Add iterator changes from #161217

Change-Id: I2703f109fda15a437bd918fbd94a97566f26e161

Author: MacDue

llvm/lib/Target/AArch64/AArch64PrologueEpilogue.cpp

@@ -723,31 +723,37 @@ void AArch64PrologueEmitter::emitPrologue() {
   StackOffset PPRLocalsSize = AFL.getPPRStackSize(MF) - PPRCalleeSavesSize;
   StackOffset ZPRLocalsSize = AFL.getZPRStackSize(MF) - ZPRCalleeSavesSize;
 
+  std::optional<MachineBasicBlock::iterator> ZPRCalleeSavesBegin,
+      ZPRCalleeSavesEnd, PPRCalleeSavesBegin, PPRCalleeSavesEnd;
+
   StackOffset CFAOffset =
       StackOffset::getFixed((int64_t)MFI.getStackSize() - NumBytes);
   MachineBasicBlock::iterator AfterSVESavesI = AfterGPRSavesI;
   if (!FPAfterSVECalleeSaves) {
     // Process the SVE callee-saves to find the starts/ends of the ZPR and PPR
     // areas.
+    PPRCalleeSavesBegin = AfterGPRSavesI;
     if (PPRCalleeSavesSize) {
       LLVM_DEBUG(dbgs() << "PPRCalleeSavedStackSize = "
                         << PPRCalleeSavesSize.getScalable() << "\n");
 
-      assert(isPartOfPPRCalleeSaves(AfterSVESavesI) &&
+      assert(isPartOfPPRCalleeSaves(*PPRCalleeSavesBegin) &&
              "Unexpected instruction");
       while (isPartOfPPRCalleeSaves(AfterSVESavesI) &&
              AfterSVESavesI != MBB.getFirstTerminator())
         ++AfterSVESavesI;
     }
+    PPRCalleeSavesEnd = ZPRCalleeSavesBegin = AfterSVESavesI;
     if (ZPRCalleeSavesSize) {
       LLVM_DEBUG(dbgs() << "ZPRCalleeSavedStackSize = "
                         << ZPRCalleeSavesSize.getScalable() << "\n");
-      assert(isPartOfZPRCalleeSaves(AfterSVESavesI) &&
+      assert(isPartOfZPRCalleeSaves(*ZPRCalleeSavesBegin) &&
              "Unexpected instruction");
       while (isPartOfZPRCalleeSaves(AfterSVESavesI) &&
              AfterSVESavesI != MBB.getFirstTerminator())
         ++AfterSVESavesI;
     }
+    ZPRCalleeSavesEnd = AfterSVESavesI;
   }
 
   if (EmitAsyncCFI)