[VPlan] Introduce VPlan-based dominator analysis.

The patch introduces dominator analysis for VPBlockBases and extend
VPlan's GraphTraits specialization with the required interfaces. Dominator
analysis will be necessary to perform some H-CFG transformations and
to introduce VPLoopInfo (LoopInfo analysis on top of the VPlan representation).

Reviewers: fhahn, rengolin, mkuper, hfinkel, mssimpso

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D48815

llvm-svn: 338310

1 files changed, 13 insertions, 2 deletions

diff --git a/llvm/unittests/Transforms/Vectorize/VPlanTestBase.h b/llvm/unittests/Transforms/Vectorize/VPlanTestBase.h
index da3b39f4df0..0fc4a9a21c8 100644
--- a/llvm/unittests/Transforms/Vectorize/VPlanTestBase.h
+++ b/llvm/unittests/Transforms/Vectorize/VPlanTestBase.h
@@ -50,8 +50,19 @@ protected:
     doAnalysis(*LoopHeader->getParent());
 
     auto Plan = llvm::make_unique<VPlan>();
-    VPlanHCFGBuilder HCFGBuilder(LI->getLoopFor(LoopHeader), LI.get());
-    HCFGBuilder.buildHierarchicalCFG(*Plan.get());
+    VPlanHCFGBuilder HCFGBuilder(LI->getLoopFor(LoopHeader), LI.get(), *Plan);
+    HCFGBuilder.buildHierarchicalCFG();
+    return Plan;
+  }
+
+  /// Build the VPlan plain CFG for the loop starting from \p LoopHeader.
+  VPlanPtr buildPlainCFG(BasicBlock *LoopHeader) {
+    doAnalysis(*LoopHeader->getParent());
+
+    auto Plan = llvm::make_unique<VPlan>();
+    VPlanHCFGBuilder HCFGBuilder(LI->getLoopFor(LoopHeader), LI.get(), *Plan);
+    VPRegionBlock *TopRegion = HCFGBuilder.buildPlainCFG();
+    Plan->setEntry(TopRegion);
     return Plan;
   }
 };