Unroll again after running BBVectorize

Because BBVectorize may significantly shorten a loop body, unroll
again after vectorization. This is especially important when using
runtime or partial unrolling.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173730 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/IPO/PassManagerBuilder.cpp b/lib/Transforms/IPO/PassManagerBuilder.cpp
index 6dc17737785ddce3c396e586b77139fa3d784d39..47b2b51899c6563349c9bd5977fc4b4b3c65b6a9 100644 (file)
--- a/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -214,6 +214,10 @@ void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) {
       MPM.add(createGVNPass());                   // Remove redundancies
     else
       MPM.add(createEarlyCSEPass());              // Catch trivial redundancies
+
+    // BBVectorize may have significantly shortened a loop body; unroll again.
+    if (!DisableUnrollLoops)
+      MPM.add(createLoopUnrollPass());
   }
 
   MPM.add(createAggressiveDCEPass());         // Delete dead instructions