PowerPC: llround/llroundf POWER8 optimization

This patch add a optimized llround/llroundf implementation for POWER8
using the new Move From VSR Doubleword instruction to gains some
cycles from FP to GRP register move.

4 files changed, 86 insertions, 5 deletions

diff --git a/sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile b/sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile
index f88247892b..0e3eac7190 100644
--- a/sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile
+++ b/sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile
@@ -24,7 +24,7 @@ libm-sysdep_routines += s_isnan-power7 s_isnan-power6x s_isnan-power6 \
 			s_modff-power5+ s_modff-ppc64 e_hypot-ppc64 \
 			e_hypot-power7 e_hypotf-ppc64 e_hypotf-power7 \
 			s_isnan-power8 s_isinf-power8 s_finite-power8 \
-			s_llrint-power8
+			s_llrint-power8 s_llround-power8
 
 CFLAGS-s_logbf-power7.c = -mcpu=power7
 CFLAGS-s_logbl-power7.c = -mcpu=power7
diff --git a/sysdeps/powerpc/powerpc64/fpu/multiarch/s_llround-power8.S b/sysdeps/powerpc/powerpc64/fpu/multiarch/s_llround-power8.S
new file mode 100644
index 0000000000..41c61a1bc8
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/fpu/multiarch/s_llround-power8.S
@@ -0,0 +1,31 @@
+/* llround().  PowerPC64 default version.
+   Copyright (C) 2014 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+#include <math_ldbl_opt.h>
+
+#undef weak_alias
+#define weak_alias(name, alias)
+#undef strong_alias
+#define strong_alias(name, alias)
+#undef compat_symbol
+#define compat_symbol(lib, name, alias, ver)
+
+#define __llround __llround_power8
+
+#include <sysdeps/powerpc/powerpc64/power8/fpu/s_llround.S>
diff --git a/sysdeps/powerpc/powerpc64/fpu/multiarch/s_llround.c b/sysdeps/powerpc/powerpc64/fpu/multiarch/s_llround.c
index a4d1bf3a2a..7dba17e96e 100644
--- a/sysdeps/powerpc/powerpc64/fpu/multiarch/s_llround.c
+++ b/sysdeps/powerpc/powerpc64/fpu/multiarch/s_llround.c
@@ -27,12 +27,15 @@
 extern __typeof (__llround) __llround_ppc64 attribute_hidden;
 extern __typeof (__llround) __llround_power5plus attribute_hidden;
 extern __typeof (__llround) __llround_power6x attribute_hidden;
+extern __typeof (__llround) __llround_power8 attribute_hidden;
 
 libc_ifunc (__llround,
-	    (hwcap & PPC_FEATURE_POWER6_EXT)
-	    ? __llround_power6x :
-	      (hwcap & PPC_FEATURE_POWER5_PLUS)
-	      ? __llround_power5plus
+	    (hwcap2 & PPC_FEATURE2_ARCH_2_07)
+	    ? __llround_power8 :
+	      (hwcap & PPC_FEATURE_POWER6_EXT)
+	      ? __llround_power6x :
+		(hwcap & PPC_FEATURE_POWER5_PLUS)
+		? __llround_power5plus
             : __llround_ppc64);
 
 weak_alias (__llround, llround)
diff --git a/sysdeps/powerpc/powerpc64/power8/fpu/s_llround.S b/sysdeps/powerpc/powerpc64/power8/fpu/s_llround.S
new file mode 100644
index 0000000000..b00d4d616f
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/power8/fpu/s_llround.S
@@ -0,0 +1,47 @@
+/* llround function.  POWER8 PowerPC64 version.
+   Copyright (C) 2014 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+#include <math_ldbl_opt.h>
+
+#define MFVSRD_R3_V1  .byte 0x7c,0x23,0x00,0x66     /* mfvsrd  r3,vs1  */
+
+/* long long [r3] llround (float x [fp1])  */
+
+ENTRY (__llround)
+	CALL_MCOUNT 0
+	frin	fp1,fp1	/* Round to nearest +-0.5.  */
+	fctidz	fp1,fp1	/* Convert To Integer DW round toward 0.  */
+	MFVSRD_R3_V1
+	blr
+END (__llround)
+
+strong_alias (__llround, __lround)
+weak_alias (__llround, llround)
+weak_alias (__lround, lround)
+
+#ifdef NO_LONG_DOUBLE
+weak_alias (__llround, llroundl)
+strong_alias (__llround, __llroundl)
+weak_alias (__lround, lroundl)
+strong_alias (__lround, __lroundl)
+#endif
+#if LONG_DOUBLE_COMPAT(libm, GLIBC_2_1)
+compat_symbol (libm, __llround, llroundl, GLIBC_2_1)
+compat_symbol (libm, __lround, lroundl, GLIBC_2_1)
+#endif