[llvm] r249493 - AMDGPU: Remove inferRegClassFromUses / inferRegClassFromDefs

[Matt Arsenault via llvm-commits]

Author: arsenm
Date: Tue Oct  6 19:42:31 2015
New Revision: 249493

URL: http://llvm.org/viewvc/llvm-project?rev=249493&view=rev
Log:
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.

Modified:
    llvm/trunk/lib/Target/AMDGPU/SIFixSGPRCopies.cpp

Modified: llvm/trunk/lib/Target/AMDGPU/SIFixSGPRCopies.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SIFixSGPRCopies.cpp?rev=249493&r1=249492&r2=249493&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/SIFixSGPRCopies.cpp (original)
+++ llvm/trunk/lib/Target/AMDGPU/SIFixSGPRCopies.cpp Tue Oct  6 19:42:31 2015
@@ -85,14 +85,6 @@ class SIFixSGPRCopies : public MachineFu
 
 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 Machin
   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::runOnMachineFuncti
       }
       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;