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Differential D89724

[Intrinsics] Added writeonly attribute to the first arg of llvm.memmove
ClosedPublic

Authored by xbolva00 on Oct 19 2020, 1:14 PM.

Details

Reviewers
jdoerfert
fhahn
Commits
rGd605a119939a: [Intrinsics] Added writeonly attribute to the first arg of llvm.memmove
Summary

D18714 introduced writeonly attribute:

"Also start using the attribute for memset, memcpy, and memmove intrinsics,
and remove their special-casing in BasicAliasAnalysis."

But actually, writeonly was not attached to memmove - oversight, it seems.

So let's add it. As we can see, this helps DSE to eliminate redundant stores.

Diff Detail

Event Timeline

xbolva00 created this revision.Oct 19 2020, 1:14 PM
Herald added a project: Restricted Project. · View Herald TranscriptOct 19 2020, 1:14 PM
Herald added a subscriber: llvm-commits. · View Herald Transcript
xbolva00 requested review of this revision.Oct 19 2020, 1:14 PM
Herald added a subscriber: jdoerfert. · View Herald TranscriptOct 19 2020, 1:14 PM
xbolva00 added reviewers: Florian, jdoerfert.Oct 19 2020, 1:15 PM
xbolva00 edited reviewers, added: fhahn; removed: Florian.Oct 19 2020, 1:18 PM
jdoerfert accepted this revision.Oct 19 2020, 1:27 PM

LGTM

This revision is now accepted and ready to land.Oct 19 2020, 1:27 PM
Closed by commit rGd605a119939a: [Intrinsics] Added writeonly attribute to the first arg of llvm.memmove (authored by xbolva00). · Explain WhyOct 19 2020, 2:09 PM
This revision was automatically updated to reflect the committed changes.
xbolva00 added a commit: rGd605a119939a: [Intrinsics] Added writeonly attribute to the first arg of llvm.memmove.

Revision Contents

PathSize
llvm/
include/
llvm/
IR/
3 lines
test/
Bitcode/
4 lines
Transforms/
DeadStoreElimination/
MSSA/
2 lines

Diff 299164

llvm/include/llvm/IR/Intrinsics.td

Show First 20 Lines • Show All 577 Lines • ▼ Show 20 Lines : Intrinsic<[],
WriteOnly<ArgIndex<0>>, ReadOnly<ArgIndex<1>>, WriteOnly<ArgIndex<0>>, ReadOnly<ArgIndex<1>>,
ImmArg<ArgIndex<2>>, ImmArg<ArgIndex<3>>]>; ImmArg<ArgIndex<2>>, ImmArg<ArgIndex<3>>]>;
def int_memmove : Intrinsic<[], def int_memmove : Intrinsic<[],
[llvm_anyptr_ty, llvm_anyptr_ty, llvm_anyint_ty, [llvm_anyptr_ty, llvm_anyptr_ty, llvm_anyint_ty,
llvm_i1_ty], llvm_i1_ty],
[IntrArgMemOnly, IntrWillReturn, [IntrArgMemOnly, IntrWillReturn,
NoCapture<ArgIndex<0>>, NoCapture<ArgIndex<1>>, NoCapture<ArgIndex<0>>, NoCapture<ArgIndex<1>>,
ReadOnly<ArgIndex<1>>, ImmArg<ArgIndex<3>>]>; WriteOnly<ArgIndex<0>>, ReadOnly<ArgIndex<1>>,
ImmArg<ArgIndex<3>>]>;
def int_memset : Intrinsic<[], def int_memset : Intrinsic<[],
[llvm_anyptr_ty, llvm_i8_ty, llvm_anyint_ty, [llvm_anyptr_ty, llvm_i8_ty, llvm_anyint_ty,
llvm_i1_ty], llvm_i1_ty],
[IntrWriteMem, IntrArgMemOnly, IntrWillReturn, [IntrWriteMem, IntrArgMemOnly, IntrWillReturn,
NoCapture<ArgIndex<0>>, WriteOnly<ArgIndex<0>>, NoCapture<ArgIndex<0>>, WriteOnly<ArgIndex<0>>,
ImmArg<ArgIndex<3>>]>; ImmArg<ArgIndex<3>>]>;
// FIXME: Add version of these floating point intrinsics which allow non-default // FIXME: Add version of these floating point intrinsics which allow non-default
▲ Show 20 Lines • Show All 998 Lines • Show Last 20 Lines

llvm/test/Bitcode/upgrade-memory-intrinsics.ll

Show All 23 Lines; CHECK: call void @llvm.memmove.p0i8.p0i8.i64(i8* %p2, i8* %p3, i64 1000, i1 false)
call void @llvm.memset.p0i8.i64(i8* %p1, i8 55, i64 100, i32 0, i1 false) call void @llvm.memset.p0i8.i64(i8* %p1, i8 55, i64 100, i32 0, i1 false)
call void @llvm.memcpy.p0i8.p0i8.i64(i8* %p1, i8* %p2, i64 50, i32 0, i1 false) call void @llvm.memcpy.p0i8.p0i8.i64(i8* %p1, i8* %p2, i64 50, i32 0, i1 false)
call void @llvm.memmove.p0i8.p0i8.i64(i8* %p2, i8* %p3, i64 1000, i32 0, i1 false) call void @llvm.memmove.p0i8.p0i8.i64(i8* %p2, i8* %p3, i64 1000, i32 0, i1 false)
ret void ret void
} }
; CHECK: declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1 immarg) ; CHECK: declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1 immarg)
; CHECK: declare void @llvm.memcpy.p0i8.p0i8.i64(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i64, i1 immarg) ; CHECK: declare void @llvm.memcpy.p0i8.p0i8.i64(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i64, i1 immarg)
; CHECK: declare void @llvm.memmove.p0i8.p0i8.i64(i8* nocapture, i8* nocapture readonly, i64, i1 immarg) ; CHECK: declare void @llvm.memmove.p0i8.p0i8.i64(i8* nocapture writeonly, i8* nocapture readonly, i64, i1 immarg)
declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i32, i1) declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i32, i1)
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly , i8* nocapture readonly, i64, i32, i1) declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly , i8* nocapture readonly, i64, i32, i1)
declare void @llvm.memmove.p0i8.p0i8.i64(i8* nocapture, i8* nocapture readonly, i64, i32, i1) declare void @llvm.memmove.p0i8.p0i8.i64(i8* nocapture writeonly, i8* nocapture readonly, i64, i32, i1)

llvm/test/Transforms/DeadStoreElimination/MSSA/memintrinsics.ll

Show All 12 Lines
; ;
store i8 0, i8* %A ;; Written to by memcpy store i8 0, i8* %A ;; Written to by memcpy
call void @llvm.memcpy.p0i8.p0i8.i8(i8* %A, i8* %B, i8 12, i1 false) call void @llvm.memcpy.p0i8.p0i8.i8(i8* %A, i8* %B, i8 12, i1 false)
ret void ret void
} }
; FIXME: We should eliminate this dead store.
define void @test2(i8* noalias %A, i8* noalias %B) { define void @test2(i8* noalias %A, i8* noalias %B) {
; CHECK-LABEL: @test2( ; CHECK-LABEL: @test2(
; CHECK-NEXT: store i8 0, i8* [[A:%.*]], align 1
; CHECK-NEXT: call void @llvm.memmove.p0i8.p0i8.i8(i8* [[A]], i8* [[B:%.*]], i8 12, i1 false) ; CHECK-NEXT: call void @llvm.memmove.p0i8.p0i8.i8(i8* [[A]], i8* [[B:%.*]], i8 12, i1 false)
; CHECK-NEXT: ret void ; CHECK-NEXT: ret void
; ;
store i8 0, i8* %A ;; Written to by memmove store i8 0, i8* %A ;; Written to by memmove
call void @llvm.memmove.p0i8.p0i8.i8(i8* %A, i8* %B, i8 12, i1 false) call void @llvm.memmove.p0i8.p0i8.i8(i8* %A, i8* %B, i8 12, i1 false)
ret void ret void
▲ Show 20 Lines • Show All 88 Lines • Show Last 20 Lines