[LoopSimplify] Use BB::instructionsWithoutDebug to skip DbgInfo (NFC).

This patch updates some code responsible the skip debug info to use
BasicBlock::instructionsWithoutDebug. I think this makes things slightly
simpler and more direct.

Reviewers: aprantl, vsk, chandlerc

Reviewed By: aprantl

Differential Revision: https://reviews.llvm.org/D46253

llvm-svn: 331217

Author: fhahn

llvm/lib/Transforms/Utils/LoopSimplify.cpp

@@ -613,11 +613,8 @@ static bool simplifyOneLoop(Loop *L, SmallVectorImpl<Loop *> &Worklist,
       // comparison and the branch.
       bool AllInvariant = true;
       bool AnyInvariant = false;
-      for (BasicBlock::iterator I = ExitingBlock->begin(); &*I != BI; ) {
+      for (auto I = ExitingBlock->instructionsWithoutDebug().begin(); &*I != BI; ) {
         Instruction *Inst = &*I++;
-        // Skip debug info intrinsics.
-        if (isa<DbgInfoIntrinsic>(Inst))
-          continue;
         if (Inst == CI)
           continue;
         if (!L->makeLoopInvariant(Inst, AnyInvariant,