77523f9d5f
`HighMask` is the value that sets bits from `Msb+1` to 63 to 1, while the other bits are set to 0.
126 lines
4.4 KiB
C++
126 lines
4.4 KiB
C++
//===- LoongArchMatInt.cpp - Immediate materialisation ---------*- C++ -*--===//
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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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#include "LoongArchMatInt.h"
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#include "MCTargetDesc/LoongArchMCTargetDesc.h"
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#include "llvm/Support/MathExtras.h"
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using namespace llvm;
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LoongArchMatInt::InstSeq LoongArchMatInt::generateInstSeq(int64_t Val) {
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// Val:
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// | hi32 | lo32 |
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// +-----------+------------------+------------------+-----------+
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// | Highest12 | Higher20 | Hi20 | Lo12 |
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// +-----------+------------------+------------------+-----------+
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// 63 52 51 32 31 12 11 0
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//
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const int64_t Highest12 = Val >> 52 & 0xFFF;
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const int64_t Higher20 = Val >> 32 & 0xFFFFF;
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const int64_t Hi20 = Val >> 12 & 0xFFFFF;
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const int64_t Lo12 = Val & 0xFFF;
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InstSeq Insts;
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// LU52I_D used for: Bits[63:52] | Bits[51:0].
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if (Highest12 != 0 && SignExtend64<52>(Val) == 0) {
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Insts.push_back(Inst(LoongArch::LU52I_D, SignExtend64<12>(Highest12)));
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return Insts;
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}
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// lo32
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if (Hi20 == 0)
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Insts.push_back(Inst(LoongArch::ORI, Lo12));
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else if (SignExtend32<1>(Lo12 >> 11) == SignExtend32<20>(Hi20))
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Insts.push_back(Inst(LoongArch::ADDI_W, SignExtend64<12>(Lo12)));
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else {
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Insts.push_back(Inst(LoongArch::LU12I_W, SignExtend64<20>(Hi20)));
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if (Lo12 != 0)
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Insts.push_back(Inst(LoongArch::ORI, Lo12));
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}
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// hi32
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// Higher20
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if (SignExtend32<1>(Hi20 >> 19) != SignExtend32<20>(Higher20))
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Insts.push_back(Inst(LoongArch::LU32I_D, SignExtend64<20>(Higher20)));
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// Highest12
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if (SignExtend32<1>(Higher20 >> 19) != SignExtend32<12>(Highest12))
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Insts.push_back(Inst(LoongArch::LU52I_D, SignExtend64<12>(Highest12)));
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size_t N = Insts.size();
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if (N < 3)
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return Insts;
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// When the number of instruction sequences is greater than 2, we have the
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// opportunity to optimize using the BSTRINS_D instruction. The scenario is as
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// follows:
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//
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// N of Insts = 3
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// 1. ORI + LU32I_D + LU52I_D => ORI + BSTRINS_D, TmpVal = ORI
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// 2. ADDI_W + LU32I_D + LU52I_D => ADDI_W + BSTRINS_D, TmpVal = ADDI_W
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// 3. LU12I_W + ORI + LU32I_D => ORI + BSTRINS_D, TmpVal = ORI
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// 4. LU12I_W + LU32I_D + LU52I_D => LU12I_W + BSTRINS_D, TmpVal = LU12I_W
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//
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// N of Insts = 4
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// 5. LU12I_W + ORI + LU32I_D + LU52I_D => LU12I_W + ORI + BSTRINS_D
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// => ORI + LU52I_D + BSTRINS_D
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// TmpVal = (LU12I_W | ORI) or (ORI | LU52I_D)
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// The BSTRINS_D instruction will use the `TmpVal` to construct the `Val`.
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uint64_t TmpVal1 = 0;
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uint64_t TmpVal2 = 0;
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switch (Insts[0].Opc) {
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default:
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llvm_unreachable("unexpected opcode");
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break;
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case LoongArch::LU12I_W:
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if (Insts[1].Opc == LoongArch::ORI) {
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TmpVal1 = Insts[1].Imm;
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if (N == 3)
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break;
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TmpVal2 = static_cast<uint64_t>(Insts[3].Imm) << 52 | TmpVal1;
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}
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TmpVal1 |= static_cast<uint64_t>(Insts[0].Imm) << 12;
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break;
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case LoongArch::ORI:
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case LoongArch::ADDI_W:
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TmpVal1 = Insts[0].Imm;
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break;
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}
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uint64_t Msb = 32;
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uint64_t HighMask = ~((1ULL << (Msb + 1)) - 1);
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for (; Msb < 64; ++Msb, HighMask = HighMask << 1) {
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for (uint64_t Lsb = Msb; Lsb > 0; --Lsb) {
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uint64_t LowMask = (1ULL << Lsb) - 1;
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uint64_t Mask = HighMask | LowMask;
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uint64_t LsbToZero = TmpVal1 & ((1ULL << (Msb - Lsb + 1)) - 1);
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uint64_t MsbToLsb = LsbToZero << Lsb;
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if ((MsbToLsb | (TmpVal1 & Mask)) == (uint64_t)Val) {
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if (Insts[1].Opc == LoongArch::ORI && N == 3)
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Insts[0] = Insts[1];
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Insts.pop_back_n(2);
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Insts.push_back(Inst(LoongArch::BSTRINS_D, Msb << 32 | Lsb));
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return Insts;
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}
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if (TmpVal2 != 0) {
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LsbToZero = TmpVal2 & ((1ULL << (Msb - Lsb + 1)) - 1);
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MsbToLsb = LsbToZero << Lsb;
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if ((MsbToLsb | (TmpVal2 & Mask)) == (uint64_t)Val) {
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Insts[0] = Insts[1];
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Insts[1] = Insts[3];
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Insts.pop_back_n(2);
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Insts.push_back(Inst(LoongArch::BSTRINS_D, Msb << 32 | Lsb));
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return Insts;
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}
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}
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}
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}
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return Insts;
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}
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