Skip to content

[MemCpyOpt] Fix the invalid code modification for GEP #68479

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Oct 9, 2023
Merged

[MemCpyOpt] Fix the invalid code modification for GEP #68479

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 7 additions & 1 deletion llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1043,12 +1043,13 @@ bool MemCpyOptPass::performCallSlotOptzn(Instruction *cpyLoad,

// Since we're changing the parameter to the callsite, we need to make sure
// that what would be the new parameter dominates the callsite.
bool NeedMoveGEP = false;
if (!DT->dominates(cpyDest, C)) {
// Support moving a constant index GEP before the call.
auto *GEP = dyn_cast<GetElementPtrInst>(cpyDest);
if (GEP && GEP->hasAllConstantIndices() &&
DT->dominates(GEP->getPointerOperand(), C))
GEP->moveBefore(C);
NeedMoveGEP = true;
else
return false;
}
Expand Down Expand Up @@ -1101,6 +1102,11 @@ bool MemCpyOptPass::performCallSlotOptzn(Instruction *cpyLoad,
cast<AllocaInst>(cpyDest)->setAlignment(srcAlign);
}

if (NeedMoveGEP) {
auto *GEP = dyn_cast<GetElementPtrInst>(cpyDest);
GEP->moveBefore(C);
}

if (SkippedLifetimeStart) {
SkippedLifetimeStart->moveBefore(C);
MSSAU->moveBefore(MSSA->getMemoryAccess(SkippedLifetimeStart),
Expand Down
60 changes: 60 additions & 0 deletions llvm/test/Transforms/MemCpyOpt/memcpy-gep-modification.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,60 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -S -passes=memcpyopt < %s -verify-memoryssa | FileCheck %s

%struct.MaskedType = type { i8, i8 }

declare void @llvm.lifetime.start.p0(i64, ptr nocapture) #0
declare void @llvm.lifetime.end.p0(i64, ptr nocapture) #0
declare void @MaskedFunction1(ptr, ptr addrspace(1))
declare void @MaskedFunction2(ptr, ptr)

define i8 @test_gep_not_modified(ptr %in0, ptr %in1) {
; CHECK-LABEL: @test_gep_not_modified(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[FUNCALLOC:%.*]] = alloca [[STRUCT_MASKEDTYPE:%.*]], align 4
; CHECK-NEXT: [[PTRALLOC:%.*]] = alloca i8, align 1
; CHECK-NEXT: call void @llvm.lifetime.start.p0(i64 4, ptr [[PTRALLOC]])
; CHECK-NEXT: [[ADDRSPACECAST:%.*]] = addrspacecast ptr [[PTRALLOC]] to ptr addrspace(1)
; CHECK-NEXT: call void @MaskedFunction1(ptr [[IN1:%.*]], ptr addrspace(1) [[ADDRSPACECAST]])
; CHECK-NEXT: [[LOAD1:%.*]] = load i8, ptr [[PTRALLOC]], align 1
; CHECK-NEXT: call void @llvm.lifetime.end.p0(i64 4, ptr [[PTRALLOC]])
; CHECK-NEXT: [[GETELEMPTR1:%.*]] = getelementptr inbounds [[STRUCT_MASKEDTYPE]], ptr [[FUNCALLOC]], i32 0, i32 1
; CHECK-NEXT: store i8 [[LOAD1]], ptr [[GETELEMPTR1]], align 1
; CHECK-NEXT: ret i8 0
;
entry:
%funcAlloc = alloca %struct.MaskedType, align 4
%ptrAlloc = alloca i8, align 1
call void @llvm.lifetime.start.p0(i64 4, ptr %ptrAlloc) #0
%addrspaceCast = addrspacecast ptr %ptrAlloc to ptr addrspace(1)
call void @MaskedFunction1(ptr %in1, ptr addrspace(1) %addrspaceCast)
%load1 = load i8, ptr %ptrAlloc, align 1
call void @llvm.lifetime.end.p0(i64 4, ptr %ptrAlloc) #0
%getElemPtr1 = getelementptr inbounds %struct.MaskedType, ptr %funcAlloc, i32 0, i32 1
store i8 %load1, ptr %getElemPtr1, align 1
ret i8 0
}

define i8 @test_gep_modified(ptr %in0, ptr %in1) {
; CHECK-LABEL: @test_gep_modified(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[FUNCALLOC:%.*]] = alloca [[STRUCT_MASKEDTYPE:%.*]], align 4
; CHECK-NEXT: [[PTRALLOC:%.*]] = alloca i8, align 1
; CHECK-NEXT: call void @llvm.lifetime.start.p0(i64 4, ptr [[PTRALLOC]])
; CHECK-NEXT: [[GETELEMPTR1:%.*]] = getelementptr inbounds [[STRUCT_MASKEDTYPE]], ptr [[FUNCALLOC]], i32 0, i32 1
; CHECK-NEXT: call void @MaskedFunction2(ptr [[IN1:%.*]], ptr [[GETELEMPTR1]])
; CHECK-NEXT: call void @llvm.lifetime.end.p0(i64 4, ptr [[PTRALLOC]])
; CHECK-NEXT: ret i8 0
;
entry:
%funcAlloc = alloca %struct.MaskedType, align 4
%ptrAlloc = alloca i8, align 1
call void @llvm.lifetime.start.p0(i64 4, ptr %ptrAlloc) #0
call void @MaskedFunction2(ptr %in1, ptr %ptrAlloc)
%load1 = load i8, ptr %ptrAlloc, align 1
call void @llvm.lifetime.end.p0(i64 4, ptr %ptrAlloc) #0
%getElemPtr1 = getelementptr inbounds %struct.MaskedType, ptr %funcAlloc, i32 0, i32 1
store i8 %load1, ptr %getElemPtr1, align 1
ret i8 0
}