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b82f8a28e8
> For functions where esi is used as base pointer, we would previously fall ba > 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 This didn't work. I was ending up with code like this: lea edi,[esi+38h] mov ecx,0Fh mov edx,esi mov esi,ebx rep movs dword ptr es:[edi],dword ptr [esi] lea ecx,[esi+74h] <-- Ooops, we're now using esi before restoring it from edx. add ebx,3Ch mov esi,edx I guess if we want to do this we need stronger glue or something, or doing the expansion much later. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204829 91177308-0d34-0410-b5e6-96231b3b80d8
18 lines
601 B
LLVM
18 lines
601 B
LLVM
; RUN: llc < %s -force-align-stack -mtriple i386-apple-darwin -mcpu=i486 | FileCheck %s
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%struct.foo = type { [88 x i8] }
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declare void @bar(i8* nocapture, %struct.foo* align 4 byval) nounwind
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; PR19012
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; Don't clobber %esi if we have inline asm that clobbers %esp.
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define void @test1(%struct.foo* nocapture %x, i32 %y, i8* %z) nounwind {
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call void @bar(i8* %z, %struct.foo* align 4 byval %x)
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call void asm sideeffect inteldialect "xor esp, esp", "=*m,~{flags},~{esp},~{esp},~{dirflag},~{fpsr},~{flags}"(i8* %z)
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ret void
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; CHECK-LABEL: test1:
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; CHECK: movl %esp, %esi
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; CHECK-NOT: rep;movsl
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}
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