PPCISelLowering.h

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//===-- PPCISelLowering.h - PPC32 DAG Lowering Interface --------*- C++ -*-===//
//
// 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 the interfaces that PPC uses to lower LLVM code into a
// selection DAG.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_LIB_TARGET_POWERPC_PPCISELLOWERING_H
#define LLVM_LIB_TARGET_POWERPC_PPCISELLOWERING_H
 
#include "PPCInstrInfo.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/SelectionDAGNodes.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/MachineValueType.h"
#include <utility>
 
namespace llvm {
 
  namespace PPCISD {
 
    // When adding a NEW PPCISD node please add it to the correct position in
    // the enum. The order of elements in this enum matters!
    // Values that are added after this entry:
    //     STBRX = ISD::FIRST_TARGET_MEMORY_OPCODE
    // are considered memory opcodes and are treated differently than entries
    // that come before it. For example, ADD or MUL should be placed before
    // the ISD::FIRST_TARGET_MEMORY_OPCODE while a LOAD or STORE should come
    // after it.
  enum NodeType : unsigned {
    // Start the numbering where the builtin ops and target ops leave off.
    FIRST_NUMBER = ISD::BUILTIN_OP_END,
 
    /// FSEL - Traditional three-operand fsel node.
    ///
    FSEL,
 
    /// XSMAXC[DQ]P, XSMINC[DQ]P - C-type min/max instructions.
    XSMAXC,
    XSMINC,
 
    /// FCFID - The FCFID instruction, taking an f64 operand and producing
    /// and f64 value containing the FP representation of the integer that
    /// was temporarily in the f64 operand.
    FCFID,
 
    /// Newer FCFID[US] integer-to-floating-point conversion instructions for
    /// unsigned integers and single-precision outputs.
    FCFIDU,
    FCFIDS,
    FCFIDUS,
 
    /// FCTI[D,W]Z - The FCTIDZ and FCTIWZ instructions, taking an f32 or f64
    /// operand, producing an f64 value containing the integer representation
    /// of that FP value.
    FCTIDZ,
    FCTIWZ,
 
    /// Newer FCTI[D,W]UZ floating-point-to-integer conversion instructions for
    /// unsigned integers with round toward zero.
    FCTIDUZ,
    FCTIWUZ,
 
    /// Floating-point-to-integer conversion instructions
    FP_TO_UINT_IN_VSR,
    FP_TO_SINT_IN_VSR,
 
    /// VEXTS, ByteWidth - takes an input in VSFRC and produces an output in
    /// VSFRC that is sign-extended from ByteWidth to a 64-byte integer.
    VEXTS,
 
    /// Reciprocal estimate instructions (unary FP ops).
    FRE,
    FRSQRTE,
 
    /// Test instruction for software square root.
    FTSQRT,
 
    /// Square root instruction.
    FSQRT,
 
    /// VPERM - The PPC VPERM Instruction.
    ///
    VPERM,
 
    /// XXSPLT - The PPC VSX splat instructions
    ///
    XXSPLT,
 
    /// XXSPLTI_SP_TO_DP - The PPC VSX splat instructions for immediates for
    /// converting immediate single precision numbers to double precision
    /// vector or scalar.
    XXSPLTI_SP_TO_DP,
 
    /// XXSPLTI32DX - The PPC XXSPLTI32DX instruction.
    ///
    XXSPLTI32DX,
 
    /// VECINSERT - The PPC vector insert instruction
    ///
    VECINSERT,
 
    /// VECSHL - The PPC vector shift left instruction
    ///
    VECSHL,
 
    /// XXPERMDI - The PPC XXPERMDI instruction
    ///
    XXPERMDI,
 
    /// The CMPB instruction (takes two operands of i32 or i64).
    CMPB,
 
    /// Hi/Lo - These represent the high and low 16-bit parts of a global
    /// address respectively.  These nodes have two operands, the first of
    /// which must be a TargetGlobalAddress, and the second of which must be a
    /// Constant.  Selected naively, these turn into 'lis G+C' and 'li G+C',
    /// though these are usually folded into other nodes.
    Hi,
    Lo,
 
    /// The following two target-specific nodes are used for calls through
    /// function pointers in the 64-bit SVR4 ABI.
 
    /// OPRC, CHAIN = DYNALLOC(CHAIN, NEGSIZE, FRAME_INDEX)
    /// This instruction is lowered in PPCRegisterInfo::eliminateFrameIndex to
    /// compute an allocation on the stack.
    DYNALLOC,
 
    /// This instruction is lowered in PPCRegisterInfo::eliminateFrameIndex to
    /// compute an offset from native SP to the address  of the most recent
    /// dynamic alloca.
    DYNAREAOFFSET,
 
    /// To avoid stack clash, allocation is performed by block and each block is
    /// probed.
    PROBED_ALLOCA,
 
    /// The result of the mflr at function entry, used for PIC code.
    GlobalBaseReg,
 
    /// These nodes represent PPC shifts.
    ///
    /// For scalar types, only the last `n + 1` bits of the shift amounts
    /// are used, where n is log2(sizeof(element) * 8). See sld/slw, etc.
    /// for exact behaviors.
    ///
    /// For vector types, only the last n bits are used. See vsld.
    SRL,
    SRA,
    SHL,
 
    /// FNMSUB - Negated multiply-subtract instruction.
    FNMSUB,
 
    /// EXTSWSLI = The PPC extswsli instruction, which does an extend-sign
    /// word and shift left immediate.
    EXTSWSLI,
 
    /// The combination of sra[wd]i and addze used to implemented signed
    /// integer division by a power of 2. The first operand is the dividend,
    /// and the second is the constant shift amount (representing the
    /// divisor).
    SRA_ADDZE,
 
    /// CALL - A direct function call.
    /// CALL_NOP is a call with the special NOP which follows 64-bit
    /// CALL_NOTOC the caller does not use the TOC.
    /// SVR4 calls and 32-bit/64-bit AIX calls.
    CALL,
    CALL_NOP,
    CALL_NOTOC,
 
    /// CHAIN,FLAG = MTCTR(VAL, CHAIN[, INFLAG]) - Directly corresponds to a
    /// MTCTR instruction.
    MTCTR,
 
    /// CHAIN,FLAG = BCTRL(CHAIN, INFLAG) - Directly corresponds to a
    /// BCTRL instruction.
    BCTRL,
 
    /// CHAIN,FLAG = BCTRL(CHAIN, ADDR, INFLAG) - The combination of a bctrl
    /// instruction and the TOC reload required on 64-bit ELF, 32-bit AIX
    /// and 64-bit AIX.
    BCTRL_LOAD_TOC,
 
    /// The variants that implicitly define rounding mode for calls with
    /// strictfp semantics.
    CALL_RM,
    CALL_NOP_RM,
    CALL_NOTOC_RM,
    BCTRL_RM,
    BCTRL_LOAD_TOC_RM,
 
    /// Return with a flag operand, matched by 'blr'
    RET_FLAG,
 
    /// R32 = MFOCRF(CRREG, INFLAG) - Represents the MFOCRF instruction.
    /// This copies the bits corresponding to the specified CRREG into the
    /// resultant GPR.  Bits corresponding to other CR regs are undefined.
    MFOCRF,
 
    /// Direct move from a VSX register to a GPR
    MFVSR,
 
    /// Direct move from a GPR to a VSX register (algebraic)
    MTVSRA,
 
    /// Direct move from a GPR to a VSX register (zero)
    MTVSRZ,
 
    /// Direct move of 2 consecutive GPR to a VSX register.
    BUILD_FP128,
 
    /// BUILD_SPE64 and EXTRACT_SPE are analogous to BUILD_PAIR and
    /// EXTRACT_ELEMENT but take f64 arguments instead of i64, as i64 is
    /// unsupported for this target.
    /// Merge 2 GPRs to a single SPE register.
    BUILD_SPE64,
 
    /// Extract SPE register component, second argument is high or low.
    EXTRACT_SPE,
 
    /// Extract a subvector from signed integer vector and convert to FP.
    /// It is primarily used to convert a (widened) illegal integer vector
    /// type to a legal floating point vector type.
    /// For example v2i32 -> widened to v4i32 -> v2f64
    SINT_VEC_TO_FP,
 
    /// Extract a subvector from unsigned integer vector and convert to FP.
    /// As with SINT_VEC_TO_FP, used for converting illegal types.
    UINT_VEC_TO_FP,
 
    /// PowerPC instructions that have SCALAR_TO_VECTOR semantics tend to
    /// place the value into the least significant element of the most
    /// significant doubleword in the vector. This is not element zero for
    /// anything smaller than a doubleword on either endianness. This node has
    /// the same semantics as SCALAR_TO_VECTOR except that the value remains in
    /// the aforementioned location in the vector register.
    SCALAR_TO_VECTOR_PERMUTED,
 
    // FIXME: Remove these once the ANDI glue bug is fixed:
    /// i1 = ANDI_rec_1_[EQ|GT]_BIT(i32 or i64 x) - Represents the result of the
    /// eq or gt bit of CR0 after executing andi. x, 1. This is used to
    /// implement truncation of i32 or i64 to i1.
    ANDI_rec_1_EQ_BIT,
    ANDI_rec_1_GT_BIT,
 
    // READ_TIME_BASE - A read of the 64-bit time-base register on a 32-bit
    // target (returns (Lo, Hi)). It takes a chain operand.
    READ_TIME_BASE,
 
    // EH_SJLJ_SETJMP - SjLj exception handling setjmp.
    EH_SJLJ_SETJMP,
 
    // EH_SJLJ_LONGJMP - SjLj exception handling longjmp.
    EH_SJLJ_LONGJMP,
 
    /// RESVEC = VCMP(LHS, RHS, OPC) - Represents one of the altivec VCMP*
    /// instructions.  For lack of better number, we use the opcode number
    /// encoding for the OPC field to identify the compare.  For example, 838
    /// is VCMPGTSH.
    VCMP,
 
    /// RESVEC, OUTFLAG = VCMP_rec(LHS, RHS, OPC) - Represents one of the
    /// altivec VCMP*_rec instructions.  For lack of better number, we use the
    /// opcode number encoding for the OPC field to identify the compare.  For
    /// example, 838 is VCMPGTSH.
    VCMP_rec,
 
    /// CHAIN = COND_BRANCH CHAIN, CRRC, OPC, DESTBB [, INFLAG] - This
    /// corresponds to the COND_BRANCH pseudo instruction.  CRRC is the
    /// condition register to branch on, OPC is the branch opcode to use (e.g.
    /// PPC::BLE), DESTBB is the destination block to branch to, and INFLAG is
    /// an optional input flag argument.
    COND_BRANCH,
 
    /// CHAIN = BDNZ CHAIN, DESTBB - These are used to create counter-based
    /// loops.
    BDNZ,
    BDZ,
 
    /// F8RC = FADDRTZ F8RC, F8RC - This is an FADD done with rounding
    /// towards zero.  Used only as part of the long double-to-int
    /// conversion sequence.
    FADDRTZ,
 
    /// F8RC = MFFS - This moves the FPSCR (not modeled) into the register.
    MFFS,
 
    /// TC_RETURN - A tail call return.
    ///   operand #0 chain
    ///   operand #1 callee (register or absolute)
    ///   operand #2 stack adjustment
    ///   operand #3 optional in flag
    TC_RETURN,
 
    /// ch, gl = CR6[UN]SET ch, inglue - Toggle CR bit 6 for SVR4 vararg calls
    CR6SET,
    CR6UNSET,
 
    /// GPRC = address of _GLOBAL_OFFSET_TABLE_. Used by initial-exec TLS
    /// for non-position independent code on PPC32.
    PPC32_GOT,
 
    /// GPRC = address of _GLOBAL_OFFSET_TABLE_. Used by general dynamic and
    /// local dynamic TLS and position indendepent code on PPC32.
    PPC32_PICGOT,
 
    /// G8RC = ADDIS_GOT_TPREL_HA %x2, Symbol - Used by the initial-exec
    /// TLS model, produces an ADDIS8 instruction that adds the GOT
    /// base to sym\@got\@tprel\@ha.
    ADDIS_GOT_TPREL_HA,
 
    /// G8RC = LD_GOT_TPREL_L Symbol, G8RReg - Used by the initial-exec
    /// TLS model, produces a LD instruction with base register G8RReg
    /// and offset sym\@got\@tprel\@l.  This completes the addition that
    /// finds the offset of "sym" relative to the thread pointer.
    LD_GOT_TPREL_L,
 
    /// G8RC = ADD_TLS G8RReg, Symbol - Used by the initial-exec TLS
    /// model, produces an ADD instruction that adds the contents of
    /// G8RReg to the thread pointer.  Symbol contains a relocation
    /// sym\@tls which is to be replaced by the thread pointer and
    /// identifies to the linker that the instruction is part of a
    /// TLS sequence.
    ADD_TLS,
 
    /// G8RC = ADDIS_TLSGD_HA %x2, Symbol - For the general-dynamic TLS
    /// model, produces an ADDIS8 instruction that adds the GOT base
    /// register to sym\@got\@tlsgd\@ha.
    ADDIS_TLSGD_HA,
 
    /// %x3 = ADDI_TLSGD_L G8RReg, Symbol - For the general-dynamic TLS
    /// model, produces an ADDI8 instruction that adds G8RReg to
    /// sym\@got\@tlsgd\@l and stores the result in X3.  Hidden by
    /// ADDIS_TLSGD_L_ADDR until after register assignment.
    ADDI_TLSGD_L,
 
    /// %x3 = GET_TLS_ADDR %x3, Symbol - For the general-dynamic TLS
    /// model, produces a call to __tls_get_addr(sym\@tlsgd).  Hidden by
    /// ADDIS_TLSGD_L_ADDR until after register assignment.
    GET_TLS_ADDR,
 
    /// G8RC = ADDI_TLSGD_L_ADDR G8RReg, Symbol, Symbol - Op that
    /// combines ADDI_TLSGD_L and GET_TLS_ADDR until expansion following
    /// register assignment.
    ADDI_TLSGD_L_ADDR,
 
    /// GPRC = TLSGD_AIX, TOC_ENTRY, TOC_ENTRY
    /// G8RC = TLSGD_AIX, TOC_ENTRY, TOC_ENTRY
    /// Op that combines two register copies of TOC entries
    /// (region handle into R3 and variable offset into R4) followed by a
    /// GET_TLS_ADDR node which will be expanded to a call to __get_tls_addr.
    /// This node is used in 64-bit mode as well (in which case the result is
    /// G8RC and inputs are X3/X4).
    TLSGD_AIX,
 
    /// G8RC = ADDIS_TLSLD_HA %x2, Symbol - For the local-dynamic TLS
    /// model, produces an ADDIS8 instruction that adds the GOT base
    /// register to sym\@got\@tlsld\@ha.
    ADDIS_TLSLD_HA,
 
    /// %x3 = ADDI_TLSLD_L G8RReg, Symbol - For the local-dynamic TLS
    /// model, produces an ADDI8 instruction that adds G8RReg to
    /// sym\@got\@tlsld\@l and stores the result in X3.  Hidden by
    /// ADDIS_TLSLD_L_ADDR until after register assignment.
    ADDI_TLSLD_L,
 
    /// %x3 = GET_TLSLD_ADDR %x3, Symbol - For the local-dynamic TLS
    /// model, produces a call to __tls_get_addr(sym\@tlsld).  Hidden by
    /// ADDIS_TLSLD_L_ADDR until after register assignment.
    GET_TLSLD_ADDR,
 
    /// G8RC = ADDI_TLSLD_L_ADDR G8RReg, Symbol, Symbol - Op that
    /// combines ADDI_TLSLD_L and GET_TLSLD_ADDR until expansion
    /// following register assignment.
    ADDI_TLSLD_L_ADDR,
 
    /// G8RC = ADDIS_DTPREL_HA %x3, Symbol - For the local-dynamic TLS
    /// model, produces an ADDIS8 instruction that adds X3 to
    /// sym\@dtprel\@ha.
    ADDIS_DTPREL_HA,
 
    /// G8RC = ADDI_DTPREL_L G8RReg, Symbol - For the local-dynamic TLS
    /// model, produces an ADDI8 instruction that adds G8RReg to
    /// sym\@got\@dtprel\@l.
    ADDI_DTPREL_L,
 
    /// G8RC = PADDI_DTPREL %x3, Symbol - For the pc-rel based local-dynamic TLS
    /// model, produces a PADDI8 instruction that adds X3 to sym\@dtprel.
    PADDI_DTPREL,
 
    /// VRRC = VADD_SPLAT Elt, EltSize - Temporary node to be expanded
    /// during instruction selection to optimize a BUILD_VECTOR into
    /// operations on splats.  This is necessary to avoid losing these
    /// optimizations due to constant folding.
    VADD_SPLAT,
 
    /// CHAIN = SC CHAIN, Imm128 - System call.  The 7-bit unsigned
    /// operand identifies the operating system entry point.
    SC,
 
    /// CHAIN = CLRBHRB CHAIN - Clear branch history rolling buffer.
    CLRBHRB,
 
    /// GPRC, CHAIN = MFBHRBE CHAIN, Entry, Dummy - Move from branch
    /// history rolling buffer entry.
    MFBHRBE,
 
    /// CHAIN = RFEBB CHAIN, State - Return from event-based branch.
    RFEBB,
 
    /// VSRC, CHAIN = XXSWAPD CHAIN, VSRC - Occurs only for little
    /// endian.  Maps to an xxswapd instruction that corrects an lxvd2x
    /// or stxvd2x instruction.  The chain is necessary because the
    /// sequence replaces a load and needs to provide the same number
    /// of outputs.
    XXSWAPD,
 
    /// An SDNode for swaps that are not associated with any loads/stores
    /// and thereby have no chain.
    SWAP_NO_CHAIN,
 
    /// An SDNode for Power9 vector absolute value difference.
    /// operand #0 vector
    /// operand #1 vector
    /// operand #2 constant i32 0 or 1, to indicate whether needs to patch
    /// the most significant bit for signed i32
    ///
    /// Power9 VABSD* instructions are designed to support unsigned integer
    /// vectors (byte/halfword/word), if we want to make use of them for signed
    /// integer vectors, we have to flip their sign bits first. To flip sign bit
    /// for byte/halfword integer vector would become inefficient, but for word
    /// integer vector, we can leverage XVNEGSP to make it efficiently. eg:
    /// abs(sub(a,b)) => VABSDUW(a+0x80000000, b+0x80000000)
    ///               => VABSDUW((XVNEGSP a), (XVNEGSP b))
    VABSD,
 
    /// FP_EXTEND_HALF(VECTOR, IDX) - Custom extend upper (IDX=0) half or
    /// lower (IDX=1) half of v4f32 to v2f64.
    FP_EXTEND_HALF,
 
    /// MAT_PCREL_ADDR = Materialize a PC Relative address. This can be done
    /// either through an add like PADDI or through a PC Relative load like
    /// PLD.
    MAT_PCREL_ADDR,
 
    /// TLS_DYNAMIC_MAT_PCREL_ADDR = Materialize a PC Relative address for
    /// TLS global address when using dynamic access models. This can be done
    /// through an add like PADDI.
    TLS_DYNAMIC_MAT_PCREL_ADDR,
 
    /// TLS_LOCAL_EXEC_MAT_ADDR = Materialize an address for TLS global address
    /// when using local exec access models, and when prefixed instructions are
    /// available. This is used with ADD_TLS to produce an add like PADDI.
    TLS_LOCAL_EXEC_MAT_ADDR,
 
    /// ACC_BUILD = Build an accumulator register from 4 VSX registers.
    ACC_BUILD,
 
    /// PAIR_BUILD = Build a vector pair register from 2 VSX registers.
    PAIR_BUILD,
 
    /// EXTRACT_VSX_REG = Extract one of the underlying vsx registers of
    /// an accumulator or pair register. This node is needed because
    /// EXTRACT_SUBVECTOR expects the input and output vectors to have the same
    /// element type.
    EXTRACT_VSX_REG,
 
    /// XXMFACC = This corresponds to the xxmfacc instruction.
    XXMFACC,
 
    // Constrained conversion from floating point to int
    STRICT_FCTIDZ = ISD::FIRST_TARGET_STRICTFP_OPCODE,
    STRICT_FCTIWZ,
    STRICT_FCTIDUZ,
    STRICT_FCTIWUZ,
 
    /// Constrained integer-to-floating-point conversion instructions.
    STRICT_FCFID,
    STRICT_FCFIDU,
    STRICT_FCFIDS,
    STRICT_FCFIDUS,
 
    /// Constrained floating point add in round-to-zero mode.
    STRICT_FADDRTZ,
 
    // NOTE: The nodes below may require PC-Rel specific patterns if the
    // address could be PC-Relative. When adding new nodes below, consider
    // whether or not the address can be PC-Relative and add the corresponding
    // PC-relative patterns and tests.
 
    /// CHAIN = STBRX CHAIN, GPRC, Ptr, Type - This is a
    /// byte-swapping store instruction.  It byte-swaps the low "Type" bits of
    /// the GPRC input, then stores it through Ptr.  Type can be either i16 or
    /// i32.
    STBRX = ISD::FIRST_TARGET_MEMORY_OPCODE,
 
    /// GPRC, CHAIN = LBRX CHAIN, Ptr, Type - This is a
    /// byte-swapping load instruction.  It loads "Type" bits, byte swaps it,
    /// then puts it in the bottom bits of the GPRC.  TYPE can be either i16
    /// or i32.
    LBRX,
 
    /// STFIWX - The STFIWX instruction.  The first operand is an input token
    /// chain, then an f64 value to store, then an address to store it to.
    STFIWX,
 
    /// GPRC, CHAIN = LFIWAX CHAIN, Ptr - This is a floating-point
    /// load which sign-extends from a 32-bit integer value into the
    /// destination 64-bit register.
    LFIWAX,
 
    /// GPRC, CHAIN = LFIWZX CHAIN, Ptr - This is a floating-point
    /// load which zero-extends from a 32-bit integer value into the
    /// destination 64-bit register.
    LFIWZX,
 
    /// GPRC, CHAIN = LXSIZX, CHAIN, Ptr, ByteWidth - This is a load of an
    /// integer smaller than 64 bits into a VSR. The integer is zero-extended.
    /// This can be used for converting loaded integers to floating point.
    LXSIZX,
 
    /// STXSIX - The STXSI[bh]X instruction. The first operand is an input
    /// chain, then an f64 value to store, then an address to store it to,
    /// followed by a byte-width for the store.
    STXSIX,
 
    /// VSRC, CHAIN = LXVD2X_LE CHAIN, Ptr - Occurs only for little endian.
    /// Maps directly to an lxvd2x instruction that will be followed by
    /// an xxswapd.
    LXVD2X,
 
    /// LXVRZX - Load VSX Vector Rightmost and Zero Extend
    /// This node represents v1i128 BUILD_VECTOR of a zero extending load
    /// instruction from <byte, halfword, word, or doubleword> to i128.
    /// Allows utilization of the Load VSX Vector Rightmost Instructions.
    LXVRZX,
 
    /// VSRC, CHAIN = LOAD_VEC_BE CHAIN, Ptr - Occurs only for little endian.
    /// Maps directly to one of lxvd2x/lxvw4x/lxvh8x/lxvb16x depending on
    /// the vector type to load vector in big-endian element order.
    LOAD_VEC_BE,
 
    /// VSRC, CHAIN = LD_VSX_LH CHAIN, Ptr - This is a floating-point load of a
    /// v2f32 value into the lower half of a VSR register.
    LD_VSX_LH,
 
    /// VSRC, CHAIN = LD_SPLAT, CHAIN, Ptr - a splatting load memory
    /// instructions such as LXVDSX, LXVWSX.
    LD_SPLAT,
 
    /// VSRC, CHAIN = ZEXT_LD_SPLAT, CHAIN, Ptr - a splatting load memory
    /// that zero-extends.
    ZEXT_LD_SPLAT,
 
    /// VSRC, CHAIN = SEXT_LD_SPLAT, CHAIN, Ptr - a splatting load memory
    /// that sign-extends.
    SEXT_LD_SPLAT,
 
    /// CHAIN = STXVD2X CHAIN, VSRC, Ptr - Occurs only for little endian.
    /// Maps directly to an stxvd2x instruction that will be preceded by
    /// an xxswapd.
    STXVD2X,
 
    /// CHAIN = STORE_VEC_BE CHAIN, VSRC, Ptr - Occurs only for little endian.
    /// Maps directly to one of stxvd2x/stxvw4x/stxvh8x/stxvb16x depending on
    /// the vector type to store vector in big-endian element order.
    STORE_VEC_BE,
 
    /// Store scalar integers from VSR.
    ST_VSR_SCAL_INT,
 
    /// ATOMIC_CMP_SWAP - the exact same as the target-independent nodes
    /// except they ensure that the compare input is zero-extended for
    /// sub-word versions because the atomic loads zero-extend.
    ATOMIC_CMP_SWAP_8,
    ATOMIC_CMP_SWAP_16,
 
    /// GPRC = TOC_ENTRY GA, TOC
    /// Loads the entry for GA from the TOC, where the TOC base is given by
    /// the last operand.
    TOC_ENTRY
  };
 
  } // end namespace PPCISD
 
  /// Define some predicates that are used for node matching.
  namespace PPC {
 
    /// isVPKUHUMShuffleMask - Return true if this is the shuffle mask for a
    /// VPKUHUM instruction.
    bool isVPKUHUMShuffleMask(ShuffleVectorSDNode *N, unsigned ShuffleKind,
                              SelectionDAG &DAG);
 
    /// isVPKUWUMShuffleMask - Return true if this is the shuffle mask for a
    /// VPKUWUM instruction.
    bool isVPKUWUMShuffleMask(ShuffleVectorSDNode *N, unsigned ShuffleKind,
                              SelectionDAG &DAG);
 
    /// isVPKUDUMShuffleMask - Return true if this is the shuffle mask for a
    /// VPKUDUM instruction.
    bool isVPKUDUMShuffleMask(ShuffleVectorSDNode *N, unsigned ShuffleKind,
                              SelectionDAG &DAG);
 
    /// isVMRGLShuffleMask - Return true if this is a shuffle mask suitable for
    /// a VRGL* instruction with the specified unit size (1,2 or 4 bytes).
    bool isVMRGLShuffleMask(ShuffleVectorSDNode *N, unsigned UnitSize,
                            unsigned ShuffleKind, SelectionDAG &DAG);
 
    /// isVMRGHShuffleMask - Return true if this is a shuffle mask suitable for
    /// a VRGH* instruction with the specified unit size (1,2 or 4 bytes).
    bool isVMRGHShuffleMask(ShuffleVectorSDNode *N, unsigned UnitSize,
                            unsigned ShuffleKind, SelectionDAG &DAG);
 
    /// isVMRGEOShuffleMask - Return true if this is a shuffle mask suitable for
    /// a VMRGEW or VMRGOW instruction
    bool isVMRGEOShuffleMask(ShuffleVectorSDNode *N, bool CheckEven,
                             unsigned ShuffleKind, SelectionDAG &DAG);
    /// isXXSLDWIShuffleMask - Return true if this is a shuffle mask suitable
    /// for a XXSLDWI instruction.
    bool isXXSLDWIShuffleMask(ShuffleVectorSDNode *N, unsigned &ShiftElts,
                              bool &Swap, bool IsLE);
 
    /// isXXBRHShuffleMask - Return true if this is a shuffle mask suitable
    /// for a XXBRH instruction.
    bool isXXBRHShuffleMask(ShuffleVectorSDNode *N);
 
    /// isXXBRWShuffleMask - Return true if this is a shuffle mask suitable
    /// for a XXBRW instruction.
    bool isXXBRWShuffleMask(ShuffleVectorSDNode *N);
 
    /// isXXBRDShuffleMask - Return true if this is a shuffle mask suitable
    /// for a XXBRD instruction.
    bool isXXBRDShuffleMask(ShuffleVectorSDNode *N);
 
    /// isXXBRQShuffleMask - Return true if this is a shuffle mask suitable
    /// for a XXBRQ instruction.
    bool isXXBRQShuffleMask(ShuffleVectorSDNode *N);
 
    /// isXXPERMDIShuffleMask - Return true if this is a shuffle mask suitable
    /// for a XXPERMDI instruction.
    bool isXXPERMDIShuffleMask(ShuffleVectorSDNode *N, unsigned &ShiftElts,
                              bool &Swap, bool IsLE);
 
    /// isVSLDOIShuffleMask - If this is a vsldoi shuffle mask, return the
    /// shift amount, otherwise return -1.
    int isVSLDOIShuffleMask(SDNode *N, unsigned ShuffleKind,
                            SelectionDAG &DAG);
 
    /// isSplatShuffleMask - Return true if the specified VECTOR_SHUFFLE operand
    /// specifies a splat of a single element that is suitable for input to
    /// VSPLTB/VSPLTH/VSPLTW.
    bool isSplatShuffleMask(ShuffleVectorSDNode *N, unsigned EltSize);
 
    /// isXXINSERTWMask - Return true if this VECTOR_SHUFFLE can be handled by
    /// the XXINSERTW instruction introduced in ISA 3.0. This is essentially any
    /// shuffle of v4f32/v4i32 vectors that just inserts one element from one
    /// vector into the other. This function will also set a couple of
    /// output parameters for how much the source vector needs to be shifted and
    /// what byte number needs to be specified for the instruction to put the
    /// element in the desired location of the target vector.
    bool isXXINSERTWMask(ShuffleVectorSDNode *N, unsigned &ShiftElts,
                         unsigned &InsertAtByte, bool &Swap, bool IsLE);
 
    /// getSplatIdxForPPCMnemonics - Return the splat index as a value that is
    /// appropriate for PPC mnemonics (which have a big endian bias - namely
    /// elements are counted from the left of the vector register).
    unsigned getSplatIdxForPPCMnemonics(SDNode *N, unsigned EltSize,
                                        SelectionDAG &DAG);
 
    /// get_VSPLTI_elt - If this is a build_vector of constants which can be
    /// formed by using a vspltis[bhw] instruction of the specified element
    /// size, return the constant being splatted.  The ByteSize field indicates
    /// the number of bytes of each element [124] -> [bhw].
    SDValue get_VSPLTI_elt(SDNode *N, unsigned ByteSize, SelectionDAG &DAG);
 
    // Flags for computing the optimal addressing mode for loads and stores.
    enum MemOpFlags {
      MOF_None = 0,
 
      // Extension mode for integer loads.
      MOF_SExt = 1,
      MOF_ZExt = 1 << 1,
      MOF_NoExt = 1 << 2,
 
      // Address computation flags.
      MOF_NotAddNorCst = 1 << 5,      // Not const. or sum of ptr and scalar.
      MOF_RPlusSImm16 = 1 << 6,       // Reg plus signed 16-bit constant.
      MOF_RPlusLo = 1 << 7,           // Reg plus signed 16-bit relocation
      MOF_RPlusSImm16Mult4 = 1 << 8,  // Reg plus 16-bit signed multiple of 4.
      MOF_RPlusSImm16Mult16 = 1 << 9, // Reg plus 16-bit signed multiple of 16.
      MOF_RPlusSImm34 = 1 << 10,      // Reg plus 34-bit signed constant.
      MOF_RPlusR = 1 << 11,           // Sum of two variables.
      MOF_PCRel = 1 << 12,            // PC-Relative relocation.
      MOF_AddrIsSImm32 = 1 << 13,     // A simple 32-bit constant.
 
      // The in-memory type.
      MOF_SubWordInt = 1 << 15,
      MOF_WordInt = 1 << 16,
      MOF_DoubleWordInt = 1 << 17,
      MOF_ScalarFloat = 1 << 18, // Scalar single or double precision.
      MOF_Vector = 1 << 19,      // Vector types and quad precision scalars.
      MOF_Vector256 = 1 << 20,
 
      // Subtarget features.
      MOF_SubtargetBeforeP9 = 1 << 22,
      MOF_SubtargetP9 = 1 << 23,
      MOF_SubtargetP10 = 1 << 24,
      MOF_SubtargetSPE = 1 << 25
    };
 
    // The addressing modes for loads and stores.
    enum AddrMode {
      AM_None,
      AM_DForm,
      AM_DSForm,
      AM_DQForm,
      AM_PrefixDForm,
      AM_XForm,
      AM_PCRel
    };
  } // end namespace PPC
 
  class PPCTargetLowering : public TargetLowering {
    const PPCSubtarget &Subtarget;
 
  public:
    explicit PPCTargetLowering(const PPCTargetMachine &TM,
                               const PPCSubtarget &STI);
 
    /// getTargetNodeName() - This method returns the name of a target specific
    /// DAG node.
    const char *getTargetNodeName(unsigned Opcode) const override;
 
    bool isSelectSupported(SelectSupportKind Kind) const override {
      // PowerPC does not support scalar condition selects on vectors.
      return (Kind != SelectSupportKind::ScalarCondVectorVal);
    }
 
    /// getPreferredVectorAction - The code we generate when vector types are
    /// legalized by promoting the integer element type is often much worse
    /// than code we generate if we widen the type for applicable vector types.
    /// The issue with promoting is that the vector is scalaraized, individual
    /// elements promoted and then the vector is rebuilt. So say we load a pair
    /// of v4i8's and shuffle them. This will turn into a mess of 8 extending
    /// loads, moves back into VSR's (or memory ops if we don't have moves) and
    /// then the VPERM for the shuffle. All in all a very slow sequence.
    TargetLoweringBase::LegalizeTypeAction getPreferredVectorAction(MVT VT)
      const override {
      // Default handling for scalable and single-element vectors.
      if (VT.isScalableVector() || VT.getVectorNumElements() == 1)
        return TargetLoweringBase::getPreferredVectorAction(VT);
 
      // Split and promote vNi1 vectors so we don't produce v256i1/v512i1
      // types as those are only for MMA instructions.
      if (VT.getScalarSizeInBits() == 1 && VT.getSizeInBits() > 16)
        return TypeSplitVector;
      if (VT.getScalarSizeInBits() == 1)
        return TypePromoteInteger;
 
      // Widen vectors that have reasonably sized elements.
      if (VT.getScalarSizeInBits() % 8 == 0)
        return TypeWidenVector;
      return TargetLoweringBase::getPreferredVectorAction(VT);
    }
 
    bool useSoftFloat() const override;
 
    bool hasSPE() const;
 
    MVT getScalarShiftAmountTy(const DataLayout &, EVT) const override {
      return MVT::i32;
    }
 
    bool isCheapToSpeculateCttz(Type *Ty) const override {
      return true;
    }
 
    bool isCheapToSpeculateCtlz(Type *Ty) const override {
      return true;
    }
 
    bool isCtlzFast() const override {
      return true;
    }
 
    bool isEqualityCmpFoldedWithSignedCmp() const override {
      return false;
    }
 
    bool hasAndNotCompare(SDValue) const override {
      return true;
    }
 
    bool preferIncOfAddToSubOfNot(EVT VT) const override;
 
    bool convertSetCCLogicToBitwiseLogic(EVT VT) const override {
      return VT.isScalarInteger();
    }
 
    SDValue getNegatedExpression(SDValue Op, SelectionDAG &DAG, bool LegalOps,
                                 bool OptForSize, NegatibleCost &Cost,
                                 unsigned Depth = 0) const override;
 
    /// getSetCCResultType - Return the ISD::SETCC ValueType
    EVT getSetCCResultType(const DataLayout &DL, LLVMContext &Context,
                           EVT VT) const override;
 
    /// Return true if target always benefits from combining into FMA for a
    /// given value type. This must typically return false on targets where FMA
    /// takes more cycles to execute than FADD.
    bool enableAggressiveFMAFusion(EVT VT) const override;
 
    /// getPreIndexedAddressParts - returns true by value, base pointer and
    /// offset pointer and addressing mode by reference if the node's address
    /// can be legally represented as pre-indexed load / store address.
    bool getPreIndexedAddressParts(SDNode *N, SDValue &Base,
                                   SDValue &Offset,
                                   ISD::MemIndexedMode &AM,
                                   SelectionDAG &DAG) const override;
 
    /// SelectAddressEVXRegReg - Given the specified addressed, check to see if
    /// it can be more efficiently represented as [r+imm].
    bool SelectAddressEVXRegReg(SDValue N, SDValue &Base, SDValue &Index,
                                SelectionDAG &DAG) const;
 
    /// SelectAddressRegReg - Given the specified addressed, check to see if it
    /// can be more efficiently represented as [r+imm]. If \p EncodingAlignment
    /// is non-zero, only accept displacement which is not suitable for [r+imm].
    /// Returns false if it can be represented by [r+imm], which are preferred.
    bool SelectAddressRegReg(SDValue N, SDValue &Base, SDValue &Index,
                             SelectionDAG &DAG,
                             MaybeAlign EncodingAlignment = None) const;
 
    /// SelectAddressRegImm - Returns true if the address N can be represented
    /// by a base register plus a signed 16-bit displacement [r+imm], and if it
    /// is not better represented as reg+reg. If \p EncodingAlignment is
    /// non-zero, only accept displacements suitable for instruction encoding
    /// requirement, i.e. multiples of 4 for DS form.
    bool SelectAddressRegImm(SDValue N, SDValue &Disp, SDValue &Base,
                             SelectionDAG &DAG,
                             MaybeAlign EncodingAlignment) const;
    bool SelectAddressRegImm34(SDValue N, SDValue &Disp, SDValue &Base,
                               SelectionDAG &DAG) const;
 
    /// SelectAddressRegRegOnly - Given the specified addressed, force it to be
    /// represented as an indexed [r+r] operation.
    bool SelectAddressRegRegOnly(SDValue N, SDValue &Base, SDValue &Index,
                                 SelectionDAG &DAG) const;
 
    /// SelectAddressPCRel - Represent the specified address as pc relative to
    /// be represented as [pc+imm]
    bool SelectAddressPCRel(SDValue N, SDValue &Base) const;
 
    Sched::Preference getSchedulingPreference(SDNode *N) const override;
 
    /// LowerOperation - Provide custom lowering hooks for some operations.
    ///
    SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const override;
 
    /// ReplaceNodeResults - Replace the results of node with an illegal result
    /// type with new values built out of custom code.
    ///
    void ReplaceNodeResults(SDNode *N, SmallVectorImpl<SDValue>&Results,
                            SelectionDAG &DAG) const override;
 
    SDValue expandVSXLoadForLE(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue expandVSXStoreForLE(SDNode *N, DAGCombinerInfo &DCI) const;
 
    SDValue PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const override;
 
    SDValue BuildSDIVPow2(SDNode *N, const APInt &Divisor, SelectionDAG &DAG,
                          SmallVectorImpl<SDNode *> &Created) const override;
 
    Register getRegisterByName(const char* RegName, LLT VT,
                               const MachineFunction &MF) const override;
 
    void computeKnownBitsForTargetNode(const SDValue Op,
                                       KnownBits &Known,
                                       const APInt &DemandedElts,
                                       const SelectionDAG &DAG,
                                       unsigned Depth = 0) const override;
 
    Align getPrefLoopAlignment(MachineLoop *ML) const override;
 
    bool shouldInsertFencesForAtomic(const Instruction *I) const override {
      return true;
    }
 
    Instruction *emitLeadingFence(IRBuilderBase &Builder, Instruction *Inst,
                                  AtomicOrdering Ord) const override;
    Instruction *emitTrailingFence(IRBuilderBase &Builder, Instruction *Inst,
                                   AtomicOrdering Ord) const override;
 
    bool shouldInlineQuadwordAtomics() const;
 
    TargetLowering::AtomicExpansionKind
    shouldExpandAtomicRMWInIR(AtomicRMWInst *AI) const override;
 
    TargetLowering::AtomicExpansionKind
    shouldExpandAtomicCmpXchgInIR(AtomicCmpXchgInst *AI) const override;
 
    Value *emitMaskedAtomicRMWIntrinsic(IRBuilderBase &Builder,
                                        AtomicRMWInst *AI, Value *AlignedAddr,
                                        Value *Incr, Value *Mask,
                                        Value *ShiftAmt,
                                        AtomicOrdering Ord) const override;
    Value *emitMaskedAtomicCmpXchgIntrinsic(IRBuilderBase &Builder,
                                            AtomicCmpXchgInst *CI,
                                            Value *AlignedAddr, Value *CmpVal,
                                            Value *NewVal, Value *Mask,
                                            AtomicOrdering Ord) const override;
 
    MachineBasicBlock *
    EmitInstrWithCustomInserter(MachineInstr &MI,
                                MachineBasicBlock *MBB) const override;
    MachineBasicBlock *EmitAtomicBinary(MachineInstr &MI,
                                        MachineBasicBlock *MBB,
                                        unsigned AtomicSize,
                                        unsigned BinOpcode,
                                        unsigned CmpOpcode = 0,
                                        unsigned CmpPred = 0) const;
    MachineBasicBlock *EmitPartwordAtomicBinary(MachineInstr &MI,
                                                MachineBasicBlock *MBB,
                                                bool is8bit,
                                                unsigned Opcode,
                                                unsigned CmpOpcode = 0,
                                                unsigned CmpPred = 0) const;
 
    MachineBasicBlock *emitEHSjLjSetJmp(MachineInstr &MI,
                                        MachineBasicBlock *MBB) const;
 
    MachineBasicBlock *emitEHSjLjLongJmp(MachineInstr &MI,
                                         MachineBasicBlock *MBB) const;
 
    MachineBasicBlock *emitProbedAlloca(MachineInstr &MI,
                                        MachineBasicBlock *MBB) const;
 
    bool hasInlineStackProbe(MachineFunction &MF) const override;
 
    unsigned getStackProbeSize(MachineFunction &MF) const;
 
    ConstraintType getConstraintType(StringRef Constraint) const override;
 
    /// Examine constraint string and operand type and determine a weight value.
    /// The operand object must already have been set up with the operand type.
    ConstraintWeight getSingleConstraintMatchWeight(
      AsmOperandInfo &info, const char *constraint) const override;
 
    std::pair<unsigned, const TargetRegisterClass *>
    getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI,
                                 StringRef Constraint, MVT VT) const override;
 
    /// getByValTypeAlignment - Return the desired alignment for ByVal aggregate
    /// function arguments in the caller parameter area.  This is the actual
    /// alignment, not its logarithm.
    uint64_t getByValTypeAlignment(Type *Ty,
                                   const DataLayout &DL) const override;
 
    /// LowerAsmOperandForConstraint - Lower the specified operand into the Ops
    /// vector.  If it is invalid, don't add anything to Ops.
    void LowerAsmOperandForConstraint(SDValue Op,
                                      std::string &Constraint,
                                      std::vector<SDValue> &Ops,
                                      SelectionDAG &DAG) const override;
 
    unsigned
    getInlineAsmMemConstraint(StringRef ConstraintCode) const override {
      if (ConstraintCode == "es")
        return InlineAsm::Constraint_es;
      else if (ConstraintCode == "Q")
        return InlineAsm::Constraint_Q;
      else if (ConstraintCode == "Z")
        return InlineAsm::Constraint_Z;
      else if (ConstraintCode == "Zy")
        return InlineAsm::Constraint_Zy;
      return TargetLowering::getInlineAsmMemConstraint(ConstraintCode);
    }
 
    /// isLegalAddressingMode - Return true if the addressing mode represented
    /// by AM is legal for this target, for a load/store of the specified type.
    bool isLegalAddressingMode(const DataLayout &DL, const AddrMode &AM,
                               Type *Ty, unsigned AS,
                               Instruction *I = nullptr) const override;
 
    /// isLegalICmpImmediate - Return true if the specified immediate is legal
    /// icmp immediate, that is the target has icmp instructions which can
    /// compare a register against the immediate without having to materialize
    /// the immediate into a register.
    bool isLegalICmpImmediate(int64_t Imm) const override;
 
    /// isLegalAddImmediate - Return true if the specified immediate is legal
    /// add immediate, that is the target has add instructions which can
    /// add a register and the immediate without having to materialize
    /// the immediate into a register.
    bool isLegalAddImmediate(int64_t Imm) const override;
 
    /// isTruncateFree - Return true if it's free to truncate a value of
    /// type Ty1 to type Ty2. e.g. On PPC it's free to truncate a i64 value in
    /// register X1 to i32 by referencing its sub-register R1.
    bool isTruncateFree(Type *Ty1, Type *Ty2) const override;
    bool isTruncateFree(EVT VT1, EVT VT2) const override;
 
    bool isZExtFree(SDValue Val, EVT VT2) const override;
 
    bool isFPExtFree(EVT DestVT, EVT SrcVT) const override;
 
    /// Returns true if it is beneficial to convert a load of a constant
    /// to just the constant itself.
    bool shouldConvertConstantLoadToIntImm(const APInt &Imm,
                                           Type *Ty) const override;
 
    bool convertSelectOfConstantsToMath(EVT VT) const override {
      return true;
    }
 
    bool decomposeMulByConstant(LLVMContext &Context, EVT VT,
                                SDValue C) const override;
 
    bool isDesirableToTransformToIntegerOp(unsigned Opc,
                                           EVT VT) const override {
      // Only handle float load/store pair because float(fpr) load/store
      // instruction has more cycles than integer(gpr) load/store in PPC.
      if (Opc != ISD::LOAD && Opc != ISD::STORE)
        return false;
      if (VT != MVT::f32 && VT != MVT::f64)
        return false;
 
      return true;
    }
 
    // Returns true if the address of the global is stored in TOC entry.
    bool isAccessedAsGotIndirect(SDValue N) const;
 
    bool isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const override;
 
    bool getTgtMemIntrinsic(IntrinsicInfo &Info,
                            const CallInst &I,
                            MachineFunction &MF,
                            unsigned Intrinsic) const override;
 
    /// It returns EVT::Other if the type should be determined using generic
    /// target-independent logic.
    EVT getOptimalMemOpType(const MemOp &Op,
                            const AttributeList &FuncAttributes) const override;
 
    /// Is unaligned memory access allowed for the given type, and is it fast
    /// relative to software emulation.
    bool allowsMisalignedMemoryAccesses(
        EVT VT, unsigned AddrSpace, Align Alignment = Align(1),
        MachineMemOperand::Flags Flags = MachineMemOperand::MONone,
        bool *Fast = nullptr) const override;
 
    /// isFMAFasterThanFMulAndFAdd - Return true if an FMA operation is faster
    /// than a pair of fmul and fadd instructions. fmuladd intrinsics will be
    /// expanded to FMAs when this method returns true, otherwise fmuladd is
    /// expanded to fmul + fadd.
    bool isFMAFasterThanFMulAndFAdd(const MachineFunction &MF,
                                    EVT VT) const override;
 
    bool isFMAFasterThanFMulAndFAdd(const Function &F, Type *Ty) const override;
 
    /// isProfitableToHoist - Check if it is profitable to hoist instruction
    /// \p I to its dominator block.
    /// For example, it is not profitable if \p I and it's only user can form a
    /// FMA instruction, because Powerpc prefers FMADD.
    bool isProfitableToHoist(Instruction *I) const override;
 
    const MCPhysReg *getScratchRegisters(CallingConv::ID CC) const override;
 
    // Should we expand the build vector with shuffles?
    bool
    shouldExpandBuildVectorWithShuffles(EVT VT,
                                        unsigned DefinedValues) const override;
 
    // Keep the zero-extensions for arguments to libcalls.
    bool shouldKeepZExtForFP16Conv() const override { return true; }
 
    /// createFastISel - This method returns a target-specific FastISel object,
    /// or null if the target does not support "fast" instruction selection.
    FastISel *createFastISel(FunctionLoweringInfo &FuncInfo,
                             const TargetLibraryInfo *LibInfo) const override;
 
    /// Returns true if an argument of type Ty needs to be passed in a
    /// contiguous block of registers in calling convention CallConv.
    bool functionArgumentNeedsConsecutiveRegisters(
        Type *Ty, CallingConv::ID CallConv, bool isVarArg,
        const DataLayout &DL) const override {
      // We support any array type as "consecutive" block in the parameter
      // save area.  The element type defines the alignment requirement and
      // whether the argument should go in GPRs, FPRs, or VRs if available.
      //
      // Note that clang uses this capability both to implement the ELFv2
      // homogeneous float/vector aggregate ABI, and to avoid having to use
      // "byval" when passing aggregates that might fully fit in registers.
      return Ty->isArrayTy();
    }
 
    /// If a physical register, this returns the register that receives the
    /// exception address on entry to an EH pad.
    Register
    getExceptionPointerRegister(const Constant *PersonalityFn) const override;
 
    /// If a physical register, this returns the register that receives the
    /// exception typeid on entry to a landing pad.
    Register
    getExceptionSelectorRegister(const Constant *PersonalityFn) const override;
 
    /// Override to support customized stack guard loading.
    bool useLoadStackGuardNode() const override;
    void insertSSPDeclarations(Module &M) const override;
    Value *getSDagStackGuard(const Module &M) const override;
 
    bool isFPImmLegal(const APFloat &Imm, EVT VT,
                      bool ForCodeSize) const override;
 
    unsigned getJumpTableEncoding() const override;
    bool isJumpTableRelative() const override;
    SDValue getPICJumpTableRelocBase(SDValue Table,
                                     SelectionDAG &DAG) const override;
    const MCExpr *getPICJumpTableRelocBaseExpr(const MachineFunction *MF,
                                               unsigned JTI,
                                               MCContext &Ctx) const override;
 
    /// SelectOptimalAddrMode - Based on a node N and it's Parent (a MemSDNode),
    /// compute the address flags of the node, get the optimal address mode
    /// based on the flags, and set the Base and Disp based on the address mode.
    PPC::AddrMode SelectOptimalAddrMode(const SDNode *Parent, SDValue N,
                                        SDValue &Disp, SDValue &Base,
                                        SelectionDAG &DAG,
                                        MaybeAlign Align) const;
    /// SelectForceXFormMode - Given the specified address, force it to be
    /// represented as an indexed [r+r] operation (an XForm instruction).
    PPC::AddrMode SelectForceXFormMode(SDValue N, SDValue &Disp, SDValue &Base,
                                       SelectionDAG &DAG) const;
 
    bool
    splitValueIntoRegisterParts(SelectionDAG &DAG, const SDLoc &DL, SDValue Val,
                                SDValue *Parts, unsigned NumParts, MVT PartVT,
                                Optional<CallingConv::ID> CC) const override;
    /// Structure that collects some common arguments that get passed around
    /// between the functions for call lowering.
    struct CallFlags {
      const CallingConv::ID CallConv;
      const bool IsTailCall : 1;
      const bool IsVarArg : 1;
      const bool IsPatchPoint : 1;
      const bool IsIndirect : 1;
      const bool HasNest : 1;
      const bool NoMerge : 1;
 
      CallFlags(CallingConv::ID CC, bool IsTailCall, bool IsVarArg,
                bool IsPatchPoint, bool IsIndirect, bool HasNest, bool NoMerge)
          : CallConv(CC), IsTailCall(IsTailCall), IsVarArg(IsVarArg),
            IsPatchPoint(IsPatchPoint), IsIndirect(IsIndirect),
            HasNest(HasNest), NoMerge(NoMerge) {}
    };
 
    CCAssignFn *ccAssignFnForCall(CallingConv::ID CC, bool Return,
                                  bool IsVarArg) const;
 
  private:
    struct ReuseLoadInfo {
      SDValue Ptr;
      SDValue Chain;
      SDValue ResChain;
      MachinePointerInfo MPI;
      bool IsDereferenceable = false;
      bool IsInvariant = false;
      Align Alignment;
      AAMDNodes AAInfo;
      const MDNode *Ranges = nullptr;
 
      ReuseLoadInfo() = default;
 
      MachineMemOperand::Flags MMOFlags() const {
        MachineMemOperand::Flags F = MachineMemOperand::MONone;
        if (IsDereferenceable)
          F |= MachineMemOperand::MODereferenceable;
        if (IsInvariant)
          F |= MachineMemOperand::MOInvariant;
        return F;
      }
    };
 
    // Map that relates a set of common address flags to PPC addressing modes.
    std::map<PPC::AddrMode, SmallVector<unsigned, 16>> AddrModesMap;
    void initializeAddrModeMap();
 
    bool canReuseLoadAddress(SDValue Op, EVT MemVT, ReuseLoadInfo &RLI,
                             SelectionDAG &DAG,
                             ISD::LoadExtType ET = ISD::NON_EXTLOAD) const;
    void spliceIntoChain(SDValue ResChain, SDValue NewResChain,
                         SelectionDAG &DAG) const;
 
    void LowerFP_TO_INTForReuse(SDValue Op, ReuseLoadInfo &RLI,
                                SelectionDAG &DAG, const SDLoc &dl) const;
    SDValue LowerFP_TO_INTDirectMove(SDValue Op, SelectionDAG &DAG,
                                     const SDLoc &dl) const;
 
    bool directMoveIsProfitable(const SDValue &Op) const;
    SDValue LowerINT_TO_FPDirectMove(SDValue Op, SelectionDAG &DAG,
                                     const SDLoc &dl) const;
 
    SDValue LowerINT_TO_FPVector(SDValue Op, SelectionDAG &DAG,
                                 const SDLoc &dl) const;
 
    SDValue LowerTRUNCATEVector(SDValue Op, SelectionDAG &DAG) const;
 
    SDValue getFramePointerFrameIndex(SelectionDAG & DAG) const;
    SDValue getReturnAddrFrameIndex(SelectionDAG & DAG) const;
 
    bool
    IsEligibleForTailCallOptimization(SDValue Callee,
                                      CallingConv::ID CalleeCC,
                                      bool isVarArg,
                                      const SmallVectorImpl<ISD::InputArg> &Ins,
                                      SelectionDAG& DAG) const;
 
    bool IsEligibleForTailCallOptimization_64SVR4(
        SDValue Callee, CallingConv::ID CalleeCC, const CallBase *CB,
        bool isVarArg, const SmallVectorImpl<ISD::OutputArg> &Outs,
        const SmallVectorImpl<ISD::InputArg> &Ins, SelectionDAG &DAG) const;
 
    SDValue EmitTailCallLoadFPAndRetAddr(SelectionDAG &DAG, int SPDiff,
                                         SDValue Chain, SDValue &LROpOut,
                                         SDValue &FPOpOut,
                                         const SDLoc &dl) const;
 
    SDValue getTOCEntry(SelectionDAG &DAG, const SDLoc &dl, SDValue GA) const;
 
    SDValue LowerRETURNADDR(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerConstantPool(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerBlockAddress(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerGlobalTLSAddressAIX(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerGlobalTLSAddressLinux(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerJumpTable(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerSETCC(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerINIT_TRAMPOLINE(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerADJUST_TRAMPOLINE(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerINLINEASM(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerVASTART(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerVAARG(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerVACOPY(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerSTACKRESTORE(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerGET_DYNAMIC_AREA_OFFSET(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerDYNAMIC_STACKALLOC(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerEH_DWARF_CFA(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerLOAD(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerSTORE(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerTRUNCATE(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerFP_TO_INT(SDValue Op, SelectionDAG &DAG,
                           const SDLoc &dl) const;
    SDValue LowerINT_TO_FP(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerFLT_ROUNDS_(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerSHL_PARTS(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerSRL_PARTS(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerSRA_PARTS(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerFunnelShift(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerVECTOR_SHUFFLE(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerINSERT_VECTOR_ELT(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerINTRINSIC_WO_CHAIN(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerINTRINSIC_VOID(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerBSWAP(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerATOMIC_CMP_SWAP(SDValue Op, SelectionDAG &DAG) const;
    SDValue lowerToLibCall(const char *LibCallName, SDValue Op,
                           SelectionDAG &DAG) const;
    SDValue lowerLibCallBasedOnType(const char *LibCallFloatName,
                                    const char *LibCallDoubleName, SDValue Op,
                                    SelectionDAG &DAG) const;
    bool isLowringToMASSFiniteSafe(SDValue Op) const;
    bool isLowringToMASSSafe(SDValue Op) const;
    bool isScalarMASSConversionEnabled() const;
    SDValue lowerLibCallBase(const char *LibCallDoubleName,
                             const char *LibCallFloatName,
                             const char *LibCallDoubleNameFinite,
                             const char *LibCallFloatNameFinite, SDValue Op,
                             SelectionDAG &DAG) const;
    SDValue lowerPow(SDValue Op, SelectionDAG &DAG) const;
    SDValue lowerSin(SDValue Op, SelectionDAG &DAG) const;
    SDValue lowerCos(SDValue Op, SelectionDAG &DAG) const;
    SDValue lowerLog(SDValue Op, SelectionDAG &DAG) const;
    SDValue lowerLog10(SDValue Op, SelectionDAG &DAG) const;
    SDValue lowerExp(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerATOMIC_LOAD_STORE(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerSCALAR_TO_VECTOR(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerMUL(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerFP_EXTEND(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerFP_ROUND(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerROTL(SDValue Op, SelectionDAG &DAG) const;
 
    SDValue LowerVectorLoad(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerVectorStore(SDValue Op, SelectionDAG &DAG) const;
 
    SDValue LowerCallResult(SDValue Chain, SDValue InFlag,
                            CallingConv::ID CallConv, bool isVarArg,
                            const SmallVectorImpl<ISD::InputArg> &Ins,
                            const SDLoc &dl, SelectionDAG &DAG,
                            SmallVectorImpl<SDValue> &InVals) const;
 
    SDValue FinishCall(CallFlags CFlags, const SDLoc &dl, SelectionDAG &DAG,
                       SmallVector<std::pair<unsigned, SDValue>, 8> &RegsToPass,
                       SDValue InFlag, SDValue Chain, SDValue CallSeqStart,
                       SDValue &Callee, int SPDiff, unsigned NumBytes,
                       const SmallVectorImpl<ISD::InputArg> &Ins,
                       SmallVectorImpl<SDValue> &InVals,
                       const CallBase *CB) const;
 
    SDValue
    LowerFormalArguments(SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
                         const SmallVectorImpl<ISD::InputArg> &Ins,
                         const SDLoc &dl, SelectionDAG &DAG,
                         SmallVectorImpl<SDValue> &InVals) const override;
 
    SDValue LowerCall(TargetLowering::CallLoweringInfo &CLI,
                      SmallVectorImpl<SDValue> &InVals) const override;
 
    bool CanLowerReturn(CallingConv::ID CallConv, MachineFunction &MF,
                        bool isVarArg,
                        const SmallVectorImpl<ISD::OutputArg> &Outs,
                        LLVMContext &Context) const override;
 
    SDValue LowerReturn(SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
                        const SmallVectorImpl<ISD::OutputArg> &Outs,
                        const SmallVectorImpl<SDValue> &OutVals,
                        const SDLoc &dl, SelectionDAG &DAG) const override;
 
    SDValue extendArgForPPC64(ISD::ArgFlagsTy Flags, EVT ObjectVT,
                              SelectionDAG &DAG, SDValue ArgVal,
                              const SDLoc &dl) const;
 
    SDValue LowerFormalArguments_AIX(
        SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
        const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &dl,
        SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const;
    SDValue LowerFormalArguments_64SVR4(
        SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
        const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &dl,
        SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const;
    SDValue LowerFormalArguments_32SVR4(
        SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
        const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &dl,
        SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const;
 
    SDValue createMemcpyOutsideCallSeq(SDValue Arg, SDValue PtrOff,
                                       SDValue CallSeqStart,
                                       ISD::ArgFlagsTy Flags, SelectionDAG &DAG,
                                       const SDLoc &dl) const;
 
    SDValue LowerCall_64SVR4(SDValue Chain, SDValue Callee, CallFlags CFlags,
                             const SmallVectorImpl<ISD::OutputArg> &Outs,
                             const SmallVectorImpl<SDValue> &OutVals,
                             const SmallVectorImpl<ISD::InputArg> &Ins,
                             const SDLoc &dl, SelectionDAG &DAG,
                             SmallVectorImpl<SDValue> &InVals,
                             const CallBase *CB) const;
    SDValue LowerCall_32SVR4(SDValue Chain, SDValue Callee, CallFlags CFlags,
                             const SmallVectorImpl<ISD::OutputArg> &Outs,
                             const SmallVectorImpl<SDValue> &OutVals,
                             const SmallVectorImpl<ISD::InputArg> &Ins,
                             const SDLoc &dl, SelectionDAG &DAG,
                             SmallVectorImpl<SDValue> &InVals,
                             const CallBase *CB) const;
    SDValue LowerCall_AIX(SDValue Chain, SDValue Callee, CallFlags CFlags,
                          const SmallVectorImpl<ISD::OutputArg> &Outs,
                          const SmallVectorImpl<SDValue> &OutVals,
                          const SmallVectorImpl<ISD::InputArg> &Ins,
                          const SDLoc &dl, SelectionDAG &DAG,
                          SmallVectorImpl<SDValue> &InVals,
                          const CallBase *CB) const;
 
    SDValue lowerEH_SJLJ_SETJMP(SDValue Op, SelectionDAG &DAG) const;
    SDValue lowerEH_SJLJ_LONGJMP(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerBITCAST(SDValue Op, SelectionDAG &DAG) const;
 
    SDValue DAGCombineExtBoolTrunc(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue DAGCombineBuildVector(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue DAGCombineTruncBoolExt(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue combineStoreFPToInt(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue combineFPToIntToFP(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue combineSHL(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue combineSRA(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue combineSRL(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue combineMUL(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue combineADD(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue combineFMALike(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue combineTRUNCATE(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue combineSetCC(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue combineABS(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue combineVSelect(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue combineVectorShuffle(ShuffleVectorSDNode *SVN,
                                 SelectionDAG &DAG) const;
    SDValue combineVReverseMemOP(ShuffleVectorSDNode *SVN, LSBaseSDNode *LSBase,
                                 DAGCombinerInfo &DCI) const;
 
    /// ConvertSETCCToSubtract - looks at SETCC that compares ints. It replaces
    /// SETCC with integer subtraction when (1) there is a legal way of doing it
    /// (2) keeping the result of comparison in GPR has performance benefit.
    SDValue ConvertSETCCToSubtract(SDNode *N, DAGCombinerInfo &DCI) const;
 
    SDValue getSqrtEstimate(SDValue Operand, SelectionDAG &DAG, int Enabled,
                            int &RefinementSteps, bool &UseOneConstNR,
                            bool Reciprocal) const override;
    SDValue getRecipEstimate(SDValue Operand, SelectionDAG &DAG, int Enabled,
                             int &RefinementSteps) const override;
    SDValue getSqrtInputTest(SDValue Operand, SelectionDAG &DAG,
                             const DenormalMode &Mode) const override;
    SDValue getSqrtResultForDenormInput(SDValue Operand,
                                        SelectionDAG &DAG) const override;
    unsigned combineRepeatedFPDivisors() const override;
 
    SDValue
    combineElementTruncationToVectorTruncation(SDNode *N,
                                               DAGCombinerInfo &DCI) const;
 
    /// lowerToVINSERTH - Return the SDValue if this VECTOR_SHUFFLE can be
    /// handled by the VINSERTH instruction introduced in ISA 3.0. This is
    /// essentially any shuffle of v8i16 vectors that just inserts one element
    /// from one vector into the other.
    SDValue lowerToVINSERTH(ShuffleVectorSDNode *N, SelectionDAG &DAG) const;
 
    /// lowerToVINSERTB - Return the SDValue if this VECTOR_SHUFFLE can be
    /// handled by the VINSERTB instruction introduced in ISA 3.0. This is
    /// essentially v16i8 vector version of VINSERTH.
    SDValue lowerToVINSERTB(ShuffleVectorSDNode *N, SelectionDAG &DAG) const;
 
    /// lowerToXXSPLTI32DX - Return the SDValue if this VECTOR_SHUFFLE can be
    /// handled by the XXSPLTI32DX instruction introduced in ISA 3.1.
    SDValue lowerToXXSPLTI32DX(ShuffleVectorSDNode *N, SelectionDAG &DAG) const;
 
    // Return whether the call instruction can potentially be optimized to a
    // tail call. This will cause the optimizers to attempt to move, or
    // duplicate return instructions to help enable tail call optimizations.
    bool mayBeEmittedAsTailCall(const CallInst *CI) const override;
    bool hasBitPreservingFPLogic(EVT VT) const override;
    bool isMaskAndCmp0FoldingBeneficial(const Instruction &AndI) const override;
 
    /// getAddrModeForFlags - Based on the set of address flags, select the most
    /// optimal instruction format to match by.
    PPC::AddrMode getAddrModeForFlags(unsigned Flags) const;
 
    /// computeMOFlags - Given a node N and it's Parent (a MemSDNode), compute
    /// the address flags of the load/store instruction that is to be matched.
    /// The address flags are stored in a map, which is then searched
    /// through to determine the optimal load/store instruction format.
    unsigned computeMOFlags(const SDNode *Parent, SDValue N,
                            SelectionDAG &DAG) const;
  }; // end class PPCTargetLowering
 
  namespace PPC {
 
    FastISel *createFastISel(FunctionLoweringInfo &FuncInfo,
                             const TargetLibraryInfo *LibInfo);
 
  } // end namespace PPC
 
  bool isIntS16Immediate(SDNode *N, int16_t &Imm);
  bool isIntS16Immediate(SDValue Op, int16_t &Imm);
  bool isIntS34Immediate(SDNode *N, int64_t &Imm);
  bool isIntS34Immediate(SDValue Op, int64_t &Imm);
 
  bool convertToNonDenormSingle(APInt &ArgAPInt);
  bool convertToNonDenormSingle(APFloat &ArgAPFloat);
  bool checkConvertToNonDenormSingle(APFloat &ArgAPFloat);
 
} // end namespace llvm
 
#endif // LLVM_LIB_TARGET_POWERPC_PPCISELLOWERING_H