Index: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
===================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -703,7 +703,10 @@
       continue;
 
     if (auto *CI = dyn_cast<CastInst>(Val)) {
-      NewInsts[CI] = NewInsts[CI->getOperand(0)];
+      // Don't get rid of the intermediate variable here; the store can grow
+      // the map which will invalidate the reference to the input value.
+      Value *V = NewInsts[CI->getOperand(0)];
+      NewInsts[CI] = V;
       continue;
     }
     if (auto *GEP = dyn_cast<GEPOperator>(Val)) {