As Chris and Evan pointed out, BreakCriticalMachineEdges doesn't really need

to be a pass of its own.  Instead, move it out into a helper method.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44002 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 1 insertions, 132 deletions

diff --git a/lib/CodeGen/BreakCriticalMachineEdges.cpp b/lib/CodeGen/BreakCriticalMachineEdges.cpp
deleted file mode 100644
index 21d9dbb..0000000
--- a/lib/CodeGen/BreakCriticalMachineEdges.cpp
+++ /dev/null
@@ -1,131 +0,0 @@
-//===----------- BreakCriticalMachineEdges - Break critical edges ---------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file was developed by Fernando Pereira and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
-//
-//===---------------------------------------------------------------------===//
-//
-// Break all of the critical edges in the CFG by inserting a dummy basic block. 
-// This pass may be "required" by passes that cannot deal with critical edges.
-// Notice that this pass invalidates the CFG, because the same BasicBlock is 
-// used as parameter for the src MachineBasicBlock and the new dummy
-// MachineBasicBlock.
-//
-//===---------------------------------------------------------------------===//
-
-#include "llvm/CodeGen/Passes.h"
-#include "llvm/CodeGen/MachineFunctionPass.h"
-#include "llvm/CodeGen/MachineInstr.h"
-#include "llvm/CodeGen/MachineJumpTableInfo.h"
-#include "llvm/Target/TargetInstrInfo.h"
-#include "llvm/Target/TargetMachine.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/Support/Compiler.h"
-
-using namespace llvm;
-
-namespace {
-  struct VISIBILITY_HIDDEN BreakCriticalMachineEdges :
-                           public MachineFunctionPass {
-    static char ID; // Pass identification
-    BreakCriticalMachineEdges() : MachineFunctionPass((intptr_t)&ID) {}
-    
-    bool runOnMachineFunction(MachineFunction& Fn);
-    void splitCriticalEdge(MachineBasicBlock* A, MachineBasicBlock* B);
-  };
-  
-  char BreakCriticalMachineEdges::ID = 0;
-  RegisterPass<BreakCriticalMachineEdges> X("critical-machine-edges",
-                                            "Break critical machine code edges");
-}
-
-const PassInfo *llvm::BreakCriticalMachineEdgesID = X.getPassInfo();
-
-void BreakCriticalMachineEdges::splitCriticalEdge(MachineBasicBlock* src,
-                                                  MachineBasicBlock* dst) {
-  const BasicBlock* srcBB = src->getBasicBlock();
-
-  MachineBasicBlock* crit_mbb = new MachineBasicBlock(srcBB);
-
-  // modify the llvm control flow graph
-  src->removeSuccessor(dst);
-  src->addSuccessor(crit_mbb);
-  crit_mbb->addSuccessor(dst);
-
-  // insert the new block into the machine function.
-  src->getParent()->getBasicBlockList().insert(src->getParent()->end(),
-                                               crit_mbb);
-
-  // insert a unconditional branch linking the new block to dst
-  const TargetMachine& TM = src->getParent()->getTarget();
-  const TargetInstrInfo* TII = TM.getInstrInfo();
-  std::vector<MachineOperand> emptyConditions;
-  TII->InsertBranch(*crit_mbb, dst, (MachineBasicBlock*)0, emptyConditions);
-
-  // modify every branch in src that points to dst to point to the new
-  // machine basic block instead:
-  MachineBasicBlock::iterator mii = src->end();
-  bool found_branch = false;
-  while (mii != src->begin()) {
-    mii--;
-    // if there are no more branches, finish the loop
-    if (!TII->isTerminatorInstr(mii->getOpcode())) {
-      break;
-    }
-    
-    // Scan the operands of this branch, replacing any uses of dst with
-    // crit_mbb.
-    for (unsigned i = 0, e = mii->getNumOperands(); i != e; ++i) {
-      MachineOperand & mo = mii->getOperand(i);
-      if (mo.isMachineBasicBlock() &&
-          mo.getMachineBasicBlock() == dst) {
-        found_branch = true;
-        mo.setMachineBasicBlock(crit_mbb);
-      }
-    }
-  }
-
-  // TODO: This is tentative. It may be necessary to fix this code. Maybe
-  // I am inserting too many gotos, but I am trusting that the asm printer
-  // will optimize the unnecessary gotos.
-  if(!found_branch) {
-    TII->InsertBranch(*src, crit_mbb, (MachineBasicBlock*)0, emptyConditions);
-  }
-
-  /// Change all the phi functions in dst, so that the incoming block be
-  /// crit_mbb, instead of src
-  for(mii = dst->begin(); mii != dst->end(); mii++) {
-    /// the first instructions are always phi functions.
-    if(mii->getOpcode() != TargetInstrInfo::PHI)
-      break;
-    
-    for (unsigned u = 0; u != mii->getNumOperands(); ++u)
-      if (mii->getOperand(u).isMachineBasicBlock() &&
-          mii->getOperand(u).getMachineBasicBlock() == src)
-        mii->getOperand(u).setMachineBasicBlock(crit_mbb);
-  }
-}
-
-bool BreakCriticalMachineEdges::runOnMachineFunction(MachineFunction& F) {
-  std::vector<MachineBasicBlock *> SourceBlocks;
-  std::vector<MachineBasicBlock *> DestBlocks;
-
-  for(MachineFunction::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI) {
-    for(MachineBasicBlock::succ_iterator SI = FI->succ_begin(),
-        SE = FI->succ_end(); SI != SE; ++SI) {
-      // predecessor with multiple successors, successor with multiple
-      // predecessors.
-      if (FI->succ_size() > 1 && (*SI)->pred_size() > 1) {
-        SourceBlocks.push_back(FI);
-        DestBlocks.push_back(*SI);
-      }
-    }
-  }
-
-  for(unsigned u = 0; u < SourceBlocks.size(); u++)
-    splitCriticalEdge(SourceBlocks[u], DestBlocks[u]);
-
-  return false;
-}
diff --git a/lib/CodeGen/StrongPHIElimination.cpp b/lib/CodeGen/StrongPHIElimination.cpp
index 5f84b58..f64186e 100644
--- a/lib/CodeGen/StrongPHIElimination.cpp
+++ b/lib/CodeGen/StrongPHIElimination.cpp
@@ -21,6 +21,7 @@
 
 #define DEBUG_TYPE "strongphielim"
 #include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/BreakCriticalMachineEdge.h"
 #include "llvm/CodeGen/LiveVariables.h"
 #include "llvm/CodeGen/MachineDominators.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp
index defd6ce..b8d38dc 100644
--- a/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -70,7 +70,6 @@ void TwoAddressInstructionPass::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.addRequired<LiveVariables>();
   AU.addPreserved<LiveVariables>();
   AU.addPreservedID(PHIEliminationID);
-  AU.addPreservedID(BreakCriticalMachineEdgesID);
   MachineFunctionPass::getAnalysisUsage(AU);
 }