| Message ID | 001c01d0bd7e$25a147c0$70e3d740$@com |
|---|---|
| State | New |
| Headers | show |
On 07/13/2015 11:11 AM, 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 <wdijkstr@arm.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). > > OK for commit? This looks good to me for 2.23, it is not OK for 2.22. Please wait until after 2.23 opens and until after you commit the benchmark. Cheers, Carlos. > --- > math/Makefile | 1 + > math/math.h | 51 ++++++++++++++++++++++++++++++--------------------- > 2 files changed, 31 insertions(+), 21 deletions(-) > > diff --git a/math/Makefile b/math/Makefile > index 9a3cf32..f78d75b 100644 > --- a/math/Makefile > +++ b/math/Makefile > @@ -155,6 +155,7 @@ CFLAGS-test-tgmath.c = -fno-builtin > CFLAGS-test-tgmath2.c = -fno-builtin > CFLAGS-test-tgmath-ret.c = -fno-builtin > CFLAGS-test-powl.c = -fno-builtin > +CFLAGS-test-snan.c = -fsignaling-nans > CPPFLAGS-test-ifloat.c = -U__LIBC_INTERNAL_MATH_INLINES -D__FAST_MATH__ \ > -DTEST_FAST_MATH -fno-builtin > CPPFLAGS-test-idouble.c = -U__LIBC_INTERNAL_MATH_INLINES -D__FAST_MATH__ \ > diff --git a/math/math.h b/math/math.h > index 22f0989..1721118 100644 > --- a/math/math.h > +++ b/math/math.h > @@ -215,8 +215,15 @@ enum > FP_NORMAL > }; > > +/* GCC bug 66462 means we cannot use the math builtins with -fsignaling-nan, > + so disable builtins if this is enabled. When fixed in a newer GCC, > + the __SUPPORT_SNAN__ check may be skipped for those versions. */ > + > /* Return number of classification appropriate for X. */ > -# ifdef __NO_LONG_DOUBLE_MATH > +# if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__ && !defined __OPTIMIZE_SIZE__ > +# define fpclassify(x) __builtin_fpclassify (FP_NAN, FP_INFINITE, \ > + FP_NORMAL, FP_SUBNORMAL, FP_ZERO, x) > +# elif defined __NO_LONG_DOUBLE_MATH > # define fpclassify(x) \ > (sizeof (x) == sizeof (float) ? __fpclassifyf (x) : __fpclassify (x)) > # else > @@ -229,32 +236,26 @@ enum > > /* Return nonzero value if sign of X is negative. */ > # if __GNUC_PREREQ (4,0) > -# ifdef __NO_LONG_DOUBLE_MATH > -# define signbit(x) \ > - (sizeof (x) == sizeof (float) \ > - ? __builtin_signbitf (x) : __builtin_signbit (x)) > -# else > -# define signbit(x) \ > - (sizeof (x) == sizeof (float) \ > - ? __builtin_signbitf (x) \ > - : sizeof (x) == sizeof (double) \ > +# define signbit(x) \ > + (sizeof (x) == sizeof (float) \ > + ? __builtin_signbitf (x) \ > + : sizeof (x) == sizeof (double) \ > ? __builtin_signbit (x) : __builtin_signbitl (x)) > -# endif > -# else > -# ifdef __NO_LONG_DOUBLE_MATH > -# define signbit(x) \ > +# elif defined __NO_LONG_DOUBLE_MATH > +# define signbit(x) \ > (sizeof (x) == sizeof (float) ? __signbitf (x) : __signbit (x)) > -# else > -# define signbit(x) \ > +# else > +# define signbit(x) \ > (sizeof (x) == sizeof (float) \ > ? __signbitf (x) \ > : sizeof (x) == sizeof (double) \ > ? __signbit (x) : __signbitl (x)) > -# endif > # endif > > /* Return nonzero value if X is not +-Inf or NaN. */ > -# ifdef __NO_LONG_DOUBLE_MATH > +# if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__ > +# define isfinite(x) __builtin_isfinite (x) > +# elif defined __NO_LONG_DOUBLE_MATH > # define isfinite(x) \ > (sizeof (x) == sizeof (float) ? __finitef (x) : __finite (x)) > # else > @@ -266,11 +267,17 @@ enum > # endif > > /* Return nonzero value if X is neither zero, subnormal, Inf, nor NaN. */ > -# define isnormal(x) (fpclassify (x) == FP_NORMAL) > +# if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__ > +# define isnormal(x) __builtin_isnormal (x) > +# else > +# define isnormal(x) (fpclassify (x) == FP_NORMAL) > +# endif > > /* Return nonzero value if X is a NaN. We could use `fpclassify' but > we already have this functions `__isnan' and it is faster. */ > -# ifdef __NO_LONG_DOUBLE_MATH > +# if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__ > +# define isnan(x) __builtin_isnan (x) > +# elif defined __NO_LONG_DOUBLE_MATH > # define isnan(x) \ > (sizeof (x) == sizeof (float) ? __isnanf (x) : __isnan (x)) > # else > @@ -282,7 +289,9 @@ enum > # endif > > /* Return nonzero value if X is positive or negative infinity. */ > -# ifdef __NO_LONG_DOUBLE_MATH > +# if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__ > +# define isinf(x) __builtin_isinf_sign (x) > +# elif defined __NO_LONG_DOUBLE_MATH > # define isinf(x) \ > (sizeof (x) == sizeof (float) ? __isinff (x) : __isinf (x)) > # else >
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 <wdijkstr@arm.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 submission.
> Joseph Myers wrote: > 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 <wdijkstr@arm.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 > submission. It was still in the quotes. Something like this? 2015-07-xx Wilco Dijkstra <wdijkstr@arm.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 - fixes [BZ #17441]. (isinf): Use __builtin_isinf_sign - fixes [BZ #15367].
On Wed, 22 Jul 2015, Wilco Dijkstra wrote: > > I don't see an updated ChangeLog entry (with the [BZ #N] notation I > > requested). Please include the ChangeLog entry with each patch > > submission. > > It was still in the quotes. Something like this? > > 2015-07-xx Wilco Dijkstra <wdijkstr@arm.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 - fixes [BZ #17441]. > (isinf): Use __builtin_isinf_sign - fixes [BZ #15367]. That's not the style used (and your line breaks are all wrong). <TAB>[BZ #N]<LF> at the start of the ChangeLog entry, after the initial author-date line and blank line and before the lines describing changes to each file.
"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 Andreas.
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
"Wilco Dijkstra" <Wilco.Dijkstra@arm.com> writes: > 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? Yes, that is correct. The references are not supposed to reappear. Andreas.
diff --git a/math/Makefile b/math/Makefile index 9a3cf32..f78d75b 100644 --- a/math/Makefile +++ b/math/Makefile @@ -155,6 +155,7 @@ CFLAGS-test-tgmath.c = -fno-builtin CFLAGS-test-tgmath2.c = -fno-builtin CFLAGS-test-tgmath-ret.c = -fno-builtin CFLAGS-test-powl.c = -fno-builtin +CFLAGS-test-snan.c = -fsignaling-nans CPPFLAGS-test-ifloat.c = -U__LIBC_INTERNAL_MATH_INLINES -D__FAST_MATH__ \ -DTEST_FAST_MATH -fno-builtin CPPFLAGS-test-idouble.c = -U__LIBC_INTERNAL_MATH_INLINES -D__FAST_MATH__ \ diff --git a/math/math.h b/math/math.h index 22f0989..1721118 100644 --- a/math/math.h +++ b/math/math.h @@ -215,8 +215,15 @@ enum FP_NORMAL }; +/* GCC bug 66462 means we cannot use the math builtins with -fsignaling-nan, + so disable builtins if this is enabled. When fixed in a newer GCC, + the __SUPPORT_SNAN__ check may be skipped for those versions. */ + /* Return number of classification appropriate for X. */ -# ifdef __NO_LONG_DOUBLE_MATH +# if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__ && !defined __OPTIMIZE_SIZE__ +# define fpclassify(x) __builtin_fpclassify (FP_NAN, FP_INFINITE, \ + FP_NORMAL, FP_SUBNORMAL, FP_ZERO, x) +# elif defined __NO_LONG_DOUBLE_MATH # define fpclassify(x) \ (sizeof (x) == sizeof (float) ? __fpclassifyf (x) : __fpclassify (x)) # else @@ -229,32 +236,26 @@ enum /* Return nonzero value if sign of X is negative. */ # if __GNUC_PREREQ (4,0) -# ifdef __NO_LONG_DOUBLE_MATH -# define signbit(x) \ - (sizeof (x) == sizeof (float) \ - ? __builtin_signbitf (x) : __builtin_signbit (x)) -# else -# define signbit(x) \ - (sizeof (x) == sizeof (float) \ - ? __builtin_signbitf (x) \ - : sizeof (x) == sizeof (double) \ +# define signbit(x) \ + (sizeof (x) == sizeof (float) \ + ? __builtin_signbitf (x) \ + : sizeof (x) == sizeof (double) \ ? __builtin_signbit (x) : __builtin_signbitl (x)) -# endif -# else -# ifdef __NO_LONG_DOUBLE_MATH -# define signbit(x) \ +# elif defined __NO_LONG_DOUBLE_MATH +# define signbit(x) \ (sizeof (x) == sizeof (float) ? __signbitf (x) : __signbit (x)) -# else -# define signbit(x) \ +# else +# define signbit(x) \ (sizeof (x) == sizeof (float) \ ? __signbitf (x) \ : sizeof (x) == sizeof (double) \ ? __signbit (x) : __signbitl (x)) -# endif # endif /* Return nonzero value if X is not +-Inf or NaN. */ -# ifdef __NO_LONG_DOUBLE_MATH +# if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__ +# define isfinite(x) __builtin_isfinite (x) +# elif defined __NO_LONG_DOUBLE_MATH # define isfinite(x) \ (sizeof (x) == sizeof (float) ? __finitef (x) : __finite (x)) # else @@ -266,11 +267,17 @@ enum # endif /* Return nonzero value if X is neither zero, subnormal, Inf, nor NaN. */ -# define isnormal(x) (fpclassify (x) == FP_NORMAL) +# if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__ +# define isnormal(x) __builtin_isnormal (x) +# else +# define isnormal(x) (fpclassify (x) == FP_NORMAL) +# endif /* Return nonzero value if X is a NaN. We could use `fpclassify' but we already have this functions `__isnan' and it is faster. */ -# ifdef __NO_LONG_DOUBLE_MATH +# if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__ +# define isnan(x) __builtin_isnan (x) +# elif defined __NO_LONG_DOUBLE_MATH # define isnan(x) \ (sizeof (x) == sizeof (float) ? __isnanf (x) : __isnan (x)) # else @@ -282,7 +289,9 @@ enum # endif /* Return nonzero value if X is positive or negative infinity. */ -# ifdef __NO_LONG_DOUBLE_MATH +# if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__ +# define isinf(x) __builtin_isinf_sign (x) +# elif defined __NO_LONG_DOUBLE_MATH # define isinf(x) \ (sizeof (x) == sizeof (float) ? __isinff (x) : __isinf (x)) # else