mirror of
https://github.com/RPCS3/llvm.git
synced 2024-12-14 07:31:53 +00:00
abf05b2dae
* Fix bug in the createNOP method, which was not marking the operands of the generated XCHG as useanddef. I don't think this method is actually used, so it wasn't breaking anything, but it should be fixed anyway... git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7539 91177308-0d34-0410-b5e6-96231b3b80d8
45 lines
1.6 KiB
C++
45 lines
1.6 KiB
C++
//===- X86InstrInfo.cpp - X86 Instruction Information -----------*- C++ -*-===//
|
|
//
|
|
// This file contains the X86 implementation of the TargetInstrInfo class.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "X86InstrInfo.h"
|
|
#include "X86.h"
|
|
#include "llvm/CodeGen/MachineInstrBuilder.h"
|
|
|
|
#include "X86GenInstrInfo.inc"
|
|
|
|
X86InstrInfo::X86InstrInfo()
|
|
: TargetInstrInfo(X86Insts, sizeof(X86Insts)/sizeof(X86Insts[0]), 0) {
|
|
}
|
|
|
|
|
|
// createNOPinstr - returns the target's implementation of NOP, which is
|
|
// usually a pseudo-instruction, implemented by a degenerate version of
|
|
// another instruction, e.g. X86: `xchg ax, ax'; SparcV9: `sethi r0, r0, r0'
|
|
//
|
|
MachineInstr* X86InstrInfo::createNOPinstr() const {
|
|
return BuildMI(X86::XCHGrr16, 2).addReg(X86::AX, MOTy::UseAndDef)
|
|
.addReg(X86::AX, MOTy::UseAndDef);
|
|
}
|
|
|
|
|
|
/// isNOPinstr - not having a special NOP opcode, we need to know if a given
|
|
/// instruction is interpreted as an `official' NOP instr, i.e., there may be
|
|
/// more than one way to `do nothing' but only one canonical way to slack off.
|
|
//
|
|
bool X86InstrInfo::isNOPinstr(const MachineInstr &MI) const {
|
|
// Make sure the instruction is EXACTLY `xchg ax, ax'
|
|
if (MI.getOpcode() == X86::XCHGrr16) {
|
|
const MachineOperand &op0 = MI.getOperand(0), &op1 = MI.getOperand(1);
|
|
if (op0.isMachineRegister() && op0.getMachineRegNum() == X86::AX &&
|
|
op1.isMachineRegister() && op1.getMachineRegNum() == X86::AX) {
|
|
return true;
|
|
}
|
|
}
|
|
// FIXME: there are several NOOP instructions, we should check for them here.
|
|
return false;
|
|
}
|
|
|