On Mon, Aug 3, 2015 at 11:14 PM, FX <fxcoud...@gmail.com> wrote:
> The attached patch extends the IEEE modules to all floating-point kinds. Last
> time, when I added IEEE support, I restricted it to the float and double
> types (real kinds 4 and 8), to be extra safe. After discussion with Uros
> Bizjak and some reading, I’ve come to the conclusion that on most hardware
> where we support IEEE at all, we do support enough IEEE features on extended
> and quad prec (long double and __float128, on x86_64 hardware) to satisfy the
> Fortran standard.
>
> So, this enables full IEEE support for all real kinds. Nothing changes to the
> underlying architecture, it’s almost exclusively mechanical changes (adding
> the necessary variants to the interfaces, etc.).
>
> Bootstrapped and regtested on x86_64-apple-darwin14 (with associated
> libquadmath patch: https://gcc.gnu.org/ml/gcc-patches/2015-08/msg00124.html).
> OK to commit to trunk?
> Index: libgfortran/config/fpu-387.h
> ===================================================================
> --- libgfortran/config/fpu-387.h (revision 226429)
> +++ libgfortran/config/fpu-387.h (working copy)
> @@ -461,12 +461,12 @@ set_fpu_state (void *state)
>
>
> int
> -support_fpu_underflow_control (int kind)
> +support_fpu_underflow_control (int kind __attribute__((unused)))
> {
> if (!has_sse())
> return 0;
>
> - return (kind == 4 || kind == 8) ? 1 : 0;
> + return 1;
> }
x86 doesn't support underflow control for long double (x87) and
__float128 types, so the above change is wrong.
> Index: libgfortran/config/fpu-glibc.h
> ===================================================================
> --- libgfortran/config/fpu-glibc.h (revision 226429)
> +++ libgfortran/config/fpu-glibc.h (working copy)
> @@ -439,7 +439,7 @@ int
> support_fpu_underflow_control (int kind __attribute__((unused)))
> {
> #if defined(__alpha__) && defined(FE_MAP_UMZ)
> - return (kind == 4 || kind == 8) ? 1 : 0;
> + return 1;
> #else
> return 0;
> #endif
I'm not sure for alpha, if it supports underflow control for extended
types. Let's keep this as is for now, it is trivial to change later.
Uros.
