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llvm-mirror/test/CodeGen/X86/stack-align-memcpy.ll
Benjamin Kramer 34ab81b7fa X86: Disable generation of rep;movsl when %esi is used as a base pointer.
This happens when there is both stack realignment and a dynamic alloca in the
function. If we overwrite %esi (rep;movsl uses fixed registers) we'll lose the
base pointer and the next register spill will write into oblivion.

Fixes PR15249 and unbreaks firefox on i386/freebsd. Mozilla uses dynamic allocas
and freebsd a 4 byte stack alignment.

llvm-svn: 175057
2013-02-13 13:40:35 +00:00

19 lines
552 B
LLVM

; RUN: llc < %s -force-align-stack -mtriple i386-apple-darwin -mcpu=i486 | FileCheck %s
%struct.foo = type { [88 x i8] }
; 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: test1:
; CHECK: andl $-16, %esp
; CHECK: movl %esp, %esi
; CHECK-NOT: rep;movsl
}
declare void @bar(i8* nocapture, %struct.foo* align 4 byval) nounwind