[PATCH] D152050: [RISCV] Begin removing hasDummyMask.

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.
craig.topper added reviewers: reames, frasercrmck, rogfer01, kito-cheng, arcbbb, pcwang-thead.
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This was used to know if we need to insert a dummy operand during
MCInstLowering. We can use the operand info from MCInstrDesc to
figure this out without needing a separate flag.

I'll remove the tablegen bits if there is consensus this is a good
idea.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D152050

Files:
  llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.h
  llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
  llvm/lib/Target/RISCV/RISCVMCInstLower.cpp


Index: llvm/lib/Target/RISCV/RISCVMCInstLower.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVMCInstLower.cpp
+++ llvm/lib/Target/RISCV/RISCVMCInstLower.cpp
@@ -146,9 +146,8 @@
   const MachineFunction *MF = MBB->getParent();
   assert(MF && "MBB expected to be in a machine function");
 
-  const TargetRegisterInfo *TRI =
-      MF->getSubtarget<RISCVSubtarget>().getRegisterInfo();
-
+  const RISCVSubtarget &Subtarget = MF->getSubtarget<RISCVSubtarget>();
+  const TargetRegisterInfo *TRI = Subtarget.getRegisterInfo();
   assert(TRI && "TargetRegisterInfo expected");
 
   uint64_t TSFlags = MI->getDesc().TSFlags;
@@ -220,8 +219,14 @@
 
   // Unmasked pseudo instructions need to append dummy mask operand to
   // V instructions. All V instructions are modeled as the masked version.
-  if (RISCVII::hasDummyMaskOp(TSFlags))
-    OutMI.addOperand(MCOperand::createReg(RISCV::NoRegister));
+  const TargetInstrInfo *TII = Subtarget.getInstrInfo();
+  const MCInstrDesc &OutMCID = TII->get(OutMI.getOpcode());
+  unsigned OutNumOperands = OutMI.getNumOperands();
+  if (OutNumOperands != OutMCID.getNumOperands()) {
+    if (OutMCID.operands()[OutNumOperands].RegClass == RISCV::VMV0RegClassID)
+      OutMI.addOperand(MCOperand::createReg(RISCV::NoRegister));
+    assert(OutMI.getNumOperands() == OutMCID.getNumOperands());
+  }
 
   return true;
 }
Index: llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
+++ llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
@@ -3182,13 +3182,10 @@
 
   unsigned Opc = UseTUPseudo ? I->UnmaskedTUPseudo : I->UnmaskedPseudo;
 
-  // Check that we're dropping the mask operand and any policy operand
-  // when we transform to this unmasked pseudo. Additionally, if this
-  // instruction is tail agnostic, the unmasked instruction should not have a
-  // merge op.
+  // If this instruction is tail agnostic, the unmasked instruction should not
+  // have a // merge op.
   uint64_t TSFlags = TII.get(Opc).TSFlags;
   assert((UseTUPseudo == RISCVII::hasMergeOp(TSFlags)) &&
-         RISCVII::hasDummyMaskOp(TSFlags) &&
          "Unexpected pseudo to transform to");
   (void)TSFlags;
 
Index: llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.h
===================================================================
--- llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.h
+++ llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.h
@@ -140,10 +140,6 @@
 static inline VLMUL getLMul(uint64_t TSFlags) {
   return static_cast<VLMUL>((TSFlags & VLMulMask) >> VLMulShift);
 }
-/// \returns true if there is a dummy mask operand for the instruction.
-static inline bool hasDummyMaskOp(uint64_t TSFlags) {
-  return TSFlags & HasDummyMaskOpMask;
-}
 /// \returns true if tail agnostic is enforced for the instruction.
 static inline bool doesForceTailAgnostic(uint64_t TSFlags) {
   return TSFlags & ForceTailAgnosticMask;


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