Address code review feedback.

Author: maarquitos14

llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp

@@ -4029,7 +4029,7 @@ bool SPIRVInstructionSelector::selectModf(Register ResVReg,
     GR.assignSPIRVTypeToVReg(PtrType, PtrTyReg, MIRBuilder.getMF());
     MachineBasicBlock &EntryBB = I.getMF()->front();
     MachineBasicBlock::iterator VarPos =
-        getPosForOpVariableWithinBlock(EntryBB);
+        getFirstValidInstructionInsertPoint(EntryBB);
     auto AllocaMIB =
         BuildMI(EntryBB, VarPos, I.getDebugLoc(), TII.get(SPIRV::OpVariable))
             .addDef(PtrTyReg)

llvm/lib/Target/SPIRV/SPIRVUtils.cpp

@@ -996,7 +996,7 @@ unsigned getArrayComponentCount(const MachineRegisterInfo *MRI,
 }
 
 MachineBasicBlock::iterator
-getPosForOpVariableWithinBlock(MachineBasicBlock &BB) {
+getFirstValidInstructionInsertPoint(MachineBasicBlock &BB) {
   // Find the position to insert the OpVariable instruction.
   // We will insert it after the last OpFunctionParameter, if any, or
   // after OpFunction otherwise.
@@ -1014,7 +1014,8 @@ getPosForOpVariableWithinBlock(MachineBasicBlock &BB) {
   }
   // VarPos is now pointing at after the last OpFunctionParameter, if any,
   // or after OpFunction, if no parameters.
-  return VarPos;
+  return VarPos != BB.end() && VarPos->getOpcode() == SPIRV::OpLabel ? ++VarPos
+                                                                     : VarPos;
 }
 
 } // namespace llvm

llvm/lib/Target/SPIRV/SPIRVUtils.h

@@ -507,7 +507,7 @@ int64_t foldImm(const MachineOperand &MO, const MachineRegisterInfo *MRI);
 unsigned getArrayComponentCount(const MachineRegisterInfo *MRI,
                                 const MachineInstr *ResType);
 MachineBasicBlock::iterator
-getPosForOpVariableWithinBlock(MachineBasicBlock &BB);
+getFirstValidInstructionInsertPoint(MachineBasicBlock &BB);
 
 } // namespace llvm
 #endif // LLVM_LIB_TARGET_SPIRV_SPIRVUTILS_H