Index: llvm/tools/llvm-reduce/deltas/ReduceUsingSimplifyCFG.cpp
===================================================================
--- llvm/tools/llvm-reduce/deltas/ReduceUsingSimplifyCFG.cpp
+++ llvm/tools/llvm-reduce/deltas/ReduceUsingSimplifyCFG.cpp
@@ -39,7 +39,22 @@
   for (auto &F : M) {
     for (auto &BB : F) {
       auto *BR = dyn_cast<BranchInst>(BB.getTerminator());
-      if (!BR || !BR->isConditional() || O.shouldKeep())
+      if (!BR || !BR->isConditional())
+        continue;
+
+      // Skip cases that already have the value we're going to set this to.
+      ConstantInt *Cond = dyn_cast<ConstantInt>(BR->getCondition());
+      if (Cond) {
+        if (Direction) {
+          if (Cond->isOne())
+            continue;
+        } else {
+          if (Cond->isZero())
+            continue;
+        }
+      }
+
+      if (O.shouldKeep())
         continue;
 
       if (Direction)