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| author | rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2006-12-07 14:24:11 +0000 |
|---|---|---|
| committer | rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2006-12-07 14:24:11 +0000 |
| commit | 5a84ba55a56a2df5d389a73adf84d8fa7282cd97 (patch) | |
| tree | 27722767a56435a8b6d77614d6158841f046d493 | |
| parent | c43a8a1a732928bf9e1c35fb60b634fd6a66b750 (diff) | |
| download | ppe42-gcc-5a84ba55a56a2df5d389a73adf84d8fa7282cd97.tar.gz ppe42-gcc-5a84ba55a56a2df5d389a73adf84d8fa7282cd97.zip | |
2006-12-07 Richard Guenther <rguenther@suse.de>
* builtins.c (expand_builtin_pow): Adjust predicates for
pow to cbrt expansion to unsafe math and !HONOR_NANS for
negative base.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@119622 138bc75d-0d04-0410-961f-82ee72b054a4
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/builtins.c | 11 |
2 files changed, 14 insertions, 3 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 4c63be49300..0926c1dc550 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2006-12-07 Richard Guenther <rguenther@suse.de> + + * builtins.c (expand_builtin_pow): Adjust predicates for + pow to cbrt expansion to unsafe math and !HONOR_NANS for + negative base. + 2006-12-07 Jan Hubicka <jh@suse.cz> * i386.c (nocona_cost, pentium4_cost): Update preffered memcpy/memset diff --git a/gcc/builtins.c b/gcc/builtins.c index fa7ed0133ba..3c7d1052cba 100644 --- a/gcc/builtins.c +++ b/gcc/builtins.c @@ -2679,9 +2679,15 @@ expand_builtin_pow (tree exp, rtx target, rtx subtarget) } /* Try if the exponent is a third of an integer. In this case - we can expand to x**(n/3) * cbrt(x)**(n%3). */ + we can expand to x**(n/3) * cbrt(x)**(n%3). As cbrt (x) is + different from pow (x, 1./3.) due to rounding and behavior + with negative x we need to constrain this transformation to + unsafe math and positive x or finite math. */ fn = mathfn_built_in (type, BUILT_IN_CBRT); - if (fn != NULL_TREE) + if (fn != NULL_TREE + && flag_unsafe_math_optimizations + && (tree_expr_nonnegative_p (arg0) + || !HONOR_NANS (mode))) { real_arithmetic (&c2, MULT_EXPR, &c, &dconst3); real_round (&c2, mode, &c2); @@ -2691,7 +2697,6 @@ expand_builtin_pow (tree exp, rtx target, rtx subtarget) real_convert (&c2, mode, &c2); if (real_identical (&c2, &c) && ((!optimize_size - && flag_unsafe_math_optimizations && powi_cost (n/3) <= POWI_MAX_MULTS) || n == 1)) { |
