llvm-project/llvm/lib/Target/RISCV/RISCVInstrInfoM.td
Craig Topper 3e7dad22f1 [RISCV] Add a bit to TSFlags to mark SignExtendingOpW instructions for SExtWRemoval.
Instead of switching on the opcode in SExtWRemoval, we can use a
bit in TSFlags. This reduces the amount of code that needs to be
generated to implement the switch. The opcodes are scattered throughout
the opcode enum, so the switch isn't very densely packed.

Reviewed By: asb

Differential Revision: https://reviews.llvm.org/D139965
2022-12-14 10:38:48 -08:00

117 lines
5.2 KiB
TableGen

//===-- RISCVInstrInfoM.td - RISC-V 'M' instructions -------*- tablegen -*-===//
//
// 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 describes the RISC-V instructions from the standard 'M', Integer
// Multiplication and Division instruction set extension.
//
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
// RISC-V specific DAG Nodes.
//===----------------------------------------------------------------------===//
def riscv_mulhsu : SDNode<"RISCVISD::MULHSU", SDTIntBinOp>;
def riscv_divw : SDNode<"RISCVISD::DIVW", SDT_RISCVIntBinOpW>;
def riscv_divuw : SDNode<"RISCVISD::DIVUW", SDT_RISCVIntBinOpW>;
def riscv_remuw : SDNode<"RISCVISD::REMUW", SDT_RISCVIntBinOpW>;
//===----------------------------------------------------------------------===//
// Instructions
//===----------------------------------------------------------------------===//
let Predicates = [HasStdExtMOrZmmul] in {
def MUL : ALU_rr<0b0000001, 0b000, "mul", /*Commutable*/1>,
Sched<[WriteIMul, ReadIMul, ReadIMul]>;
def MULH : ALU_rr<0b0000001, 0b001, "mulh", /*Commutable*/1>,
Sched<[WriteIMul, ReadIMul, ReadIMul]>;
def MULHSU : ALU_rr<0b0000001, 0b010, "mulhsu">,
Sched<[WriteIMul, ReadIMul, ReadIMul]>;
def MULHU : ALU_rr<0b0000001, 0b011, "mulhu", /*Commutable*/1>,
Sched<[WriteIMul, ReadIMul, ReadIMul]>;
} // Predicates = [HasStdExtMOrZmmul]
let Predicates = [HasStdExtM] in {
def DIV : ALU_rr<0b0000001, 0b100, "div">,
Sched<[WriteIDiv, ReadIDiv, ReadIDiv]>;
def DIVU : ALU_rr<0b0000001, 0b101, "divu">,
Sched<[WriteIDiv, ReadIDiv, ReadIDiv]>;
def REM : ALU_rr<0b0000001, 0b110, "rem">,
Sched<[WriteIDiv, ReadIDiv, ReadIDiv]>;
def REMU : ALU_rr<0b0000001, 0b111, "remu">,
Sched<[WriteIDiv, ReadIDiv, ReadIDiv]>;
} // Predicates = [HasStdExtM]
let Predicates = [HasStdExtMOrZmmul, IsRV64], IsSignExtendingOpW = 1 in {
def MULW : ALUW_rr<0b0000001, 0b000, "mulw", /*Commutable*/1>,
Sched<[WriteIMul32, ReadIMul32, ReadIMul32]>;
} // Predicates = [HasStdExtMOrZmmul, IsRV64]
let Predicates = [HasStdExtM, IsRV64], IsSignExtendingOpW = 1 in {
def DIVW : ALUW_rr<0b0000001, 0b100, "divw">,
Sched<[WriteIDiv32, ReadIDiv32, ReadIDiv32]>;
def DIVUW : ALUW_rr<0b0000001, 0b101, "divuw">,
Sched<[WriteIDiv32, ReadIDiv32, ReadIDiv32]>;
def REMW : ALUW_rr<0b0000001, 0b110, "remw">,
Sched<[WriteIDiv32, ReadIDiv32, ReadIDiv32]>;
def REMUW : ALUW_rr<0b0000001, 0b111, "remuw">,
Sched<[WriteIDiv32, ReadIDiv32, ReadIDiv32]>;
} // Predicates = [HasStdExtM, IsRV64]
//===----------------------------------------------------------------------===//
// Pseudo-instructions and codegen patterns
//===----------------------------------------------------------------------===//
let Predicates = [HasStdExtMOrZmmul] in {
def : PatGprGpr<mul, MUL>;
def : PatGprGpr<mulhs, MULH>;
def : PatGprGpr<mulhu, MULHU>;
def : PatGprGpr<riscv_mulhsu, MULHSU>;
} // Predicates = [HasStdExtMOrZmmul]
let Predicates = [HasStdExtM] in {
def : PatGprGpr<sdiv, DIV>;
def : PatGprGpr<udiv, DIVU>;
def : PatGprGpr<srem, REM>;
def : PatGprGpr<urem, REMU>;
} // Predicates = [HasStdExtM]
// Select W instructions if only the lower 32-bits of the result are used.
let Predicates = [HasStdExtMOrZmmul, IsRV64] in
def : PatGprGpr<binop_allwusers<mul>, MULW>;
let Predicates = [HasStdExtM, IsRV64] in {
def : PatGprGpr<riscv_divw, DIVW>;
def : PatGprGpr<riscv_divuw, DIVUW>;
def : PatGprGpr<riscv_remuw, REMUW>;
// Handle the specific cases where using DIVU/REMU would be correct and result
// in fewer instructions than emitting DIVUW/REMUW then zero-extending the
// result.
def : Pat<(and (riscv_divuw (assertzexti32 GPR:$rs1),
(assertzexti32 GPR:$rs2)), 0xffffffff),
(DIVU GPR:$rs1, GPR:$rs2)>;
def : Pat<(and (riscv_remuw (assertzexti32 GPR:$rs1),
(assertzexti32 GPR:$rs2)), 0xffffffff),
(REMU GPR:$rs1, GPR:$rs2)>;
// Although the sexti32 operands may not have originated from an i32 srem,
// this pattern is safe as it is impossible for two sign extended inputs to
// produce a result where res[63:32]=0 and res[31]=1.
def : Pat<(srem (sexti32 (i64 GPR:$rs1)), (sexti32 (i64 GPR:$rs2))),
(REMW GPR:$rs1, GPR:$rs2)>;
} // Predicates = [HasStdExtM, IsRV64]
let Predicates = [HasStdExtMOrZmmul, IsRV64, NotHasStdExtZba] in {
// Special case for calculating the full 64-bit product of a 32x32 unsigned
// multiply where the inputs aren't known to be zero extended. We can shift the
// inputs left by 32 and use a MULHU. This saves two SRLIs needed to finish
// zeroing the upper 32 bits.
def : Pat<(i64 (mul (and GPR:$rs1, 0xffffffff), (and GPR:$rs2, 0xffffffff))),
(MULHU (SLLI GPR:$rs1, 32), (SLLI GPR:$rs2, 32))>;
} // Predicates = [HasStdExtMOrZmmul, IsRV64, NotHasStdExtZba]