Merge "Update prebuilt Clang to r353983." into p9.0HEADp9.0-backupp9.0

1 files changed, 85 insertions, 0 deletions

diff --git a/clang-r353983/include/llvm/Analysis/SyncDependenceAnalysis.h b/clang-r353983/include/llvm/Analysis/SyncDependenceAnalysis.h
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+++ b/clang-r353983/include/llvm/Analysis/SyncDependenceAnalysis.h
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+//===- SyncDependenceAnalysis.h - Divergent Branch Dependence -*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// \file
+// This file defines the SyncDependenceAnalysis class, which computes for
+// every divergent branch the set of phi nodes that the branch will make
+// divergent.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_SYNC_DEPENDENCE_ANALYSIS_H
+#define LLVM_ANALYSIS_SYNC_DEPENDENCE_ANALYSIS_H
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/PostOrderIterator.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Analysis/LoopInfo.h"
+#include <memory>
+
+namespace llvm {
+
+class BasicBlock;
+class DominatorTree;
+class Loop;
+class PostDominatorTree;
+
+using ConstBlockSet = SmallPtrSet<const BasicBlock *, 4>;
+
+/// \brief Relates points of divergent control to join points in
+/// reducible CFGs.
+///
+/// This analysis relates points of divergent control to points of converging
+/// divergent control. The analysis requires all loops to be reducible.
+class SyncDependenceAnalysis {
+  void visitSuccessor(const BasicBlock &succBlock, const Loop *termLoop,
+                      const BasicBlock *defBlock);
+
+public:
+  bool inRegion(const BasicBlock &BB) const;
+
+  ~SyncDependenceAnalysis();
+  SyncDependenceAnalysis(const DominatorTree &DT, const PostDominatorTree &PDT,
+                         const LoopInfo &LI);
+
+  /// \brief Computes divergent join points and loop exits caused by branch
+  /// divergence in \p Term.
+  ///
+  /// The set of blocks which are reachable by disjoint paths from \p Term.
+  /// The set also contains loop exits if there two disjoint paths:
+  /// one from \p Term to the loop exit and another from \p Term to the loop
+  /// header. Those exit blocks are added to the returned set.
+  /// If L is the parent loop of \p Term and an exit of L is in the returned
+  /// set then L is a divergent loop.
+  const ConstBlockSet &join_blocks(const Instruction &Term);
+
+  /// \brief Computes divergent join points and loop exits (in the surrounding
+  /// loop) caused by the divergent loop exits of\p Loop.
+  ///
+  /// The set of blocks which are reachable by disjoint paths from the
+  /// loop exits of \p Loop.
+  /// This treats the loop as a single node in \p Loop's parent loop.
+  /// The returned set has the same properties as for join_blocks(TermInst&).
+  const ConstBlockSet &join_blocks(const Loop &Loop);
+
+private:
+  static ConstBlockSet EmptyBlockSet;
+
+  ReversePostOrderTraversal<const Function *> FuncRPOT;
+  const DominatorTree &DT;
+  const PostDominatorTree &PDT;
+  const LoopInfo &LI;
+
+  std::map<const Loop *, std::unique_ptr<ConstBlockSet>> CachedLoopExitJoins;
+  std::map<const Instruction *, std::unique_ptr<ConstBlockSet>>
+      CachedBranchJoins;
+};
+
+} // namespace llvm
+
+#endif // LLVM_ANALYSIS_SYNC_DEPENDENCE_ANALYSIS_H