LegalizeDAG.cpp | Explore in Territory

//===- LegalizeDAG.cpp - Implement SelectionDAG::Legalize -----------------===//
//
// 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 implements the SelectionDAG::Legalize method.
//
//===----------------------------------------------------------------------===//

#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/FloatingPointMode.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/CodeGen/ISDOpcodes.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/RuntimeLibcallUtil.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/SelectionDAGNodes.h"
#include "llvm/CodeGen/TargetFrameLowering.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/CodeGenTypes/MachineValueType.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include <cassert>
#include <cstdint>
#include <tuple>
#include <utility>

usingnamespacellvm;

#define DEBUG_TYPE …

namespace {

/// Keeps track of state when getting the sign of a floating-point value as an
/// integer.
struct FloatSignAsInt { … };

//===----------------------------------------------------------------------===//
/// This takes an arbitrary SelectionDAG as input and
/// hacks on it until the target machine can handle it.  This involves
/// eliminating value sizes the machine cannot handle (promoting small sizes to
/// large sizes or splitting up large values into small values) as well as
/// eliminating operations the machine cannot handle.
///
/// This code also does a small amount of optimization and recognition of idioms
/// as part of its processing.  For example, if a target does not support a
/// 'setcc' instruction efficiently, but does support 'brcc' instruction, this
/// will attempt merge setcc and brc instructions into brcc's.
class SelectionDAGLegalize { … };

} // end anonymous namespace

// Helper function that generates an MMO that considers the alignment of the
// stack, and the size of the stack object
static MachineMemOperand *getStackAlignedMMO(SDValue StackPtr,
                                             MachineFunction &MF,
                                             bool isObjectScalable) { … }

/// Return a vector shuffle operation which
/// performs the same shuffle in terms of order or result bytes, but on a type
/// whose vector element type is narrower than the original shuffle type.
/// e.g. <v4i32> <0, 1, 0, 1> -> v8i16 <0, 1, 2, 3, 0, 1, 2, 3>
SDValue SelectionDAGLegalize::ShuffleWithNarrowerEltType(
    EVT NVT, EVT VT, const SDLoc &dl, SDValue N1, SDValue N2,
    ArrayRef<int> Mask) const { … }

/// Expands the ConstantFP node to an integer constant or
/// a load from the constant pool.
SDValue
SelectionDAGLegalize::ExpandConstantFP(ConstantFPSDNode *CFP, bool UseCP) { … }

/// Expands the Constant node to a load from the constant pool.
SDValue SelectionDAGLegalize::ExpandConstant(ConstantSDNode *CP) { … }

SDValue SelectionDAGLegalize::ExpandINSERT_VECTOR_ELT(SDValue Op) { … }

SDValue SelectionDAGLegalize::OptimizeFloatStore(StoreSDNode* ST) { … }

void SelectionDAGLegalize::LegalizeStoreOps(SDNode *Node) { … }

void SelectionDAGLegalize::LegalizeLoadOps(SDNode *Node) { … }

/// Return a legal replacement for the given operation, with all legal operands.
void SelectionDAGLegalize::LegalizeOp(SDNode *Node) { … }

SDValue SelectionDAGLegalize::ExpandExtractFromVectorThroughStack(SDValue Op) { … }

SDValue SelectionDAGLegalize::ExpandInsertToVectorThroughStack(SDValue Op) { … }

SDValue SelectionDAGLegalize::ExpandVectorBuildThroughStack(SDNode* Node) { … }

/// Bitcast a floating-point value to an integer value. Only bitcast the part
/// containing the sign bit if the target has no integer value capable of
/// holding all bits of the floating-point value.
void SelectionDAGLegalize::getSignAsIntValue(FloatSignAsInt &State,
                                             const SDLoc &DL,
                                             SDValue Value) const { … }

/// Replace the integer value produced by getSignAsIntValue() with a new value
/// and cast the result back to a floating-point type.
SDValue SelectionDAGLegalize::modifySignAsInt(const FloatSignAsInt &State,
                                              const SDLoc &DL,
                                              SDValue NewIntValue) const { … }

SDValue SelectionDAGLegalize::ExpandFCOPYSIGN(SDNode *Node) const { … }

SDValue SelectionDAGLegalize::ExpandFNEG(SDNode *Node) const { … }

SDValue SelectionDAGLegalize::ExpandFABS(SDNode *Node) const { … }

void SelectionDAGLegalize::ExpandDYNAMIC_STACKALLOC(SDNode* Node,
                                           SmallVectorImpl<SDValue> &Results) { … }

/// Emit a store/load combination to the stack.  This stores
/// SrcOp to a stack slot of type SlotVT, truncating it if needed.  It then does
/// a load from the stack slot to DestVT, extending it if needed.
/// The resultant code need not be legal.
SDValue SelectionDAGLegalize::EmitStackConvert(SDValue SrcOp, EVT SlotVT,
                                               EVT DestVT, const SDLoc &dl) { … }

SDValue SelectionDAGLegalize::EmitStackConvert(SDValue SrcOp, EVT SlotVT,
                                               EVT DestVT, const SDLoc &dl,
                                               SDValue Chain) { … }

SDValue SelectionDAGLegalize::ExpandSCALAR_TO_VECTOR(SDNode *Node) { … }

static bool
ExpandBVWithShuffles(SDNode *Node, SelectionDAG &DAG,
                     const TargetLowering &TLI, SDValue &Res) { … }

/// Expand a BUILD_VECTOR node on targets that don't
/// support the operation, but do support the resultant vector type.
SDValue SelectionDAGLegalize::ExpandBUILD_VECTOR(SDNode *Node) { … }

SDValue SelectionDAGLegalize::ExpandSPLAT_VECTOR(SDNode *Node) { … }

// Expand a node into a call to a libcall, returning the value as the first
// result and the chain as the second.  If the result value does not fit into a
// register, return the lo part and set the hi part to the by-reg argument in
// the first.  If it does fit into a single register, return the result and
// leave the Hi part unset.
std::pair<SDValue, SDValue> SelectionDAGLegalize::ExpandLibCall(RTLIB::Libcall LC, SDNode *Node,
                                            TargetLowering::ArgListTy &&Args,
                                            bool isSigned) { … }

std::pair<SDValue, SDValue> SelectionDAGLegalize::ExpandLibCall(RTLIB::Libcall LC, SDNode *Node,
                                            bool isSigned) { … }

void SelectionDAGLegalize::ExpandFrexpLibCall(
    SDNode *Node, SmallVectorImpl<SDValue> &Results) { … }

void SelectionDAGLegalize::ExpandFPLibCall(SDNode* Node,
                                           RTLIB::Libcall LC,
                                           SmallVectorImpl<SDValue> &Results) { … }

/// Expand the node to a libcall based on the result type.
void SelectionDAGLegalize::ExpandFPLibCall(SDNode* Node,
                                           RTLIB::Libcall Call_F32,
                                           RTLIB::Libcall Call_F64,
                                           RTLIB::Libcall Call_F80,
                                           RTLIB::Libcall Call_F128,
                                           RTLIB::Libcall Call_PPCF128,
                                           SmallVectorImpl<SDValue> &Results) { … }

SDValue SelectionDAGLegalize::ExpandIntLibCall(SDNode* Node, bool isSigned,
                                               RTLIB::Libcall Call_I8,
                                               RTLIB::Libcall Call_I16,
                                               RTLIB::Libcall Call_I32,
                                               RTLIB::Libcall Call_I64,
                                               RTLIB::Libcall Call_I128) { … }

/// Expand the node to a libcall based on first argument type (for instance
/// lround and its variant).
void SelectionDAGLegalize::ExpandArgFPLibCall(SDNode* Node,
                                            RTLIB::Libcall Call_F32,
                                            RTLIB::Libcall Call_F64,
                                            RTLIB::Libcall Call_F80,
                                            RTLIB::Libcall Call_F128,
                                            RTLIB::Libcall Call_PPCF128,
                                            SmallVectorImpl<SDValue> &Results) { … }

/// Issue libcalls to __{u}divmod to compute div / rem pairs.
void
SelectionDAGLegalize::ExpandDivRemLibCall(SDNode *Node,
                                          SmallVectorImpl<SDValue> &Results) { … }

/// Return true if sincos libcall is available.
static bool isSinCosLibcallAvailable(SDNode *Node, const TargetLowering &TLI) { … }

/// Only issue sincos libcall if both sin and cos are needed.
static bool useSinCos(SDNode *Node) { … }

/// Issue libcalls to sincos to compute sin / cos pairs.
void SelectionDAGLegalize::ExpandSinCosLibCall(
    SDNode *Node, SmallVectorImpl<SDValue> &Results) { … }

SDValue SelectionDAGLegalize::expandLdexp(SDNode *Node) const { … }

SDValue SelectionDAGLegalize::expandFrexp(SDNode *Node) const { … }

/// This function is responsible for legalizing a
/// INT_TO_FP operation of the specified operand when the target requests that
/// we expand it.  At this point, we know that the result and operand types are
/// legal for the target.
SDValue SelectionDAGLegalize::ExpandLegalINT_TO_FP(SDNode *Node,
                                                   SDValue &Chain) { … }

/// This function is responsible for legalizing a
/// *INT_TO_FP operation of the specified operand when the target requests that
/// we promote it.  At this point, we know that the result and operand types are
/// legal for the target, and that there is a legal UINT_TO_FP or SINT_TO_FP
/// operation that takes a larger input.
void SelectionDAGLegalize::PromoteLegalINT_TO_FP(
    SDNode *N, const SDLoc &dl, SmallVectorImpl<SDValue> &Results) { … }

/// This function is responsible for legalizing a
/// FP_TO_*INT operation of the specified operand when the target requests that
/// we promote it.  At this point, we know that the result and operand types are
/// legal for the target, and that there is a legal FP_TO_UINT or FP_TO_SINT
/// operation that returns a larger result.
void SelectionDAGLegalize::PromoteLegalFP_TO_INT(SDNode *N, const SDLoc &dl,
                                                 SmallVectorImpl<SDValue> &Results) { … }

/// Promote FP_TO_*INT_SAT operation to a larger result type. At this point
/// the result and operand types are legal and there must be a legal
/// FP_TO_*INT_SAT operation for a larger result type.
SDValue SelectionDAGLegalize::PromoteLegalFP_TO_INT_SAT(SDNode *Node,
                                                        const SDLoc &dl) { … }

/// Open code the operations for PARITY of the specified operation.
SDValue SelectionDAGLegalize::ExpandPARITY(SDValue Op, const SDLoc &dl) { … }

SDValue SelectionDAGLegalize::PromoteReduction(SDNode *Node) { … }

bool SelectionDAGLegalize::ExpandNode(SDNode *Node) { … }

void SelectionDAGLegalize::ConvertNodeToLibcall(SDNode *Node) { … }

// Determine the vector type to use in place of an original scalar element when
// promoting equally sized vectors.
static MVT getPromotedVectorElementType(const TargetLowering &TLI,
                                        MVT EltVT, MVT NewEltVT) { … }

void SelectionDAGLegalize::PromoteNode(SDNode *Node) { … }

/// This is the entry point for the file.
void SelectionDAG::Legalize() { … }

bool SelectionDAG::LegalizeOp(SDNode *N,
                              SmallSetVector<SDNode *, 16> &UpdatedNodes) { … }
llvm/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
