GCC viciously beaten by ICC in trig test!

[Ranjit Mathew]

Roger Sayle wrote:
> Compiling with gcc -O2 -ffast-math on Linux generates x86 code that's
> significantly slower than Intel's compiler output.  However, commenting
> out the "#include <math.h>" corrects the situation and GCC can then
> generate *exactly* the same sequence as icc.

Thank you *so much* for that insight!

Looking at the glibc 2.3.2 headers (bits/mathinline.h)
on my RHEL3 system, a simple workaround might be to
add -D__NO_MATH_INLINES to the compiler command line.

Depending on when we started to do magic with trig.
functions, perhaps the glibc maintainers ought to \
modify that "#if __GNU_PREREQ (2, 8)" guard for
the inlined trig. functions appropriately.

Ranjit.

-- 
Ranjit Mathew          Email: rmathew AT hotmail DOT com

Bangalore, INDIA.      Web: http://ranjitmathew.tripod.com/