diff --git a/llvm/lib/Analysis/InlineCost.cpp b/llvm/lib/Analysis/InlineCost.cpp
--- a/llvm/lib/Analysis/InlineCost.cpp
+++ b/llvm/lib/Analysis/InlineCost.cpp
@@ -844,6 +844,9 @@
     APInt CycleSavings(128, 0);
 
     for (auto &BB : F) {
+      // Skip dead blocks since they are going to be simplified away.
+      if (DeadBlocks.count(&BB))
+       continue;
       APInt CurrentSavings(128, 0);
       for (auto &I : BB) {
         if (BranchInst *BI = dyn_cast<BranchInst>(&I)) {