1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-10-29 23:12:55 +01:00
llvm-mirror/test/CodeGen/X86/stack-align-memcpy.ll
Hans Wennborg 114745e7d4 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

llvm-svn: 204174
2014-03-18 20:04:34 +00:00

49 lines
1.4 KiB
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
declare void @baz(i8*) nounwind
; PR15249
; We can't use rep;movsl here because it clobbers the base pointer in %esi.
define void @test1(%struct.foo* nocapture %x, i32 %y) nounwind {
%dynalloc = alloca i8, i32 %y, align 1
call void @bar(i8* %dynalloc, %struct.foo* align 4 byval %x)
ret void
; CHECK-LABEL: test1:
; CHECK: andl $-16, %esp
; CHECK: movl %esp, %esi
; CHECK: movl %esi, %edx
; CHECK: rep;movsl
; CHECK: movl %edx, %esi
}
; PR19012
; Also don't clobber %esi if the dynamic alloca comes after the memcpy.
define void @test2(%struct.foo* nocapture %x, i32 %y, i8* %z) nounwind {
call void @bar(i8* %z, %struct.foo* align 4 byval %x)
%dynalloc = alloca i8, i32 %y, align 1
call void @baz(i8* %dynalloc)
ret void
; CHECK-LABEL: test2:
; CHECK: movl %esp, %esi
; CHECK: movl %esi, %edx
; CHECK: rep;movsl
; CHECK: movl %edx, %esi
}
; Check that we do use rep movs if we make the alloca static.
define void @test3(%struct.foo* nocapture %x, i32 %y, i8* %z) nounwind {
call void @bar(i8* %z, %struct.foo* align 4 byval %x)
%statalloc = alloca i8, i32 8, align 1
call void @baz(i8* %statalloc)
ret void
; CHECK-LABEL: test3:
; CHECK-NOT: movl %esi, %edx
; CHECK: rep;movsl
}