[fortran, patch] Add Fortran 2003 IEEE intrinsic modules

[Joseph S. Myers]

On Thu, 21 Nov 2013, FX wrote:

> Indeed, 387/SSE has flush-to-zero modes. But other APIs do not (glibc, 
> SysV, AIX).

Note that glibc libm functions may not work when called in a flush-to-zero 
mode, only in modes that can be established by the <fenv.h> functions.  
If any argument to a function is subnormal or the function result 
underflows, you certainly get undefined behavior in such a mode (I've seen 
infinite loops in libm functions running the glibc testsuite in such 
configurations); if things work in non-underflowing cases with normal 
arguments to functions, that's probably a side effect of the functions 
trying to avoid raising undue underflow exceptions and so not using 
underflowing arithmetic internally unless the final result will underflow.

-- 
Joseph S. Myers
joseph@codesourcery.com