Turn the EdgeBundles class into a stand-alone machine CFG analysis pass.

The analysis will be needed by both the greedy register allocator and the
X86FloatingPoint pass. It only needs to be computed once when the CFG doesn't
change.

This pass is very fast, usually showing up as 0.0% wall time.

llvm-svn: 122832

3 files changed, 63 insertions, 0 deletions

diff --git a/llvm/include/llvm/CodeGen/EdgeBundles.h b/llvm/include/llvm/CodeGen/EdgeBundles.h
new file mode 100644
index 0000000..0929d93
--- /dev/null
+++ b/llvm/include/llvm/CodeGen/EdgeBundles.h
@@ -0,0 +1,58 @@
+//===-------- EdgeBundles.h - Bundles of CFG edges --------------*- c++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// The EdgeBundles analysis forms equivalence classes of CFG edges such that all
+// edges leaving a machine basic block are in the same bundle, and all edges
+// leaving a basic block are in the same bundle.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_EDGEBUNDLES_H
+#define LLVM_CODEGEN_EDGEBUNDLES_H
+
+#include "llvm/ADT/IntEqClasses.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+
+namespace llvm {
+
+class EdgeBundles : public MachineFunctionPass {
+  const MachineFunction *MF;
+
+  /// EC - Each edge bundle is an equivalence class. The keys are:
+  ///   2*BB->getNumber()   -> Ingoing bundle.
+  ///   2*BB->getNumber()+1 -> Outgoing bundle.
+  IntEqClasses EC;
+
+public:
+  static char ID;
+  EdgeBundles() : MachineFunctionPass(ID) {}
+
+  /// getBundle - Return the ingoing (Out = false) or outgoing (Out = true)
+  /// bundle number for basic block #N
+  unsigned getBundle(unsigned N, bool Out) const { return EC[2 * N + Out]; }
+
+  /// getMachineFunction - Return the last machine function computed.
+  const MachineFunction *getMachineFunction() const { return MF; }
+
+  /// view - Visualize the annotated bipartite CFG with Graphviz.
+  void view() const;
+
+private:
+  virtual bool runOnMachineFunction(MachineFunction&);
+  virtual void getAnalysisUsage(AnalysisUsage&) const;
+};
+
+/// Specialize WriteGraph, the standard implementation won't work.
+raw_ostream &WriteGraph(raw_ostream &O, const EdgeBundles &G,
+                        bool ShortNames = false,
+                        const std::string &Title = "");
+
+} // end namespace llvm
+
+#endif
diff --git a/llvm/include/llvm/CodeGen/Passes.h b/llvm/include/llvm/CodeGen/Passes.h
index d4ed994..6f53d34 100644
--- a/llvm/include/llvm/CodeGen/Passes.h
+++ b/llvm/include/llvm/CodeGen/Passes.h
@@ -54,6 +54,10 @@ namespace llvm {
   ///
   extern char &MachineDominatorsID;
 
+  /// EdgeBundles analysis - Bundle machine CFG edges.
+  ///
+  extern char &EdgeBundlesID;
+
   /// PHIElimination pass - This pass eliminates machine instruction PHI nodes
   /// by inserting copy instructions.  This destroys SSA information, but is the
   /// desired input for some register allocators.  This pass is "required" by
diff --git a/llvm/include/llvm/InitializePasses.h b/llvm/include/llvm/InitializePasses.h
index c89d4fe..dc45716 100644
--- a/llvm/include/llvm/InitializePasses.h
+++ b/llvm/include/llvm/InitializePasses.h
@@ -91,6 +91,7 @@ void initializeDomPrinterPass(PassRegistry&);
 void initializeDomViewerPass(PassRegistry&);
 void initializeDominanceFrontierPass(PassRegistry&);
 void initializeDominatorTreePass(PassRegistry&);
+void initializeEdgeBundlesPass(PassRegistry&);
 void initializeEdgeProfilerPass(PassRegistry&);
 void initializeEarlyCSEPass(PassRegistry&);
 void initializeExpandISelPseudosPass(PassRegistry&);