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llvm-mirror/lib/Target/NVPTX/NVPTXSubtarget.cpp
Artem Belevich f89a861f79 [NVPTX] Added support for half-precision floating point.
Only scalar half-precision operations are supported at the moment.

- Adds general support for 'half' type in NVPTX.
- fp16 math operations are supported on sm_53+ GPUs only
  (can be disabled with --nvptx-no-f16-math).
- Type conversions to/from fp16 are supported on all GPU variants.
- On GPU variants that do not have full fp16 support (or if it's disabled),
  fp16 operations are promoted to fp32 and results are converted back
  to fp16 for storage.

Differential Revision: https://reviews.llvm.org/D28540

llvm-svn: 291956
2017-01-13 20:56:17 +00:00

69 lines
2.1 KiB
C++

//===- NVPTXSubtarget.cpp - NVPTX Subtarget Information -------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the NVPTX specific subclass of TargetSubtarget.
//
//===----------------------------------------------------------------------===//
#include "NVPTXSubtarget.h"
#include "NVPTXTargetMachine.h"
using namespace llvm;
#define DEBUG_TYPE "nvptx-subtarget"
#define GET_SUBTARGETINFO_ENUM
#define GET_SUBTARGETINFO_TARGET_DESC
#define GET_SUBTARGETINFO_CTOR
#include "NVPTXGenSubtargetInfo.inc"
static cl::opt<bool>
NoF16Math("nvptx-no-f16-math", cl::ZeroOrMore, cl::Hidden,
cl::desc("NVPTX Specific: Disable generation of f16 math ops."),
cl::init(false));
// Pin the vtable to this file.
void NVPTXSubtarget::anchor() {}
NVPTXSubtarget &NVPTXSubtarget::initializeSubtargetDependencies(StringRef CPU,
StringRef FS) {
// Provide the default CPU if we don't have one.
TargetName = CPU.empty() ? "sm_20" : CPU;
ParseSubtargetFeatures(TargetName, FS);
// Set default to PTX 3.2 (CUDA 5.5)
if (PTXVersion == 0) {
PTXVersion = 32;
}
return *this;
}
NVPTXSubtarget::NVPTXSubtarget(const Triple &TT, const std::string &CPU,
const std::string &FS,
const NVPTXTargetMachine &TM)
: NVPTXGenSubtargetInfo(TT, CPU, FS), PTXVersion(0), SmVersion(20), TM(TM),
InstrInfo(), TLInfo(TM, initializeSubtargetDependencies(CPU, FS)),
FrameLowering() {}
bool NVPTXSubtarget::hasImageHandles() const {
// Enable handles for Kepler+, where CUDA supports indirect surfaces and
// textures
if (TM.getDrvInterface() == NVPTX::CUDA)
return (SmVersion >= 30);
// Disabled, otherwise
return false;
}
bool NVPTXSubtarget::allowFP16Math() const {
return hasFP16Math() && NoF16Math == false;
}