llvm-6502/test/CodeGen/X86/inline-asm-sp-clobber-memcpy.ll
Hans Wennborg 523f800e90 X86 memcpy lowering: use "rep movs" even when esi is used as base pointer
For functions where esi is used as base pointer, we would previously fall back
from lowering memcpy with "rep movs" because that clobbers esi.

With this patch, we just store esi in another physical register, and restore
it afterwards. This adds a little bit of register preassure, but the more
efficient memcpy should be worth it.

Differential Revision: http://llvm-reviews.chandlerc.com/D2968

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204174 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-18 20:04:34 +00:00

20 lines
647 B
LLVM

; RUN: llc < %s -force-align-stack -mtriple i386-apple-darwin -mcpu=i486 | FileCheck %s
%struct.foo = type { [88 x i8] }
declare void @bar(i8* nocapture, %struct.foo* align 4 byval) nounwind
; PR19012
; Don't clobber %esi if we have inline asm that clobbers %esp.
define void @test1(%struct.foo* nocapture %x, i32 %y, i8* %z) nounwind {
call void @bar(i8* %z, %struct.foo* align 4 byval %x)
call void asm sideeffect inteldialect "xor esp, esp", "=*m,~{flags},~{esp},~{esp},~{dirflag},~{fpsr},~{flags}"(i8* %z)
ret void
; CHECK-LABEL: test1:
; CHECK: movl %esp, %esi
; CHECK: movl %esi, %edx
; CHECK: rep;movsl
; CHECK: movl %edx, %esi
}