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Commit dd1ef4ec authored Mar 12, 2009 by Jan Beulich Committed by Ingo Molnar Mar 12, 2009

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>

parent c2810188

arch/x86/lib/memcpy_64.S

+0 −7

Original line number	Original line	Diff line number	Diff line
	@@ -33,9 +33,6 @@ ENDPROC(memcpy_c)
	ENTRY(__memcpy)		ENTRY(__memcpy)
	ENTRY(memcpy)		ENTRY(memcpy)
	CFI_STARTPROC		CFI_STARTPROC
	pushq %rbx
	CFI_ADJUST_CFA_OFFSET 8
	CFI_REL_OFFSET rbx, 0
	movq %rdi,%rax		movq %rdi,%rax

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

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