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

Impact: micro-optimization

This should slightly improve its performance.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <49B8F641.76E4.0078.0@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S
index c22981fa2f3a95240f3a4c99d00da41d1b7392ec..10c067694af4630072795a125927cf413251805f 100644 (file)
--- a/arch/x86/lib/memcpy_64.S
+++ b/arch/x86/lib/memcpy_64.S
@@ -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)