AMDGPU: Temporarily select trap to s_endpgm

This should select to s_trap, but that requires
additonal work to setup and enable the trap handler.
For now emit s_endpgm so bugpoint stops getting stuck
on the unsupported call to abort.

Emit a warning that this will only terminate the wave and
not really trap.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@273062 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/AMDGPU/SIISelLowering.cpp

@@ -200,6 +200,7 @@ SITargetLowering::SITargetLowering(TargetMachine &TM,
 
   // On SI this is s_memtime and s_memrealtime on VI.
   setOperationAction(ISD::READCYCLECOUNTER, MVT::i64, Legal);
+  setOperationAction(ISD::TRAP, MVT::Other, Custom);
 
   setOperationAction(ISD::FMINNUM, MVT::f64, Legal);
   setOperationAction(ISD::FMAXNUM, MVT::f64, Legal);
@@ -1178,6 +1179,7 @@ SDValue SITargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   case ISD::INTRINSIC_W_CHAIN: return LowerINTRINSIC_W_CHAIN(Op, DAG);
   case ISD::INTRINSIC_VOID: return LowerINTRINSIC_VOID(Op, DAG);
   case ISD::ADDRSPACECAST: return lowerADDRSPACECAST(Op, DAG);
+  case ISD::TRAP: return lowerTRAP(Op, DAG);
   }
   return SDValue();
 }
@@ -1450,6 +1452,23 @@ SDValue SITargetLowering::LowerGlobalAddress(AMDGPUMachineFunction *MFI,
   return DAG.getNode(AMDGPUISD::PC_ADD_REL_OFFSET, DL, PtrVT, GA);
 }
 
+SDValue SITargetLowering::lowerTRAP(SDValue Op,
+                                    SelectionDAG &DAG) const {
+  const MachineFunction &MF = DAG.getMachineFunction();
+  DiagnosticInfoUnsupported NoTrap(*MF.getFunction(),
+                                   "trap handler not supported",
+                                   Op.getDebugLoc(),
+                                   DS_Warning);
+  DAG.getContext()->diagnose(NoTrap);
+
+  // Emit s_endpgm.
+
+  // FIXME: This should really be selected to s_trap, but that requires
+  // setting up the trap handler for it o do anything.
+  return DAG.getNode(AMDGPUISD::RET_FLAG, SDLoc(Op), MVT::Other, Op.
+                     getOperand(0));
+}
+
 SDValue SITargetLowering::copyToM0(SelectionDAG &DAG, SDValue Chain,
                                    const SDLoc &DL, SDValue V) const {
   // We can't use S_MOV_B32 directly, because there is no way to specify m0 as

lib/Target/AMDGPU/SIISelLowering.h

@@ -46,6 +46,7 @@ class SITargetLowering final : public AMDGPUTargetLowering {
 
   SDValue getSegmentAperture(unsigned AS, SelectionDAG &DAG) const;
   SDValue lowerADDRSPACECAST(SDValue Op, SelectionDAG &DAG) const;
+  SDValue lowerTRAP(SDValue Op, SelectionDAG &DAG) const;
 
   void adjustWritemask(MachineSDNode *&N, SelectionDAG &DAG) const;
 

lib/Target/AMDGPU/SIInstructions.td

@@ -430,6 +430,7 @@ def S_ENDPGM : SOPP <0x00000001, (ins), "s_endpgm",
   let simm16 = 0;
   let isBarrier = 1;
   let hasCtrlDep = 1;
+  let hasSideEffects = 1;
 }
 
 let isBranch = 1 in {

test/CodeGen/AMDGPU/trap.ll

@@ -0,0 +1,15 @@
+; RUN: llc -march=amdgcn -verify-machineinstrs < %s 2>&1 | FileCheck -check-prefix=GCN %s
+
+; GCN: warning: <unknown>:0:0: in function trap void (): trap handler not supported
+
+declare void @llvm.trap() #0
+
+; GCN-LABEL: {{^}}trap:
+; GCN: s_endpgm
+; GCN-NEXT: s_endpgm
+define void @trap() {
+  call void @llvm.trap()
+  ret void
+}
+
+attributes #0 = { nounwind noreturn }