[PATCH] Inline C99 math functions

[Joseph Myers]

On Mon, 15 Jun 2015, Ondøej Bílka wrote:

> As I wrote in other thread that gcc builtins have poor performance a
> benchmark is tricky. Main problem is that these tests are in branch and
> gcc will simplify them. As builtins are branchless it obviously couldn't
> simplify them.

Even a poor benchmark, checked into the benchtests directory, would be a 
starting point for improved benchmarks as well as for benchmarking any 
future improvements to these functions.  Having a benchmark that everyone 
can readily use with glibc is better than having a performance improvement 
asserted in a patch submission without the benchmark being available at 
all.

It isn't necessary to show that the use of built-in functions here is 
optimal.  Simply provide evidence that (a) it's at least as good as the 
existing out-of-line functions, for calls from user programs, and (b) libm 
functions that previously used glibc-internal inlines, and would use GCC 
built-in functions after the patch, don't suffer any significant 
performance regression from that change.

-- 
Joseph S. Myers
joseph@codesourcery.com