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release/20.x: [LLVM][MemCpyOpt] Unify alias tags if we optimize allocas (#129537) #135615

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release/20.x: [LLVM][MemCpyOpt] Unify alias tags if we optimize allocas (#129537) #135615

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19 changes: 12 additions & 7 deletions llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1518,7 +1518,7 @@ bool MemCpyOptPass::performStackMoveOptzn(Instruction *Load, Instruction *Store,
// to remove them.

SmallVector<Instruction *, 4> LifetimeMarkers;
SmallSet<Instruction *, 4> NoAliasInstrs;
SmallSet<Instruction *, 4> AAMetadataInstrs;
bool SrcNotDom = false;

// Recursively track the user and check whether modified alias exist.
Expand Down Expand Up @@ -1573,8 +1573,8 @@ bool MemCpyOptPass::performStackMoveOptzn(Instruction *Load, Instruction *Store,
continue;
}
}
if (UI->hasMetadata(LLVMContext::MD_noalias))
NoAliasInstrs.insert(UI);
AAMetadataInstrs.insert(UI);

if (!ModRefCallback(UI))
return false;
}
Expand Down Expand Up @@ -1679,11 +1679,16 @@ bool MemCpyOptPass::performStackMoveOptzn(Instruction *Load, Instruction *Store,
}

// As this transformation can cause memory accesses that didn't previously
// alias to begin to alias one another, we remove !noalias metadata from any
// uses of either alloca. This is conservative, but more precision doesn't
// seem worthwhile right now.
for (Instruction *I : NoAliasInstrs)
// alias to begin to alias one another, we remove !alias.scope, !noalias,
// !tbaa and !tbaa_struct metadata from any uses of either alloca.
// This is conservative, but more precision doesn't seem worthwhile
// right now.
for (Instruction *I : AAMetadataInstrs) {
I->setMetadata(LLVMContext::MD_alias_scope, nullptr);
I->setMetadata(LLVMContext::MD_noalias, nullptr);
I->setMetadata(LLVMContext::MD_tbaa, nullptr);
I->setMetadata(LLVMContext::MD_tbaa_struct, nullptr);
}

LLVM_DEBUG(dbgs() << "Stack Move: Performed staack-move optimization\n");
NumStackMove++;
Expand Down
77 changes: 77 additions & 0 deletions llvm/test/Transforms/MemCpyOpt/memcpy-tbaa.ll
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@@ -0,0 +1,77 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt < %s -passes=memcpyopt,dse -S -verify-memoryssa | FileCheck %s

define void @test() local_unnamed_addr {
; CHECK-LABEL: define void @test() local_unnamed_addr {
; CHECK-NEXT: [[TEST_ARRAY_B:%.*]] = alloca [31 x float], align 4
; CHECK-NEXT: [[TMP1:%.*]] = getelementptr float, ptr [[TEST_ARRAY_B]], i64 1
; CHECK-NEXT: store float 0x3E6AA51880000000, ptr [[TMP1]], align 4
; CHECK-NEXT: [[TMP2:%.*]] = getelementptr float, ptr [[TEST_ARRAY_B]], i64 1
; CHECK-NEXT: [[TMP3:%.*]] = load float, ptr [[TMP2]], align 4
; CHECK-NEXT: ret void
;
%test_array_a = alloca [31 x float], align 4
%test_array_b = alloca [31 x float], align 4
%1 = getelementptr float, ptr %test_array_b, i64 1
store float 0x3E6AA51880000000, ptr %1, align 4, !tbaa !4
call void @llvm.memcpy.p0.p0.i64(ptr noundef nonnull align 4 dereferenceable(124) %test_array_a, ptr noundef nonnull align 4 dereferenceable(124) %test_array_b, i64 124, i1 false)
%2 = getelementptr float, ptr %test_array_a, i64 1
%3 = load float, ptr %2, align 4, !tbaa !7
ret void
}

%struct.Outer = type { float, double, %struct.Inner }
%struct.Inner = type { i32, float }

; Function Attrs: nounwind uwtable
define dso_local float @f() {
; CHECK-LABEL: define dso_local float @f() {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: [[TEST1:%.*]] = alloca [[STRUCT_OUTER:%.*]], align 8
; CHECK-NEXT: [[F:%.*]] = getelementptr inbounds nuw [[STRUCT_OUTER]], ptr [[TEST1]], i32 0, i32 0
; CHECK-NEXT: store float 0.000000e+00, ptr [[F]], align 8
; CHECK-NEXT: [[F1:%.*]] = getelementptr inbounds nuw [[STRUCT_OUTER]], ptr [[TEST1]], i32 0, i32 0
; CHECK-NEXT: [[TMP0:%.*]] = load float, ptr [[F1]], align 8
; CHECK-NEXT: [[ADD:%.*]] = fadd float [[TMP0]], 2.000000e+00
; CHECK-NEXT: store float [[ADD]], ptr [[F1]], align 8
; CHECK-NEXT: [[F2:%.*]] = getelementptr inbounds nuw [[STRUCT_OUTER]], ptr [[TEST1]], i32 0, i32 0
; CHECK-NEXT: [[TMP1:%.*]] = load float, ptr [[F2]], align 8
; CHECK-NEXT: ret float [[TMP1]]
;
entry:
%test = alloca %struct.Outer, align 8
%test1 = alloca %struct.Outer, align 8
%f = getelementptr inbounds nuw %struct.Outer, ptr %test1, i32 0, i32 0
store float 0.000000e+00, ptr %f, align 8, !tbaa !9
%inner_a = getelementptr inbounds nuw %struct.Outer, ptr %test1, i32 0, i32 2
%i = getelementptr inbounds nuw %struct.Inner, ptr %inner_a, i32 0, i32 0
store i32 0, ptr %i, align 8, !tbaa !17
call void @llvm.memcpy.p0.p0.i64(ptr align 8 %test, ptr align 8 %test1, i64 24, i1 false)
%f1 = getelementptr inbounds nuw %struct.Outer, ptr %test, i32 0, i32 0
%0 = load float, ptr %f1, align 8, !tbaa !9
%add = fadd float %0, 2.000000e+00
store float %add, ptr %f1, align 8, !tbaa !9
%f2 = getelementptr inbounds nuw %struct.Outer, ptr %test, i32 0, i32 0
%1 = load float, ptr %f2, align 8, !tbaa !9
ret float %1
}

!1 = !{!"any data access", !2, i64 0}
!2 = !{!"any access", !3, i64 0}
!3 = !{!"Flang function root test"}
!4 = !{!5, !5, i64 0}
!5 = !{!"allocated data/test_array_a", !6, i64 0}
!6 = !{!"allocated data", !1, i64 0}
!7 = !{!8, !8, i64 0}
!8 = !{!"allocated data/test_array_b", !6, i64 0}
!9 = !{!10, !11, i64 0}
!10 = !{!"Outer", !11, i64 0, !14, i64 8, !15, i64 16}
!11 = !{!"float", !12, i64 0}
!12 = !{!"omnipotent char", !13, i64 0}
!13 = !{!"Simple C/C++ TBAA"}
!14 = !{!"double", !12, i64 0}
!15 = !{!"Inner", !16, i64 0, !11, i64 4}
!16 = !{!"int", !12, i64 0}
!17 = !{!10, !16, i64 16}


10 changes: 5 additions & 5 deletions llvm/test/Transforms/MemCpyOpt/stack-move.ll
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Expand Up @@ -259,7 +259,7 @@ define void @remove_scoped_noalias() {
; CHECK-LABEL: define void @remove_scoped_noalias() {
; CHECK-NEXT: [[SRC:%.*]] = alloca [[STRUCT_FOO:%.*]], align 4
; CHECK-NEXT: store [[STRUCT_FOO]] { i32 10, i32 20, i32 30 }, ptr [[SRC]], align 4
; CHECK-NEXT: [[TMP1:%.*]] = call i32 @use_nocapture(ptr nocapture [[SRC]]), !alias.scope !0
; CHECK-NEXT: [[TMP1:%.*]] = call i32 @use_nocapture(ptr nocapture [[SRC]])
; CHECK-NEXT: [[TMP2:%.*]] = call i32 @use_nocapture(ptr nocapture [[SRC]])
; CHECK-NEXT: ret void
;
Expand All @@ -283,7 +283,7 @@ define void @remove_alloca_metadata() {
; CHECK-LABEL: define void @remove_alloca_metadata() {
; CHECK-NEXT: [[SRC:%.*]] = alloca [[STRUCT_FOO:%.*]], align 4
; CHECK-NEXT: store [[STRUCT_FOO]] { i32 10, i32 20, i32 30 }, ptr [[SRC]], align 4
; CHECK-NEXT: [[TMP1:%.*]] = call i32 @use_nocapture(ptr nocapture [[SRC]]), !alias.scope !0
; CHECK-NEXT: [[TMP1:%.*]] = call i32 @use_nocapture(ptr nocapture [[SRC]])
; CHECK-NEXT: [[TMP2:%.*]] = call i32 @use_nocapture(ptr nocapture [[SRC]])
; CHECK-NEXT: ret void
;
Expand All @@ -308,7 +308,7 @@ define void @noalias_on_lifetime() {
; CHECK-LABEL: define void @noalias_on_lifetime() {
; CHECK-NEXT: [[SRC:%.*]] = alloca [[STRUCT_FOO:%.*]], align 4
; CHECK-NEXT: store [[STRUCT_FOO]] { i32 10, i32 20, i32 30 }, ptr [[SRC]], align 4
; CHECK-NEXT: [[TMP1:%.*]] = call i32 @use_nocapture(ptr nocapture [[SRC]]), !alias.scope !0
; CHECK-NEXT: [[TMP1:%.*]] = call i32 @use_nocapture(ptr nocapture [[SRC]])
; CHECK-NEXT: [[TMP2:%.*]] = call i32 @use_nocapture(ptr nocapture [[SRC]])
; CHECK-NEXT: ret void
;
Expand Down Expand Up @@ -399,10 +399,10 @@ define void @terminator_lastuse() personality i32 0 {
; CHECK-NEXT: store [[STRUCT_FOO]] { i32 10, i32 20, i32 30 }, ptr [[SRC]], align 4
; CHECK-NEXT: [[TMP1:%.*]] = call i32 @use_nocapture(ptr nocapture [[SRC]])
; CHECK-NEXT: [[RV:%.*]] = invoke i32 @use_nocapture(ptr [[SRC]])
; CHECK-NEXT: to label [[SUC:%.*]] unwind label [[UNW:%.*]]
; CHECK-NEXT: to label [[SUC:%.*]] unwind label [[UNW:%.*]]
; CHECK: unw:
; CHECK-NEXT: [[LP:%.*]] = landingpad i32
; CHECK-NEXT: cleanup
; CHECK-NEXT: cleanup
; CHECK-NEXT: resume i32 0
; CHECK: suc:
; CHECK-NEXT: ret void
Expand Down
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