Rename the Region::block_iterator to Region::block_node_iterator, and
add a new Region::block_iterator which actually iterates over the basic
blocks of the region.

The old iterator, now call 'block_node_iterator' iterates over
RegionNodes which contain a single basic block. This works well with the
GraphTraits-based iterator design, however most users actually want an
iterator over the BasicBlocks inside these RegionNodes. Now the
'block_iterator' is a wrapper which exposes exactly this interface.
Internally it uses the block_node_iterator to walk all nodes which are
single basic blocks, but transparently unwraps the basic block to make
user code simpler.

While this patch is a bit of a wash, most of the updates are to internal
users, not external users of the RegionInfo. I have an accompanying
patch to Polly that is a strict simplification of every user of this
interface, and I'm working on a pass that also wants the same simplified
interface.

This patch alone should have no functional impact.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156202 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/RegionPrinter.cpp b/lib/Analysis/RegionPrinter.cpp
index a1730b0..8b23cc7 100644
--- a/lib/Analysis/RegionPrinter.cpp
+++ b/lib/Analysis/RegionPrinter.cpp
@@ -122,13 +122,11 @@
     RegionInfo *RI = R->getRegionInfo();
 
     for (Region::const_block_iterator BI = R->block_begin(),
-         BE = R->block_end(); BI != BE; ++BI) {
-      BasicBlock *BB = (*BI)->getNodeAs<BasicBlock>();
-      if (RI->getRegionFor(BB) == R)
+         BE = R->block_end(); BI != BE; ++BI)
+      if (RI->getRegionFor(*BI) == R)
         O.indent(2 * (depth + 1)) << "Node"
-          << static_cast<const void*>(RI->getTopLevelRegion()->getBBNode(BB))
+          << static_cast<const void*>(RI->getTopLevelRegion()->getBBNode(*BI))
           << ";\n";
-    }
 
     O.indent(2 * depth) << "}\n";
   }