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R600/SI: Implement VGPR register spilling for compute at -O0 v3

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VGPRs are spilled to LDS.  This still needs more testing, but
we need to at least enable it at -O0, because the fast register
allocator spills all registers that are live at the end of blocks
and without this some future commits will break the
flat-address-space.ll test.

v2: Only calculate thread id once

v3: Move insertion of spill instructions to
    SIRegisterInfo::eliminateFrameIndex()

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218348 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Tom Stellard
2014-09-24 01:33:17 +00:00
parent 6717f9d907
commit 860cabe1e6
8 changed files with 332 additions and 48 deletions
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186
lib/Target/R600/SIInstrInfo.cpp
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@@ -21,6 +21,7 @@
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/MC/MCInstrDesc.h"
using namespace llvm;
@@ -433,6 +434,19 @@ unsigned SIInstrInfo::commuteOpcode(unsigned Opcode) const {
return Opcode;
}
static bool shouldTryToSpillVGPRs(MachineFunction *MF) {
SIMachineFunctionInfo *MFI = MF->getInfo<SIMachineFunctionInfo>();
const TargetMachine &TM = MF->getTarget();
// FIXME: Even though it can cause problems, we need to enable
// spilling at -O0, since the fast register allocator always
// spills registers that are live at the end of blocks.
return MFI->getShaderType() == ShaderType::COMPUTE &&
TM.getOptLevel() == CodeGenOpt::None;
}
void SIInstrInfo::storeRegToStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
unsigned SrcReg, bool isKill,
@@ -442,32 +456,41 @@ void SIInstrInfo::storeRegToStackSlot(MachineBasicBlock &MBB,
MachineFunction *MF = MBB.getParent();
MachineFrameInfo *FrameInfo = MF->getFrameInfo();
DebugLoc DL = MBB.findDebugLoc(MI);
int Opcode = -1;
if (RI.hasVGPRs(RC)) {
LLVMContext &Ctx = MF->getFunction()->getContext();
Ctx.emitError("SIInstrInfo::storeRegToStackSlot - Can't spill VGPR!");
BuildMI(MBB, MI, DL, get(AMDGPU::V_MOV_B32_e32), AMDGPU::VGPR0)
.addReg(SrcReg);
} else if (RI.isSGPRClass(RC)) {
if (RI.isSGPRClass(RC)) {
// We are only allowed to create one new instruction when spilling
// registers, so we need to use pseudo instruction for spilling
// SGPRs.
unsigned Opcode;
switch (RC->getSize() * 8) {
case 32: Opcode = AMDGPU::SI_SPILL_S32_SAVE; break;
case 64: Opcode = AMDGPU::SI_SPILL_S64_SAVE; break;
case 128: Opcode = AMDGPU::SI_SPILL_S128_SAVE; break;
case 256: Opcode = AMDGPU::SI_SPILL_S256_SAVE; break;
case 512: Opcode = AMDGPU::SI_SPILL_S512_SAVE; break;
default: llvm_unreachable("Cannot spill register class");
case 32: Opcode = AMDGPU::SI_SPILL_S32_SAVE; break;
case 64: Opcode = AMDGPU::SI_SPILL_S64_SAVE; break;
case 128: Opcode = AMDGPU::SI_SPILL_S128_SAVE; break;
case 256: Opcode = AMDGPU::SI_SPILL_S256_SAVE; break;
case 512: Opcode = AMDGPU::SI_SPILL_S512_SAVE; break;
}
} else if(shouldTryToSpillVGPRs(MF) && RI.hasVGPRs(RC)) {
switch(RC->getSize() * 8) {
case 32: Opcode = AMDGPU::SI_SPILL_V32_SAVE; break;
case 64: Opcode = AMDGPU::SI_SPILL_V64_SAVE; break;
case 96: Opcode = AMDGPU::SI_SPILL_V96_SAVE; break;
case 128: Opcode = AMDGPU::SI_SPILL_V128_SAVE; break;
case 256: Opcode = AMDGPU::SI_SPILL_V256_SAVE; break;
case 512: Opcode = AMDGPU::SI_SPILL_V512_SAVE; break;
}
}
if (Opcode != -1) {
FrameInfo->setObjectAlignment(FrameIndex, 4);
BuildMI(MBB, MI, DL, get(Opcode))
.addReg(SrcReg)
.addFrameIndex(FrameIndex);
} else {
llvm_unreachable("VGPR spilling not supported");
LLVMContext &Ctx = MF->getFunction()->getContext();
Ctx.emitError("SIInstrInfo::storeRegToStackSlot - Do not know how to"
" spill register");
BuildMI(MBB, MI, DL, get(AMDGPU::V_MOV_B32_e32), AMDGPU::VGPR0)
.addReg(SrcReg);
}
}
@@ -479,31 +502,138 @@ void SIInstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
MachineFunction *MF = MBB.getParent();
MachineFrameInfo *FrameInfo = MF->getFrameInfo();
DebugLoc DL = MBB.findDebugLoc(MI);
int Opcode = -1;
if (RI.hasVGPRs(RC)) {
LLVMContext &Ctx = MF->getFunction()->getContext();
Ctx.emitError("SIInstrInfo::loadRegToStackSlot - Can't retrieve spilled VGPR!");
BuildMI(MBB, MI, DL, get(AMDGPU::V_MOV_B32_e32), DestReg)
.addImm(0);
} else if (RI.isSGPRClass(RC)){
unsigned Opcode;
if (RI.isSGPRClass(RC)){
switch(RC->getSize() * 8) {
case 32: Opcode = AMDGPU::SI_SPILL_S32_RESTORE; break;
case 64: Opcode = AMDGPU::SI_SPILL_S64_RESTORE; break;
case 128: Opcode = AMDGPU::SI_SPILL_S128_RESTORE; break;
case 256: Opcode = AMDGPU::SI_SPILL_S256_RESTORE; break;
case 512: Opcode = AMDGPU::SI_SPILL_S512_RESTORE; break;
default: llvm_unreachable("Cannot spill register class");
case 32: Opcode = AMDGPU::SI_SPILL_S32_RESTORE; break;
case 64: Opcode = AMDGPU::SI_SPILL_S64_RESTORE; break;
case 128: Opcode = AMDGPU::SI_SPILL_S128_RESTORE; break;
case 256: Opcode = AMDGPU::SI_SPILL_S256_RESTORE; break;
case 512: Opcode = AMDGPU::SI_SPILL_S512_RESTORE; break;
}
} else if(shouldTryToSpillVGPRs(MF) && RI.hasVGPRs(RC)) {
switch(RC->getSize() * 8) {
case 32: Opcode = AMDGPU::SI_SPILL_V32_RESTORE; break;
case 64: Opcode = AMDGPU::SI_SPILL_V64_RESTORE; break;
case 96: Opcode = AMDGPU::SI_SPILL_V96_RESTORE; break;
case 128: Opcode = AMDGPU::SI_SPILL_V128_RESTORE; break;
case 256: Opcode = AMDGPU::SI_SPILL_V256_RESTORE; break;
case 512: Opcode = AMDGPU::SI_SPILL_V512_RESTORE; break;
}
}
if (Opcode != -1) {
FrameInfo->setObjectAlignment(FrameIndex, 4);
BuildMI(MBB, MI, DL, get(Opcode), DestReg)
.addFrameIndex(FrameIndex);
} else {
llvm_unreachable("VGPR spilling not supported");
LLVMContext &Ctx = MF->getFunction()->getContext();
Ctx.emitError("SIInstrInfo::loadRegFromStackSlot - Do not know how to"
" restore register");
BuildMI(MBB, MI, DL, get(AMDGPU::V_MOV_B32_e32), DestReg)
.addReg(AMDGPU::VGPR0);
}
}
/// \param @Offset Offset in bytes of the FrameIndex being spilled
unsigned SIInstrInfo::calculateLDSSpillAddress(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
RegScavenger *RS, unsigned TmpReg,
unsigned FrameOffset,
unsigned Size) const {
MachineFunction *MF = MBB.getParent();
SIMachineFunctionInfo *MFI = MF->getInfo<SIMachineFunctionInfo>();
const AMDGPUSubtarget &ST = MF->getTarget().getSubtarget<AMDGPUSubtarget>();
const SIRegisterInfo *TRI =
static_cast<const SIRegisterInfo*>(ST.getRegisterInfo());
DebugLoc DL = MBB.findDebugLoc(MI);
unsigned WorkGroupSize = MFI->getMaximumWorkGroupSize(*MF);
unsigned WavefrontSize = ST.getWavefrontSize();
unsigned TIDReg = MFI->getTIDReg();
if (!MFI->hasCalculatedTID()) {
MachineBasicBlock &Entry = MBB.getParent()->front();
MachineBasicBlock::iterator Insert = Entry.front();
DebugLoc DL = Insert->getDebugLoc();
TIDReg = RI.findUnusedVGPR(MF->getRegInfo());
if (TIDReg == AMDGPU::NoRegister)
return TIDReg;
if (MFI->getShaderType() == ShaderType::COMPUTE &&
WorkGroupSize > WavefrontSize) {
unsigned TIDIGXReg = TRI->getPreloadedValue(*MF, SIRegisterInfo::TIDIG_X);
unsigned TIDIGYReg = TRI->getPreloadedValue(*MF, SIRegisterInfo::TIDIG_Y);
unsigned TIDIGZReg = TRI->getPreloadedValue(*MF, SIRegisterInfo::TIDIG_Z);
unsigned InputPtrReg =
TRI->getPreloadedValue(*MF, SIRegisterInfo::INPUT_PTR);
static const unsigned TIDIGRegs[3] = {
TIDIGXReg, TIDIGYReg, TIDIGZReg
};
for (unsigned Reg : TIDIGRegs) {
if (!Entry.isLiveIn(Reg))
Entry.addLiveIn(Reg);
}
RS->enterBasicBlock(&Entry);
unsigned STmp0 = RS->scavengeRegister(&AMDGPU::SGPR_32RegClass, 0);
unsigned STmp1 = RS->scavengeRegister(&AMDGPU::SGPR_32RegClass, 0);
BuildMI(Entry, Insert, DL, get(AMDGPU::S_LOAD_DWORD_IMM), STmp0)
.addReg(InputPtrReg)
.addImm(SI::KernelInputOffsets::NGROUPS_Z);
BuildMI(Entry, Insert, DL, get(AMDGPU::S_LOAD_DWORD_IMM), STmp1)
.addReg(InputPtrReg)
.addImm(SI::KernelInputOffsets::NGROUPS_Y);
// NGROUPS.X * NGROUPS.Y
BuildMI(Entry, Insert, DL, get(AMDGPU::S_MUL_I32), STmp1)
.addReg(STmp1)
.addReg(STmp0);
// (NGROUPS.X * NGROUPS.Y) * TIDIG.X
BuildMI(Entry, Insert, DL, get(AMDGPU::V_MUL_U32_U24_e32), TIDReg)
.addReg(STmp1)
.addReg(TIDIGXReg);
// NGROUPS.Z * TIDIG.Y + (NGROUPS.X * NGROPUS.Y * TIDIG.X)
BuildMI(Entry, Insert, DL, get(AMDGPU::V_MAD_U32_U24), TIDReg)
.addReg(STmp0)
.addReg(TIDIGYReg)
.addReg(TIDReg);
// (NGROUPS.Z * TIDIG.Y + (NGROUPS.X * NGROPUS.Y * TIDIG.X)) + TIDIG.Z
BuildMI(Entry, Insert, DL, get(AMDGPU::V_ADD_I32_e32), TIDReg)
.addReg(TIDReg)
.addReg(TIDIGZReg);
} else {
// Get the wave id
BuildMI(Entry, Insert, DL, get(AMDGPU::V_MBCNT_LO_U32_B32_e64),
TIDReg)
.addImm(-1)
.addImm(0);
BuildMI(Entry, Insert, DL, get(AMDGPU::V_MBCNT_HI_U32_B32_e32),
TIDReg)
.addImm(-1)
.addReg(TIDReg);
}
BuildMI(Entry, Insert, DL, get(AMDGPU::V_LSHLREV_B32_e32),
TIDReg)
.addImm(2)
.addReg(TIDReg);
MFI->setTIDReg(TIDReg);
}
// Add FrameIndex to LDS offset
unsigned LDSOffset = MFI->LDSSize + (FrameOffset * WorkGroupSize);
BuildMI(MBB, MI, DL, get(AMDGPU::V_ADD_I32_e32), TmpReg)
.addImm(LDSOffset)
.addReg(TIDReg);
return TmpReg;
}
void SIInstrInfo::insertNOPs(MachineBasicBlock::iterator MI,
int Count) const {
while (Count > 0) {