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499a26b0c7
There's no target independent ISD opcode for MULHSU, so custom legalize 2*XLen multiplies ourselves. We have to be a little careful to prefer MULHU or MULHSU. I thought about doing this in isel by pattern matching the (add (mul X, (srai Y, XLen-1)), (mulhu X, Y)) pattern. I decided against this because the add might become part of a chain of adds. I don't trust DAG combine not to reassociate with other adds making it difficult to find both pieces again. Reviewed By: asb Differential Revision: https://reviews.llvm.org/D99479
116 lines
5.3 KiB
TableGen
116 lines
5.3 KiB
TableGen
//===-- RISCVInstrInfoM.td - RISC-V 'M' instructions -------*- tablegen -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file describes the RISC-V instructions from the standard 'M', Integer
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// Multiplication and Division instruction set extension.
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//
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//===----------------------------------------------------------------------===//
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//===----------------------------------------------------------------------===//
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// RISC-V specific DAG Nodes.
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//===----------------------------------------------------------------------===//
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def riscv_mulhsu : SDNode<"RISCVISD::MULHSU", SDTIntBinOp>;
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def riscv_divw : SDNode<"RISCVISD::DIVW", SDT_RISCVIntBinOpW>;
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def riscv_divuw : SDNode<"RISCVISD::DIVUW", SDT_RISCVIntBinOpW>;
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def riscv_remuw : SDNode<"RISCVISD::REMUW", SDT_RISCVIntBinOpW>;
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//===----------------------------------------------------------------------===//
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// Instructions
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//===----------------------------------------------------------------------===//
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let Predicates = [HasStdExtM] in {
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def MUL : ALU_rr<0b0000001, 0b000, "mul">,
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Sched<[WriteIMul, ReadIMul, ReadIMul]>;
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def MULH : ALU_rr<0b0000001, 0b001, "mulh">,
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Sched<[WriteIMul, ReadIMul, ReadIMul]>;
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def MULHSU : ALU_rr<0b0000001, 0b010, "mulhsu">,
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Sched<[WriteIMul, ReadIMul, ReadIMul]>;
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def MULHU : ALU_rr<0b0000001, 0b011, "mulhu">,
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Sched<[WriteIMul, ReadIMul, ReadIMul]>;
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def DIV : ALU_rr<0b0000001, 0b100, "div">,
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Sched<[WriteIDiv, ReadIDiv, ReadIDiv]>;
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def DIVU : ALU_rr<0b0000001, 0b101, "divu">,
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Sched<[WriteIDiv, ReadIDiv, ReadIDiv]>;
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def REM : ALU_rr<0b0000001, 0b110, "rem">,
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Sched<[WriteIDiv, ReadIDiv, ReadIDiv]>;
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def REMU : ALU_rr<0b0000001, 0b111, "remu">,
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Sched<[WriteIDiv, ReadIDiv, ReadIDiv]>;
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} // Predicates = [HasStdExtM]
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let Predicates = [HasStdExtM, IsRV64] in {
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def MULW : ALUW_rr<0b0000001, 0b000, "mulw">,
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Sched<[WriteIMul32, ReadIMul32, ReadIMul32]>;
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def DIVW : ALUW_rr<0b0000001, 0b100, "divw">,
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Sched<[WriteIDiv32, ReadIDiv32, ReadIDiv32]>;
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def DIVUW : ALUW_rr<0b0000001, 0b101, "divuw">,
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Sched<[WriteIDiv32, ReadIDiv32, ReadIDiv32]>;
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def REMW : ALUW_rr<0b0000001, 0b110, "remw">,
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Sched<[WriteIDiv32, ReadIDiv32, ReadIDiv32]>;
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def REMUW : ALUW_rr<0b0000001, 0b111, "remuw">,
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Sched<[WriteIDiv32, ReadIDiv32, ReadIDiv32]>;
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} // Predicates = [HasStdExtM, IsRV64]
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//===----------------------------------------------------------------------===//
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// Pseudo-instructions and codegen patterns
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//===----------------------------------------------------------------------===//
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let Predicates = [HasStdExtM] in {
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def : PatGprGpr<mul, MUL>;
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def : PatGprGpr<mulhs, MULH>;
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def : PatGprGpr<mulhu, MULHU>;
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def : PatGprGpr<riscv_mulhsu, MULHSU>;
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def : PatGprGpr<sdiv, DIV>;
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def : PatGprGpr<udiv, DIVU>;
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def : PatGprGpr<srem, REM>;
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def : PatGprGpr<urem, REMU>;
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} // Predicates = [HasStdExtM]
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let Predicates = [HasStdExtM, IsRV64] in {
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def : Pat<(sext_inreg (mul GPR:$rs1, GPR:$rs2), i32),
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(MULW GPR:$rs1, GPR:$rs2)>;
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def : PatGprGpr<riscv_divw, DIVW>;
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def : PatGprGpr<riscv_divuw, DIVUW>;
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def : PatGprGpr<riscv_remuw, REMUW>;
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// Handle the specific cases where using DIVU/REMU would be correct and result
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// in fewer instructions than emitting DIVUW/REMUW then zero-extending the
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// result.
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def : Pat<(and (riscv_divuw (assertzexti32 GPR:$rs1),
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(assertzexti32 GPR:$rs2)), 0xffffffff),
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(DIVU GPR:$rs1, GPR:$rs2)>;
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def : Pat<(and (riscv_remuw (assertzexti32 GPR:$rs1),
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(assertzexti32 GPR:$rs2)), 0xffffffff),
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(REMU GPR:$rs1, GPR:$rs2)>;
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// Although the sexti32 operands may not have originated from an i32 srem,
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// this pattern is safe as it is impossible for two sign extended inputs to
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// produce a result where res[63:32]=0 and res[31]=1.
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def : Pat<(srem (sexti32 (i64 GPR:$rs1)), (sexti32 (i64 GPR:$rs2))),
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(REMW GPR:$rs1, GPR:$rs2)>;
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} // Predicates = [HasStdExtM, IsRV64]
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let Predicates = [HasStdExtM, IsRV64, NotHasStdExtZba] in {
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// Special case for calculating the full 64-bit product of a 32x32 unsigned
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// multiply where the inputs aren't known to be zero extended. We can shift the
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// inputs left by 32 and use a MULHU. This saves two SRLIs needed to finish
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// zeroing the upper 32 bits.
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// TODO: If one of the operands is zero extended and the other isn't, we might
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// still be better off shifting both left by 32.
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def : Pat<(i64 (mul (and GPR:$rs1, 0xffffffff), (and GPR:$rs2, 0xffffffff))),
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(MULHU (SLLI GPR:$rs1, 32), (SLLI GPR:$rs2, 32))>;
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// Prevent matching the first part of this pattern to mulw. The mul here has
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// additionals users or the ANDs would have been removed. The above pattern
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// will be used for the other users. If we form a mulw we'll keep the ANDs alive
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// and they'll still become SLLI+SRLI.
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def : Pat<(sext_inreg (mul (and GPR:$rs1, 0xffffffff),
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(and GPR:$rs2, 0xffffffff)), i32),
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(ADDIW (MULHU (SLLI GPR:$rs1, 32), (SLLI GPR:$rs2, 32)), 0)>;
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} // Predicates = [HasStdExtM, IsRV64, NotHasStdExtZba]
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