Use of C99 extra long double math functions after r236148

Bruce Evans brde at optusnet.com.au
Tue May 28 11:12:12 UTC 2013


On Tue, 28 May 2013, David Schultz wrote:

> On Tue, May 28, 2013, Bruce Evans wrote:
>>
>> I think I tested "inline" on the large functions (just 2) and found
>> it useful for efficiency.  This is like inline on large trig support
>> functions being useful.  The inline parts are duplicated once per
>> C99-API function, and often the caller only uses on C99-API function.
>> Actually, the large inlines are not duplicated that much.  cacosh()
>> and casinh() are just wrappers that call cacos() and casin(),
>> respectively.  There is no inlining for the last 2 (even larger)
>> functions.  The overhead for the wrappers is noticeable, but more
>> inlining didn't seem to reduce it much.
>
> If you did benchmarks to show that using inline is worthwhile
> despite the cache pressure, then it's fine with me. I had assumed
> that it was added without much thought.

I retested.  Inlining the big function do_hard_work() helps for gcc on
amd64 (about 5% faster), but makes no significant difference for clang.
The previous testing was mostly with gcc.

Bruce


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