Move where undef sgpr spills are deleted

Author: arsenm

llvm/lib/Target/AMDGPU/SILowerSGPRSpills.cpp

@@ -422,6 +422,13 @@ bool SILowerSGPRSpills::run(MachineFunction &MF) {
         if (!TII->isSGPRSpill(MI))
           continue;
 
+        if (MI.getOperand(0).isUndef()) {
+          if (Indexes)
+            Indexes->removeMachineInstrFromMaps(MI);
+          MI.eraseFromParent();
+          continue;
+        }
+
         int FI = TII->getNamedOperand(MI, AMDGPU::OpName::addr)->getIndex();
         assert(MFI.getStackID(FI) == TargetStackID::SGPRSpill);
 

llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp

@@ -1956,12 +1956,8 @@ bool SIRegisterInfo::spillSGPR(MachineBasicBlock::iterator MI, int Index,
                                RegScavenger *RS, SlotIndexes *Indexes,
                                LiveIntervals *LIS, bool OnlyToVGPR,
                                bool SpillToPhysVGPRLane) const {
-  if (MI->getOperand(0).isUndef()) {
-    if (Indexes)
-      Indexes->removeMachineInstrFromMaps(*MI);
-    MI->eraseFromParent();
-    return true;
-  }
+  assert(!MI->getOperand(0).isUndef() &&
+         "undef spill should have been deleted earlier");
 
   SGPRSpillBuilder SB(*this, *ST.getInstrInfo(), isWave32, MI, Index, RS);