llvm-6502/lib/Target/SystemZ/SystemZRegisterInfo.cpp
Richard Sandiford 55d7d83b6c [SystemZ] Use upper words of GR64s for codegen
This just adds the basics necessary for allocating the upper words to
virtual registers (move, load and store).  The move support is parameterised
in a way that makes it easy to handle zero extensions, but the associated
zero-extend patterns are added by a later patch.

The easiest way of testing this seemed to be add a new "h" register
constraint for high words.  I don't expect the constraint to be useful
in real inline asms, but it should work, so I didn't try to hide it
behind an option.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191739 91177308-0d34-0410-b5e6-96231b3b80d8
2013-10-01 11:26:28 +00:00

142 lines
5.2 KiB
C++

//===-- SystemZRegisterInfo.cpp - SystemZ register information ------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "SystemZRegisterInfo.h"
#include "SystemZTargetMachine.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#define GET_REGINFO_TARGET_DESC
#include "SystemZGenRegisterInfo.inc"
using namespace llvm;
SystemZRegisterInfo::SystemZRegisterInfo(SystemZTargetMachine &tm)
: SystemZGenRegisterInfo(SystemZ::R14D), TM(tm) {}
const uint16_t*
SystemZRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
static const uint16_t CalleeSavedRegs[] = {
SystemZ::R6D, SystemZ::R7D, SystemZ::R8D, SystemZ::R9D,
SystemZ::R10D, SystemZ::R11D, SystemZ::R12D, SystemZ::R13D,
SystemZ::R14D, SystemZ::R15D,
SystemZ::F8D, SystemZ::F9D, SystemZ::F10D, SystemZ::F11D,
SystemZ::F12D, SystemZ::F13D, SystemZ::F14D, SystemZ::F15D,
0
};
return CalleeSavedRegs;
}
BitVector
SystemZRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
BitVector Reserved(getNumRegs());
const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
if (TFI->hasFP(MF)) {
// R11D is the frame pointer. Reserve all aliases.
Reserved.set(SystemZ::R11D);
Reserved.set(SystemZ::R11L);
Reserved.set(SystemZ::R11H);
Reserved.set(SystemZ::R10Q);
}
// R15D is the stack pointer. Reserve all aliases.
Reserved.set(SystemZ::R15D);
Reserved.set(SystemZ::R15L);
Reserved.set(SystemZ::R15H);
Reserved.set(SystemZ::R14Q);
return Reserved;
}
void
SystemZRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator MI,
int SPAdj, unsigned FIOperandNum,
RegScavenger *RS) const {
assert(SPAdj == 0 && "Outgoing arguments should be part of the frame");
MachineBasicBlock &MBB = *MI->getParent();
MachineFunction &MF = *MBB.getParent();
const SystemZInstrInfo &TII =
*static_cast<const SystemZInstrInfo*>(TM.getInstrInfo());
const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
DebugLoc DL = MI->getDebugLoc();
// Decompose the frame index into a base and offset.
int FrameIndex = MI->getOperand(FIOperandNum).getIndex();
unsigned BasePtr = getFrameRegister(MF);
int64_t Offset = (TFI->getFrameIndexOffset(MF, FrameIndex) +
MI->getOperand(FIOperandNum + 1).getImm());
// Special handling of dbg_value instructions.
if (MI->isDebugValue()) {
MI->getOperand(FIOperandNum).ChangeToRegister(BasePtr, /*isDef*/ false);
MI->getOperand(FIOperandNum + 1).ChangeToImmediate(Offset);
return;
}
// See if the offset is in range, or if an equivalent instruction that
// accepts the offset exists.
unsigned Opcode = MI->getOpcode();
unsigned OpcodeForOffset = TII.getOpcodeForOffset(Opcode, Offset);
if (OpcodeForOffset)
MI->getOperand(FIOperandNum).ChangeToRegister(BasePtr, false);
else {
// Create an anchor point that is in range. Start at 0xffff so that
// can use LLILH to load the immediate.
int64_t OldOffset = Offset;
int64_t Mask = 0xffff;
do {
Offset = OldOffset & Mask;
OpcodeForOffset = TII.getOpcodeForOffset(Opcode, Offset);
Mask >>= 1;
assert(Mask && "One offset must be OK");
} while (!OpcodeForOffset);
unsigned ScratchReg =
MF.getRegInfo().createVirtualRegister(&SystemZ::ADDR64BitRegClass);
int64_t HighOffset = OldOffset - Offset;
if (MI->getDesc().TSFlags & SystemZII::HasIndex
&& MI->getOperand(FIOperandNum + 2).getReg() == 0) {
// Load the offset into the scratch register and use it as an index.
// The scratch register then dies here.
TII.loadImmediate(MBB, MI, ScratchReg, HighOffset);
MI->getOperand(FIOperandNum).ChangeToRegister(BasePtr, false);
MI->getOperand(FIOperandNum + 2).ChangeToRegister(ScratchReg,
false, false, true);
} else {
// Load the anchor address into a scratch register.
unsigned LAOpcode = TII.getOpcodeForOffset(SystemZ::LA, HighOffset);
if (LAOpcode)
BuildMI(MBB, MI, DL, TII.get(LAOpcode),ScratchReg)
.addReg(BasePtr).addImm(HighOffset).addReg(0);
else {
// Load the high offset into the scratch register and use it as
// an index.
TII.loadImmediate(MBB, MI, ScratchReg, HighOffset);
BuildMI(MBB, MI, DL, TII.get(SystemZ::AGR),ScratchReg)
.addReg(ScratchReg, RegState::Kill).addReg(BasePtr);
}
// Use the scratch register as the base. It then dies here.
MI->getOperand(FIOperandNum).ChangeToRegister(ScratchReg,
false, false, true);
}
}
MI->setDesc(TII.get(OpcodeForOffset));
MI->getOperand(FIOperandNum + 1).ChangeToImmediate(Offset);
}
unsigned
SystemZRegisterInfo::getFrameRegister(const MachineFunction &MF) const {
const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
return TFI->hasFP(MF) ? SystemZ::R11D : SystemZ::R15D;
}