diff --git a/include/llvm/CodeGen/MachineInstrBuilder.h b/include/llvm/CodeGen/MachineInstrBuilder.h index 770685358ab..408c2a8789c 100644 --- a/include/llvm/CodeGen/MachineInstrBuilder.h +++ b/include/llvm/CodeGen/MachineInstrBuilder.h @@ -331,6 +331,70 @@ inline unsigned getInternalReadRegState(bool B) { return B ? RegState::InternalRead : 0; } + +/// Helper class for constructing bundles of MachineInstrs. +/// +/// MIBundleBuilder can create a bundle from scratch by inserting new +/// MachineInstrs one at a time, or it can create a bundle from a sequence of +/// existing MachineInstrs in a basic block. +class MIBundleBuilder { + MachineBasicBlock &MBB; + MachineBasicBlock::instr_iterator Begin; + MachineBasicBlock::instr_iterator End; + +public: + /// Create an MIBundleBuilder that inserts instructions into a new bundle in + /// BB above the bundle or instruction at Pos. + MIBundleBuilder(MachineBasicBlock &BB, + MachineBasicBlock::iterator Pos) + : MBB(BB), Begin(Pos.getInstrIterator()), End(Begin) {} + + /// Create a bundle from the sequence of instructions between B and E. + MIBundleBuilder(MachineBasicBlock &BB, + MachineBasicBlock::iterator B, + MachineBasicBlock::iterator E) + : MBB(BB), Begin(B.getInstrIterator()), End(E.getInstrIterator()) { + assert(B != E && "No instructions to bundle"); + ++B; + while (B != E) { + MachineInstr *MI = B; + ++B; + MI->bundleWithPred(); + } + } + + /// Return true if no instructions have been inserted in this bundle yet. + /// Empty bundles aren't representable in a MachineBasicBlock. + bool empty() const { return Begin == End; } + + /// Return an iterator to the first bundled instruction. + MachineBasicBlock::instr_iterator begin() const { return Begin; } + + /// Return an iterator beyond the last bundled instruction. + MachineBasicBlock::instr_iterator end() const { return End; } + + /// Insert MI into MBB by prepending it to the instructions in the bundle. + /// MI will become the first instruction in the bundle. + MIBundleBuilder &prepend(MachineInstr *MI) { + MBB.insert(Begin, MI); + if (!empty()) + MI->bundleWithSucc(); + Begin = MI; + return *this; + } + + /// Insert MI into MBB by appending it to the instructions in the bundle. + /// MI will become the last instruction in the bundle. + MIBundleBuilder &append(MachineInstr *MI) { + MBB.insert(End, MI); + if (empty()) + Begin = MI; + else + MI->bundleWithPred(); + return *this; + } +}; + } // End llvm namespace #endif