Files
clang-p2996/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.h
Fraser Cormack 6449bea508 [RISCV] Select unmasked RVV pseudos in a DAG post-process
This patch drops TableGen patterns matching all-ones masked RVV pseudos
in the case where there are fallback patterns matching the generic
masked forms to "_MASK" pseudos. This optimization is now performed with
a SelectionDAG post-processing step which peephole-optimizes these same
pseudos with all-ones masks and swaps them out to their unmasked
pseudos.

This cuts our generated ISel table down by around ~5% (~110kB) in lieu
of a far smaller auto-generated table to help with the peephole.

This only targets our custom RISCVISD::*_VL binary operator nodes, which
use the one form for both masked and unmasked variants. A similar
approach could be used for our intrinsics but we'd need to do some work,
e.g., to represent unmasked intrinsics as true-masked intrinsics at the
IR or ISel level. At a rough estimate, this could save us a further 9%
on the size of our ISel table for the binary intrinsic patterns alone.

There is no observable impact on our tests.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D118810
2022-02-09 07:50:15 +00:00

212 lines
6.0 KiB
C++

//===---- RISCVISelDAGToDAG.h - A dag to dag inst selector for RISCV ------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines an instruction selector for the RISCV target.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_RISCV_RISCVISELDAGTODAG_H
#define LLVM_LIB_TARGET_RISCV_RISCVISELDAGTODAG_H
#include "RISCV.h"
#include "RISCVTargetMachine.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
// RISCV-specific code to select RISCV machine instructions for
// SelectionDAG operations.
namespace llvm {
class RISCVDAGToDAGISel : public SelectionDAGISel {
const RISCVSubtarget *Subtarget = nullptr;
public:
explicit RISCVDAGToDAGISel(RISCVTargetMachine &TargetMachine)
: SelectionDAGISel(TargetMachine) {}
StringRef getPassName() const override {
return "RISCV DAG->DAG Pattern Instruction Selection";
}
bool runOnMachineFunction(MachineFunction &MF) override {
Subtarget = &MF.getSubtarget<RISCVSubtarget>();
return SelectionDAGISel::runOnMachineFunction(MF);
}
void PreprocessISelDAG() override;
void PostprocessISelDAG() override;
void Select(SDNode *Node) override;
bool SelectInlineAsmMemoryOperand(const SDValue &Op, unsigned ConstraintID,
std::vector<SDValue> &OutOps) override;
bool SelectAddrFI(SDValue Addr, SDValue &Base);
bool SelectBaseAddr(SDValue Addr, SDValue &Base);
bool selectShiftMask(SDValue N, unsigned ShiftWidth, SDValue &ShAmt);
bool selectShiftMaskXLen(SDValue N, SDValue &ShAmt) {
return selectShiftMask(N, Subtarget->getXLen(), ShAmt);
}
bool selectShiftMask32(SDValue N, SDValue &ShAmt) {
return selectShiftMask(N, 32, ShAmt);
}
bool selectSExti32(SDValue N, SDValue &Val);
bool selectZExti32(SDValue N, SDValue &Val);
bool hasAllNBitUsers(SDNode *Node, unsigned Bits) const;
bool hasAllHUsers(SDNode *Node) const { return hasAllNBitUsers(Node, 16); }
bool hasAllWUsers(SDNode *Node) const { return hasAllNBitUsers(Node, 32); }
bool selectVLOp(SDValue N, SDValue &VL);
bool selectVSplat(SDValue N, SDValue &SplatVal);
bool selectVSplatSimm5(SDValue N, SDValue &SplatVal);
bool selectVSplatUimm5(SDValue N, SDValue &SplatVal);
bool selectVSplatSimm5Plus1(SDValue N, SDValue &SplatVal);
bool selectVSplatSimm5Plus1NonZero(SDValue N, SDValue &SplatVal);
bool selectRVVSimm5(SDValue N, unsigned Width, SDValue &Imm);
template <unsigned Width> bool selectRVVSimm5(SDValue N, SDValue &Imm) {
return selectRVVSimm5(N, Width, Imm);
}
void addVectorLoadStoreOperands(SDNode *Node, unsigned SEWImm,
const SDLoc &DL, unsigned CurOp,
bool IsMasked, bool IsStridedOrIndexed,
SmallVectorImpl<SDValue> &Operands,
bool IsLoad = false, MVT *IndexVT = nullptr);
void selectVLSEG(SDNode *Node, bool IsMasked, bool IsStrided);
void selectVLSEGFF(SDNode *Node, bool IsMasked);
void selectVLXSEG(SDNode *Node, bool IsMasked, bool IsOrdered);
void selectVSSEG(SDNode *Node, bool IsMasked, bool IsStrided);
void selectVSXSEG(SDNode *Node, bool IsMasked, bool IsOrdered);
void selectVSETVLI(SDNode *Node);
// Return the RISC-V condition code that matches the given DAG integer
// condition code. The CondCode must be one of those supported by the RISC-V
// ISA (see translateSetCCForBranch).
static RISCVCC::CondCode getRISCVCCForIntCC(ISD::CondCode CC) {
switch (CC) {
default:
llvm_unreachable("Unsupported CondCode");
case ISD::SETEQ:
return RISCVCC::COND_EQ;
case ISD::SETNE:
return RISCVCC::COND_NE;
case ISD::SETLT:
return RISCVCC::COND_LT;
case ISD::SETGE:
return RISCVCC::COND_GE;
case ISD::SETULT:
return RISCVCC::COND_LTU;
case ISD::SETUGE:
return RISCVCC::COND_GEU;
}
}
// Include the pieces autogenerated from the target description.
#include "RISCVGenDAGISel.inc"
private:
bool doPeepholeLoadStoreADDI(SDNode *Node);
bool doPeepholeSExtW(SDNode *Node);
bool doPeepholeMaskedRVV(SDNode *Node);
};
namespace RISCV {
struct VLSEGPseudo {
uint16_t NF : 4;
uint16_t Masked : 1;
uint16_t Strided : 1;
uint16_t FF : 1;
uint16_t Log2SEW : 3;
uint16_t LMUL : 3;
uint16_t Pseudo;
};
struct VLXSEGPseudo {
uint16_t NF : 4;
uint16_t Masked : 1;
uint16_t Ordered : 1;
uint16_t Log2SEW : 3;
uint16_t LMUL : 3;
uint16_t IndexLMUL : 3;
uint16_t Pseudo;
};
struct VSSEGPseudo {
uint16_t NF : 4;
uint16_t Masked : 1;
uint16_t Strided : 1;
uint16_t Log2SEW : 3;
uint16_t LMUL : 3;
uint16_t Pseudo;
};
struct VSXSEGPseudo {
uint16_t NF : 4;
uint16_t Masked : 1;
uint16_t Ordered : 1;
uint16_t Log2SEW : 3;
uint16_t LMUL : 3;
uint16_t IndexLMUL : 3;
uint16_t Pseudo;
};
struct VLEPseudo {
uint16_t Masked : 1;
uint16_t IsTU : 1;
uint16_t Strided : 1;
uint16_t FF : 1;
uint16_t Log2SEW : 3;
uint16_t LMUL : 3;
uint16_t Pseudo;
};
struct VSEPseudo {
uint16_t Masked :1;
uint16_t Strided : 1;
uint16_t Log2SEW : 3;
uint16_t LMUL : 3;
uint16_t Pseudo;
};
struct VLX_VSXPseudo {
uint16_t Masked : 1;
uint16_t IsTU : 1;
uint16_t Ordered : 1;
uint16_t Log2SEW : 3;
uint16_t LMUL : 3;
uint16_t IndexLMUL : 3;
uint16_t Pseudo;
};
struct RISCVMaskedPseudoInfo {
uint16_t MaskedPseudo;
uint16_t UnmaskedPseudo;
uint8_t MaskOpIdx;
};
#define GET_RISCVVSSEGTable_DECL
#define GET_RISCVVLSEGTable_DECL
#define GET_RISCVVLXSEGTable_DECL
#define GET_RISCVVSXSEGTable_DECL
#define GET_RISCVVLETable_DECL
#define GET_RISCVVSETable_DECL
#define GET_RISCVVLXTable_DECL
#define GET_RISCVVSXTable_DECL
#define GET_RISCVMaskedPseudosTable_DECL
#include "RISCVGenSearchableTables.inc"
} // namespace RISCV
} // namespace llvm
#endif