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builtins.c (fold_builtin_logarithm): if N can't be truncated to MODE exactly...

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* 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
This commit is contained in:
Kaveh R. Ghazi 2003-09-11 22:51:20 +00:00 committed by Kaveh Ghazi
parent ab01a87cbc
commit fe27b7cc41
2 changed files with 14 additions and 5 deletions
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4
gcc/ChangeLog
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@ -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.

15
gcc/builtins.c
View File

@ -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