diff --git a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp index d30c68a2f0871..6f9fe67e66ca0 100644 --- a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp +++ b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp @@ -1274,7 +1274,8 @@ struct DSEState { if (CB->onlyAccessesInaccessibleMemory()) return false; - return isRefSet(BatchAA.getModRefInfo(UseInst, DefLoc)); + AAQueryInfo TmpAAQI(AA, &EI); + return isRefSet(AA.getModRefInfo(UseInst, DefLoc, TmpAAQI)); } /// Returns true if a dependency between \p Current and \p KillingDef is diff --git a/llvm/test/Transforms/DeadStoreElimination/read-clobber-skipped.ll b/llvm/test/Transforms/DeadStoreElimination/read-clobber-skipped.ll new file mode 100644 index 0000000000000..fd4c3bf1351df --- /dev/null +++ b/llvm/test/Transforms/DeadStoreElimination/read-clobber-skipped.ll @@ -0,0 +1,41 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4 +; RUN: opt -S -passes=dse < %s | FileCheck %s +; +; DSE kills both `store i32 44, ptr %struct.byte.4, align 4` and +; `call void @llvm.memset.p0.i64(...)` but the memset should not be killed +; because it has a clobber read: `%ret = load ptr, ptr %struct.byte.8` + +%struct.type = type { ptr, ptr } + +define ptr @foo(ptr noundef %ptr) { +; CHECK-LABEL: define ptr @foo( +; CHECK-SAME: ptr noundef [[PTR:%.*]]) { +; CHECK-NEXT: [[STRUCT_ALLOCA:%.*]] = alloca [[STRUCT_TYPE:%.*]], align 8 +; CHECK-NEXT: call void @llvm.lifetime.start.p0(i64 56, ptr nonnull [[STRUCT_ALLOCA]]) #[[ATTR2:[0-9]+]] +; CHECK-NEXT: [[STRUCT_BYTE_8:%.*]] = getelementptr inbounds i8, ptr [[STRUCT_ALLOCA]], i64 8 +; CHECK-NEXT: [[TMP1:%.*]] = getelementptr inbounds i8, ptr [[STRUCT_BYTE_8]], i64 4 +; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr noundef nonnull align 4 [[TMP1]], i8 42, i64 4, i1 false) +; CHECK-NEXT: store i32 43, ptr [[STRUCT_BYTE_8]], align 4 +; CHECK-NEXT: [[RET:%.*]] = load ptr, ptr [[STRUCT_BYTE_8]], align 8 +; CHECK-NEXT: call void @llvm.lifetime.end.p0(i64 56, ptr nonnull [[STRUCT_ALLOCA]]) #[[ATTR2]] +; CHECK-NEXT: ret ptr [[RET]] +; + %struct.alloca = alloca %struct.type, align 8 + call void @llvm.lifetime.start.p0(i64 56, ptr nonnull %struct.alloca) nounwind + %struct.byte.8 = getelementptr inbounds i8, ptr %struct.alloca, i64 8 + ; Set %struct.alloca[8, 16) to 42. + call void @llvm.memset.p0.i64(ptr noundef nonnull align 4 %struct.byte.8, i8 42, i64 8, i1 false) + ; Set %struct.alloca[8, 12) to 43. + store i32 43, ptr %struct.byte.8, align 4 + ; Set %struct.alloca[4, 8) to 44. + %struct.byte.4 = getelementptr inbounds i8, ptr %struct.alloca, i64 4 + store i32 44, ptr %struct.byte.4, align 4 + ; Return %struct.alloca[8, 16). + %ret = load ptr, ptr %struct.byte.8 + call void @llvm.lifetime.end.p0(i64 56, ptr nonnull %struct.alloca) nounwind + ret ptr %ret +} + +declare void @llvm.memset.p0.i64(ptr nocapture writeonly, i8, i64, i1 immarg) #0 +declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #2 +declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #2