------- Additional Comments From rguenth at gcc dot gnu dot org 2005-08-02
12:07 -------
Well...
int
tree_expr_nonnegative_p (tree t)
{
...
CASE_BUILTIN_F (BUILT_IN_FREXP)
...
/* Always true. */
return 1;
Which the manpage of frexp seems to support:
DESCRIPTION
The frexp() function is used to split the number x into a normalized
fraction and an exponent which is stored in exp.
RETURN VALUE
The frexp() function returns the normalized fraction. If the argument
x is not zero, the normalized fraction is x times a power of two, and
is always in the range 1/2 (inclusive) to 1 (exclusive). If x is zero,
then the normalized fraction is zero and zero is stored in exp.
so, we just fold away the fabs. Your libm is broken. And:
src/tests> ./test_frexp
q: -123.456 a: 0.9645 e: 7
q: -123.456 a: 0.9645 b: -0.9645 e: 7
though why b is negative here, contradicting the manpage, is unclear to me.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23195
