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llvm-mirror/lib/Target/Mips/MipsISelDAGToDAG.h
Roman Lebedev 7beb057809 [MIPS] For vectors, select add %x, C as sub %x, -C if it results in inline immediate
Summary:
As discussed in https://reviews.llvm.org/D62341#1515637,
for MIPS `add %x, -1` isn't optimal. Unlike X86 there
are no fastpaths to matearialize such `-1`/`1` vector constants,
and `sub %x, 1` results in better codegen,
so undo canonicalization

Reviewers: atanasyan, Petar.Avramovic, RKSimon

Reviewed By: atanasyan

Subscribers: sdardis, arichardson, hiraditya, jrtc27, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66805

llvm-svn: 372254
2019-09-18 19:34:41 +00:00

151 lines
6.1 KiB
C++

//===---- MipsISelDAGToDAG.h - A Dag to Dag Inst Selector for Mips --------===//
//
// 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 MIPS target.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_MIPS_MIPSISELDAGTODAG_H
#define LLVM_LIB_TARGET_MIPS_MIPSISELDAGTODAG_H
#include "Mips.h"
#include "MipsSubtarget.h"
#include "MipsTargetMachine.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
//===----------------------------------------------------------------------===//
// Instruction Selector Implementation
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
// MipsDAGToDAGISel - MIPS specific code to select MIPS machine
// instructions for SelectionDAG operations.
//===----------------------------------------------------------------------===//
namespace llvm {
class MipsDAGToDAGISel : public SelectionDAGISel {
public:
explicit MipsDAGToDAGISel(MipsTargetMachine &TM, CodeGenOpt::Level OL)
: SelectionDAGISel(TM, OL), Subtarget(nullptr) {}
// Pass Name
StringRef getPassName() const override {
return "MIPS DAG->DAG Pattern Instruction Selection";
}
bool runOnMachineFunction(MachineFunction &MF) override;
void getAnalysisUsage(AnalysisUsage &AU) const override;
protected:
SDNode *getGlobalBaseReg();
/// Keep a pointer to the MipsSubtarget around so that we can make the right
/// decision when generating code for different targets.
const MipsSubtarget *Subtarget;
private:
// Include the pieces autogenerated from the target description.
#include "MipsGenDAGISel.inc"
// Complex Pattern.
/// (reg + imm).
virtual bool selectAddrRegImm(SDValue Addr, SDValue &Base,
SDValue &Offset) const;
/// Fall back on this function if all else fails.
virtual bool selectAddrDefault(SDValue Addr, SDValue &Base,
SDValue &Offset) const;
/// Match integer address pattern.
virtual bool selectIntAddr(SDValue Addr, SDValue &Base,
SDValue &Offset) const;
virtual bool selectIntAddr11MM(SDValue Addr, SDValue &Base,
SDValue &Offset) const;
virtual bool selectIntAddr12MM(SDValue Addr, SDValue &Base,
SDValue &Offset) const;
virtual bool selectIntAddr16MM(SDValue Addr, SDValue &Base,
SDValue &Offset) const;
virtual bool selectIntAddrLSL2MM(SDValue Addr, SDValue &Base,
SDValue &Offset) const;
/// Match addr+simm10 and addr
virtual bool selectIntAddrSImm10(SDValue Addr, SDValue &Base,
SDValue &Offset) const;
virtual bool selectIntAddrSImm10Lsl1(SDValue Addr, SDValue &Base,
SDValue &Offset) const;
virtual bool selectIntAddrSImm10Lsl2(SDValue Addr, SDValue &Base,
SDValue &Offset) const;
virtual bool selectIntAddrSImm10Lsl3(SDValue Addr, SDValue &Base,
SDValue &Offset) const;
virtual bool selectAddr16(SDValue Addr, SDValue &Base, SDValue &Offset);
virtual bool selectAddr16SP(SDValue Addr, SDValue &Base, SDValue &Offset);
/// Select constant vector splats.
virtual bool selectVSplat(SDNode *N, APInt &Imm,
unsigned MinSizeInBits) const;
/// Select constant vector splats whose value fits in a uimm1.
virtual bool selectVSplatUimm1(SDValue N, SDValue &Imm) const;
/// Select constant vector splats whose value fits in a uimm2.
virtual bool selectVSplatUimm2(SDValue N, SDValue &Imm) const;
/// Select constant vector splats whose value fits in a uimm3.
virtual bool selectVSplatUimm3(SDValue N, SDValue &Imm) const;
/// Select constant vector splats whose value fits in a uimm4.
virtual bool selectVSplatUimm4(SDValue N, SDValue &Imm) const;
/// Select constant vector splats whose value fits in a uimm5.
virtual bool selectVSplatUimm5(SDValue N, SDValue &Imm) const;
/// Select constant vector splats whose value fits in a uimm6.
virtual bool selectVSplatUimm6(SDValue N, SDValue &Imm) const;
/// Select constant vector splats whose value fits in a uimm8.
virtual bool selectVSplatUimm8(SDValue N, SDValue &Imm) const;
/// Select constant vector splats whose value fits in a simm5.
virtual bool selectVSplatSimm5(SDValue N, SDValue &Imm) const;
/// Select constant vector splats whose value is a power of 2.
virtual bool selectVSplatUimmPow2(SDValue N, SDValue &Imm) const;
/// Select constant vector splats whose value is the inverse of a
/// power of 2.
virtual bool selectVSplatUimmInvPow2(SDValue N, SDValue &Imm) const;
/// Select constant vector splats whose value is a run of set bits
/// ending at the most significant bit
virtual bool selectVSplatMaskL(SDValue N, SDValue &Imm) const;
/// Select constant vector splats whose value is a run of set bits
/// starting at bit zero.
virtual bool selectVSplatMaskR(SDValue N, SDValue &Imm) const;
/// Convert vector addition with vector subtraction if that allows to encode
/// constant as an immediate and thus avoid extra 'ldi' instruction.
/// add X, <-1, -1...> --> sub X, <1, 1...>
bool selectVecAddAsVecSubIfProfitable(SDNode *Node);
void Select(SDNode *N) override;
virtual bool trySelect(SDNode *Node) = 0;
// getImm - Return a target constant with the specified value.
inline SDValue getImm(const SDNode *Node, uint64_t Imm) {
return CurDAG->getTargetConstant(Imm, SDLoc(Node), Node->getValueType(0));
}
virtual void processFunctionAfterISel(MachineFunction &MF) = 0;
bool SelectInlineAsmMemoryOperand(const SDValue &Op,
unsigned ConstraintID,
std::vector<SDValue> &OutOps) override;
};
}
#endif