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[MemCpyOpt] Look at any dependency -not just source- for memset+memcpy.

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This fixes another miscompile introduced by r235232: when there was a
dependency on the memcpy destination other than the memset, we would
ignore it, because we only looked at the source dependency.

It was a mistake to use SrcDepInfo.  Instead, just use DepInfo.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237066 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Ahmed Bougacha
2015-05-11 23:09:46 +00:00
parent 12a7fbc55c
commit 6eb095d7ae
2 changed files with 25 additions and 6 deletions
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18
test/Transforms/MemCpyOpt/memset-memcpy-redundant-memset.ll
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@@ -126,6 +126,24 @@ define void @test_different_dst(i8* %dst2, i8* %src, i64 %src_size, i8* %dst, i6
ret void
}
; Make sure we also take into account dependencies on the destination.
; CHECK-LABEL: define i8 @test_intermediate_read
; CHECK-NEXT: %ca = alloca [64 x i8], align 8
; CHECK-NEXT: %c = getelementptr [64 x i8], [64 x i8]* %ca, i64 0, i64 0
; CHECK-NEXT: call void @llvm.memset.p0i8.i64(i8* %a, i8 0, i64 64, i32 1, i1 false)
; CHECK-NEXT: %r = load i8, i8* %a
; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %a, i8* %b, i64 24, i32 1, i1 false)
; CHECK-NEXT: ret i8 %r
define i8 @test_intermediate_read(i8* %a, i8* %b) #0 {
%ca = alloca [64 x i8], align 8
%c = getelementptr [64 x i8], [64 x i8]* %ca, i64 0, i64 0
call void @llvm.memset.p0i8.i64(i8* %a, i8 0, i64 64, i32 1, i1 false)
%r = load i8, i8* %a
call void @llvm.memcpy.p0i8.p0i8.i64(i8* %a, i8* %b, i64 24, i32 1, i1 false)
ret i8 %r
}
declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i32, i1)
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture readonly, i64, i32, i1)
declare void @llvm.memset.p0i8.i32(i8* nocapture, i8, i32, i32, i1)