[clang] [llvm] [RISCV] Add scheduling model for mips p8700 CPU (PR #119885)

[Djordje Todorovic via cfe-commits]

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+//===-- RISCVSchedMIPSP8700.td - MIPS RISC-V Processor -----*- 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
+//
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+// P8700 - a RISC-V processor by MIPS.
+// Pipelines:
+//   - 2 Integer Arithmetic and Logical Units (ALU and AL2)
+//   - Multiply / Divide Unit (MDU)
+//   - Branch Unit (CTI)
+//   - Load Store Unit (LSU)
+//   - Short Floating Point Pipe (FPUS)
+//   - Long Floating Point Pipe (FPUL)
+//===----------------------------------------------------------------------===//
+
+def MIPSP8700Model : SchedMachineModel {
+  int IssueWidth = 4;
+  int MicroOpBufferSize = 96;
+  int LoadLatency = 4;
+  int MispredictPenalty = 8;
+  let CompleteModel = 0;
+}
+
+let SchedModel = MIPSP8700Model in {
+// Handle ALQ Pipelines.
+// It contains 1 ALU Unit only.
+def p8700ALQ : ProcResource<1> { let BufferSize = 16; }
+
+// Handle AGQ Pipelines.
+def p8700AGQ : ProcResource<3> { let BufferSize = 16; }
+def p8700IssueAL2 : ProcResource<1> { let Super = p8700AGQ; }
+def p8700IssueCTI : ProcResource<1> { let Super = p8700AGQ; }
+def p8700IssueLSU : ProcResource<1> { let Super = p8700AGQ; }
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djtodoro wrote:

The datasheet figure might indeed be a bit misleading. While there's a separate load queue and store queue, it's essentially a single LSU composed of these integrated blocks, not distinct pipelines. We'll consider clarifying this in a future revision of the datasheet.

https://github.com/llvm/llvm-project/pull/119885