diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp --- a/llvm/lib/Transforms/Scalar/GVN.cpp +++ b/llvm/lib/Transforms/Scalar/GVN.cpp @@ -2168,6 +2168,12 @@ if (Value *V = SimplifyInstruction(I, {DL, TLI, DT, AC})) { bool Changed = false; if (!I->use_empty()) { + // Simplification can cause a special instruction to become not special. + // For example, devirtualization to a willreturn function. + for (auto *U : I->users()) { + if (auto *UI = dyn_cast(U)) + ICF->removeInstruction(UI); + } I->replaceAllUsesWith(V); Changed = true; } diff --git a/llvm/test/Transforms/GVN/simplify-icf-cache-invalidation.ll b/llvm/test/Transforms/GVN/simplify-icf-cache-invalidation.ll new file mode 100644 --- /dev/null +++ b/llvm/test/Transforms/GVN/simplify-icf-cache-invalidation.ll @@ -0,0 +1,50 @@ +; RUN: opt -passes=gvn -S < %s | FileCheck %s + +; CHECK: define {{.*}}@eggs + +%struct.zot = type { i32 (...)** } +%struct.wombat = type { i8* } +%struct.baz = type { i8, i8* } + +@global = hidden unnamed_addr constant { [4 x i8*] } { [4 x i8*] [i8* null, i8* null, i8* undef, i8* bitcast (void (%struct.zot*, i1)* @quux to i8*)] }, align 8 + +define hidden void @eggs(%struct.zot* %arg) unnamed_addr align 2 { +bb: + %tmp = alloca %struct.wombat, align 8 + %tmp1 = getelementptr %struct.zot, %struct.zot* %arg, i64 0, i32 0 + store i32 (...)** bitcast (i8** getelementptr inbounds ({ [4 x i8*] }, { [4 x i8*] }* @global, i64 0, inrange i32 0, i64 2) to i32 (...)**), i32 (...)*** %tmp1, align 8, !invariant.group !0 + br i1 undef, label %bb4, label %bb2 + +bb2: ; preds = %bb + %tmp3 = atomicrmw sub i32* undef, i32 undef acq_rel, align 4 + br label %bb4 + +bb4: ; preds = %bb2, %bb + %tmp5 = load %struct.baz*, %struct.baz** null, align 8 + %tmp6 = getelementptr inbounds %struct.baz, %struct.baz* %tmp5, i64 0, i32 1 + br i1 undef, label %bb9, label %bb7 + +bb7: ; preds = %bb4 + %tmp8 = tail call i8* undef() + br label %bb9 + +bb9: ; preds = %bb7, %bb4 + %tmp10 = load %struct.baz*, %struct.baz** null, align 8 + %tmp11 = getelementptr inbounds %struct.baz, %struct.baz* %tmp10, i64 0, i32 0 + %tmp12 = bitcast %struct.zot* %arg to void (%struct.zot*, i1)*** + %tmp13 = load void (%struct.zot*, i1)**, void (%struct.zot*, i1)*** %tmp12, align 8, !invariant.group !0 + %tmp14 = getelementptr inbounds void (%struct.zot*, i1)*, void (%struct.zot*, i1)** %tmp13, i64 1 + %tmp15 = load void (%struct.zot*, i1)*, void (%struct.zot*, i1)** %tmp14, align 8 + tail call void %tmp15(%struct.zot* %arg, i1 undef) + %tmp16 = getelementptr inbounds %struct.wombat, %struct.wombat* %tmp, i64 0, i32 0 + %tmp17 = load i8*, i8** %tmp16, align 8 + %tmp18 = icmp eq i8* %tmp17, null + ret void +} + +; Function Attrs: nounwind willreturn +declare hidden void @quux(%struct.zot*, i1) unnamed_addr #0 align 2 + +attributes #0 = { nounwind willreturn } + +!0 = !{}