AMDGPU: Produce error on dynamic_stackalloc

[• tstellarAMD]

LGTM.

[arsenm]

r246048

lib/Target/AMDGPU/AMDGPUISelLowering.h

public:
   SDValue LowerReturn(SDValue Chain, CallingConv::ID CallConv,
                       bool isVarArg,
                       const SmallVectorImpl<ISD::OutputArg> &Outs,
                       const SmallVectorImpl<SDValue> &OutVals,
                       SDLoc DL, SelectionDAG &DAG) const override;
   SDValue LowerCall(CallLoweringInfo &CLI,
                     SmallVectorImpl<SDValue> &InVals) const override;
 
+  SDValue LowerDYNAMIC_STACKALLOC(SDValue Op,
+                                  SelectionDAG &DAG) const;
+
   SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const override;
   SDValue PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const override;
   void ReplaceNodeResults(SDNode * N,
                           SmallVectorImpl<SDValue> &Results,
                           SelectionDAG &DAG) const override;
 
   SDValue LowerIntrinsicIABS(SDValue Op, SelectionDAG &DAG) const;
   SDValue LowerIntrinsicLRP(SDValue Op, SelectionDAG &DAG) const;

lib/Target/AMDGPU/AMDGPUISelLowering.cpp

AMDGPUTargetLowering::AMDGPUTargetLowering(TargetMachine &TM,
   setOperationAction(ISD::Constant, MVT::i32, Legal);
   setOperationAction(ISD::Constant, MVT::i64, Legal);
   setOperationAction(ISD::ConstantFP, MVT::f32, Legal);
   setOperationAction(ISD::ConstantFP, MVT::f64, Legal);
 
   setOperationAction(ISD::BR_JT, MVT::Other, Expand);
   setOperationAction(ISD::BRIND, MVT::Other, Expand);
 
+  // This is totally unsupported, just custom lower to produce an error.
+  setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i32, Custom);
+
   // We need to custom lower some of the intrinsics
   setOperationAction(ISD::INTRINSIC_WO_CHAIN, MVT::Other, Custom);
 
   // Library functions.  These default to Expand, but we have instructions
   // for them.
   setOperationAction(ISD::FCEIL,  MVT::f32, Legal);
   setOperationAction(ISD::FEXP2,  MVT::f32, Legal);
   setOperationAction(ISD::FPOW,   MVT::f32, Legal);
SDValue AMDGPUTargetLowering::LowerCall(CallLoweringInfo &CLI,
   else if (const GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
     FuncName = G->getGlobal()->getName();
 
   DiagnosticInfoUnsupported NoCalls(Fn, "call to function " + FuncName);
   DAG.getContext()->diagnose(NoCalls);
   return SDValue();
 }
 
+SDValue AMDGPUTargetLowering::LowerDYNAMIC_STACKALLOC(SDValue Op,
+                                                      SelectionDAG &DAG) const {
+  const Function &Fn = *DAG.getMachineFunction().getFunction();
+
+  DiagnosticInfoUnsupported NoDynamicAlloca(Fn, "dynamic alloca");
+  DAG.getContext()->diagnose(NoDynamicAlloca);
+  return SDValue();
+}
+
 SDValue AMDGPUTargetLowering::LowerOperation(SDValue Op,
                                              SelectionDAG &DAG) const {
   switch (Op.getOpcode()) {
   default:
     Op.getNode()->dump();
     llvm_unreachable("Custom lowering code for this"
                      "instruction is not implemented yet!");
     break;
SDValue AMDGPUTargetLowering::LowerOperation(SDValue Op,
   case ISD::FRINT: return LowerFRINT(Op, DAG);
   case ISD::FNEARBYINT: return LowerFNEARBYINT(Op, DAG);
   case ISD::FROUND: return LowerFROUND(Op, DAG);
   case ISD::FFLOOR: return LowerFFLOOR(Op, DAG);
   case ISD::SINT_TO_FP: return LowerSINT_TO_FP(Op, DAG);
   case ISD::UINT_TO_FP: return LowerUINT_TO_FP(Op, DAG);
   case ISD::FP_TO_SINT: return LowerFP_TO_SINT(Op, DAG);
   case ISD::FP_TO_UINT: return LowerFP_TO_UINT(Op, DAG);
+  case ISD::DYNAMIC_STACKALLOC: return LowerDYNAMIC_STACKALLOC(Op, DAG);
   }
   return Op;
 }
 
 void AMDGPUTargetLowering::ReplaceNodeResults(SDNode *N,
                                               SmallVectorImpl<SDValue> &Results,
                                               SelectionDAG &DAG) const {
   switch (N->getOpcode()) {

lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp

for (User *User : Val->users()) {
     WorkList.push_back(User);
 
     Success &= collectUsesWithPtrTypes(User, WorkList);
   }
   return Success;
 }
 
 void AMDGPUPromoteAlloca::visitAlloca(AllocaInst &I) {
+  if (!I.isStaticAlloca())
+    return;
+
   IRBuilder<> Builder(&I);
 
   // First try to replace the alloca with a vector
   Type *AllocaTy = I.getAllocatedType();
 
   DEBUG(dbgs() << "Trying to promote " << I << '\n');
 
   if (tryPromoteAllocaToVector(&I))

test/CodeGen/AMDGPU/dynamic_stackalloc.ll

+; RUN: not llc -march=amdgcn -mcpu=tahiti -mattr=+promote-alloca -verify-machineinstrs < %s 2>&1 | FileCheck %s
+; RUN: not llc -march=amdgcn -mcpu=tahiti -mattr=-promote-alloca -verify-machineinstrs < %s 2>&1 | FileCheck %s
+; RUN: not llc -march=r600 -mcpu=cypress < %s 2>&1 | FileCheck %s
+
+; CHECK: error: unsupported dynamic alloca in test_dynamic_stackalloc
+
+define void @test_dynamic_stackalloc(i32 addrspace(1)* %out, i32 %n) {
+  %alloca = alloca i32, i32 %n
+  store volatile i32 0, i32* %alloca
+  ret void
+}