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From: Roland McGrath <roland@hack.frob.com>
To: libc-ports@sourceware.org
Subject: [PATCH roland/arm-memcpy] ARM: Make multiarch memcpy always use   NEON when compiler does
Date: Mon, 13 May 2013 22:47:00 -0000	[thread overview]
Message-ID: <20130513224722.9F17C2C05E@topped-with-meat.com> (raw)

When the compiler is emitting NEON instructions anyway, there is no point
in using IFUNC when we can just use the NEON memcpy unconditionally.

Tested on armv7l-linux-gnueabihf with CC='gcc -mfpu=neon',
no check-abi failures, no regressions in 'make check subdirs=string'.


Thanks,
Roland


ports/ChangeLog.arm
2013-05-13  Roland McGrath  <roland@hack.frob.com>

	* sysdeps/arm/armv7/multiarch/memcpy.S [__ARM_NEON__]: Don't define
	memcpy here, just __memcpy_arm and __aeabi_memcpy*.
	* sysdeps/arm/armv7/multiarch/memcpy_neon.S [__ARM_NEON__]:
	Define memcpy here, not __memcpy_neon.
	* sysdeps/arm/armv7/multiarch/memcpy_vfp.S [__ARM_NEON__]:
	Define nothing here.
	* sysdeps/arm/armv7/multiarch/ifunc-impl-list.c
	(__libc_ifunc_impl_list) [__ARM_NEON__]: Don't list __memcpy_vfp;
	use memcpy name for NEON implementation.

--- a/ports/sysdeps/arm/armv7/multiarch/ifunc-impl-list.c
+++ b/ports/sysdeps/arm/armv7/multiarch/ifunc-impl-list.c
@@ -35,9 +35,16 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 
   IFUNC_IMPL (i, name, memcpy,
 	      IFUNC_IMPL_ADD (array, i, memcpy, hwcap & HWCAP_ARM_NEON,
-			      __memcpy_neon)
+#ifdef __ARM_NEON__
+                              memcpy
+#else
+			      __memcpy_neon
+#endif
+                              )
+#ifndef __ARM_NEON__
 	      IFUNC_IMPL_ADD (array, i, memcpy, hwcap & HWCAP_ARM_VFP,
 			      __memcpy_vfp)
+#endif
 	      IFUNC_IMPL_ADD (array, i, memcpy, 1, __memcpy_arm));
 
   return i;
--- a/ports/sysdeps/arm/armv7/multiarch/memcpy.S
+++ b/ports/sysdeps/arm/armv7/multiarch/memcpy.S
@@ -22,27 +22,29 @@
 #include <sysdep.h>
 #include <rtld-global-offsets.h>
 
-#if !defined NOT_IN_libc
+#ifndef NOT_IN_libc
+/* Under __ARM_NEON__, memcpy_neon.S defines the name memcpy.  */
+# ifndef __ARM_NEON__
 	.text
 ENTRY(memcpy)
 	.type	memcpy, %gnu_indirect_function
-#ifdef __SOFTFP__
+# ifdef __SOFTFP__
 	ldr	r1, .Lmemcpy_arm
 	tst	r0, #HWCAP_ARM_VFP
 	ldrne	r1, .Lmemcpy_vfp
-#else
+# else
 	ldr	r1, .Lmemcpy_vfp
-#endif
+# endif
 	tst	r0, #HWCAP_ARM_NEON
 	ldrne	r1, .Lmemcpy_neon
 1:
 	add	r0, r1, pc
 	DO_RET(lr)
 
-#ifdef __SOFTFP__
+# ifdef __SOFTFP__
 .Lmemcpy_arm:
 	.long	C_SYMBOL_NAME(__memcpy_arm) - 1b - PC_OFS
-#endif
+# endif
 .Lmemcpy_neon:
 	.long	C_SYMBOL_NAME(__memcpy_neon) - 1b - PC_OFS
 .Lmemcpy_vfp:
@@ -51,6 +53,7 @@ ENTRY(memcpy)
 END(memcpy)
 
 libc_hidden_builtin_def (memcpy)
+#endif  /* Not __ARM_NEON__.  */
 
 /* These versions of memcpy are defined not to clobber any VFP or NEON
    registers so they must always call the ARM variant of the memcpy code.  */
--- a/ports/sysdeps/arm/armv7/multiarch/memcpy_neon.S
+++ b/ports/sysdeps/arm/armv7/multiarch/memcpy_neon.S
@@ -1,3 +1,9 @@
+#ifdef __ARM_NEON__
+/* Under __ARM_NEON__, this file defines memcpy directly.  */
+libc_hidden_builtin_def (memcpy)
+#else
+# define memcpy __memcpy_neon
+#endif
+
 #define MEMCPY_NEON
-#define memcpy __memcpy_neon
 #include "memcpy_impl.S"
--- a/ports/sysdeps/arm/armv7/multiarch/memcpy_vfp.S
+++ b/ports/sysdeps/arm/armv7/multiarch/memcpy_vfp.S
@@ -1,3 +1,7 @@
-#define MEMCPY_VFP
-#define memcpy __memcpy_vfp
-#include "memcpy_impl.S"
+/* Under __ARM_NEON__, memcpy_neon.S defines memcpy directly
+   and the __memcpy_vfp code will never be used.  */
+#ifndef __ARM_NEON__
+# define MEMCPY_VFP
+# define memcpy __memcpy_vfp
+# include "memcpy_impl.S"
+#endif

             reply	other threads:[~2013-05-13 22:47 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-13 22:47 Roland McGrath [this message]
2013-05-13 23:12 ` Joseph S. Myers
2013-05-14  7:47 ` Andreas Schwab
2013-05-17  0:31   ` Roland McGrath
2013-05-14 15:47 ` Richard Henderson
2013-05-17  0:32   ` Roland McGrath

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