1//===- SPIRVTargetTransformInfo.h - SPIR-V specific TTI ---------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8// \file
9// This file contains a TargetTransformInfoImplBase conforming object specific
10// to the SPIRV target machine. It uses the target's detailed information to
11// provide more precise answers to certain TTI queries, while letting the
12// target independent and default TTI implementations handle the rest.
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_LIB_TARGET_SPIRV_SPIRVTARGETTRANSFORMINFO_H
17#define LLVM_LIB_TARGET_SPIRV_SPIRVTARGETTRANSFORMINFO_H
18
19#include "SPIRV.h"
20#include "SPIRVTargetMachine.h"
21#include "llvm/Analysis/TargetTransformInfo.h"
22#include "llvm/CodeGen/BasicTTIImpl.h"
23
24namespace llvm {
25class SPIRVTTIImpl final : public BasicTTIImplBase<SPIRVTTIImpl> {
26 using BaseT = BasicTTIImplBase<SPIRVTTIImpl>;
27 using TTI = TargetTransformInfo;
28
29 friend BaseT;
30
31 const SPIRVSubtarget *ST;
32 const SPIRVTargetLowering *TLI;
33
34 const TargetSubtargetInfo *getST() const { return ST; }
35 const SPIRVTargetLowering *getTLI() const { return TLI; }
36
37public:
38 explicit SPIRVTTIImpl(const SPIRVTargetMachine *TM, const Function &F)
39 : BaseT(TM, F.getDataLayout()), ST(TM->getSubtargetImpl(F)),
40 TLI(ST->getTargetLowering()) {}
41
42 TTI::PopcntSupportKind getPopcntSupport(unsigned TyWidth) const override {
43 // SPIR-V natively supports OpBitcount, per 3.53.14 in the spec, as such it
44 // is reasonable to assume the Op is fast / preferable to the expanded loop.
45 // Furthermore, this prevents information being lost if transforms are
46 // applied to SPIR-V before lowering to a concrete target.
47 if (!isPowerOf2_32(Value: TyWidth) || TyWidth > 64)
48 return TTI::PSK_Software; // Arbitrary bit-width INT is not core SPIR-V.
49 return TTI::PSK_FastHardware;
50 }
51
52 unsigned getFlatAddressSpace() const override {
53 if (ST->isShader())
54 return 0;
55 // FIXME: Clang has 2 distinct address space maps. One where
56 // default=4=Generic, and one with default=0=Function. This depends on the
57 // environment. For OpenCL, we don't need to run the InferAddrSpace pass, so
58 // we can return -1, but we might want to fix this.
59 return -1;
60 }
61};
62
63} // namespace llvm
64
65#endif // LLVM_LIB_TARGET_SPIRV_SPIRVTARGETTRANSFORMINFO_H
66