Add InsertBranch() hook for tail mergeing

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70754 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/MSP430/MSP430InstrInfo.cpp

@@ -149,3 +149,29 @@ MSP430InstrInfo::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
 
   return true;
 }
+
+unsigned
+MSP430InstrInfo::InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
+                              MachineBasicBlock *FBB,
+                            const SmallVectorImpl<MachineOperand> &Cond) const {
+  // FIXME this should probably have a DebugLoc operand
+  DebugLoc dl = DebugLoc::getUnknownLoc();
+
+  // Shouldn't be a fall through.
+  assert(TBB && "InsertBranch must not be told to insert a fallthrough");
+  assert((Cond.size() == 1 || Cond.size() == 0) &&
+         "MSP430 branch conditions have one component!");
+
+  if (Cond.empty()) {
+    // Unconditional branch?
+    assert(!FBB && "Unconditional branch with multiple successors!");
+    BuildMI(&MBB, dl, get(MSP430::JMP)).addMBB(TBB);
+    return 1;
+  }
+
+  // Conditional branch.
+  unsigned Count = 0;
+  assert(0 && "Implement conditional branches!");
+
+  return Count;
+}

lib/Target/MSP430/MSP430InstrInfo.h

@@ -73,6 +73,10 @@ public:
                                            MachineBasicBlock::iterator MI,
                                  const std::vector<CalleeSavedInfo> &CSI) const;
 
+  virtual unsigned InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
+                                MachineBasicBlock *FBB,
+                             const SmallVectorImpl<MachineOperand> &Cond) const;
+
 };
 
 }