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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122832 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 81 insertions, 88 deletions

diff --git a/lib/CodeGen/CMakeLists.txt b/lib/CodeGen/CMakeLists.txt
index a43a0c5d53..b4da151a3a 100644
--- a/lib/CodeGen/CMakeLists.txt
+++ b/lib/CodeGen/CMakeLists.txt
@@ -10,6 +10,7 @@ add_llvm_library(LLVMCodeGen
   CriticalAntiDepBreaker.cpp
   DeadMachineInstructionElim.cpp
   DwarfEHPrepare.cpp
+  EdgeBundles.cpp
   ELFCodeEmitter.cpp
   ELFWriter.cpp
   ExpandISelPseudos.cpp
diff --git a/lib/CodeGen/EdgeBundles.cpp b/lib/CodeGen/EdgeBundles.cpp
new file mode 100644
index 0000000000..d7e73d160e
--- /dev/null
+++ b/lib/CodeGen/EdgeBundles.cpp
@@ -0,0 +1,79 @@
+//===-------- EdgeBundles.cpp - Bundles of CFG edges ----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides the implementation of the EdgeBundles analysis.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/EdgeBundles.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/Support/GraphWriter.h"
+
+using namespace llvm;
+
+char EdgeBundles::ID = 0;
+
+INITIALIZE_PASS(EdgeBundles, "edge-bundles", "Bundle Machine CFG Edges",
+                /* cfg = */true, /* analysis = */ true)
+
+char &llvm::EdgeBundlesID = EdgeBundles::ID;
+
+void EdgeBundles::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.setPreservesAll();
+  MachineFunctionPass::getAnalysisUsage(AU);
+}
+
+bool EdgeBundles::runOnMachineFunction(MachineFunction &mf) {
+  MF = &mf;
+  EC.clear();
+  EC.grow(2 * MF->size());
+
+  for (MachineFunction::const_iterator I = MF->begin(), E = MF->end(); I != E;
+       ++I) {
+    const MachineBasicBlock &MBB = *I;
+    unsigned OutE = 2 * MBB.getNumber() + 1;
+    // Join the outgoing bundle with the ingoing bundles of all successors.
+    for (MachineBasicBlock::const_succ_iterator SI = MBB.succ_begin(),
+           SE = MBB.succ_end(); SI != SE; ++SI)
+      EC.join(OutE, 2 * (*SI)->getNumber());
+  }
+  EC.compress();
+  return false;
+}
+
+/// view - Visualize the annotated bipartite CFG with Graphviz.
+void EdgeBundles::view() const {
+  ViewGraph(*this, "EdgeBundles");
+}
+
+/// Specialize WriteGraph, the standard implementation won't work.
+raw_ostream &llvm::WriteGraph(raw_ostream &O, const EdgeBundles &G,
+                              bool ShortNames,
+                              const std::string &Title) {
+  const MachineFunction *MF = G.getMachineFunction();
+
+  O << "digraph {\n";
+  for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
+       I != E; ++I) {
+    unsigned BB = I->getNumber();
+    O << "\t\"BB#" << BB << "\" [ shape=box ]\n"
+      << '\t' << G.getBundle(BB, false) << " -> \"BB#" << BB << "\"\n"
+      << "\t\"BB#" << BB << "\" -> " << G.getBundle(BB, true) << '\n';
+    for (MachineBasicBlock::const_succ_iterator SI = I->succ_begin(),
+           SE = I->succ_end(); SI != SE; ++SI)
+      O << "\t\"BB#" << BB << "\" -> \"BB#" << (*SI)->getNumber()
+        << "\" [ color=lightgray ]\n";
+  }
+  O << "}\n";
+  return O;
+}
+
+
diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp
index d0971fea48..4bb13e44b8 100644
--- a/lib/CodeGen/SplitKit.cpp
+++ b/lib/CodeGen/SplitKit.cpp
@@ -24,7 +24,6 @@
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
-#include "llvm/Support/GraphWriter.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Target/TargetMachine.h"
@@ -36,56 +35,6 @@ AllowSplit("spiller-splits-edges",
            cl::desc("Allow critical edge splitting during spilling"));
 
 //===----------------------------------------------------------------------===//
-//                                 Edge Bundles
-//===----------------------------------------------------------------------===//
-
-/// compute - Compute the edge bundles for MF. Bundles depend only on the CFG.
-void EdgeBundles::compute(const MachineFunction *mf) {
-  MF = mf;
-  EC.clear();
-  EC.grow(2 * MF->size());
-
-  for (MachineFunction::const_iterator I = MF->begin(), E = MF->end(); I != E;
-       ++I) {
-    const MachineBasicBlock &MBB = *I;
-    unsigned OutE = 2 * MBB.getNumber() + 1;
-    // Join the outgoing bundle with the ingoing bundles of all successors.
-    for (MachineBasicBlock::const_succ_iterator SI = MBB.succ_begin(),
-           SE = MBB.succ_end(); SI != SE; ++SI)
-      EC.join(OutE, 2 * (*SI)->getNumber());
-  }
-  EC.compress();
-}
-
-/// view - Visualize the annotated bipartite CFG with Graphviz.
-void EdgeBundles::view() const {
-  ViewGraph(*this, "EdgeBundles");
-}
-
-/// Specialize WriteGraph, the standard implementation won't work.
-raw_ostream &llvm::WriteGraph(raw_ostream &O, const EdgeBundles &G,
-                              bool ShortNames,
-                              const std::string &Title) {
-  const MachineFunction *MF = G.getMachineFunction();
-
-  O << "digraph {\n";
-  for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
-       I != E; ++I) {
-    unsigned BB = I->getNumber();
-    O << "\t\"BB#" << BB << "\" [ shape=box ]\n"
-      << '\t' << G.getBundle(BB, false) << " -> \"BB#" << BB << "\"\n"
-      << "\t\"BB#" << BB << "\" -> " << G.getBundle(BB, true) << '\n';
-    for (MachineBasicBlock::const_succ_iterator SI = I->succ_begin(),
-           SE = I->succ_end(); SI != SE; ++SI)
-      O << "\t\"BB#" << BB << "\" -> \"BB#" << (*SI)->getNumber()
-        << "\" [ color=lightgray ]\n";
-  }
-  O << "}\n";
-  return O;
-}
-
-
-//===----------------------------------------------------------------------===//
 //                                 Split Analysis
 //===----------------------------------------------------------------------===//
 
diff --git a/lib/CodeGen/SplitKit.h b/lib/CodeGen/SplitKit.h
index a6ba37610a..236986e4af 100644
--- a/lib/CodeGen/SplitKit.h
+++ b/lib/CodeGen/SplitKit.h
@@ -1,4 +1,4 @@
-//===-------- SplitKit.cpp - Toolkit for splitting live ranges --*- C++ -*-===//
+//===-------- SplitKit.h - Toolkit for splitting live ranges ----*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -13,12 +13,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/IntEqClasses.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/CodeGen/SlotIndexes.h"
 
-#include <string>
-
 namespace llvm {
 
 class LiveInterval;
@@ -40,39 +37,6 @@ template <class NodeT> class DomTreeNodeBase;
 typedef DomTreeNodeBase<MachineBasicBlock> MachineDomTreeNode;
 
 
-/// EdgeBundles - Group CFG edges into equivalence classes where registers must
-/// be allocated identically. This annotates the CFG to form a bipartite graph
-/// where each block is connected to an ingoing and an outgoing bundle.
-/// Edge bundles are simply numbered, there is no object representation.
-class EdgeBundles {
-  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:
-  /// compute - Compute the edge bundles for MF. Bundles depend only on the CFG.
-  void compute(const MachineFunction *MF);
-
-  /// 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;
-};
-
-/// Specialize WriteGraph, the standard implementation won't work.
-raw_ostream &WriteGraph(raw_ostream &O, const EdgeBundles &G,
-                        bool ShortNames = false,
-                        const std::string &Title = "");
-
-
 /// SplitAnalysis - Analyze a LiveInterval, looking for live range splitting
 /// opportunities.
 class SplitAnalysis {