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[PATCH 01/05] Math optimizations for POWER8


POWER8 follows ISA 2.07 and it adds the mfvsrd/mtvsrd instruction class to
transfer data between GRP register to/from FPR register without the need of
memory access. These instructions shows a better latency than the sequence
std,...,ld which may create load-hit-stores and stalls in some CPUs. 

These patches add a slight more optimized implementations of
isnan/isinf/finite/llround/llrint using these instruction to gains some
cycles by avoiding the possible load-hit-store of FP<->INT conversion.

Tested on powerpc64 and powerpc64le.

---

2014-02-17  Adhemerval Zanella  <azanella@linux.vnet.ibm.com>

        * sysdeps/powerpc/powerpc32/power4/multiarch/init-arch.h (INIT_ARCH):
	Add hwcap2 initialization.
        * sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile: Add isnan power8
	implementation.
        * sysdeps/powerpc/powerpc64/fpu/multiarch/s_isnan-power8.S: New file:
	POWER8 isnan ifunc implementation.
        * sysdeps/powerpc/powerpc64/fpu/multiarch/s_isnan.c (__isnan): Add
	POWER8 implementation.
        * sysdeps/powerpc/powerpc64/fpu/multiarch/s_isnanf.c (__isnanf):
	Likewise.
	* sysdeps/powerpc/powerpc64/power8/fpu/s_isnan.S: New file:
	POWER8 isnan implementation.
	* sysdeps/powerpc/powerpc64/power8/fpu/s_isnanf.S: New file.

--

diff --git a/sysdeps/powerpc/powerpc32/power4/multiarch/init-arch.h b/sysdeps/powerpc/powerpc32/power4/multiarch/init-arch.h
index 51a34f2..72d720d 100644
--- a/sysdeps/powerpc/powerpc32/power4/multiarch/init-arch.h
+++ b/sysdeps/powerpc/powerpc32/power4/multiarch/init-arch.h
@@ -36,6 +36,7 @@
    and fills the previous ones.  */
 #define INIT_ARCH() \
   unsigned long int hwcap = __GLRO(dl_hwcap); 			\
+  unsigned long int __attribute__((unused)) hwcap2 = __GLRO(dl_hwcap2); \
   if (hwcap & PPC_FEATURE_ARCH_2_06)				\
     hwcap |= PPC_FEATURE_ARCH_2_05 |				\
 	     PPC_FEATURE_POWER5_PLUS |				\
diff --git a/sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile b/sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile
index ebf957e..124d325 100644
--- a/sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile
+++ b/sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile
@@ -4,7 +4,7 @@ sysdep_routines += s_isnan-power7 s_isnan-power6x s_isnan-power6 \
 		   s_copysign-ppc64 s_finite-power7 s_finite-ppc64 \
 		   s_finitef-ppc64 s_isinff-ppc64 s_isinf-power7 \
 		   s_isinf-ppc64 s_modf-power5+ s_modf-ppc64 \
-		   s_modff-power5+ s_modff-ppc64
+		   s_modff-power5+ s_modff-ppc64 s_isnan-power8
 
 libm-sysdep_routines += s_isnan-power7 s_isnan-power6x s_isnan-power6 \
 			s_isnan-power5 s_isnan-ppc64 s_llround-power6x \
@@ -21,7 +21,8 @@ libm-sysdep_routines += s_isnan-power7 s_isnan-power6x s_isnan-power6 \
 			s_logbl-power7 s_logb-ppc64 s_logbf-ppc64 \
 			s_logbl-ppc64 s_modf-power5+ s_modf-ppc64 \
 			s_modff-power5+ s_modff-ppc64 e_hypot-ppc64 \
-			e_hypot-power7 e_hypotf-ppc64 e_hypotf-power7
+			e_hypot-power7 e_hypotf-ppc64 e_hypotf-power7 \
+			s_isnan-power8
 
 CFLAGS-s_logbf-power7.c = -mcpu=power7
 CFLAGS-s_logbl-power7.c = -mcpu=power7
diff --git a/sysdeps/powerpc/powerpc64/fpu/multiarch/s_isnan-power8.S b/sysdeps/powerpc/powerpc64/fpu/multiarch/s_isnan-power8.S
new file mode 100644
index 0000000..337e06f
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/fpu/multiarch/s_isnan-power8.S
@@ -0,0 +1,33 @@
+/* isnan().  PowerPC64/POWER7 version.
+   Copyright (C) 2013 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 hidden_def
+#define hidden_def(name)
+#undef weak_alias
+#define weak_alias(name, alias)
+#undef strong_alias
+#define strong_alias(name, alias)
+#undef compat_symbol
+#define compat_symbol(lib, name, symbol, ver)
+
+#define __isnan __isnan_power8
+
+#include <sysdeps/powerpc/powerpc64/power8/fpu/s_isnan.S>
diff --git a/sysdeps/powerpc/powerpc64/fpu/multiarch/s_isnan.c b/sysdeps/powerpc/powerpc64/fpu/multiarch/s_isnan.c
index 0de833e..65a5ca0 100644
--- a/sysdeps/powerpc/powerpc64/fpu/multiarch/s_isnan.c
+++ b/sysdeps/powerpc/powerpc64/fpu/multiarch/s_isnan.c
@@ -26,16 +26,19 @@ extern __typeof (__isnan) __isnan_power5 attribute_hidden;
 extern __typeof (__isnan) __isnan_power6 attribute_hidden;
 extern __typeof (__isnan) __isnan_power6x attribute_hidden;
 extern __typeof (__isnan) __isnan_power7 attribute_hidden;
+extern __typeof (__isnan) __isnan_power8 attribute_hidden;
 
 libc_ifunc (__isnan,
-	    (hwcap & PPC_FEATURE_ARCH_2_06)
-	    ? __isnan_power7 :
-	      (hwcap & PPC_FEATURE_POWER6_EXT)
+	    (hwcap2 & PPC_FEATURE2_ARCH_2_07)
+	    ? __isnan_power8 :
+	      (hwcap & PPC_FEATURE_ARCH_2_06)
+	      ? __isnan_power7 :
+		(hwcap & PPC_FEATURE_POWER6_EXT)
 		? __isnan_power6x :
-		(hwcap & PPC_FEATURE_ARCH_2_05)
-		  ? __isnan_power6 :
-		  (hwcap & PPC_FEATURE_POWER5)
-		    ? __isnan_power5
+		  (hwcap & PPC_FEATURE_ARCH_2_05)
+		    ? __isnan_power6 :
+		    (hwcap & PPC_FEATURE_POWER5)
+		      ? __isnan_power5
             : __isnan_ppc64);
 
 weak_alias (__isnan, isnan)
diff --git a/sysdeps/powerpc/powerpc64/fpu/multiarch/s_isnanf.c b/sysdeps/powerpc/powerpc64/fpu/multiarch/s_isnanf.c
index b237455..eb68a50 100644
--- a/sysdeps/powerpc/powerpc64/fpu/multiarch/s_isnanf.c
+++ b/sysdeps/powerpc/powerpc64/fpu/multiarch/s_isnanf.c
@@ -25,16 +25,19 @@ extern __typeof (__isnanf) __isnan_power5 attribute_hidden;
 extern __typeof (__isnanf) __isnan_power6 attribute_hidden;
 extern __typeof (__isnanf) __isnan_power6x attribute_hidden;
 extern __typeof (__isnanf) __isnan_power7 attribute_hidden;
+extern __typeof (__isnanf) __isnan_power8 attribute_hidden;
 
 libc_ifunc (__isnanf,
-	    (hwcap & PPC_FEATURE_ARCH_2_06)
-	    ? __isnan_power7 :
-	      (hwcap & PPC_FEATURE_POWER6_EXT)
-		? __isnan_power6x :
-		(hwcap & PPC_FEATURE_ARCH_2_05)
-		  ? __isnan_power6 :
-		  (hwcap & PPC_FEATURE_POWER5)
-		    ? __isnan_power5
+	    (hwcap2 & PPC_FEATURE2_ARCH_2_07)
+	    ? __isnan_power8 :
+	      (hwcap & PPC_FEATURE_ARCH_2_06)
+	      ? __isnan_power7 :
+		(hwcap & PPC_FEATURE_POWER6_EXT)
+		  ? __isnan_power6x :
+		  (hwcap & PPC_FEATURE_ARCH_2_05)
+		    ? __isnan_power6 :
+		    (hwcap & PPC_FEATURE_POWER5)
+		      ? __isnan_power5
             : __isnan_ppc64);
 
 weak_alias (__isnanf, isnanf)
diff --git a/sysdeps/powerpc/powerpc64/power8/fpu/s_isnan.S b/sysdeps/powerpc/powerpc64/power8/fpu/s_isnan.S
new file mode 100644
index 0000000..d41be3d
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/power8/fpu/s_isnan.S
@@ -0,0 +1,52 @@
+/* isnan().  PowerPC64/POWER8 version.
+   Copyright (C) 2013 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>
+
+/* int [r3] __isnan([f1] x)  */
+
+	.machine   power8
+EALIGN (__isnan, 4, 0)
+	CALL_MCOUNT 0
+	mfvsrd  r3,v1         /* r3 = fp1 bitwise  */
+	lis     r9,0x7ff0
+	clrldi  r3,r3,1       /* r3 = r3 & 0x8000000000000000  */
+	rldicr  r9,r9,32,31   /* r9 = (r9 << 32) & 0xffffffff  */
+	subf    r3,r3,r9
+	rldicl  r3,r3,1,63
+	blr
+END (__isnan)
+
+/* It turns out that the 'double' version will also always work for
+   single-precision.  */
+strong_alias (__isnan, __isnanf)
+hidden_def (__isnanf)
+weak_alias (__isnanf, isnanf)
+
+#ifdef NO_LONG_DOUBLE
+strong_alias (__isnan, __isnanl)
+weak_alias (__isnan, isnanl)
+#endif
+
+#ifndef IS_IN_libm
+# if LONG_DOUBLE_COMPAT(libc, GLIBC_2_0)
+compat_symbol (libc, __isnan, __isnanl, GLIBC_2_0);
+compat_symbol (libc, isnan, isnanl, GLIBC_2_0);
+# endif
+#endif
diff --git a/sysdeps/powerpc/powerpc64/power8/fpu/s_isnanf.S b/sysdeps/powerpc/powerpc64/power8/fpu/s_isnanf.S
new file mode 100644
index 0000000..b48c85e
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/power8/fpu/s_isnanf.S
@@ -0,0 +1 @@
+/* This function uses the same code as s_isnan.S.  */ 


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