[RISCV][GISel] Add isPreISelGenericFloatingPointOpcode and FPConstraints. NFC

This brings us closer to how AArch64 is structured. I plan to use
isPreISelGenericFloatingPointOpcode in another change.

Author: topperc

llvm/lib/Target/RISCV/GISel/RISCVRegisterBankInfo.cpp

@@ -123,70 +123,87 @@ static const RegisterBankInfo::ValueMapping *getFPValueMapping(unsigned Size) {
   return &RISCV::ValueMappings[Idx];
 }
 
-// TODO: Make this more like AArch64?
-bool RISCVRegisterBankInfo::onlyUsesFP(const MachineInstr &MI,
-                                       const MachineRegisterInfo &MRI,
-                                       const TargetRegisterInfo &TRI) const {
-  switch (MI.getOpcode()) {
+/// Returns whether opcode \p Opc is a pre-isel generic floating-point opcode,
+/// having only floating-point operands.
+/// FIXME: this is copied from target AArch64. Needs some code refactor here to
+/// put this function in GlobalISel/Utils.cpp.
+static bool isPreISelGenericFloatingPointOpcode(unsigned Opc) {
+  switch (Opc) {
   case TargetOpcode::G_FADD:
   case TargetOpcode::G_FSUB:
   case TargetOpcode::G_FMUL:
+  case TargetOpcode::G_FMA:
   case TargetOpcode::G_FDIV:
+  case TargetOpcode::G_FCONSTANT:
+  case TargetOpcode::G_FPEXT:
+  case TargetOpcode::G_FPTRUNC:
+  case TargetOpcode::G_FCEIL:
+  case TargetOpcode::G_FFLOOR:
+  case TargetOpcode::G_FNEARBYINT:
   case TargetOpcode::G_FNEG:
-  case TargetOpcode::G_FABS:
+  case TargetOpcode::G_FCOS:
+  case TargetOpcode::G_FSIN:
+  case TargetOpcode::G_FLOG10:
+  case TargetOpcode::G_FLOG:
+  case TargetOpcode::G_FLOG2:
   case TargetOpcode::G_FSQRT:
+  case TargetOpcode::G_FABS:
+  case TargetOpcode::G_FEXP:
+  case TargetOpcode::G_FRINT:
+  case TargetOpcode::G_INTRINSIC_TRUNC:
+  case TargetOpcode::G_INTRINSIC_ROUND:
+  case TargetOpcode::G_INTRINSIC_ROUNDEVEN:
   case TargetOpcode::G_FMAXNUM:
   case TargetOpcode::G_FMINNUM:
-  case TargetOpcode::G_FPEXT:
-  case TargetOpcode::G_FPTRUNC:
-  case TargetOpcode::G_FCMP:
+  case TargetOpcode::G_FMAXIMUM:
+  case TargetOpcode::G_FMINIMUM:
+    return true;
+  }
+  return false;
+}
+
+// TODO: Make this more like AArch64?
+bool RISCVRegisterBankInfo::hasFPConstraints(
+    const MachineInstr &MI, const MachineRegisterInfo &MRI,
+    const TargetRegisterInfo &TRI) const {
+  if (isPreISelGenericFloatingPointOpcode(MI.getOpcode()))
+    return true;
+
+  // If we have a copy instruction, we could be feeding floating point
+  // instructions.
+  if (MI.getOpcode() != TargetOpcode::COPY)
+    return false;
+
+  return getRegBank(MI.getOperand(0).getReg(), MRI, TRI) == &RISCV::FPRBRegBank;
+}
+
+bool RISCVRegisterBankInfo::onlyUsesFP(const MachineInstr &MI,
+                                       const MachineRegisterInfo &MRI,
+                                       const TargetRegisterInfo &TRI) const {
+  switch (MI.getOpcode()) {
   case TargetOpcode::G_FPTOSI:
   case TargetOpcode::G_FPTOUI:
+  case TargetOpcode::G_FCMP:
     return true;
   default:
     break;
   }
 
-  // If we have a copy instruction, we could be feeding floating point
-  // instructions.
-  if (MI.getOpcode() == TargetOpcode::COPY)
-    return getRegBank(MI.getOperand(0).getReg(), MRI, TRI) ==
-           &RISCV::FPRBRegBank;
-
-  return false;
+  return hasFPConstraints(MI, MRI, TRI);
 }
 
-// TODO: Make this more like AArch64?
 bool RISCVRegisterBankInfo::onlyDefinesFP(const MachineInstr &MI,
                                           const MachineRegisterInfo &MRI,
                                           const TargetRegisterInfo &TRI) const {
   switch (MI.getOpcode()) {
-  case TargetOpcode::G_FADD:
-  case TargetOpcode::G_FSUB:
-  case TargetOpcode::G_FMUL:
-  case TargetOpcode::G_FDIV:
-  case TargetOpcode::G_FNEG:
-  case TargetOpcode::G_FABS:
-  case TargetOpcode::G_FSQRT:
-  case TargetOpcode::G_FMAXNUM:
-  case TargetOpcode::G_FMINNUM:
-  case TargetOpcode::G_FPEXT:
-  case TargetOpcode::G_FPTRUNC:
   case TargetOpcode::G_SITOFP:
   case TargetOpcode::G_UITOFP:
-  case TargetOpcode::G_FCONSTANT:
     return true;
   default:
     break;
   }
 
-  // If we have a copy instruction, we could be fed by floating point
-  // instructions.
-  if (MI.getOpcode() == TargetOpcode::COPY)
-    return getRegBank(MI.getOperand(0).getReg(), MRI, TRI) ==
-           &RISCV::FPRBRegBank;
-
-  return false;
+  return hasFPConstraints(MI, MRI, TRI);
 }
 
 const RegisterBankInfo::InstructionMapping &

llvm/lib/Target/RISCV/GISel/RISCVRegisterBankInfo.h

@@ -40,6 +40,10 @@ class RISCVRegisterBankInfo final : public RISCVGenRegisterBankInfo {
   getInstrMapping(const MachineInstr &MI) const override;
 
 private:
+  /// \returns true if \p MI only uses and defines FPRs.
+  bool hasFPConstraints(const MachineInstr &MI, const MachineRegisterInfo &MRI,
+                        const TargetRegisterInfo &TRI) const;
+
   /// \returns true if \p MI only uses FPRs.
   bool onlyUsesFP(const MachineInstr &MI, const MachineRegisterInfo &MRI,
                   const TargetRegisterInfo &TRI) const;