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Re: [PATCH][PING] Inline C99 math functions
- From: Joseph Myers <joseph at codesourcery dot com>
- To: Wilco Dijkstra <wdijkstr at arm dot com>
- Cc: 'GNU C Library' <libc-alpha at sourceware dot org>
- Date: Wed, 22 Jul 2015 15:16:02 +0000
- Subject: Re: [PATCH][PING] Inline C99 math functions
- Authentication-results: sourceware.org; auth=none
- References: <001c01d0bd7e$25a147c0$70e3d740$ at com>
On Mon, 13 Jul 2015, Wilco Dijkstra wrote:
> > Wilco Dijkstra wrote:
> > Add inlining of the C99 math functions isinf/isnan/signbit/isfinite/isnormal/fpclassify using
> > GCC built-ins when available. Since going through the PLT is expensive for these small
> > functions, inlining results in major speedups (about 7x on Cortex-A57 for isinf). The GCC
> > built-ins are not correct if signalling NaN support is required, and thus are turned off in
> > that case (see GCC bug 66462). The test-snan.c tests sNaNs and so must be explicitly built
> > with -fsignaling-nans.
> > As a result of this many target overrides and the various __isnan/__finite inlines in
> > math_private.h are no longer required. If agreed we could remove all this code and only keep
> > the generic definition of isinf/etc which will use the builtin.
> > Tested on AArch64. OK for commit?
> > ChangeLog:
> > 2015-06-15 Wilco Dijkstra <email@example.com>
> > * math/Makefile: Build test-snan.c with -fsignaling-nans.
> > * math/math.h (fpclassify): Use __builtin_fpclassify when
> > available. (signbit): Use __builtin_signbit(f/l).
> > (isfinite): Use__builtin_isfinite. (isnormal): Use
> > __builtin_isnormal. (isnan): Use __builtin_isnan.
> > (isinf): Use __builtin_isinf_sign.
> As suggested __fpclassify is not inlined when optimizing for size, and a benchmark
> has been created (json output for x64 attached showing the large gains due to inlining).
I don't see an updated ChangeLog entry (with the [BZ #N] notation I
requested). Please include the ChangeLog entry with each patch
Joseph S. Myers