From fe27b7cc414a7b57ef801872157b596f4f39c1f6 Mon Sep 17 00:00:00 2001
From: "Kaveh R. Ghazi" <ghazi@caip.rutgers.edu>
Date: Thu, 11 Sep 2003 22:51:20 +0000
Subject: [PATCH] builtins.c (fold_builtin_logarithm): if N can't be truncated
to MODE exactly...
* builtins.c (fold_builtin_logarithm): if N can't be truncated to
MODE exactly, then only convert logN(N) -> 1.0 if
flag_unsafe_math_optimizations is set.
From-SVN: r71322
---
gcc/ChangeLog | 4 ++++
gcc/builtins.c | 15 ++++++++++-----
2 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d6d762417e8a..df66b3e2640b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,9 @@
2003-09-11 Kaveh R. Ghazi <ghazi@caip.rutgers.edu>
+ * builtins.c (fold_builtin_logarithm): if N can't be truncated to
+ MODE exactly, then only convert logN(N) -> 1.0 if
+ flag_unsafe_math_optimizations is set.
+
* builtins.c (builtin_dconsts_init, dconstpi, dconste,
init_builtin_dconsts): Delete.
* emit-rtl.c (dconstpi, dconste): Define.
diff --git a/gcc/builtins.c b/gcc/builtins.c
index 4df0e95b7f6a..2e8189d106cd 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -5949,16 +5949,21 @@ fold_builtin_logarithm (tree exp, const REAL_VALUE_TYPE *value)
tree type = TREE_TYPE (TREE_TYPE (fndecl));
tree arg = TREE_VALUE (arglist);
const enum built_in_function fcode = builtin_mathfn_code (arg);
- const REAL_VALUE_TYPE value_mode =
- real_value_truncate (TYPE_MODE (type), *value);
/* Optimize log*(1.0) = 0.0. */
if (real_onep (arg))
return build_real (type, dconst0);
- /* Optimize logN(N) = 1.0. */
- if (real_dconstp (arg, &value_mode))
- return build_real (type, dconst1);
+ /* Optimize logN(N) = 1.0. If N can't be truncated to MODE
+ exactly, then only do this if flag_unsafe_math_optimizations. */
+ if (exact_real_truncate (TYPE_MODE (type), value)
+ || flag_unsafe_math_optimizations)
+ {
+ const REAL_VALUE_TYPE value_truncate =
+ real_value_truncate (TYPE_MODE (type), *value);
+ if (real_dconstp (arg, &value_truncate))
+ return build_real (type, dconst1);
+ }
/* Special case, optimize logN(expN(x)) = x. */
if (flag_unsafe_math_optimizations
--
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