The variable "Latch" is only used in an assert, which makes builds that use "-DNDEBUG" fail with unused variable messages.

[saugustine]

Summary

Move the logic into the assert itself.

llvm/lib/Transforms/Scalar/IndVarSimplify.cpp

bool IndVarSimplify::sinkUnusedInvariants(Loop *L) {
   }
 
   return MadeAnyChanges;
 }
 
 bool IndVarSimplify::optimizeLoopExits(Loop *L) {
   SmallVector<BasicBlock*, 16> ExitingBlocks;
   L->getExitingBlocks(ExitingBlocks);
-  BasicBlock * const Latch = L->getLoopLatch();
 
   // Form an expression for the maximum exit count possible for this loop. We
   // merge the max and exact information to approximate a version of
   // getMaxBackedgeTakenInfo which isn't restricted to just constants.
   // TODO: factor this out as a version of getMaxBackedgeTakenCount which
   // isn't guaranteed to return a constant.
   SmallVector<const SCEV*, 4> ExitCounts;
   const SCEV *MaxConstEC = SE->getMaxBackedgeTakenCount(L);
   if (!isa<SCEVCouldNotCompute>(MaxConstEC))
     ExitCounts.push_back(MaxConstEC);
   for (BasicBlock *ExitingBB : ExitingBlocks) {
     const SCEV *ExitCount = SE->getExitCount(L, ExitingBB);
     if (!isa<SCEVCouldNotCompute>(ExitCount)) {
-      assert(DT->dominates(ExitingBB, Latch) &&
+      assert(DT->dominates(ExitingBB, L->getLoopLatch()) &&
              "We should only have known counts for exiting blocks that "
              "dominate latch!");
       ExitCounts.push_back(ExitCount);
     }
   }
   if (ExitCounts.empty())
     return false;
   const SCEV *MaxExitCount = SE->getUMinFromMismatchedTypes(ExitCounts);