613 {
10616 strict_overflow_p);
10624 strict_overflow_p);
10639 strict_overflow_p);
10643 strict_overflow_p);
10646 {
10658 }
10662 }
10664 }
10666 /* Return true when T is an address and is known to be nonzero.
10667 Handle warnings about undefined signed overflow. */
10669 bool
10671 {
10678 "determining that expression is always "
10680 WARN_STRICT_OVERFLOW_MISC);
10682 }
10684 /* Return true if T is known not to be equal to an integer W. */
10686 bool
10688 {
10689 value_range vr;
10691 {
10702 /* If T has some known zero bits and W has any of those bits set,
10703 then T is known not to be equal to W. */
10711 }
10712 }
10714 /* Fold a binary expression of code CODE and type TYPE with operands
10715 OP0 and OP1. LOC is the location of the resulting expression.
10716 Return the folded expression if folding is successful. Otherwise,
10717 return NULL_TREE. */
10719 tree
10722 {
10737 /* Strip any conversions that don't change the mode. This is
10738 safe for every expression, except for a comparison expression
10739 because its signedness is derived from its operands. So, in
10740 the latter case, only strip conversions that don't change the
10741 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
10742 preserved.
10744 Note that this is done as an internal manipulation within the
10745 constant folder, in order to find the simplest representation
10746 of the arguments so that their form can be studied. In any
10747 cases, the appropriate type conversions should be put back in
10748 the tree that will get out of the constant folder. */
10751 {
10754 }
10755 else
10756 {
10759 }
10761 /* Note that TREE_CONSTANT isn't enough: static var addresses are
10762 constant but we can't do arithmetic on them. */
10764 {
10767 {
10771 }
10772 }
10774 /* If this is a commutative operation, and ARG0 is a constant, move it
10775 to ARG1 to reduce the number of tests below. */
10780 /* Likewise if this is a comparison, and ARG0 is a constant, move it
10781 to ARG1 to reduce the number of tests below. */
10790 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
10792 First check for cases where an arithmetic operation is applied to a
10793 compound, conditional, or comparison operation. Push the arithmetic
10794 operation inside the compound or conditional to see if any folding
10795 can then be done. Convert comparison to conditional for this purpose.
10796 The also optimizes non-constant cases that used to be done in
10797 expand_expr.
10799 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
10800 one of the operands is a comparison and the other is a comparison, a
10801 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
10802 code below would make the expression more complex. Change it to a
10803 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
10804 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
10817 {
10821 boolean_type_node,
10829 }
10833 {
10835 {
10840 tem);
10841 }
10843 {
10848 tem);
10849 }
10854 {
10860 }
10865 {
10871 }
10872 }
10875 {
10877 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
10880 {
10886 }
10888 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
10891 {
10892 tree base;
10893 poly_int64 coffset;
10902 }
10907 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
10913 arg1),
10915 arg0)));
10921 {
10922 /* X + (X / CST) * -CST is X % CST. */
10927 {
10936 cst0));
10937 }
10938 }
10940 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
10941 one. Make sure the type is not saturating and has the signedness of
10942 the stripped operands, as fold_plusminus_mult_expr will re-associate.
10943 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
10950 {
10954 }
10957 {
10958 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
10959 (plus (plus (mult) (mult)) (foo)) so that we can
10960 take advantage of the factoring cases below. */
10969 {
10975 else
10988 parg0),
10990 marg)),
10994 return
11000 parg1)));
11001 }
11002 }
11003 else
11004 {
11005 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
11006 to __complex__ ( x, y ). This is not the same for SNaNs or
11007 if signed zeros are involved. */
11011 {
11018 {
11022 {
11028 }
11030 {
11036 }
11037 }
11038 }
11040 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
11041 We associate floats only if the user has specified
11042 -fassociative-math. */
11046 {
11051 {
11052 tree tree0;
11055 }
11056 }
11057 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
11058 We associate floats only if the user has specified
11059 -fassociative-math. */
11063 {
11068 {
11069 tree tree0;
11072 }
11073 }
11074 }
11076 bit_rotate:
11077 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
11078 is a rotate of A by C1 bits. */
11079 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
11080 is a rotate of A by B bits.
11081 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
11082 though in this case CODE must be | and not + or ^, otherwise
11083 it doesn't return A when B is 0. */
11084 {
11086 tree rtype;
11095 /* Only create rotates in complete modes. Other cases are not
11096 expanded properly. */
11099 {
11112 {
11117 }
11122 {
11125 code0 == LSHIFT_EXPR
11128 }
11130 {
11140 {
11144 orig_tree01);
11146 }
11147 }
11151 {
11162 {
11166 orig_tree01);
11168 }
11169 }
11170 }
11171 }
11173 associate:
11174 /* In most languages, can't associate operations on floats through
11175 parentheses. Rather than remember where the parentheses were, we
11176 don't associate floats at all, unless the user has specified
11177 -fassociative-math.
11178 And, we need to make sure type is not saturating. */
11182 {
11188 /* Split both trees into variables, constants, and literals. Then
11189 associate each group together, the constants with literals,
11190 then the result with variables. This increases the chances of
11191 literals being recombined later and of generating relocatable
11192 expressions for the sum of a constant and literal. */
11200 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
11204 /* With undefined overflow prefer doing association in a type
11205 which wraps on overflow, if that is one of the operand types. */
11208 {
11216 }
11218 /* With undefined overflow we can only associate constants with one
11219 variable, and constants whose association doesn't overflow. */
11222 {
11224 {
11225 /* ??? If split_tree would handle NEGATE_EXPR we could
11226 simply reject these cases and the allowed cases would
11227 be the var0/minus_var1 ones. */
11233 {
11236 }
11243 {
11246 }
11252 /* The only case we can still associate with two variables
11253 is if they cancel out. */
11257 }
11263 }
11265 /* Only do something if we found more than two objects. Otherwise,
11266 nothing has changed and we risk infinite recursion. */
11274 {
11286 {
11290 }
11292 {
11296 }
11298 /* Preserve the MINUS_EXPR if the negative part of the literal is
11299 greater than the positive part. Otherwise, the multiplicative
11300 folding code (i.e extract_muldiv) may be fooled in case
11301 unsigned constants are subtracted, like in the following
11302 example: ((X*2 + 4) - 8U)/2. */
11304 {
11308 /* But avoid ending up with only negated parts. */
11310 {
11314 }
11315 else
11316 {
11320 }
11321 }
11323 /* Don't introduce overflows through reassociation. */
11328 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
11335 /* Eliminate minus_con0. */
11337 {
11344 else
11347 }
11349 /* Eliminate minus_var0. */
11351 {
11355 else
11358 }
11360 return
11363 }
11364 }
11370 /* Fold &a[i] - &a[j] to i-j. */
11375 {
11379 code
11383 }
11385 /* Further transformations are not for pointers. */
11389 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
11392 /* If arg0 is e.g. unsigned int and type is int, then this could
11393 introduce UB, because if A is INT_MIN at runtime, the original
11394 expression can be well defined while the latter is not.
11395 See PR83269. */
11404 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
11405 __complex__ ( x, -y ). This is not the same for SNaNs or if
11406 signed zeros are involved. */
11410 {
11417 {
11421 {
11423 arg1r ? arg1r
11428 }
11430 {
11434 arg1i ? arg1i
11437 }
11438 }
11439 }
11441 /* A - B -> A + (-B) if B is easily negatable. */
11445 /* Avoid this transformation if B is a positive REAL_CST. */
11453 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
11454 one. Make sure the type is not saturating and has the signedness of
11455 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11456 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11463 {
11467 }
11473 {
11474 /* Transform x * -C into -x * C if x is easily negatable. */
11489 {
11492 "occur when simplifying "
11494 WARN_STRICT_OVERFLOW_MISC);
11496 }
11498 /* Optimize z * conj(z) for integer complex numbers. */
11505 }
11506 else
11507 {
11508 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
11509 This is not the same for NaNs or if signed zeros are
11510 involved. */
11516 {
11519 return
11525 return
11530 }
11532 /* Optimize z * conj(z) for floating point complex numbers.
11533 Guarded by flag_unsafe_math_optimizations as non-finite
11534 imaginary components don't produce scalar results. */
11543 }
11547 /* Canonicalize (X & C1) | C2. */
11551 {
11556 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
11564 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
11566 {
11569 }
11571 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
11572 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
11573 mode which allows further optimizations. */
11578 {
11583 {
11586 }
11587 }
11590 {
11595 }
11596 }
11598 /* See if this can be simplified into a rotate first. If that
11599 is unsuccessful continue in the association code. */
11603 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
11611 /* See if this can be simplified into a rotate first. If that
11612 is unsuccessful continue in the association code. */
11616 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
11621 {
11622 tree tem2;
11629 }
11630 /* Fold ~X & 1 as (X & 1) == 0. */
11634 {
11635 tree tem2;
11642 }
11643 /* Fold !X & 1 as X == 0. */
11646 {
11650 }
11652 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
11653 multiple of 1 << CST. */
11655 {
11662 }
11664 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
11665 bits from CST2. */
11669 {
11671 wide_int masked
11678 {
11679 /* Avoid the transform if arg1 is a mask of some
11680 mode which allows further optimizations. */
11687 }
11688 }
11690 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11693 {
11698 return
11700 }
11705 /* Don't touch a floating-point divide by zero unless the mode
11706 of the constant can represent infinity. */
11712 /* (-A) / (-B) -> A / B */
11724 /* Fall through */
11727 /* Simplify A / (B << N) where A and B are positive and B is
11728 a power of 2, to A >> (N + log2(B)). */
11733 {
11736 {
11744 WARN_STRICT_OVERFLOW_MISC);
11750 }
11751 }
11753 /* Fall through */
11761 /* Convert -A / -B to A / B when the type is signed and overflow is
11762 undefined. */
11766 {
11769 "when distributing negation across "
11771 WARN_STRICT_OVERFLOW_MISC);
11776 }
11780 {
11783 "when distributing negation across "
11785 WARN_STRICT_OVERFLOW_MISC);
11790 }
11792 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11793 operation, EXACT_DIV_EXPR.
11795 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11796 At one time others generated faster code, it's not clear if they do
11797 after the last round to changes to the DIV code in expmed.c. */
11808 {
11812 WARN_STRICT_OVERFLOW_MISC);
11814 }
11826 {
11830 WARN_STRICT_OVERFLOW_MISC);
11832 }
11840 /* Since negative shift count is not well-defined,
11841 don't try to compute it in the compiler. */
11847 /* If we have a rotate of a bit operation with the rotate count and
11848 the second operand of the bit operation both constant,
11849 permute the two operations. */
11855 {
11863 }
11865 /* Two consecutive rotates adding up to the some integer
11866 multiple of the precision of the type can be ignored. */
11882 /* Note that the operands of this must be ints
11883 and their values must be 0 or 1.
11884 ("true" is a fixed value perhaps depending on the language.) */
11885 /* If first arg is constant zero, return it. */
11888 /* FALLTHRU */
11890 /* If either arg is constant true, drop it. */
11894 /* Preserve sequence points. */
11897 /* If second arg is constant zero, result is zero, but first arg
11898 must be evaluated. */
11901 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11902 case will be handled here. */
11906 /* !X && X is always false. */
11910 /* X && !X is always false. */
11915 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11916 means A >= Y && A != MAX, but in this case we know that
11917 A < X <= MAX. */
11921 {
11929 }
11938 /* Note that the operands of this must be ints
11939 and their values must be 0 or true.
11940 ("true" is a fixed value perhaps depending on the language.) */
11941 /* If first arg is constant true, return it. */
11944 /* FALLTHRU */
11946 /* If either arg is constant zero, drop it. */
11950 /* Preserve sequence points. */
11953 /* If second arg is constant true, result is true, but we must
11954 evaluate first arg. */
11957 /* Likewise for first arg, but note this only occurs here for
11958 TRUTH_OR_EXPR. */
11962 /* !X || X is always true. */
11966 /* X || !X is always true. */
11971 /* (X && !Y) || (!X && Y) is X ^ Y */
11974 {
11991 }
12000 /* If the second arg is constant zero, drop it. */
12003 /* If the second arg is constant true, this is a logical inversion. */
12005 {
12008 }
12009 /* Identical arguments cancel to zero. */
12013 /* !X ^ X is always true. */
12018 /* X ^ !X is always true. */
12034 /* bool_var != 1 becomes !bool_var. */
12041 /* bool_var == 0 becomes !bool_var. */
12048 /* !exp != 0 becomes !exp */
12053 /* If this is an EQ or NE comparison with zero and ARG0 is
12054 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
12055 two operations, but the latter can be done in one less insn
12056 on machines that have only two-operand insns or on which a
12057 constant cannot be the first operand. */
12060 {
12065 {
12073 }
12076 {
12084 }
12085 }
12087 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
12088 C1 is a valid shift constant, and C2 is a power of two, i.e.
12089 a single bit. */
12093 {
12098 {
12103 /* Check for a valid shift count. */
12105 {
12109 /* If (C2 << C1) doesn't overflow, then
12110 ((X >> C1) & C2) != 0 can be rewritten as
12111 (X & (C2 << C1)) != 0. */
12113 {
12120 }
12121 /* Otherwise, for signed (arithmetic) shifts,
12122 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
12123 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
12129 /* Otherwise, of unsigned (logical) shifts,
12130 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
12131 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
12132 else
12136 arg000);
12137 }
12138 }
12139 }
12141 /* If this is a comparison of a field, we may be able to simplify it. */
12144 /* Handle the constant case even without -O
12145 to make sure the warnings are given. */
12147 {
12151 }
12153 /* Optimize comparisons of strlen vs zero to a compare of the
12154 first character of the string vs zero. To wit,
12155 strlen(ptr) == 0 => *ptr == 0
12156 strlen(ptr) != 0 => *ptr != 0
12157 Other cases should reduce to one of these two (or a constant)
12158 due to the return value of strlen being unsigned. */
12160 {
12168 {
12169 tree ptrtype
12171 TYPE_QUAL_CONST));
12177 }
12178 }
12180 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12181 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12185 {
12190 {
12192 {
12195 }
12198 }
12199 }
12201 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12202 (X & C) == 0 when C is a single bit. */
12207 {
12214 arg1));
12215 }
12217 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12218 constant C is a power of two, i.e. a single bit. */
12225 {
12229 }
12231 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12232 when is C is a power of two, i.e. a single bit. */
12239 {
12245 }
12249 {
12252 }
12256 {
12263 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12264 operand_equal_p guarantees no side-effects so we don't need
12265 to use omit_one_operand on Z. */
12269 arg10));
12273 arg11));
12277 arg10));
12281 arg11));
12283 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12286 {
12292 }
12293 }
12295 /* Attempt to simplify equality/inequality comparisons of complex
12296 values. Only lower the comparison if the result is known or
12297 can be simplified to a single scalar comparison. */
12302 {
12307 {
12310 }
12311 else
12312 {
12315 }
12318 {
12321 }
12322 else
12323 {
12326 }
12330 {
12332 {
12337 }
12338 else
12339 {
12344 }
12345 }
12349 {
12351 {
12356 }
12357 else
12358 {
12363 }
12364 }
12365 }
12377 /* Transform comparisons of the form X +- C CMP X. */
12382 {
12387 /* (X - c) > X becomes false. */
12393 /* Likewise (X + c) < X becomes false. */
12399 /* Convert (X - c) <= X to true. */
12406 /* Convert (X + c) >= X to true. */
12412 }
12414 /* If we are comparing an ABS_EXPR with a constant, we can
12415 convert all the cases into explicit comparisons, but they may
12416 well not be faster than doing the ABS and one comparison.
12417 But ABS (X) <= C is a range comparison, which becomes a subtraction
12418 and a comparison, and is probably faster. */
12432 /* Convert ABS_EXPR<x> >= 0 to true. */
12439 {
12442 "when simplifying comparison of "
12444 WARN_STRICT_OVERFLOW_CONDITIONAL);
12447 arg0);
12448 }
12450 /* Convert ABS_EXPR<x> < 0 to false. */
12455 {
12458 "when simplifying comparison of "
12460 WARN_STRICT_OVERFLOW_CONDITIONAL);
12463 arg0);
12464 }
12466 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12467 and similarly for >= into !=. */
12477 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
12478 otherwise Y might be >= # of bits in X's type and thus e.g.
12479 (unsigned char) (1 << Y) for Y 15 might be 0.
12480 If the cast is widening, then 1 << Y should have unsigned type,
12481 otherwise if Y is number of bits in the signed shift type minus 1,
12482 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
12483 31 might be 0xffffffff80000000. */
12494 {
12500 }
12512 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12513 {
12525 }
12530 /* When pedantic, a compound expression can be neither an lvalue
12531 nor an integer constant expression. */
12534 /* Don't let (0, 0) be null pointer constant. */
12540 /* An ASSERT_EXPR should never be passed to fold_binary. */
12546 }
12548 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
12549 ((A & N) + B) & M -> (A + B) & M
12550 Similarly if (N & M) == 0,
12551 ((A | N) + B) & M -> (A + B) & M
12552 and for - instead of + (or unary - instead of +)
12553 and/or ^ instead of |.
12554 If B is constant and (B & M) == 0, fold into A & M.
12556 This function is a helper for match.pd patterns. Return non-NULL
12557 type in which the simplified operation should be performed only
12558 if any optimization is possible.
12560 ARG1 is M above, ARG00 is left operand of +/-, if CODE00 is BIT_*_EXPR,
12561 then ARG00{0,1} are operands of that bitop, otherwise CODE00 is ERROR_MARK.
12562 Similarly for ARG01, CODE01 and ARG01{0,1}, just for the right operand of
12563 +/-. */
12564 tree
12569 {
12584 wide_int cst0;
12586 /* Now we know that arg0 is (C + D) or (C - D) or -C and
12587 arg1 (M) is == (1LL << cst) - 1.
12588 Store C into PMOP[0] and D into PMOP[1]. */
12595 {
12602 {
12605 }
12608 /* If C or D is of the form (A & N) where
12609 (N & M) == M, or of the form (A | N) or
12610 (A ^ N) where (N & M) == 0, replace it with A. */
12616 /* If C or D is a N where (N & M) == 0, it can be
12617 omitted (replaced with 0). */
12622 /* Similarly, with C - N where (-N & M) == 0. */
12630 }
12632 /* Only build anything new if we optimized one or both arguments above. */
12638 else
12640 }
12642 /* Used by contains_label_[p1]. */
12644 struct contains_label_data
12645 {
12648 };
12650 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
12651 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
12652 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
12654 static tree
12656 {
12659 {
12670 {
12678 }
12687 }
12688 }
12690 /* Return whether the sub-tree ST contains a label which is accessible from
12691 outside the sub-tree. */
12693 static bool
12695 {
12699 }
12701 /* Fold a ternary expression of code CODE and type TYPE with operands
12702 OP0, OP1, and OP2. Return the folded expression if folding is
12703 successful. Otherwise, return NULL_TREE. */
12705 tree
12708 {
12709 tree tem;
12716 /* If this is a commutative operation, and OP0 is a constant, move it
12717 to OP1 to reduce the number of tests below. */
12726 /* Strip any conversions that don't change the mode. This is safe
12727 for every expression, except for a comparison expression because
12728 its signedness is derived from its operands. So, in the latter
12729 case, only strip conversions that don't change the signedness.
12731 Note that this is done as an internal manipulation within the
12732 constant folder, in order to find the simplest representation of
12733 the arguments so that their form can be studied. In any cases,
12734 the appropriate type conversions should be put back in the tree
12735 that will get out of the constant folder. */
12737 {
12740 }
12743 {
12746 }
12749 {
12752 }
12755 {
12759 {
12765 }
12770 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12771 so all simple results must be passed through pedantic_non_lvalue. */
12773 {
12776 /* Only optimize constant conditions when the selected branch
12777 has the same type as the COND_EXPR. This avoids optimizing
12778 away "c ? x : throw", where the throw has a void type.
12779 Avoid throwing away that operand which contains label. */
12786 }
12788 {
12795 {
12798 {
12806 }
12811 }
12812 }
12814 /* If we have A op B ? A : C, we may be able to convert this to a
12815 simpler expression, depending on the operation and the values
12816 of B and C. Signed zeros prevent all of these transformations,
12817 for reasons given above each one.
12819 Also try swapping the arguments and inverting the conditional. */
12823 {
12827 }
12832 {
12836 {
12840 }
12841 }
12843 /* If the second operand is simpler than the third, swap them
12844 since that produces better jump optimization results. */
12847 {
12849 /* See if this can be inverted. If it can't, possibly because
12850 it was a floating-point inequality comparison, don't do
12851 anything. */
12855 }
12857 /* Convert A ? 1 : 0 to simply A. */
12862 /* If we try to convert OP0 to our type, the
12863 call to fold will try to move the conversion inside
12864 a COND, which will recurse. In that case, the COND_EXPR
12865 is probably the best choice, so leave it alone. */
12869 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12870 over COND_EXPR in cases such as floating point comparisons. */
12879 arg0)));
12881 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12886 {
12887 /* sign_bit_p looks through both zero and sign extensions,
12888 but for this optimization only sign extensions are
12889 usable. */
12892 {
12895 {
12898 }
12900 }
12901 /* sign_bit_p only checks ARG1 bits within A's precision.
12902 If <sign bit of A> has wider type than A, bits outside
12903 of A's precision in <sign bit of A> need to be checked.
12904 If they are all 0, this optimization needs to be done
12905 in unsigned A's type, if they are all 1 in signed A's type,
12906 otherwise this can't be done. */
12912 {
12914 tree tem_type;
12927 {
12930 }
12932 {
12935 }
12936 else
12938 }
12941 return
12947 arg1)));
12948 }
12950 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
12951 already handled above. */
12956 {
12966 op1);
12967 }
12969 /* A & N ? N : 0 is simply A & N if N is a power of two. This
12970 is probably obsolete because the first operand should be a
12971 truth value (that's why we have the two cases above), but let's
12972 leave it in until we can confirm this for all front-ends. */
12980 /* operand_equal_p compares just value, not precision, so e.g.
12981 arg1 could be 8-bit -128 and be power of two, but BIT_AND_EXPR
12982 second operand 32-bit -128, which is not a power of two (or vice
12983 versa. */
12990 /* Disable the transformations below for vectors, since
12991 fold_binary_op_with_conditional_arg may undo them immediately,
12992 yielding an infinite loop. */
12996 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13005 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13010 {
13012 /* Only perform transformation if ARG0 is easily inverted. */
13016 ? BIT_IOR_EXPR
13019 op1);
13020 }
13022 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13027 {
13029 /* Only perform transformation if ARG0 is easily inverted. */
13035 op2);
13036 }
13038 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13050 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13051 of fold_ternary on them. */
13061 {
13063 unsigned HOST_WIDE_INT width
13074 {
13079 {
13081 {
13086 }
13092 }
13093 }
13094 }
13096 /* On constants we can use native encode/interpret to constant
13097 fold (nearly) all BIT_FIELD_REFs. */
13103 {
13106 /* Limit us to a reasonable amount of work. To relax the
13107 other limitations we need bit-shifting of the buffer
13108 and rounding up the size. */
13112 {
13114 unsigned HOST_WIDE_INT len
13119 {
13124 }
13125 }
13126 }
13131 /* Perform constant folding of BIT_INSERT_EXPR. */
13135 {
13136 /* Build a vector of integers from the tree mask. */
13137 vec_perm_builder builder;
13141 /* Create a vec_perm_indices for the integer vector. */
13146 }
13150 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
13153 {
13159 wide_int tem2
13163 }
13168 {
13170 unsigned HOST_WIDE_INT elsize
13173 {
13179 {
13185 }
13186 }
13187 }
13193 }
13195 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
13196 of an array (or vector). *CTOR_IDX if non-NULL is updated with the
13197 constructor element index of the value returned. If the element is
13198 not found NULL_TREE is returned and *CTOR_IDX is updated to
13199 the index of the element after the ACCESS_INDEX position (which
13200 may be outside of the CTOR array). */
13202 tree
13205 {
13211 {
13214 {
13215 /* Static constructors for variably sized objects makes no sense. */
13218 /* ??? When it is obvious that the range is signed, treat it so. */
13223 {
13225 low_bound
13227 SIGNED);
13228 }
13229 else
13230 {
13233 }
13234 }
13235 }
13239 index_sgn);
13251 {
13252 /* Array constructor might explicitly set index, or specify a range,
13253 or leave index NULL meaning that it is next index after previous
13254 one. */
13256 {
13258 max_index = index
13260 else
13261 {
13264 index_sgn);
13265 max_index
13267 index_sgn);
13269 }
13270 }
13272 {
13278 }
13279 else
13282 /* Do we have match? */
13284 {
13286 {
13290 }
13291 }
13293 /* We're past the element we search for. Note during parsing
13294 the elements might not be sorted.
13295 ??? We should use a binary search and a flag on the
13296 CONSTRUCTOR as to whether elements are sorted in declaration
13297 order. */
13299 }
13303 }
13305 /* Perform constant folding and related simplification of EXPR.
13306 The related simplifications include x*1 => x, x*0 => 0, etc.,
13307 and application of the associative law.
13308 NOP_EXPR conversions may be removed freely (as long as we
13309 are careful not to change the type of the overall expression).
13310 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13311 but we can constant-fold them if they have constant operands. */
13313 #ifdef ENABLE_FOLD_CHECKING
13314 # define fold(x) fold_1 (x)
13316 static
13317 #endif
13318 tree
13320 {
13324 tree tem;
13327 /* Return right away if a constant. */
13331 /* CALL_EXPR-like objects with variable numbers of operands are
13332 treated specially. */
13334 {
13336 {
13339 }
13341 }
13344 {
13349 {
13367 }
13368 }
13371 {
13373 {
13380 {
13385 }
13388 }
13390 /* Return a VECTOR_CST if possible. */
13392 {
13398 tree val;
13404 }
13412 }
13414 #ifdef ENABLE_FOLD_CHECKING
13415 #undef fold
13422 /* When --enable-checking=fold, compute a digest of expr before
13423 and after actual fold call to see if fold did not accidentally
13424 change original expr. */
13426 tree
13428 {
13429 tree ret;
13449 }
13451 void
13453 {
13464 }
13466 static void
13468 {
13470 }
13472 static void
13475 {
13481 recursive_label:
13491 {
13492 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
13500 }
13508 {
13509 /* Allow these fields to be modified. */
13510 tree tmp;
13521 {
13524 }
13525 }
13527 {
13528 /* Allow TREE_NO_WARNING to be set. Perhaps we shouldn't allow that
13529 and change builtins.c etc. instead - see PR89543. */
13535 }
13546 {
13549 {
13565 }
13569 {
13582 }
13599 {
13605 }
13608 {
13610 {
13613 }
13615 }
13626 {
13629 }
13639 }
13640 }
13642 /* Helper function for outputting the checksum of a tree T. When
13643 debugging with gdb, you can "define mynext" to be "next" followed
13644 by "call debug_fold_checksum (op0)", then just trace down till the
13645 outputs differ. */
13647 DEBUG_FUNCTION void
13649 {
13664 }
13666 #endif
13668 /* Fold a unary tree expression with code CODE of type TYPE with an
13669 operand OP0. LOC is the location of the resulting expression.
13670 Return a folded expression if successful. Otherwise, return a tree
13671 expression with code CODE of type TYPE with an operand OP0. */
13673 tree
13676 {
13677 tree tem;
13678 #ifdef ENABLE_FOLD_CHECKING
13687 #endif
13693 #ifdef ENABLE_FOLD_CHECKING
13700 #endif
13702 }
13704 /* Fold a binary tree expression with code CODE of type TYPE with
13705 operands OP0 and OP1. LOC is the location of the resulting
13706 expression. Return a folded expression if successful. Otherwise,
13707 return a tree expression with code CODE of type TYPE with operands
13708 OP0 and OP1. */
13710 tree
13713 MEM_STAT_DECL)
13714 {
13715 tree tem;
13716 #ifdef ENABLE_FOLD_CHECKING
13733 #endif
13739 #ifdef ENABLE_FOLD_CHECKING
13754 #endif
13756 }
13758 /* Fold a ternary tree expression with code CODE of type TYPE with
13759 operands OP0, OP1, and OP2. Return a folded expression if
13760 successful. Otherwise, return a tree expression with code CODE of
13761 type TYPE with operands OP0, OP1, and OP2. */
13763 tree
13766 {
13767 tree tem;
13768 #ifdef ENABLE_FOLD_CHECKING
13792 #endif
13799 #ifdef ENABLE_FOLD_CHECKING
13822 #endif
13824 }
13826 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13827 arguments in ARGARRAY, and a null static chain.
13828 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13829 of type TYPE from the given operands as constructed by build_call_array. */
13831 tree
13834 {
13835 tree tem;
13836 #ifdef ENABLE_FOLD_CHECKING
13855 #endif
13861 #ifdef ENABLE_FOLD_CHECKING
13877 #endif
13879 }
13881 /* Perform constant folding and related simplification of initializer
13882 expression EXPR. These behave identically to "fold_buildN" but ignore
13883 potential run-time traps and exceptions that fold must preserve. */
13885 #define START_FOLD_INIT \
13886 int saved_signaling_nans = flag_signaling_nans;\
13887 int saved_trapping_math = flag_trapping_math;\
13888 int saved_rounding_math = flag_rounding_math;\
13889 int saved_trapv = flag_trapv;\
13890 int saved_folding_initializer = folding_initializer;\
13891 flag_signaling_nans = 0;\
13892 flag_trapping_math = 0;\
13893 flag_rounding_math = 0;\
13894 flag_trapv = 0;\
13895 folding_initializer = 1;
13897 #define END_FOLD_INIT \
13898 flag_signaling_nans = saved_signaling_nans;\
13899 flag_trapping_math = saved_trapping_math;\
13900 flag_rounding_math = saved_rounding_math;\
13901 flag_trapv = saved_trapv;\
13902 folding_initializer = saved_folding_initializer;
13904 tree
13907 {
13908 tree result;
13909 START_FOLD_INIT;
13913 END_FOLD_INIT;
13915 }
13917 tree
13920 {
13921 tree result;
13922 START_FOLD_INIT;
13926 END_FOLD_INIT;
13928 }
13930 tree
13933 {
13934 tree result;
13935 START_FOLD_INIT;
13939 END_FOLD_INIT;
13941 }
13943 #undef START_FOLD_INIT
13944 #undef END_FOLD_INIT
13946 /* Determine if first argument is a multiple of second argument. Return 0 if
13947 it is not, or we cannot easily determined it to be.
13949 An example of the sort of thing we care about (at this point; this routine
13950 could surely be made more general, and expanded to do what the *_DIV_EXPR's
13951 fold cases do now) is discovering that
13953 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13955 is a multiple of
13957 SAVE_EXPR (J * 8)
13959 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
13961 This code also handles discovering that
13963 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13965 is a multiple of 8 so we don't have to worry about dealing with a
13966 possible remainder.
13968 Note that we *look* inside a SAVE_EXPR only to determine how it was
13969 calculated; it is not safe for fold to do much of anything else with the
13970 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
13971 at run time. For example, the latter example above *cannot* be implemented
13972 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
13973 evaluation time of the original SAVE_EXPR is not necessarily the same at
13974 the time the new expression is evaluated. The only optimization of this
13975 sort that would be valid is changing
13977 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
13979 divided by 8 to
13981 SAVE_EXPR (I) * SAVE_EXPR (J)
13983 (where the same SAVE_EXPR (J) is used in the original and the
13984 transformed version). */
13986 int
13988 {
13999 {
14001 /* Bitwise and provides a power of two multiple. If the mask is
14002 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
14010 {
14016 {
14019 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
14021 {
14025 {
14028 }
14029 }
14031 }
14032 }
14037 /* It is impossible to prove if op0 - op1 is multiple of bottom
14038 precisely, so be conservative here checking if both op0 and op1
14039 are multiple of bottom. Note we check the second operand first
14040 since it's usually simpler. */
14045 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
14046 as op0 - 3 if the expression has unsigned type. For example,
14047 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
14057 {
14059 /* const_binop may not detect overflow correctly,
14060 so check for it explicitly here. */
14068 }
14072 /* Can't handle conversions from non-integral or wider integral type. */
14078 /* fall through */
14095 SIGNED);
14101 {
14104 /* Check for special cases to see if top is defined as multiple
14105 of bottom:
14107 top = (X & ~(bottom - 1) ; bottom is power of 2
14109 or
14111 Y = X % bottom
14112 top = X - Y. */
14131 }
14133 /* fall through */
14141 }
14142 }
14144 /* Return true if expression X cannot be (or contain) a NaN or infinity.
14145 This function returns true for integer expressions, and returns
14146 false if uncertain. */
14148 bool
14150 {
14155 {
14178 {
14179 CASE_CFN_FABS:
14181 CASE_CFN_FMAX:
14182 CASE_CFN_FMIN:
14187 }
14191 }
14192 }
14194 /* Return true if expression X evaluates to an infinity.
14195 This function returns false for integer expressions. */
14197 bool
14199 {
14203 {
14216 }
14217 }
14219 /* Return true if expression X could evaluate to an infinity.
14220 This function returns false for integer expressions, and returns
14221 true if uncertain. */
14223 bool
14225 {
14229 {
14242 }
14243 }
14245 /* Return true if expression X evaluates to a signaling NaN.
14246 This function returns false for integer expressions. */
14248 bool
14250 {
14254 {
14265 }
14266 }
14268 /* Return true if expression X could evaluate to a signaling NaN.
14269 This function returns false for integer expressions, and returns
14270 true if uncertain. */
14272 bool
14274 {
14278 {
14298 {
14299 CASE_CFN_FABS:
14301 CASE_CFN_FMAX:
14302 CASE_CFN_FMIN:
14307 }
14310 }
14311 }
14313 /* Return true if expression X evaluates to a NaN.
14314 This function returns false for integer expressions. */
14316 bool
14318 {
14322 {
14333 }
14334 }
14336 /* Return true if expression X could evaluate to a NaN.
14337 This function returns false for integer expressions, and returns
14338 true if uncertain. */
14340 bool
14342 {
14346 {
14371 {
14372 CASE_CFN_FABS:
14374 CASE_CFN_FMAX:
14375 CASE_CFN_FMIN:
14380 }
14383 }
14384 }
14386 #define tree_expr_nonnegative_warnv_p(X, Y) \
14389 #define RECURSE(X) \
14390 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
14392 /* Return true if CODE or TYPE is known to be non-negative. */
14394 static bool
14396 {
14399 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14400 have a signed:1 type (where the value is -1 and 0). */
14403 }
14405 /* Return true if (CODE OP0) is known to be non-negative. If the return
14406 value is based on the assumption that signed overflow is undefined,
14407 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14408 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14410 bool
14413 {
14418 {
14420 /* We can't return 1 if flag_wrapv is set because
14421 ABS_EXPR<INT_MIN> = INT_MIN. */
14425 {
14428 }
14436 CASE_CONVERT:
14437 {
14442 {
14446 {
14450 }
14451 }
14453 {
14459 }
14460 }
14465 }
14467 /* We don't know sign of `t', so be conservative and return false. */
14469 }
14471 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
14472 value is based on the assumption that signed overflow is undefined,
14473 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14474 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14476 bool
14480 {
14485 {
14491 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14492 both unsigned and at least 2 bits shorter than the result. */
14496 {
14501 {
14505 }
14506 }
14511 {
14512 /* x * x is always non-negative for floating point x
14513 or without overflow. */
14516 {
14521 }
14522 }
14524 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14525 both unsigned and their total bits is shorter than the result. */
14529 {
14548 {
14558 }
14559 }
14566 /* Usually RECURSE (op0) || RECURSE (op1) but NaNs complicate
14567 things. */
14592 }
14594 /* We don't know sign of `t', so be conservative and return false. */
14596 }
14598 /* Return true if T is known to be non-negative. If the return
14599 value is based on the assumption that signed overflow is undefined,
14600 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14601 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14603 bool
14605 {
14610 {
14624 /* Limit the depth of recursion to avoid quadratic behavior.
14625 This is expected to catch almost all occurrences in practice.
14626 If this code misses important cases that unbounded recursion
14627 would not, passes that need this information could be revised
14628 to provide it through dataflow propagation. */
14636 }
14637 }
14639 /* Return true if T is known to be non-negative. If the return
14640 value is based on the assumption that signed overflow is undefined,
14641 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14642 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14644 bool
14647 {
14649 {
14650 CASE_CFN_ACOS:
14651 CASE_CFN_ACOSH:
14652 CASE_CFN_CABS:
14653 CASE_CFN_COSH:
14654 CASE_CFN_ERFC:
14655 CASE_CFN_EXP:
14656 CASE_CFN_EXP10:
14657 CASE_CFN_EXP2:
14658 CASE_CFN_FABS:
14659 CASE_CFN_FDIM:
14660 CASE_CFN_HYPOT:
14661 CASE_CFN_POW10:
14662 CASE_CFN_FFS:
14663 CASE_CFN_PARITY:
14664 CASE_CFN_POPCOUNT:
14665 CASE_CFN_CLZ:
14666 CASE_CFN_CLRSB:
14671 /* Always true. */
14674 CASE_CFN_SQRT:
14675 CASE_CFN_SQRT_FN:
14676 /* sqrt(-0.0) is -0.0. */
14681 CASE_CFN_ASINH:
14682 CASE_CFN_ATAN:
14683 CASE_CFN_ATANH:
14684 CASE_CFN_CBRT:
14685 CASE_CFN_CEIL:
14686 CASE_CFN_CEIL_FN:
14687 CASE_CFN_ERF:
14688 CASE_CFN_EXPM1:
14689 CASE_CFN_FLOOR:
14690 CASE_CFN_FLOOR_FN:
14691 CASE_CFN_FMOD:
14692 CASE_CFN_FREXP:
14693 CASE_CFN_ICEIL:
14694 CASE_CFN_IFLOOR:
14695 CASE_CFN_IRINT:
14696 CASE_CFN_IROUND:
14697 CASE_CFN_LCEIL:
14698 CASE_CFN_LDEXP:
14699 CASE_CFN_LFLOOR:
14700 CASE_CFN_LLCEIL:
14701 CASE_CFN_LLFLOOR:
14702 CASE_CFN_LLRINT:
14703 CASE_CFN_LLROUND:
14704 CASE_CFN_LRINT:
14705 CASE_CFN_LROUND:
14706 CASE_CFN_MODF:
14707 CASE_CFN_NEARBYINT:
14708 CASE_CFN_NEARBYINT_FN:
14709 CASE_CFN_RINT:
14710 CASE_CFN_RINT_FN:
14711 CASE_CFN_ROUND:
14712 CASE_CFN_ROUND_FN:
14713 CASE_CFN_ROUNDEVEN:
14714 CASE_CFN_ROUNDEVEN_FN:
14715 CASE_CFN_SCALB:
14716 CASE_CFN_SCALBLN:
14717 CASE_CFN_SCALBN:
14718 CASE_CFN_SIGNBIT:
14719 CASE_CFN_SIGNIFICAND:
14720 CASE_CFN_SINH:
14721 CASE_CFN_TANH:
14722 CASE_CFN_TRUNC:
14723 CASE_CFN_TRUNC_FN:
14724 /* True if the 1st argument is nonnegative. */
14727 CASE_CFN_FMAX:
14728 CASE_CFN_FMAX_FN:
14729 /* Usually RECURSE (arg0) || RECURSE (arg1) but NaNs complicate
14730 things. In the presence of sNaNs, we're only guaranteed to be
14731 non-negative if both operands are non-negative. In the presence
14732 of qNaNs, we're non-negative if either operand is non-negative
14733 and can't be a qNaN, or if both operands are non-negative. */
14742 CASE_CFN_FMIN:
14743 CASE_CFN_FMIN_FN:
14744 /* True if the 1st AND 2nd arguments are nonnegative. */
14747 CASE_CFN_COPYSIGN:
14748 CASE_CFN_COPYSIGN_FN:
14749 /* True if the 2nd argument is nonnegative. */
14752 CASE_CFN_POWI:
14753 /* True if the 1st argument is nonnegative or the second
14754 argument is an even integer. */
14760 CASE_CFN_POW:
14761 /* True if the 1st argument is nonnegative or the second
14762 argument is an even integer valued real. */
14764 {
14765 REAL_VALUE_TYPE c;
14766 HOST_WIDE_INT n;
14771 {
14772 REAL_VALUE_TYPE cint;
14776 }
14777 }
14782 }
14784 }
14786 /* Return true if T is known to be non-negative. If the return
14787 value is based on the assumption that signed overflow is undefined,
14788 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14789 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14791 static bool
14793 {
14799 {
14801 {
14805 /* If the initializer is non-void, then it's a normal expression
14806 that will be assigned to the slot. */
14810 /* Otherwise, the initializer sets the slot in some way. One common
14811 way is an assignment statement at the end of the initializer. */
14813 {
14821 else
14823 }
14829 }
14832 {
14838 arg0,
14839 arg1,
14841 }
14854 }
14855 }
14857 #undef RECURSE
14858 #undef tree_expr_nonnegative_warnv_p
14860 /* Return true if T is known to be non-negative. If the return
14861 value is based on the assumption that signed overflow is undefined,
14862 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14863 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14865 bool
14867 {
14874 {
14896 }
14899 {
14925 }
14926 }
14928 /* Return true if `t' is known to be non-negative. Handle warnings
14929 about undefined signed overflow. */
14931 bool
14933 {
14940 "determining that expression is always "
14942 WARN_STRICT_OVERFLOW_MISC);
14944 }
14947 /* Return true when (CODE OP0) is an address and is known to be nonzero.
14948 For floating point we further ensure that T is not denormal.
14949 Similar logic is present in nonzero_address in rtlanal.h.
14951 If the return value is based on the assumption that signed overflow
14952 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14953 change *STRICT_OVERFLOW_P. */
14955 bool
14958 {
14960 {
14963 strict_overflow_p);
14966 {
14972 strict_overflow_p));
14973 }
14978 strict_overflow_p);
14982 }
14985 }
14987 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
14988 For floating point we further ensure that T is not denormal.
14989 Similar logic is present in nonzero_address in rtlanal.h.
14991 If the return value is based on the assumption that signed overflow
14992 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14993 change *STRICT_OVERFLOW_P. */
14995 bool
14997 tree type,
14998 tree op0,
15000 {
15003 {
15007 {
15008 /* With the presence of negative values it is hard
15009 to say something. */
15016 /* One of operands must be positive and the other non-negative. */
15017 /* We don't set *STRICT_OVERFLOW_P here: even if this value
15018 overflows, on a twos-complement machine the sum of two
15019 nonnegative numbers can never be zero. */
15021 strict_overflow_p)
15023 strict_overflow_p));
15024 }
15029 {
15031 strict_overflow_p)
15033 strict_overflow_p))
15034 {
15037 }
15038 }
15047 {
15050 }
15057 {
15061 /* When both operands are nonzero, then MAX must be too. */
15063 strict_overflow_p))
15066 /* MAX where operand 0 is positive is positive. */
15068 strict_overflow_p);
15069 }
15070 /* MAX where operand 1 is positive is positive. */
15075 {
15079 }
15084 strict_overflow_p)
15086 strict_overflow_p));
15090 }
15093 }
15095 /* Return true when T is an address and is known to be nonzero.
15096 For floating point we further ensure that T is not denormal.
15097 Similar logic is present in nonzero_address in rtlanal.h.
15099 If the return value is based on the assumption that signed overflow
15100 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15101 change *STRICT_OVERFLOW_P. */
15103 bool
15105 {
15108 {
15113 {
15125 /* For objects in symbol table check if we know they are non-zero.
15126 Don't do anything for variables and functions before symtab is built;
15127 it is quite possible that they will be declared weak later. */
15132 /* Constants are never weak. */
15137 }
15145 {
15149 }
15159 }
15161 }
15163 #define integer_valued_real_p(X) \
15166 #define RECURSE(X) \
15167 ((integer_valued_real_p) (X, depth + 1))
15169 /* Return true if the floating point result of (CODE OP0) has an
15170 integer value. We also allow +Inf, -Inf and NaN to be considered
15171 integer values. Return false for signaling NaN.
15173 DEPTH is the current nesting depth of the query. */
15175 bool
15177 {
15179 {
15186 CASE_CONVERT:
15187 {
15194 }
15198 }
15200 }
15202 /* Return true if the floating point result of (CODE OP0 OP1) has an
15203 integer value. We also allow +Inf, -Inf and NaN to be considered
15204 integer values. Return false for signaling NaN.
15206 DEPTH is the current nesting depth of the query. */
15208 bool
15210 {
15212 {
15222 }
15224 }
15226 /* Return true if the floating point result of calling FNDECL with arguments
15227 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
15228 considered integer values. Return false for signaling NaN. If FNDECL
15229 takes fewer than 2 arguments, the remaining ARGn are null.
15231 DEPTH is the current nesting depth of the query. */
15233 bool
15235 {
15237 {
15238 CASE_CFN_CEIL:
15239 CASE_CFN_CEIL_FN:
15240 CASE_CFN_FLOOR:
15241 CASE_CFN_FLOOR_FN:
15242 CASE_CFN_NEARBYINT:
15243 CASE_CFN_NEARBYINT_FN:
15244 CASE_CFN_RINT:
15245 CASE_CFN_RINT_FN:
15246 CASE_CFN_ROUND:
15247 CASE_CFN_ROUND_FN:
15248 CASE_CFN_ROUNDEVEN:
15249 CASE_CFN_ROUNDEVEN_FN:
15250 CASE_CFN_TRUNC:
15251 CASE_CFN_TRUNC_FN:
15254 CASE_CFN_FMIN:
15255 CASE_CFN_FMIN_FN:
15256 CASE_CFN_FMAX:
15257 CASE_CFN_FMAX_FN:
15262 }
15264 }
15266 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
15267 has an integer value. We also allow +Inf, -Inf and NaN to be
15268 considered integer values. Return false for signaling NaN.
15270 DEPTH is the current nesting depth of the query. */
15272 bool
15274 {
15276 {
15284 /* Limit the depth of recursion to avoid quadratic behavior.
15285 This is expected to catch almost all occurrences in practice.
15286 If this code misses important cases that unbounded recursion
15287 would not, passes that need this information could be revised
15288 to provide it through dataflow propagation. */
15292 depth));
15296 }
15298 }
15300 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
15301 has an integer value. We also allow +Inf, -Inf and NaN to be
15302 considered integer values. Return false for signaling NaN.
15304 DEPTH is the current nesting depth of the query. */
15306 static bool
15308 {
15310 {
15321 }
15323 }
15325 #undef RECURSE
15326 #undef integer_valued_real_p
15328 /* Return true if the floating point expression T has an integer value.
15329 We also allow +Inf, -Inf and NaN to be considered integer values.
15330 Return false for signaling NaN.
15332 DEPTH is the current nesting depth of the query. */
15334 bool
15336 {
15344 {
15360 }
15363 {
15369 {
15378 }
15382 }
15383 }
15385 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
15386 attempt to fold the expression to a constant without modifying TYPE,
15387 OP0 or OP1.
15389 If the expression could be simplified to a constant, then return
15390 the constant. If the expression would not be simplified to a
15391 constant, then return NULL_TREE. */
15393 tree
15395 {
15398 }
15400 /* Given the components of a unary expression CODE, TYPE and OP0,
15401 attempt to fold the expression to a constant without modifying
15402 TYPE or OP0.
15404 If the expression could be simplified to a constant, then return
15405 the constant. If the expression would not be simplified to a
15406 constant, then return NULL_TREE. */
15408 tree
15410 {
15413 }
15415 /* If EXP represents referencing an element in a constant string
15416 (either via pointer arithmetic or array indexing), return the
15417 tree representing the value accessed, otherwise return NULL. */
15419 tree
15421 {
15425 {
15427 tree index;
15428 tree string;
15433 else
15434 {
15438 /* Optimize the special-case of a zero lower bound.
15440 We convert the low_bound to sizetype to avoid some problems
15441 with constant folding. (E.g. suppose the lower bound is 1,
15442 and its mode is QI. Without the conversion,l (ARRAY
15443 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
15444 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
15450 }
15452 scalar_int_mode char_mode;
15464 }
15466 }
15468 /* Folds a read from vector element at IDX of vector ARG. */
15470 tree
15472 {
15477 {
15481 {
15485 }
15486 }
15488 }
15490 /* Return the tree for neg (ARG0) when ARG0 is known to be either
15491 an integer constant, real, or fixed-point constant.
15493 TYPE is the type of the result. */
15495 static tree
15497 {
15501 {
15507 {
15508 FIXED_VALUE_TYPE f;
15513 /* Propagate overflow flags. */
15517 }
15521 {
15528 }
15531 }
15534 }
15536 /* Return the tree for abs (ARG0) when ARG0 is known to be either
15537 an integer constant or real constant.
15539 TYPE is the type of the result. */
15541 tree
15543 {
15547 {
15549 {
15550 /* If the value is unsigned or non-negative, then the absolute value
15551 is the same as the ordinary value. */
15555 ;
15557 /* If the value is negative, then the absolute value is
15558 its negation. */
15559 else
15562 /* Force to the destination type, set TREE_OVERFLOW for signed
15563 TYPE only. */
15565 }
15571 else
15577 }
15580 }
15582 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
15583 constant. TYPE is the type of the result. */
15585 static tree
15587 {
15591 }
15593 /* Given CODE, a relational operator, the target type, TYPE and two
15594 constant operands OP0 and OP1, return the result of the
15595 relational operation. If the result is not a compile time
15596 constant, then return NULL_TREE. */
15598 static tree
15600 {
15603 /* From here on, the only cases we handle are when the result is
15604 known to be a constant. */
15607 {
15611 /* Handle the cases where either operand is a NaN. */
15613 {
15615 {
15643 }
15646 }
15649 }
15652 {
15656 }
15658 /* Handle equality/inequality of complex constants. */
15660 {
15671 else
15673 }
15676 {
15678 {
15679 /* Have vector comparison with scalar boolean result. */
15687 {
15695 }
15697 }
15698 tree_vector_builder elts;
15703 {
15716 }
15719 }
15721 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15723 To compute GT, swap the arguments and do LT.
15724 To compute GE, do LT and invert the result.
15725 To compute LE, swap the arguments, do LT and invert the result.
15726 To compute NE, do EQ and invert the result.
15728 Therefore, the code below must handle only EQ and LT. */
15731 {
15734 }
15736 /* Note that it is safe to invert for real values here because we
15737 have already handled the one case that it matters. */
15741 {
15744 }
15746 /* Compute a result for LT or EQ if args permit;
15747 Otherwise return T. */
15749 {
15752 else
15754 }
15755 else
15761 }
15763 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15764 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15765 itself. */
15767 tree
15769 {
15770 /* If the expression does not have side effects then we don't have to wrap
15771 it with a cleanup point expression. */
15775 /* If the expression is a return, check to see if the expression inside the
15776 return has no side effects or the right hand side of the modify expression
15777 inside the return. If either don't have side effects set we don't need to
15778 wrap the expression in a cleanup point expression. Note we don't check the
15779 left hand side of the modify because it should always be a return decl. */
15781 {
15788 }
15791 }
15793 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15794 of an indirection through OP0, or NULL_TREE if no simplification is
15795 possible. */
15797 tree
15799 {
15801 tree subtype;
15802 poly_uint64 const_op01;
15811 {
15815 /* *&CONST_DECL -> to the value of the const decl. */
15818 /* *&p => p; make sure to handle *&"str"[cst] here. */
15820 {
15824 else
15826 }
15827 /* *(foo *)&fooarray => fooarray[0] */
15830 && (!in_gimple_form
15832 {
15842 }
15843 /* *(foo *)&complexfoo => __real__ complexfoo */
15847 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
15850 {
15854 index);
15855 }
15856 }
15860 {
15866 {
15867 tree op00type;
15871 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
15874 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
15875 but we want to treat offsets with MSB set as negative.
15876 For the code below negative offsets are invalid and
15877 TYPE_SIZE of the element is something unsigned, so
15878 check whether op01 fits into poly_int64, which implies
15879 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
15880 then just use poly_uint64 because we want to treat the
15881 value as unsigned. */
15883 {
15885 poly_uint64 max_offset
15889 {
15894 }
15895 }
15896 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15899 {
15901 const_op01))
15903 }
15904 /* ((foo *)&fooarray)[1] => fooarray[1] */
15907 {
15916 {
15921 }
15922 }
15923 }
15924 }
15926 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15929 && (!in_gimple_form
15931 {
15932 tree type_domain;
15942 NULL_TREE);
15943 }
15946 }
15948 /* Builds an expression for an indirection through T, simplifying some
15949 cases. */
15951 tree
15953 {
15961 }
15963 /* Given an INDIRECT_REF T, return either T or a simplified version. */
15965 tree
15967 {
15972 else
15974 }
15976 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15977 whose result is ignored. The type of the returned tree need not be
15978 the same as the original expression. */
15980 tree
15982 {
15988 {
15999 else
16005 {
16021 }
16026 }
16027 }
16029 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
16031 tree
16033 {
16039 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16040 have to do anything. Only do this when we are not given a const,
16041 because in that case, this check is more expensive than just
16042 doing it. */
16044 {
16049 }
16051 /* If divisor is a power of two, simplify this to bit manipulation. */
16053 {
16055 {
16069 }
16070 else
16071 {
16072 tree t;
16078 }
16079 }
16080 else
16081 {
16086 }
16089 }
16091 /* Likewise, but round down. */
16093 tree
16095 {
16102 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16103 have to do anything. Only do this when we are not given a const,
16104 because in that case, this check is more expensive than just
16105 doing it. */
16107 {
16112 }
16114 /* If divisor is a power of two, simplify this to bit manipulation. */
16116 {
16117 tree t;
16121 }
16122 else
16123 {
16128 }
16131 }
16133 /* Returns the pointer to the base of the object addressed by EXP and
16134 extracts the information about the offset of the access, storing it
16135 to PBITPOS and POFFSET. */
16137 static tree
16140 {
16141 tree core;
16142 machine_mode mode;
16144 poly_int64 bitsize;
16148 {
16153 }
16155 {
16161 {
16162 poly_offset_int tem
16168 }
16169 }
16170 else
16171 {
16175 }
16178 }
16180 /* Returns true if addresses of E1 and E2 differ by a constant, false
16181 otherwise. If they do, E1 - E2 is stored in *DIFF. */
16183 bool
16185 {
16200 {
16210 }
16212 {
16213 /* If only one of the offsets is non-constant, the difference cannot
16214 be a constant. */
16216 }
16217 else
16222 }
16224 /* Return OFF converted to a pointer offset type suitable as offset for
16225 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
16226 tree
16228 {
16232 }
16234 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16235 tree
16237 {
16240 }
16242 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16243 tree
16245 {
16248 }
16250 /* Return a pointer to a NUL-terminated string containing the sequence
16251 of bytes corresponding to the representation of the object referred to
16252 by SRC (or a subsequence of such bytes within it if SRC is a reference
16253 to an initialized constant array plus some constant offset).
16254 Set *STRSIZE the number of bytes in the constant sequence including
16255 the terminating NUL byte. *STRSIZE is equal to sizeof(A) - OFFSET
16256 where A is the array that stores the constant sequence that SRC points
16257 to and OFFSET is the byte offset of SRC from the beginning of A. SRC
16258 need not point to a string or even an array of characters but may point
16259 to an object of any type. */
16263 {
16264 /* The offset into the array A storing the string, and A's byte size. */
16265 tree offset_node;
16266 tree mem_size;
16273 else
16280 {
16283 else
16285 }
16290 /* ARRAY_SIZE is the byte size of the array the constant sequence
16291 is stored in and equal to sizeof A. INIT_BYTES is the number
16292 of bytes in the constant sequence used to initialize the array,
16293 including any embedded NULs as well as the terminating NUL (for
16294 strings), but not including any trailing zeros/NULs past
16295 the terminating one appended implicitly to a string literal to
16296 zero out the remainder of the array it's stored in. For example,
16297 given:
16298 const char a[7] = "abc\0d";
16299 n = strlen (a + 1);
16300 ARRAY_SIZE is 7, INIT_BYTES is 6, and OFFSET is 1. For a valid
16301 (i.e., nul-terminated) string with no embedded nuls, INIT_BYTES
16302 is equal to strlen (A) + 1. */
16307 /* Ideally this would turn into a gcc_checking_assert over time. */
16315 {
16316 /* Compute and store the number of characters from the beginning
16317 of the substring at OFFSET to the end, including the terminating
16318 nul. Offsets past the initial length refer to null strings. */
16321 else
16323 }
16324 else
16325 {
16327 /* Support only properly NUL-terminated single byte strings. */
16332 }
16335 }
16337 /* Return a pointer to a NUL-terminated string corresponding to
16338 the expression STR referencing a constant string, possibly
16339 involving a constant offset. Return null if STR either doesn't
16340 reference a constant string or if it involves a nonconstant
16341 offset. */
16345 {
16347 }
16349 /* Given a tree T, compute which bits in T may be nonzero. */
16351 wide_int
16353 {
16355 {
16373 CASE_CONVERT:
16379 {
16384 }
16388 {
16396 }
16400 {
16408 }
16412 }
16415 }
16417 #if CHECKING_P
16421 /* Helper functions for writing tests of folding trees. */
16423 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
16425 static void
16427 tree constant)
16428 {
16430 }
16432 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
16433 wrapping WRAPPED_EXPR. */
16435 static void
16437 tree wrapped_expr)
16438 {
16443 }
16445 /* Verify that various arithmetic binary operations are folded
16446 correctly. */
16448 static void
16450 {
16456 /* Addition. */
16457 /* 1 <-- (0 + 1) */
16459 one);
16461 one);
16463 /* (nonlvalue)x <-- (x + 0) */
16465 x);
16467 /* Subtraction. */
16468 /* 0 <-- (x - x) */
16470 zero);
16472 x);
16474 /* Multiplication. */
16475 /* 0 <-- (x * 0) */
16477 zero);
16479 /* (nonlvalue)x <-- (x * 1) */
16481 x);
16482 }
16484 /* Verify that various binary operations on vectors are folded
16485 correctly. */
16487 static void
16489 {
16496 /* Verify equality tests that return a scalar boolean result. */
16509 }
16511 /* Verify folding of VEC_DUPLICATE_EXPRs. */
16513 static void
16515 {
16518 /* This will be 1 if VEC_MODE isn't a vector mode. */
16525 }
16527 /* Run all of the selftests within this file. */
16529 void
16531 {
16535 }