[LICM] Don't verify domtree/loopinfo unless EXPENSIVE_CHECKS is enabled.

For large functions, verifying the whole function after each loop takes
non-linear time.

Differential Revision: https://reviews.llvm.org/D67571

llvm-svn: 372924

llvm/lib/Transforms/Scalar/LICM.cpp

@@ -963,7 +963,7 @@ bool llvm::hoistRegion(DomTreeNode *N, AliasAnalysis *AA, LoopInfo *LI,
 
     // Now that we've finished hoisting make sure that LI and DT are still
     // valid.
-#ifndef NDEBUG
+#ifdef EXPENSIVE_CHECKS
   if (Changed) {
     assert(DT->verify(DominatorTree::VerificationLevel::Fast) &&
            "Dominator tree verification failed");