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//===- X86InstrInfo.cpp - X86 Instruction Information -----------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the X86 implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#include "X86InstrInfo.h"
#include "X86.h"
#include "X86InstrBuilder.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "X86GenInstrInfo.inc"
using namespace llvm;
X86InstrInfo::X86InstrInfo()
: TargetInstrInfo(X86Insts, sizeof(X86Insts)/sizeof(X86Insts[0])) {
}
bool X86InstrInfo::isMoveInstr(const MachineInstr& MI,
unsigned& sourceReg,
unsigned& destReg) const {
MachineOpCode oc = MI.getOpcode();
if (oc == X86::MOV8rr || oc == X86::MOV16rr || oc == X86::MOV32rr ||
oc == X86::FpMOV || oc == X86::MOVAPDrr || oc == X86::MOVAPSrr) {
assert(MI.getNumOperands() == 2 &&
MI.getOperand(0).isRegister() &&
MI.getOperand(1).isRegister() &&
"invalid register-register move instruction");
sourceReg = MI.getOperand(1).getReg();
destReg = MI.getOperand(0).getReg();
return true;
}
return false;
}
/// convertToThreeAddress - This method must be implemented by targets that
/// set the M_CONVERTIBLE_TO_3_ADDR flag. When this flag is set, the target
/// may be able to convert a two-address instruction into a true
/// three-address instruction on demand. This allows the X86 target (for
/// example) to convert ADD and SHL instructions into LEA instructions if they
/// would require register copies due to two-addressness.
///
/// This method returns a null pointer if the transformation cannot be
/// performed, otherwise it returns the new instruction.
///
MachineInstr *X86InstrInfo::convertToThreeAddress(MachineInstr *MI) const {
// All instructions input are two-addr instructions. Get the known operands.
unsigned Dest = MI->getOperand(0).getReg();
unsigned Src = MI->getOperand(1).getReg();
// FIXME: None of these instructions are promotable to LEAs without
// additional information. In particular, LEA doesn't set the flags that
// add and inc do. :(
return 0;
// FIXME: 16-bit LEA's are really slow on Athlons, but not bad on P4's. When
// we have subtarget support, enable the 16-bit LEA generation here.
bool DisableLEA16 = true;
switch (MI->getOpcode()) {
case X86::INC32r:
assert(MI->getNumOperands() == 2 && "Unknown inc instruction!");
return addRegOffset(BuildMI(X86::LEA32r, 5, Dest), Src, 1);
case X86::INC16r:
if (DisableLEA16) return 0;
assert(MI->getNumOperands() == 2 && "Unknown inc instruction!");
return addRegOffset(BuildMI(X86::LEA16r, 5, Dest), Src, 1);
case X86::DEC32r:
assert(MI->getNumOperands() == 2 && "Unknown dec instruction!");
return addRegOffset(BuildMI(X86::LEA32r, 5, Dest), Src, -1);
case X86::DEC16r:
if (DisableLEA16) return 0;
assert(MI->getNumOperands() == 2 && "Unknown dec instruction!");
return addRegOffset(BuildMI(X86::LEA16r, 5, Dest), Src, -1);
case X86::ADD32rr:
assert(MI->getNumOperands() == 3 && "Unknown add instruction!");
return addRegReg(BuildMI(X86::LEA32r, 5, Dest), Src,
MI->getOperand(2).getReg());
case X86::ADD16rr:
if (DisableLEA16) return 0;
assert(MI->getNumOperands() == 3 && "Unknown add instruction!");
return addRegReg(BuildMI(X86::LEA16r, 5, Dest), Src,
MI->getOperand(2).getReg());
case X86::ADD32ri:
assert(MI->getNumOperands() == 3 && "Unknown add instruction!");
if (MI->getOperand(2).isImmediate())
return addRegOffset(BuildMI(X86::LEA32r, 5, Dest), Src,
MI->getOperand(2).getImmedValue());
return 0;
case X86::ADD16ri:
if (DisableLEA16) return 0;
assert(MI->getNumOperands() == 3 && "Unknown add instruction!");
if (MI->getOperand(2).isImmediate())
return addRegOffset(BuildMI(X86::LEA16r, 5, Dest), Src,
MI->getOperand(2).getImmedValue());
break;
case X86::SHL16ri:
if (DisableLEA16) return 0;
case X86::SHL32ri:
assert(MI->getNumOperands() == 3 && MI->getOperand(2).isImmediate() &&
"Unknown shl instruction!");
unsigned ShAmt = MI->getOperand(2).getImmedValue();
if (ShAmt == 1 || ShAmt == 2 || ShAmt == 3) {
X86AddressMode AM;
AM.Scale = 1 << ShAmt;
AM.IndexReg = Src;
unsigned Opc = MI->getOpcode() == X86::SHL32ri ? X86::LEA32r :X86::LEA16r;
return addFullAddress(BuildMI(Opc, 5, Dest), AM);
}
break;
}
return 0;
}
/// commuteInstruction - We have a few instructions that must be hacked on to
/// commute them.
///
MachineInstr *X86InstrInfo::commuteInstruction(MachineInstr *MI) const {
switch (MI->getOpcode()) {
case X86::SHRD16rri8: // A = SHRD16rri8 B, C, I -> A = SHLD16rri8 C, B, (16-I)
case X86::SHLD16rri8: // A = SHLD16rri8 B, C, I -> A = SHRD16rri8 C, B, (16-I)
case X86::SHRD32rri8: // A = SHRD32rri8 B, C, I -> A = SHLD32rri8 C, B, (32-I)
case X86::SHLD32rri8:{// A = SHLD32rri8 B, C, I -> A = SHRD32rri8 C, B, (32-I)
unsigned Opc;
unsigned Size;
switch (MI->getOpcode()) {
default: assert(0 && "Unreachable!");
case X86::SHRD16rri8: Size = 16; Opc = X86::SHLD16rri8; break;
case X86::SHLD16rri8: Size = 16; Opc = X86::SHRD16rri8; break;
case X86::SHRD32rri8: Size = 32; Opc = X86::SHLD32rri8; break;
case X86::SHLD32rri8: Size = 32; Opc = X86::SHRD32rri8; break;
}
unsigned Amt = MI->getOperand(3).getImmedValue();
unsigned A = MI->getOperand(0).getReg();
unsigned B = MI->getOperand(1).getReg();
unsigned C = MI->getOperand(2).getReg();
return BuildMI(Opc, 3, A).addReg(C).addReg(B).addImm(Size-Amt);
}
default:
return TargetInstrInfo::commuteInstruction(MI);
}
}
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) {
default: assert(0 && "Cannot reverse unconditional branches!");
case X86::JB: ROpcode = X86::JAE; break;
case X86::JAE: ROpcode = X86::JB; break;
case X86::JE: ROpcode = X86::JNE; break;
case X86::JNE: ROpcode = X86::JE; break;
case X86::JBE: ROpcode = X86::JA; break;
case X86::JA: ROpcode = X86::JBE; break;
case X86::JS: ROpcode = X86::JNS; break;
case X86::JNS: ROpcode = X86::JS; break;
case X86::JP: ROpcode = X86::JNP; break;
case X86::JNP: ROpcode = X86::JP; break;
case X86::JL: ROpcode = X86::JGE; break;
case X86::JGE: ROpcode = X86::JL; break;
case X86::JLE: ROpcode = X86::JG; break;
case X86::JG: ROpcode = X86::JLE; break;
}
MachineBasicBlock* MBB = MI->getParent();
MachineBasicBlock* TMBB = MI->getOperand(0).getMachineBasicBlock();
return BuildMI(*MBB, MBB->erase(MI), ROpcode, 1).addMBB(TMBB);
}
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