diff options
| -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; +} |