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author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2019-03-11 03:29:37 +0000 |
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committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2019-06-12 14:32:39 -0300 |
commit | 119269606996258ee0a53ff9e5828d474ee0f698 (patch) | |
tree | a8b24ad011f24ce14d08aea07f6eeab4735dcbbf /sysdeps/powerpc/powerpc64/power7 | |
parent | a72186761b2ed913fd5ea3df2de2aa446456aa98 (diff) | |
download | glibc-119269606996258ee0a53ff9e5828d474ee0f698.tar.gz glibc-119269606996258ee0a53ff9e5828d474ee0f698.tar.xz glibc-119269606996258ee0a53ff9e5828d474ee0f698.zip |
powerpc: Remove optimized finite
The powerpc finite optimization do not show much gain: - GCC will call libm iff -fsignaling-nans is used. This usage pattern is usually not performance oriented and for such calls PLT overhead should dominate execution time. - The power7 uses ftdiv to optimize for some input patterns, but at cost of others. Comparing against generic C implementation built for powerpc64-linux-gnu-power7 (--with-cpu=power7): - Generic sysdeps/ieee754 implementation: "isfinite": { "": { "duration": 5.0082e+09, "iterations": 2.45299e+09, "max": 43.824, "min": 2.008, "mean": 2.04167 }, "INF": { "duration": 4.66554e+09, "iterations": 2.28288e+09, "max": 35.73, "min": 2.008, "mean": 2.04371 }, "NAN": { "duration": 4.66274e+09, "iterations": 2.28716e+09, "max": 34.161, "min": 2.009, "mean": 2.03866 } } - power7 optimized one: "isfinite": { "": { "duration": 4.99111e+09, "iterations": 2.65566e+09, "max": 25.015, "min": 1.716, "mean": 1.87942 }, "INF": { "duration": 4.6783e+09, "iterations": 2.0999e+09, "max": 35.264, "min": 1.868, "mean": 2.22787 }, "NAN": { "duration": 4.67915e+09, "iterations": 2.08678e+09, "max": 38.099, "min": 1.869, "mean": 2.24228 } } So it basically optimizes marginally for normal numbers while increasing the latency for other kind of FP. - The power8 implementation is just the generic implementation using ISA 2.07 mfvsrd instruction (which GCC uses for generic implementation). So generic implementation is the best option for powerpc64le. Checked on powerpc-linux-gnu (built without --with-cpu, with --with-cpu=power4 and with --with-cpu=power5+ and --disable-multi-arch), powerpc64-linux-gnu (built without --with-cp and with --with-cpu=power5+ and --disable-multi-arch). * sysdeps/powerpc/powerpc32/power4/fpu/multiarch/Makefile (sysdeps_routines, libm-sysdep_routines): Remove s_finite* objects. * sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_finite-power7.S: Remove file. * sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_finite-ppc32.c: Likewise. * sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_finite.c: Likewise. * sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_finitef-ppc32.c: Likewise. * sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_finitef.c: Likewise. * sysdeps/powerpc/powerpc32/power7/fpu/s_finite.S: Likewise. * sysdeps/powerpc/powerpc32/power7/fpu/s_finitef.S: Likewise. * sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile (sysdep_call): Remove s_finite* objects. * sysdeps/powerpc/powerpc64/fpu/multiarch/s_finite-power7.S: Remove file. * sysdeps/powerpc/powerpc64/fpu/multiarch/s_finite-power8.S: Likewise. * sysdeps/powerpc/powerpc64/fpu/multiarch/s_finite-ppc64.c: Likewise. * sysdeps/powerpc/powerpc64/fpu/multiarch/s_finite.c: Likewise. * sysdeps/powerpc/powerpc64/fpu/multiarch/s_finitef-ppc64.c: Likewise. * sysdeps/powerpc/powerpc64/fpu/multiarch/s_finitef.c: Likewise. * sysdeps/powerpc/powerpc64/power7/fpu/s_finite.S: Likewise. * sysdeps/powerpc/powerpc64/power7/fpu/s_finitef.S: Likewise. * sysdeps/powerpc/powerpc64/power8/fpu/s_finite.S: Likewise. * sysdeps/powerpc/powerpc64/power8/fpu/s_finitef.S: Likewise. Reviewed-by: Gabriel F. T. Gomes <gabrielftg@linux.ibm.com>
Diffstat (limited to 'sysdeps/powerpc/powerpc64/power7')
-rw-r--r-- | sysdeps/powerpc/powerpc64/power7/fpu/s_finite.S | 70 | ||||
-rw-r--r-- | sysdeps/powerpc/powerpc64/power7/fpu/s_finitef.S | 1 |
2 files changed, 0 insertions, 71 deletions
diff --git a/sysdeps/powerpc/powerpc64/power7/fpu/s_finite.S b/sysdeps/powerpc/powerpc64/power7/fpu/s_finite.S deleted file mode 100644 index 5b5746c9a5..0000000000 --- a/sysdeps/powerpc/powerpc64/power7/fpu/s_finite.S +++ /dev/null @@ -1,70 +0,0 @@ -/* finite(). PowerPC64/POWER7 version. - Copyright (C) 2010-2019 Free Software Foundation, Inc. - Contributed by Luis Machado <luisgpm@br.ibm.com>. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - <http://www.gnu.org/licenses/>. */ - -#include <sysdep.h> -#include <math_ldbl_opt.h> - -/* int __finite(x) */ - .section ".toc","aw" -.LC0: /* 1.0 */ - .tc FD_ONE[TC],0x3ff0000000000000 - .section ".text" - .type __finite, @function - .machine power7 -ENTRY (__finite, 4) - CALL_MCOUNT 0 - lfd fp0,.LC0@toc(r2) - ftdiv cr7,fp1,fp0 - li r3,1 - bflr 30 - - /* If we are here, we either have +/-INF, - NaN or denormal. */ - - stfd fp1,-16(r1) /* Transfer FP to GPR's. */ - ori 2,2,0 /* Force a new dispatch group. */ - lhz r4,-16+HISHORT(r1) /* Fetch the upper 16 bits of the FP value - (biased exponent and sign bit). */ - clrlwi r4,r4,17 /* r4 = abs(r4). */ - cmpwi cr7,r4,0x7ff0 /* r4 == 0x7ff0? */ - bltlr cr7 /* LT means finite, other non-finite. */ - li r3,0 - blr - END (__finite) - -hidden_def (__finite) -weak_alias (__finite, finite) - -/* It turns out that the 'double' version will also always work for - single-precision. */ -strong_alias (__finite, __finitef) -hidden_def (__finitef) -weak_alias (__finitef, finitef) - -#if IS_IN (libm) -# if LONG_DOUBLE_COMPAT (libm, GLIBC_2_0) -compat_symbol (libm, __finite, __finitel, GLIBC_2_0) -compat_symbol (libm, finite, finitel, GLIBC_2_0) -# endif -#else -# if LONG_DOUBLE_COMPAT (libc, GLIBC_2_0) -compat_symbol (libc, __finite, __finitel, GLIBC_2_0); -compat_symbol (libc, finite, finitel, GLIBC_2_0); -# endif -#endif diff --git a/sysdeps/powerpc/powerpc64/power7/fpu/s_finitef.S b/sysdeps/powerpc/powerpc64/power7/fpu/s_finitef.S deleted file mode 100644 index 54bd94176d..0000000000 --- a/sysdeps/powerpc/powerpc64/power7/fpu/s_finitef.S +++ /dev/null @@ -1 +0,0 @@ -/* This function uses the same code as s_finite.S. */ |