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| author | Richard Guenther <rguenth@gcc.gnu.org> | 2005-02-07 13:24:38 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2005-02-07 13:24:38 +0000 |
| commit | 6a96f5c111327ebb22e3c6bff923f8c1b2e175f1 (patch) | |
| tree | f3c9b917a0f61ec5e98c3b1be02adc081d56f541 /gcc/builtins.c | |
| parent | 48c4e71107bd32507fe3a52c85601fce53a4b1ef (diff) | |
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re PR middle-end/19775 (sqrt(pow(x,y)) != pow(x,y*0.5) (with -ffast-math))
2005-02-07 Richard Guenther <rguenth@gcc.gnu.org>
PR middle-end/19775
* builtins.c (fold_builtin_sqrt): Transform
sqrt(pow(x,y)) to pow(fabs(x),y*0.5), not
pow(x,y*0.5).
* gcc.dg/torture/builtin-power-1.c: Disable test for
invalid transformation.
* gcc.dg/builtins-10.c: Likewise. Disable one test we
no longer optimize.
* gcc.dg/builtins-47.c: New testcase.
From-SVN: r94701
Diffstat (limited to 'gcc/builtins.c')
| -rw-r--r-- | gcc/builtins.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/gcc/builtins.c b/gcc/builtins.c index dada41e..09c5b6b 100644 --- a/gcc/builtins.c +++ b/gcc/builtins.c @@ -6186,7 +6186,7 @@ fold_builtin_sqrt (tree arglist, tree type) } } - /* Optimize sqrt(pow(x,y)) = pow(x,y*0.5). */ + /* Optimize sqrt(pow(x,y)) = pow(|x|,y*0.5). */ if (flag_unsafe_math_optimizations && (fcode == BUILT_IN_POW || fcode == BUILT_IN_POWF @@ -6195,8 +6195,11 @@ fold_builtin_sqrt (tree arglist, tree type) tree powfn = TREE_OPERAND (TREE_OPERAND (arg, 0), 0); tree arg0 = TREE_VALUE (TREE_OPERAND (arg, 1)); tree arg1 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg, 1))); - tree narg1 = fold (build2 (MULT_EXPR, type, arg1, - build_real (type, dconsthalf))); + tree narg1; + if (!tree_expr_nonnegative_p (arg0)) + arg0 = build1 (ABS_EXPR, type, arg0); + narg1 = fold (build2 (MULT_EXPR, type, arg1, + build_real (type, dconsthalf))); arglist = tree_cons (NULL_TREE, arg0, build_tree_list (NULL_TREE, narg1)); return build_function_call_expr (powfn, arglist); |