Revert "SystemZ: Fold copy of vector immediate to gr128" (#91099)

Fails here:
https://lab.llvm.org/buildbot/#/builders/239/builds/6893
https://lab.llvm.org/buildbot/#/builders/5/builds/43113
https://lab.llvm.org/buildbot/#/builders/168/builds/20228

Reverts #90706

Author: vitalybuka

llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp

@@ -640,51 +640,6 @@ bool SystemZInstrInfo::foldImmediate(MachineInstr &UseMI, MachineInstr &DefMI,
                                      Register Reg,
                                      MachineRegisterInfo *MRI) const {
   unsigned DefOpc = DefMI.getOpcode();
-
-  if (DefOpc == SystemZ::VGBM) {
-    int64_t ImmVal = DefMI.getOperand(1).getImm();
-    if (ImmVal != 0) // TODO: Handle other values
-      return false;
-
-    // Fold gr128 = COPY (vr128 VGBM imm)
-    //
-    // %tmp:gr64 = LGHI 0
-    // to  gr128 = REG_SEQUENCE %tmp, %tmp
-    assert(DefMI.getOperand(0).getReg() == Reg);
-
-    if (!UseMI.isCopy())
-      return false;
-
-    Register CopyDstReg = UseMI.getOperand(0).getReg();
-    if (CopyDstReg.isVirtual() &&
-        MRI->getRegClass(CopyDstReg) == &SystemZ::GR128BitRegClass &&
-        MRI->hasOneNonDBGUse(Reg)) {
-      // TODO: Handle physical registers
-      // TODO: Handle gr64 uses with subregister indexes
-      // TODO: Should this multi-use cases?
-      Register TmpReg = MRI->createVirtualRegister(&SystemZ::GR64BitRegClass);
-      MachineBasicBlock &MBB = *UseMI.getParent();
-
-      // FIXME: probably should be DefMI's DebugLoc but this matches
-      // loadImmediate's guessing
-      const DebugLoc &DL = UseMI.getDebugLoc();
-
-      loadImmediate(MBB, UseMI.getIterator(), TmpReg, ImmVal);
-
-      BuildMI(MBB, UseMI.getIterator(), DL, get(SystemZ::REG_SEQUENCE),
-              CopyDstReg)
-          .addReg(TmpReg)
-          .addImm(SystemZ::subreg_h64)
-          .addReg(TmpReg)
-          .addImm(SystemZ::subreg_l64);
-
-      UseMI.eraseFromParent();
-      return true;
-    }
-
-    return false;
-  }
-
   if (DefOpc != SystemZ::LHIMux && DefOpc != SystemZ::LHI &&
       DefOpc != SystemZ::LGHI)
     return false;
@@ -2282,16 +2237,3 @@ areMemAccessesTriviallyDisjoint(const MachineInstr &MIa,
 
   return false;
 }
-
-bool SystemZInstrInfo::getConstValDefinedInReg(const MachineInstr &MI,
-                                               const Register Reg,
-                                               int64_t &ImmVal) const {
-
-  if (MI.getOpcode() == SystemZ::VGBM && Reg == MI.getOperand(0).getReg()) {
-    ImmVal = MI.getOperand(1).getImm();
-    // TODO: Handle non-0 values
-    return ImmVal == 0;
-  }
-
-  return false;
-}

llvm/lib/Target/SystemZ/SystemZInstrInfo.h

@@ -383,9 +383,6 @@ class SystemZInstrInfo : public SystemZGenInstrInfo {
   bool
   areMemAccessesTriviallyDisjoint(const MachineInstr &MIa,
                                   const MachineInstr &MIb) const override;
-
-  bool getConstValDefinedInReg(const MachineInstr &MI, const Register Reg,
-                               int64_t &ImmVal) const override;
 };
 
 } // end namespace llvm