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| author | Jakub Jelinek <jakub@redhat.com> | 2013-02-08 16:06:26 +0100 |
|---|---|---|
| committer | Jakub Jelinek <jakub@gcc.gnu.org> | 2013-02-08 16:06:26 +0100 |
| commit | 600a5961b24faccf68ef5287fb3a6ed3c6b79224 (patch) | |
| tree | 3bef1543331fe45a7c674d160d1cafa5e1587232 /gcc | |
| parent | be59c9322ac42053f9a752fd0748513f27cc1c96 (diff) | |
| download | gcc-600a5961b24faccf68ef5287fb3a6ed3c6b79224.zip gcc-600a5961b24faccf68ef5287fb3a6ed3c6b79224.tar.gz gcc-600a5961b24faccf68ef5287fb3a6ed3c6b79224.tar.bz2 | |
re PR tree-optimization/56250 (Wrong constant folding on unsigned int)
PR tree-optimization/56250
* fold-const.c (extract_muldiv_1) <case NEGATE_EXPR>: Don't optimize
if type is unsigned and code isn't MULT_EXPR.
* gcc.c-torture/execute/pr56250.c: New test.
From-SVN: r195888
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/fold-const.c | 5 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.c-torture/execute/pr56250.c | 13 |
4 files changed, 29 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 55e90b4..4c6bfba 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2013-02-08 Jakub Jelinek <jakub@redhat.com> + + PR tree-optimization/56250 + * fold-const.c (extract_muldiv_1) <case NEGATE_EXPR>: Don't optimize + if type is unsigned and code isn't MULT_EXPR. + 2013-02-08 Georg-Johann Lay <avr@gjlay.de> PR tree-optimization/56064 diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 93f38cb..5acb4ad 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -5695,6 +5695,11 @@ extract_muldiv_1 (tree t, tree c, enum tree_code code, tree wide_type, break; /* FALLTHROUGH */ case NEGATE_EXPR: + /* For division and modulus, type can't be unsigned, as e.g. + (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2. + For signed types, even with wrapping overflow, this is fine. */ + if (code != MULT_EXPR && TYPE_UNSIGNED (type)) + break; if ((t1 = extract_muldiv (op0, c, code, wide_type, strict_overflow_p)) != 0) return fold_build1 (tcode, ctype, fold_convert (ctype, t1)); diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 31f0bf2..ae21e6b 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2013-02-08 Jakub Jelinek <jakub@redhat.com> + + PR tree-optimization/56250 + * gcc.c-torture/execute/pr56250.c: New test. + 2013-02-08 Georg-Johann Lay <avr@gjlay.de> PR tree-optimization/56064 diff --git a/gcc/testsuite/gcc.c-torture/execute/pr56250.c b/gcc/testsuite/gcc.c-torture/execute/pr56250.c new file mode 100644 index 0000000..8da36f8 --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/execute/pr56250.c @@ -0,0 +1,13 @@ +/* PR tree-optimization/56250 */ + +extern void abort (void); + +int +main () +{ + unsigned int x = 2; + unsigned int y = (0U - x / 2) / 2; + if (-1U / x != y) + abort (); + return 0; +} |