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RE: [PATCH][PING] Inline C99 math functions
- From: "Wilco Dijkstra" <Wilco dot Dijkstra at arm dot com>
- To: "'Andreas Schwab'" <schwab at suse dot de>
- Cc: "'GNU C Library'" <libc-alpha at sourceware dot org>
- Date: Fri, 6 Nov 2015 14:29:37 -0000
- Subject: RE: [PATCH][PING] Inline C99 math functions
- Authentication-results: sourceware.org; auth=none
- References: <001c01d0bd7e$25a147c0$70e3d740$ at com> <mvmziyt3iwm dot fsf at hawking dot suse dot de>
Andreas Schwab wrote:
> "Wilco Dijkstra" <wdijkstr@arm.com> writes:
>
> >> 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?
>
> FAIL: elf/check-localplt
> $ cat elf/check-localplt.out
> Missing required PLT reference: libm.so: __signbitl Missing required PLT
> reference: libc.so: __signbitl Missing required PLT reference: libm.so:
> __signbitf Missing required PLT reference: libm.so: __signbit Missing
> required PLT reference: libc.so: __signbit
I'm not exactly sure what this means - should we now remove the __signbit*
from
all the localplt.data files now that signbit is always inlined on all
targets?
Wilco