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| author | Jakub Jelinek <jakub@redhat.com> | 2010-08-12 17:21:34 +0200 |
|---|---|---|
| committer | Jakub Jelinek <jakub@gcc.gnu.org> | 2010-08-12 17:21:34 +0200 |
| commit | a8c56818780786dd56e9656ddfa9806da4387e9c (patch) | |
| tree | 639f56221290e502c4e4cfc6c62da003331396f5 /gcc | |
| parent | d2be8071543ab02afcf36637d0f02da2d51e3f41 (diff) | |
| download | gcc-a8c56818780786dd56e9656ddfa9806da4387e9c.zip gcc-a8c56818780786dd56e9656ddfa9806da4387e9c.tar.gz gcc-a8c56818780786dd56e9656ddfa9806da4387e9c.tar.bz2 | |
re PR middle-end/45262 (Optimization results in wrong result on expression x>>31||(-x)>>31)
PR middle-end/45262
* fold-const.c (make_range) <case NEGATE_EXPR>: Punt if
-a overflows. Normalize the range.
* gcc.c-torture/execute/pr45262.c: New test.
From-SVN: r163193
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/fold-const.c | 7 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.c-torture/execute/pr45262.c | 33 |
4 files changed, 46 insertions, 3 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 09da08d..31dd288 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -3,6 +3,10 @@ * builtins.c (fold_builtin_memory_op): Avoid -Wsign-compare warning. + PR middle-end/45262 + * fold-const.c (make_range) <case NEGATE_EXPR>: Punt if + -a overflows. Normalize the range. + 2010-08-12 Richard Guenther <rguenther@suse.de> PR tree-optimization/45232 diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 9ca5eff..d63411e 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -3985,9 +3985,9 @@ make_range (tree exp, int *pin_p, tree *plow, tree *phigh, n_high = range_binop (MINUS_EXPR, exp_type, build_int_cst (exp_type, 0), 0, low, 0); - low = n_low, high = n_high; - exp = arg0; - continue; + if (n_high != 0 && TREE_OVERFLOW (n_high)) + break; + goto normalize; case BIT_NOT_EXPR: /* ~ X -> -X - 1 */ @@ -4021,6 +4021,7 @@ make_range (tree exp, int *pin_p, tree *plow, tree *phigh, if (TYPE_OVERFLOW_UNDEFINED (arg0_type)) *strict_overflow_p = true; + normalize: /* Check for an unsigned range which has wrapped around the maximum value thus making n_high < n_low, and normalize it. */ if (n_low && n_high && tree_int_cst_lt (n_high, n_low)) diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index dd180c6..840253d 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2010-08-12 Jakub Jelinek <jakub@redhat.com> + + PR middle-end/45262 + * gcc.c-torture/execute/pr45262.c: New test. + 2010-08-12 Uros Bizjak <ubizjak@gmail.com> * gcc.dg/profile-generate-3.c: Call dg-require-profiling with diff --git a/gcc/testsuite/gcc.c-torture/execute/pr45262.c b/gcc/testsuite/gcc.c-torture/execute/pr45262.c new file mode 100644 index 0000000..72e186b --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/execute/pr45262.c @@ -0,0 +1,33 @@ +/* PR middle-end/45262 */ + +extern void abort (void); + +int +foo (unsigned int x) +{ + return ((int) x < 0) || ((int) (-x) < 0); +} + +int +bar (unsigned int x) +{ + return x >> 31 || (-x) >> 31; +} + +int +main (void) +{ + if (foo (1) != 1) + abort (); + if (foo (0) != 0) + abort (); + if (foo (-1) != 1) + abort (); + if (bar (1) != 1) + abort (); + if (bar (0) != 0) + abort (); + if (bar (-1) != 1) + abort (); + return 0; +} |