diff --git a/llvm/lib/Target/PowerPC/PPCLoopInstrFormPrep.cpp b/llvm/lib/Target/PowerPC/PPCLoopInstrFormPrep.cpp
--- a/llvm/lib/Target/PowerPC/PPCLoopInstrFormPrep.cpp
+++ b/llvm/lib/Target/PowerPC/PPCLoopInstrFormPrep.cpp
@@ -606,6 +606,10 @@
       NewBasePtr = NewPHI;
   }
 
+  // Clear the rewriter cache, because values that are in the rewriter's cache
+  // can be deleted below, causing the AssertingVH in the cache to trigger.
+  SCEVE.clear();
+
   if (Instruction *IDel = dyn_cast<Instruction>(BasePtr))
     BBChanged.insert(IDel->getParent());
   BasePtr->replaceAllUsesWith(NewBasePtr);