From 119269606996258ee0a53ff9e5828d474ee0f698 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Mon, 11 Mar 2019 03:29:37 +0000 Subject: 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 --- sysdeps/powerpc/powerpc64/power8/fpu/s_finite.S | 56 ------------------------- 1 file changed, 56 deletions(-) delete mode 100644 sysdeps/powerpc/powerpc64/power8/fpu/s_finite.S (limited to 'sysdeps/powerpc/powerpc64/power8/fpu/s_finite.S') diff --git a/sysdeps/powerpc/powerpc64/power8/fpu/s_finite.S b/sysdeps/powerpc/powerpc64/power8/fpu/s_finite.S deleted file mode 100644 index f5316e898f..0000000000 --- a/sysdeps/powerpc/powerpc64/power8/fpu/s_finite.S +++ /dev/null @@ -1,56 +0,0 @@ -/* isfinite(). PowerPC64/POWER8 version. - Copyright (C) 2014-2019 Free Software Foundation, Inc. - 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 - . */ - -#include -#include - -#define MFVSRD_R3_V1 .long 0x7c230066 /* mfvsrd r3,vs1 */ - -/* int [r3] __finite ([fp1] x) */ - -ENTRY_TOCLESS (__finite, 4) - CALL_MCOUNT 0 - MFVSRD_R3_V1 - lis r9,0x8010 - clrldi r3,r3,1 /* r3 = r3 & 0x8000000000000000 */ - rldicr r9,r9,32,31 /* r9 = (r9 << 32) & 0xffffffff */ - add r3,r3,r9 - rldicl r3,r3,1,63 - 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 -- cgit 1.4.1