Use make_range(rbegin(), rend()) to allow foreach loops.  NFC.

Instead of the pattern

for (auto I = x.rbegin(), E = x.end(); I != E; ++I)

we can use make_range to construct the reverse range and iterate using
that instead.

llvm-svn: 243163
diff --git a/llvm/lib/Transforms/Scalar/LoopDistribute.cpp b/llvm/lib/Transforms/Scalar/LoopDistribute.cpp
index 1b9859b..96ac582 100644
--- a/llvm/lib/Transforms/Scalar/LoopDistribute.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopDistribute.cpp
@@ -164,9 +164,7 @@
 
     // Delete the instructions backwards, as it has a reduced likelihood of
     // having to update as many def-use and use-def chains.
-    for (auto I = Unused.rbegin(), E = Unused.rend(); I != E; ++I) {
-      auto *Inst = *I;
-
+    for (auto *Inst : make_range(Unused.rbegin(), Unused.rend())) {
       if (!Inst->use_empty())
         Inst->replaceAllUsesWith(UndefValue::get(Inst->getType()));
       Inst->eraseFromParent();