1 files changed, 92 insertions, 0 deletions
diff --git a/include/llvm/Transforms/Utils/SSAUpdaterBulk.h b/include/llvm/Transforms/Utils/SSAUpdaterBulk.h
new file mode 100644
index 000000000000..53a608f01804
--- /dev/null
+++ b/include/llvm/Transforms/Utils/SSAUpdaterBulk.h
@@ -0,0 +1,92 @@
+//===- SSAUpdaterBulk.h - Unstructured SSA Update Tool ----------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares the SSAUpdaterBulk class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H
+#define LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/IR/PredIteratorCache.h"
+
+namespace llvm {
+
+class BasicBlock;
+class PHINode;
+template <typename T> class SmallVectorImpl;
+class Type;
+class Use;
+class Value;
+class DominatorTree;
+
+/// Helper class for SSA formation on a set of values defined in multiple
+/// blocks.
+///
+/// This is used when code duplication or another unstructured transformation
+/// wants to rewrite a set of uses of one value with uses of a set of values.
+/// The update is done only when RewriteAllUses is called, all other methods are
+/// used for book-keeping. That helps to share some common computations between
+/// updates of different uses (which is not the case when traditional SSAUpdater
+/// is used).
+class SSAUpdaterBulk {
+  struct RewriteInfo {
+    DenseMap<BasicBlock *, Value *> Defines;
+    SmallVector<Use *, 4> Uses;
+    StringRef Name;
+    Type *Ty;
+    RewriteInfo(){};
+    RewriteInfo(StringRef &N, Type *T) : Name(N), Ty(T){};
+  };
+  SmallVector<RewriteInfo, 4> Rewrites;
+
+  PredIteratorCache PredCache;
+
+  Value *computeValueAt(BasicBlock *BB, RewriteInfo &R, DominatorTree *DT);
+
+public:
+  explicit SSAUpdaterBulk(){};
+  SSAUpdaterBulk(const SSAUpdaterBulk &) = delete;
+  SSAUpdaterBulk &operator=(const SSAUpdaterBulk &) = delete;
+  ~SSAUpdaterBulk(){};
+
+  /// Add a new variable to the SSA rewriter. This needs to be called before
+  /// AddAvailableValue or AddUse calls. The return value is the variable ID,
+  /// which needs to be passed to AddAvailableValue and AddUse.
+  unsigned AddVariable(StringRef Name, Type *Ty);
+
+  /// Indicate that a rewritten value is available in the specified block with
+  /// the specified value.
+  void AddAvailableValue(unsigned Var, BasicBlock *BB, Value *V);
+
+  /// Record a use of the symbolic value. This use will be updated with a
+  /// rewritten value when RewriteAllUses is called.
+  void AddUse(unsigned Var, Use *U);
+
+  /// Return true if the SSAUpdater already has a value for the specified
+  /// variable in the specified block.
+  bool HasValueForBlock(unsigned Var, BasicBlock *BB);
+
+  /// Perform all the necessary updates, including new PHI-nodes insertion and
+  /// the requested uses update.
+  ///
+  /// The function requires dominator tree DT, which is used for computing
+  /// locations for new phi-nodes insertions. If a nonnull pointer to a vector
+  /// InsertedPHIs is passed, all the new phi-nodes will be added to this
+  /// vector.
+  void RewriteAllUses(DominatorTree *DT,
+                      SmallVectorImpl<PHINode *> *InsertedPHIs = nullptr);
+};
+
+} // end namespace llvm
+
+#endif // LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H