Implement insertGoto and reverseBranchCondition for the X86.
llvm-svn: 15362
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@ -38,3 +38,36 @@ bool X86InstrInfo::isMoveInstr(const MachineInstr& MI,
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}
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return false;
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}
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void X86InstrInfo::insertGoto(MachineBasicBlock& MBB,
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MachineBasicBlock& TMBB) const {
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BuildMI(MBB, MBB.end(), X86::JMP, 1).addMBB(&TMBB);
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}
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MachineBasicBlock::iterator
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X86InstrInfo::reverseBranchCondition(MachineBasicBlock::iterator MI) const {
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unsigned Opcode = MI->getOpcode();
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assert(isBranch(Opcode) && "MachineInstr must be a branch");
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unsigned ROpcode;
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switch (Opcode) {
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case X86::JB: ROpcode = X86::JAE;
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case X86::JAE: ROpcode = X86::JB;
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case X86::JE: ROpcode = X86::JNE;
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case X86::JNE: ROpcode = X86::JE;
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case X86::JBE: ROpcode = X86::JA;
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case X86::JA: ROpcode = X86::JBE;
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case X86::JS: ROpcode = X86::JNS;
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case X86::JNS: ROpcode = X86::JS;
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case X86::JL: ROpcode = X86::JGE;
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case X86::JGE: ROpcode = X86::JL;
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case X86::JLE: ROpcode = X86::JG;
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case X86::JG: ROpcode = X86::JLE;
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default:
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assert(0 && "Cannot reverse uncodnitional branches!");
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}
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MachineBasicBlock* MBB = MI->getParent();
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MachineBasicBlock* TMBB = MI->getOperand(0).getMachineBasicBlock();
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MachineInstrBuilder IB = BuildMI(*MBB, MBB->erase(MI), ROpcode, 1);
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IB.addMBB(TMBB);
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return IB;
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}
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@ -203,6 +203,16 @@ public:
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unsigned& sourceReg,
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unsigned& destReg) const;
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/// Insert a goto (unconditional branch) sequence to TMBB, at the
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/// end of MBB
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virtual void insertGoto(MachineBasicBlock& MBB,
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MachineBasicBlock& TMBB) const;
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/// Reverses the branch condition of the MachineInstr pointed by
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/// MI. The instruction is replaced and the new MI is returned.
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virtual MachineBasicBlock::iterator
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reverseBranchCondition(MachineBasicBlock::iterator MI) const;
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// getBaseOpcodeFor - This function returns the "base" X86 opcode for the
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// specified opcode number.
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//
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