[PATCH] x86-64: remove unnecessary spill/reload of rbx from memcpy

From: Jan Beulich
Date: Thu Mar 12 2009 - 06:46:44 EST


This should slightly improve its performance.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

---
arch/x86/lib/memcpy_64.S | 7 -------
1 file changed, 7 deletions(-)

--- linux-2.6.29-rc7/arch/x86/lib/memcpy_64.S 2008-01-24 23:58:37.000000000 +0100
+++ 2.6.29-rc7-x86_64-memcpy-rbx/arch/x86/lib/memcpy_64.S 2008-12-18 10:58:11.000000000 +0100
@@ -33,9 +33,6 @@ ENDPROC(memcpy_c)
ENTRY(__memcpy)
ENTRY(memcpy)
CFI_STARTPROC
- pushq %rbx
- CFI_ADJUST_CFA_OFFSET 8
- CFI_REL_OFFSET rbx, 0
movq %rdi,%rax

movl %edx,%ecx
@@ -102,11 +99,7 @@ ENTRY(memcpy)
jnz .Lloop_1

.Lende:
- popq %rbx
- CFI_ADJUST_CFA_OFFSET -8
- CFI_RESTORE rbx
ret
-.Lfinal:
CFI_ENDPROC
ENDPROC(memcpy)
ENDPROC(__memcpy)



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