[PATCH] D70400: [AMDGPU][GFX10] Disabled v_movrel*[sdwa|dpp] opcodes in codegen

[Dmitry Preobrazhensky via Phabricator via llvm-commits]

dp created this revision.
dp added reviewers: arsenm, rampitec, vpykhtin.
Herald added subscribers: llvm-commits, kbarton, hiraditya, t-tye, tpr, dstuttard, yaxunl, nhaehnle, wdng, jvesely, nemanjai, kzhuravl.
Herald added a project: LLVM.

These opcodes use indirect register addressing so they need special handling by codegen (currently missing).
This patch also adds a check to dpp combiner to make sure that the selected dpp opcode is supported by target.


https://reviews.llvm.org/D70400

Files:
  llvm/lib/Target/AMDGPU/GCNDPPCombine.cpp
  llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
  llvm/lib/Target/AMDGPU/SIInstrInfo.h


Index: llvm/lib/Target/AMDGPU/SIInstrInfo.h
===================================================================
--- llvm/lib/Target/AMDGPU/SIInstrInfo.h
+++ llvm/lib/Target/AMDGPU/SIInstrInfo.h
@@ -1017,6 +1017,10 @@
   /// not exist. If Opcode is not a pseudo instruction, this is identity.
   int pseudoToMCOpcode(int Opcode) const;
 
+  /// \brief Check if this instruction should only be used by assembler.
+  /// Return true if this opcode should not be used by codegen.
+  bool isAsmOnlyOpcode(int MCOp) const;
+
   const TargetRegisterClass *getRegClass(const MCInstrDesc &TID, unsigned OpNum,
                                          const TargetRegisterInfo *TRI,
                                          const MachineFunction &MF)
Index: llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
+++ llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
@@ -6329,6 +6329,26 @@
   llvm_unreachable("Unknown subtarget generation!");
 }
 
+bool SIInstrInfo::isAsmOnlyOpcode(int MCOp) const {
+  switch(MCOp) {
+  // These opcodes use indirect register addressing so
+  // they need special handling by codegen (currently missing).
+  // Therefore it is too risky to allow these opcodes
+  // to be selected by dpp combiner or sdwa peepholer.
+  case AMDGPU::V_MOVRELS_B32_dpp_gfx10:
+  case AMDGPU::V_MOVRELS_B32_sdwa_gfx10:
+  case AMDGPU::V_MOVRELD_B32_dpp_gfx10:
+  case AMDGPU::V_MOVRELD_B32_sdwa_gfx10:
+  case AMDGPU::V_MOVRELSD_B32_dpp_gfx10:
+  case AMDGPU::V_MOVRELSD_B32_sdwa_gfx10:
+  case AMDGPU::V_MOVRELSD_2_B32_dpp_gfx10:
+  case AMDGPU::V_MOVRELSD_2_B32_sdwa_gfx10:
+    return true;
+  default:
+    return false;
+  }
+}
+
 int SIInstrInfo::pseudoToMCOpcode(int Opcode) const {
   SIEncodingFamily Gen = subtargetEncodingFamily(ST);
 
@@ -6367,6 +6387,9 @@
   if (MCOp == (uint16_t)-1)
     return -1;
 
+  if (isAsmOnlyOpcode(MCOp))
+    return -1;
+
   return MCOp;
 }
 
Index: llvm/lib/Target/AMDGPU/GCNDPPCombine.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/GCNDPPCombine.cpp
+++ llvm/lib/Target/AMDGPU/GCNDPPCombine.cpp
@@ -104,6 +104,9 @@
     AU.setPreservesCFG();
     MachineFunctionPass::getAnalysisUsage(AU);
   }
+
+private:
+  int getDPPOp(unsigned Op) const;
 };
 
 } // end anonymous namespace
@@ -118,13 +121,13 @@
   return new GCNDPPCombine();
 }
 
-static int getDPPOp(unsigned Op) {
+int GCNDPPCombine::getDPPOp(unsigned Op) const {
   auto DPP32 = AMDGPU::getDPPOp32(Op);
-  if (DPP32 != -1)
-    return DPP32;
-
-  auto E32 = AMDGPU::getVOPe32(Op);
-  return E32 != -1 ? AMDGPU::getDPPOp32(E32) : -1;
+  if (DPP32 == -1) {
+    auto E32 = AMDGPU::getVOPe32(Op);
+    DPP32 = (E32 == -1)? -1 : AMDGPU::getDPPOp32(E32);
+  }
+  return (DPP32 == -1 || TII->pseudoToMCOpcode(DPP32) == -1) ? -1 : DPP32;
 }
 
 // tracks the register operand definition and returns:


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