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| author | Richard Guenther <rguenther@suse.de> | 2010-01-21 12:15:40 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2010-01-21 12:15:40 +0000 |
| commit | 4e62a0175be3a34d66a8b395589897f0d2f53f46 (patch) | |
| tree | 758eccb5e66ab481705e497e8b218d2fa1fb2f1b /gcc/fold-const.c | |
| parent | ebfe4897fc27440325d1a23908b5a49c99ddb4ca (diff) | |
| download | gcc-4e62a0175be3a34d66a8b395589897f0d2f53f46.zip gcc-4e62a0175be3a34d66a8b395589897f0d2f53f46.tar.gz gcc-4e62a0175be3a34d66a8b395589897f0d2f53f46.tar.bz2 | |
re PR middle-end/19988 (pessimizes fp multiply-add/subtract combo)
2010-01-21 Richard Guenther <rguenther@suse.de>
PR middle-end/19988
* fold-const.c (negate_expr_p): Pretend only negative
real constants are easily negatable.
* gcc.dg/pr19988.c: New testcase.
From-SVN: r156152
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 9d249cc..e7a4b8c 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -1129,10 +1129,14 @@ negate_expr_p (tree t) && TYPE_OVERFLOW_WRAPS (type)); case FIXED_CST: - case REAL_CST: case NEGATE_EXPR: return true; + case REAL_CST: + /* We want to canonicalize to positive real constants. Pretend + that only negative ones can be easily negated. */ + return REAL_VALUE_NEGATIVE (TREE_REAL_CST (t)); + case COMPLEX_CST: return negate_expr_p (TREE_REALPART (t)) && negate_expr_p (TREE_IMAGPART (t)); |