diff --git a/llvm/include/llvm/Analysis/InstructionPrecedenceTracking.h b/llvm/include/llvm/Analysis/InstructionPrecedenceTracking.h index 46bc974c4a7f73..192630e62a54cf 100644 --- a/llvm/include/llvm/Analysis/InstructionPrecedenceTracking.h +++ b/llvm/include/llvm/Analysis/InstructionPrecedenceTracking.h @@ -80,6 +80,11 @@ class InstructionPrecedenceTracking { /// It makes all necessary updates to internal caches to keep them consistent. void removeInstruction(const Instruction *Inst); + /// Notifies this tracking that we are going to replace all uses of \p Inst. + /// It makes all necessary updates to internal caches to keep them consistent. + /// Should typically be called before a RAUW. + void removeUsersOf(const Instruction *Inst); + /// Invalidates all information from this tracking. void clear(); }; diff --git a/llvm/lib/Analysis/InstructionPrecedenceTracking.cpp b/llvm/lib/Analysis/InstructionPrecedenceTracking.cpp index c26cdf2266da89..7d1e630e6e8055 100644 --- a/llvm/lib/Analysis/InstructionPrecedenceTracking.cpp +++ b/llvm/lib/Analysis/InstructionPrecedenceTracking.cpp @@ -111,6 +111,13 @@ void InstructionPrecedenceTracking::removeInstruction(const Instruction *Inst) { FirstSpecialInsts.erase(Inst->getParent()); } +void InstructionPrecedenceTracking::removeUsersOf(const Instruction *Inst) { + for (const auto *U : Inst->users()) { + if (const auto *UI = dyn_cast(U)) + removeInstruction(UI); + } +} + void InstructionPrecedenceTracking::clear() { FirstSpecialInsts.clear(); #ifndef NDEBUG diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp index cafb6ad94a2eb8..50fe373cf69022 100644 --- a/llvm/lib/Transforms/Scalar/GVN.cpp +++ b/llvm/lib/Transforms/Scalar/GVN.cpp @@ -2168,6 +2168,9 @@ bool GVN::processInstruction(Instruction *I) { 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. + ICF->removeUsersOf(I); 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 index 00000000000000..ebd91322588246 --- /dev/null +++ b/llvm/test/Transforms/GVN/simplify-icf-cache-invalidation.ll @@ -0,0 +1,52 @@ +; 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 i8* bitcast (void (%struct.zot*, i1)* @quux to i8*) + +declare i8* @f() + +define hidden void @eggs(%struct.zot* %arg, i1 %arg2, i32* %arg3, i32 %arg4, %struct.baz** %arg5) 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** @global to i32 (...)**), i32 (...)*** %tmp1, align 8, !invariant.group !0 + br i1 %arg2, label %bb4, label %bb2 + +bb2: ; preds = %bb + %tmp3 = atomicrmw sub i32* %arg3, i32 %arg4 acq_rel, align 4 + br label %bb4 + +bb4: ; preds = %bb2, %bb + %tmp5 = load %struct.baz*, %struct.baz** %arg5, align 8 + %tmp6 = getelementptr inbounds %struct.baz, %struct.baz* %tmp5, i64 0, i32 1 + br i1 %arg2, label %bb9, label %bb7 + +bb7: ; preds = %bb4 + %tmp8 = tail call i8* @f() + br label %bb9 + +bb9: ; preds = %bb7, %bb4 + %tmp10 = load %struct.baz*, %struct.baz** %arg5, 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 0 + %tmp15 = load void (%struct.zot*, i1)*, void (%struct.zot*, i1)** %tmp14, align 8 + tail call void %tmp15(%struct.zot* %arg, i1 %arg2) + %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 = !{}