[PATCH] D21217: AMDGPU: Temporarily select trap to s_endpgm

[Matt Arsenault via llvm-commits]

arsenm created this revision.
arsenm added a reviewer: tstellarAMD.
arsenm added a subscriber: llvm-commits.
Herald added subscribers: kzhuravl, arsenm.

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.

http://reviews.llvm.org/D21217

Files:
  lib/Target/AMDGPU/SIISelLowering.cpp
  lib/Target/AMDGPU/SIISelLowering.h
  lib/Target/AMDGPU/SIInstructions.td
  test/CodeGen/AMDGPU/trap.ll

Index: test/CodeGen/AMDGPU/trap.ll
===================================================================
--- /dev/null
+++ 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 }
Index: lib/Target/AMDGPU/SIInstructions.td
===================================================================
--- lib/Target/AMDGPU/SIInstructions.td
+++ lib/Target/AMDGPU/SIInstructions.td
@@ -430,6 +430,7 @@
   let simm16 = 0;
   let isBarrier = 1;
   let hasCtrlDep = 1;
+  let hasSideEffects = 1;
 }
 
 let isBranch = 1 in {
Index: lib/Target/AMDGPU/SIISelLowering.h
===================================================================
--- lib/Target/AMDGPU/SIISelLowering.h
+++ lib/Target/AMDGPU/SIISelLowering.h
@@ -45,6 +45,7 @@
 
   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;
 
Index: lib/Target/AMDGPU/SIISelLowering.cpp
===================================================================
--- lib/Target/AMDGPU/SIISelLowering.cpp
+++ lib/Target/AMDGPU/SIISelLowering.cpp
@@ -200,6 +200,7 @@
 
   // 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 @@
   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();
 }
@@ -1416,6 +1418,23 @@
   return DAG.getUNDEF(ASC->getValueType(0));
 }
 
+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, SDLoc DL,
                                    SDValue V) const {
   // We can't use S_MOV_B32 directly, because there is no way to specify m0 as


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