diff --git a/include/llvm/Intrinsics.td b/include/llvm/Intrinsics.td index 8ef4e02499a..95fd8430511 100644 --- a/include/llvm/Intrinsics.td +++ b/include/llvm/Intrinsics.td @@ -412,6 +412,9 @@ def int_trap : Intrinsic<[], [], [IntrNoReturn]>, def int_debugtrap : Intrinsic<[]>, GCCBuiltin<"__builtin_debugtrap">; +// NOP: calls/invokes to this intrinsic are removed by codegen +def int_donothing : Intrinsic<[], [], [IntrNoMem]>; + // Intrisics to support half precision floating point format let Properties = [IntrNoMem] in { def int_convert_to_fp16 : Intrinsic<[llvm_i16_ty], [llvm_float_ty]>, diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp index 0d2d9dae2bc..957d00ac32b 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp @@ -1828,9 +1828,13 @@ void SelectionDAGBuilder::visitInvoke(const InvokeInst &I) { MachineBasicBlock *LandingPad = FuncInfo.MBBMap[I.getSuccessor(1)]; const Value *Callee(I.getCalledValue()); + const Function *Fn = dyn_cast(Callee); if (isa(Callee)) visitInlineAsm(&I); - else + else if (Fn && Fn->isIntrinsic()) { + assert(Fn->getIntrinsicID() == Intrinsic::donothing); + return; // ignore invokes to @llvm.donothing + } else LowerCallTo(&I, getValue(Callee), false, LandingPad); // If the value of the invoke is used outside of its defining block, make it @@ -5178,6 +5182,9 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) { case Intrinsic::lifetime_end: // Discard region information. return 0; + case Intrinsic::donothing: + // ignore + return 0; } } diff --git a/test/CodeGen/Generic/donothing.ll b/test/CodeGen/Generic/donothing.ll new file mode 100644 index 00000000000..d6ba138fc6d --- /dev/null +++ b/test/CodeGen/Generic/donothing.ll @@ -0,0 +1,31 @@ +; RUN: llc < %s | FileCheck %s + +declare i32 @__gxx_personality_v0(...) +declare void @__cxa_call_unexpected(i8*) +declare void @llvm.donothing() readnone + +; CHECK: f1 +define void @f1() nounwind uwtable ssp { +entry: +; CHECK-NOT donothing + invoke void @llvm.donothing() + to label %invoke.cont unwind label %lpad + +invoke.cont: + ret void + +lpad: + %0 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) + filter [0 x i8*] zeroinitializer + %1 = extractvalue { i8*, i32 } %0, 0 + tail call void @__cxa_call_unexpected(i8* %1) noreturn nounwind + unreachable +} + +; CHECK: f2 +define void @f2() nounwind { +entry: +; CHECK-NOT donothing + call void @llvm.donothing() + ret void +}