AMDGPU: Remove inferRegClassFromUses / inferRegClassFromDefs

I'm not sure why this would be necessary, and no tests fail with
them removed. Looking at the uses is suspect as well because
the use reg classes will likely change when the users are moved
as a result of moving this instruction.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@249493 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/AMDGPU/SIFixSGPRCopies.cpp b/lib/Target/AMDGPU/SIFixSGPRCopies.cpp
index 448cf91e3c2a073d6e133dbfd3728199a84b62e5..8aa6abf7ca7bba32f6168a17bd50e32ecd4f1ce3 100644 (file)
--- a/lib/Target/AMDGPU/SIFixSGPRCopies.cpp
+++ b/lib/Target/AMDGPU/SIFixSGPRCopies.cpp
@@ -85,14 +85,6 @@ class SIFixSGPRCopies : public MachineFunctionPass {
 
 private:
   static char ID;
-  const TargetRegisterClass *inferRegClassFromUses(const SIRegisterInfo *TRI,
-                                           const MachineRegisterInfo &MRI,
-                                           unsigned Reg,
-                                           unsigned SubReg) const;
-  const TargetRegisterClass *inferRegClassFromDef(const SIRegisterInfo *TRI,
-                                                 const MachineRegisterInfo &MRI,
-                                                 unsigned Reg,
-                                                 unsigned SubReg) const;
   bool isVGPRToSGPRCopy(const MachineInstr &Copy, const SIRegisterInfo *TRI,
                         const MachineRegisterInfo &MRI) const;
 
@@ -132,53 +124,6 @@ static bool hasVGPROperands(const MachineInstr &MI, const SIRegisterInfo *TRI) {
   return false;
 }
 
-/// This functions walks the use list of Reg until it finds an Instruction
-/// that isn't a COPY returns the register class of that instruction.
-/// \return The register defined by the first non-COPY instruction.
-const TargetRegisterClass *SIFixSGPRCopies::inferRegClassFromUses(
-                                                 const SIRegisterInfo *TRI,
-                                                 const MachineRegisterInfo &MRI,
-                                                 unsigned Reg,
-                                                 unsigned SubReg) const {
-
-  const TargetRegisterClass *RC
-    = TargetRegisterInfo::isVirtualRegister(Reg) ?
-    MRI.getRegClass(Reg) :
-    TRI->getPhysRegClass(Reg);
-
-  RC = TRI->getSubRegClass(RC, SubReg);
-  for (MachineRegisterInfo::use_instr_iterator
-       I = MRI.use_instr_begin(Reg), E = MRI.use_instr_end(); I != E; ++I) {
-    switch (I->getOpcode()) {
-    case AMDGPU::COPY:
-      RC = TRI->getCommonSubClass(RC, inferRegClassFromUses(TRI, MRI,
-                                  I->getOperand(0).getReg(),
-                                  I->getOperand(0).getSubReg()));
-      break;
-    }
-  }
-
-  return RC;
-}
-
-const TargetRegisterClass *SIFixSGPRCopies::inferRegClassFromDef(
-                                                 const SIRegisterInfo *TRI,
-                                                 const MachineRegisterInfo &MRI,
-                                                 unsigned Reg,
-                                                 unsigned SubReg) const {
-  if (!TargetRegisterInfo::isVirtualRegister(Reg)) {
-    const TargetRegisterClass *RC = TRI->getPhysRegClass(Reg);
-    return TRI->getSubRegClass(RC, SubReg);
-  }
-  MachineInstr *Def = MRI.getVRegDef(Reg);
-  if (Def->getOpcode() != AMDGPU::COPY) {
-    return TRI->getSubRegClass(MRI.getRegClass(Reg), SubReg);
-  }
-
-  return inferRegClassFromDef(TRI, MRI, Def->getOperand(1).getReg(),
-                                   Def->getOperand(1).getSubReg());
-}
-
 bool SIFixSGPRCopies::isVGPRToSGPRCopy(const MachineInstr &Copy,
                                       const SIRegisterInfo *TRI,
                                       const MachineRegisterInfo &MRI) const {
@@ -229,22 +174,7 @@ bool SIFixSGPRCopies::runOnMachineFunction(MachineFunction &MF) {
       }
       case AMDGPU::PHI: {
         DEBUG(dbgs() << "Fixing PHI: " << MI);
-
-        for (unsigned i = 1; i < MI.getNumOperands(); i += 2) {
-          const MachineOperand &Op = MI.getOperand(i);
-          unsigned Reg = Op.getReg();
-          const TargetRegisterClass *RC
-            = inferRegClassFromDef(TRI, MRI, Reg, Op.getSubReg());
-
-          MRI.constrainRegClass(Op.getReg(), RC);
-        }
         unsigned Reg = MI.getOperand(0).getReg();
-        const TargetRegisterClass *RC = inferRegClassFromUses(TRI, MRI, Reg,
-                                                  MI.getOperand(0).getSubReg());
-        if (TRI->getCommonSubClass(RC, &AMDGPU::VGPR_32RegClass)) {
-          MRI.constrainRegClass(Reg, &AMDGPU::VGPR_32RegClass);
-        }
-
         if (!TRI->isSGPRClass(MRI.getRegClass(Reg)))
           break;