------- Comment #6 from ebotcazou at gcc dot gnu dot org 2006-01-28 21:44
-------
> Yet such code DOES compile with gcc -O under gcc4.0.2. However, the following
> does not compile, with or without -O :-
>
> int something(float f)
> {
> f = f*f ;
> }
> int main ()
> {
> float f ;
>
> if(isinf(f))
> return 1 ;
> else
> return 2 ;
> return 0;
> }
>
> Here, the optimiser is obviously unable to make assumptions about the value
> that would be returned by isinf() if the function were present, and the code
> is rejected.
>
> This 'bug' breaks autoconf tests for the presence of isinf()
Then autoconf should be more clever, for example by compiling w/o optimization
or by using a robust test or by passing -fno-builtin to the compiler.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26005
