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Implement insertGoto and reverseBranchCondition for the X86.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15362 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Alkis Evlogimenos 2004-07-31 09:38:47 +00:00
parent e4d32f6cf9
commit 36f506eddb
2 changed files with 43 additions and 0 deletions
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33
lib/Target/X86/X86InstrInfo.cpp
View File

@ -38,3 +38,36 @@ bool X86InstrInfo::isMoveInstr(const MachineInstr& MI,
}
return false;
}
void X86InstrInfo::insertGoto(MachineBasicBlock& MBB,
MachineBasicBlock& TMBB) const {
BuildMI(MBB, MBB.end(), X86::JMP, 1).addMBB(&TMBB);
}
MachineBasicBlock::iterator
X86InstrInfo::reverseBranchCondition(MachineBasicBlock::iterator MI) const {
unsigned Opcode = MI->getOpcode();
assert(isBranch(Opcode) && "MachineInstr must be a branch");
unsigned ROpcode;
switch (Opcode) {
case X86::JB: ROpcode = X86::JAE;
case X86::JAE: ROpcode = X86::JB;
case X86::JE: ROpcode = X86::JNE;
case X86::JNE: ROpcode = X86::JE;
case X86::JBE: ROpcode = X86::JA;
case X86::JA: ROpcode = X86::JBE;
case X86::JS: ROpcode = X86::JNS;
case X86::JNS: ROpcode = X86::JS;
case X86::JL: ROpcode = X86::JGE;
case X86::JGE: ROpcode = X86::JL;
case X86::JLE: ROpcode = X86::JG;
case X86::JG: ROpcode = X86::JLE;
default:
assert(0 && "Cannot reverse uncodnitional branches!");
}
MachineBasicBlock* MBB = MI->getParent();
MachineBasicBlock* TMBB = MI->getOperand(0).getMachineBasicBlock();
MachineInstrBuilder IB = BuildMI(*MBB, MBB->erase(MI), ROpcode, 1);
IB.addMBB(TMBB);
return IB;
}

10
lib/Target/X86/X86InstrInfo.h
View File

@ -203,6 +203,16 @@ public:
unsigned& sourceReg,
unsigned& destReg) const;
/// Insert a goto (unconditional branch) sequence to TMBB, at the
/// end of MBB
virtual void insertGoto(MachineBasicBlock& MBB,
MachineBasicBlock& TMBB) const;
/// Reverses the branch condition of the MachineInstr pointed by
/// MI. The instruction is replaced and the new MI is returned.
virtual MachineBasicBlock::iterator
reverseBranchCondition(MachineBasicBlock::iterator MI) const;
// getBaseOpcodeFor - This function returns the "base" X86 opcode for the
// specified opcode number.
//