llvm-6502/lib/Target/R600/AMDGPUSubtarget.cpp
Tom Stellard a787066317 R600/SI: Initial support for assembler and inline assembly
This is currently considered experimental, but most of the more
commonly used instructions should work.

So far only SI has been extensively tested, CI and VI probably work too,
but may be buggy.  The current set of tests cases do not give complete
coverage, but I think it is sufficient for an experimental assembler.

See the documentation in R600Usage for more information.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234381 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-08 01:09:26 +00:00

134 lines
4.7 KiB
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//===-- AMDGPUSubtarget.cpp - AMDGPU Subtarget Information ----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// \file
/// \brief Implements the AMDGPU specific subclass of TargetSubtarget.
//
//===----------------------------------------------------------------------===//
#include "AMDGPUSubtarget.h"
#include "R600ISelLowering.h"
#include "R600InstrInfo.h"
#include "R600MachineScheduler.h"
#include "SIISelLowering.h"
#include "SIInstrInfo.h"
#include "SIMachineFunctionInfo.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/CodeGen/MachineScheduler.h"
using namespace llvm;
#define DEBUG_TYPE "amdgpu-subtarget"
#define GET_SUBTARGETINFO_ENUM
#define GET_SUBTARGETINFO_TARGET_DESC
#define GET_SUBTARGETINFO_CTOR
#include "AMDGPUGenSubtargetInfo.inc"
AMDGPUSubtarget &
AMDGPUSubtarget::initializeSubtargetDependencies(StringRef TT, StringRef GPU,
StringRef FS) {
// Determine default and user-specified characteristics
// On SI+, we want FP64 denormals to be on by default. FP32 denormals can be
// enabled, but some instructions do not respect them and they run at the
// double precision rate, so don't enable by default.
//
// We want to be able to turn these off, but making this a subtarget feature
// for SI has the unhelpful behavior that it unsets everything else if you
// disable it.
SmallString<256> FullFS("+promote-alloca,+fp64-denormals,");
FullFS += FS;
if (GPU == "" && Triple(TT).getArch() == Triple::amdgcn)
GPU = "SI";
ParseSubtargetFeatures(GPU, FullFS);
// FIXME: I don't think think Evergreen has any useful support for
// denormals, but should be checked. Should we issue a warning somewhere
// if someone tries to enable these?
if (getGeneration() <= AMDGPUSubtarget::NORTHERN_ISLANDS) {
FP32Denormals = false;
FP64Denormals = false;
}
return *this;
}
AMDGPUSubtarget::AMDGPUSubtarget(StringRef TT, StringRef GPU, StringRef FS,
TargetMachine &TM)
: AMDGPUGenSubtargetInfo(TT, GPU, FS), DevName(GPU), Is64bit(false),
DumpCode(false), R600ALUInst(false), HasVertexCache(false),
TexVTXClauseSize(0), Gen(AMDGPUSubtarget::R600), FP64(false),
FP64Denormals(false), FP32Denormals(false), FastFMAF32(false),
CaymanISA(false), FlatAddressSpace(false), EnableIRStructurizer(true),
EnablePromoteAlloca(false), EnableIfCvt(true), EnableLoadStoreOpt(false),
WavefrontSize(0), CFALUBug(false), LocalMemorySize(0),
EnableVGPRSpilling(false), SGPRInitBug(false),
IsGCN(false), GCN1Encoding(false), GCN3Encoding(false),
FrameLowering(TargetFrameLowering::StackGrowsUp,
64 * 16, // Maximum stack alignment (long16)
0),
InstrItins(getInstrItineraryForCPU(GPU)), TargetTriple(TT) {
initializeSubtargetDependencies(TT, GPU, FS);
if (getGeneration() <= AMDGPUSubtarget::NORTHERN_ISLANDS) {
InstrInfo.reset(new R600InstrInfo(*this));
TLInfo.reset(new R600TargetLowering(TM, *this));
} else {
InstrInfo.reset(new SIInstrInfo(*this));
TLInfo.reset(new SITargetLowering(TM, *this));
}
}
unsigned AMDGPUSubtarget::getStackEntrySize() const {
assert(getGeneration() <= NORTHERN_ISLANDS);
switch(getWavefrontSize()) {
case 16:
return 8;
case 32:
return hasCaymanISA() ? 4 : 8;
case 64:
return 4;
default:
llvm_unreachable("Illegal wavefront size.");
}
}
unsigned AMDGPUSubtarget::getAmdKernelCodeChipID() const {
switch(getGeneration()) {
default: llvm_unreachable("ChipID unknown");
case SEA_ISLANDS: return 12;
}
}
bool AMDGPUSubtarget::isVGPRSpillingEnabled(
const SIMachineFunctionInfo *MFI) const {
return MFI->getShaderType() == ShaderType::COMPUTE || EnableVGPRSpilling;
}
void AMDGPUSubtarget::overrideSchedPolicy(MachineSchedPolicy &Policy,
MachineInstr *begin,
MachineInstr *end,
unsigned NumRegionInstrs) const {
if (getGeneration() >= SOUTHERN_ISLANDS) {
// Track register pressure so the scheduler can try to decrease
// pressure once register usage is above the threshold defined by
// SIRegisterInfo::getRegPressureSetLimit()
Policy.ShouldTrackPressure = true;
// Enabling both top down and bottom up scheduling seems to give us less
// register spills than just using one of these approaches on its own.
Policy.OnlyTopDown = false;
Policy.OnlyBottomUp = false;
}
}