Add new RegionInfo pass.

The RegionInfo pass detects single entry single exit regions in a function,
where a region is defined as any subgraph that is connected to the remaining
graph at only two spots.
Furthermore an hierarchical region tree is built.
Use it by calling "opt -regions analyze" or "opt -view-regions".

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109089 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/Passes.html b/docs/Passes.html
index fb3bc94..12a936a 100644
--- a/docs/Passes.html
+++ b/docs/Passes.html
@@ -120,6 +120,7 @@
 <tr><td><a href="#print-used-types">-print-used-types</a></td><td>Find Used Types</td></tr>
 <tr><td><a href="#profile-estimator">-profile-estimator</a></td><td>Estimate profiling information</td></tr>
 <tr><td><a href="#profile-loader">-profile-loader</a></td><td>Load profile information from llvmprof.out</td></tr>
+<tr><td><a href="#regions">-regions</a></td><td>Detect single entry single exit regions in a function</td></tr>
 <tr><td><a href="#profile-verifier">-profile-verifier</a></td><td>Verify profiling information</td></tr>
 <tr><td><a href="#scalar-evolution">-scalar-evolution</a></td><td>Scalar Evolution Analysis</td></tr>
 <tr><td><a href="#scev-aa">-scev-aa</a></td><td>ScalarEvolution-based Alias Analysis</td></tr>
@@ -771,6 +772,17 @@
 <div class="doc_text">
   <p>Pass that checks profiling information for plausibility.</p>
 </div>
+<div class="doc_subsection">
+  <a name="regions">-regions: Detect single entry single exit regions in a function</a>
+</div>
+<div class="doc_text">
+  <p>
+  The <code>RegionInfo</code> pass detects single entry single exit regions in a
+  function, where a region is defined as any subgraph that is connected to the
+  remaining graph at only two spots. Furthermore, an hierarchical region tree is
+  built.
+  </p>
+</div>
 
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 <div class="doc_subsection">