[all-commits] [llvm/llvm-project] 55f0a1: [RISCV] Optimize multiplication with constant

[Ben Shi via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 55f0a1b06632688f08eb616fe02674cf2e666080
      https://github.com/llvm/llvm-project/commit/55f0a1b06632688f08eb616fe02674cf2e666080
  Author: Ben Shi <powerman1st at 163.com>
  Date:   2021-01-09 (Sat, 09 Jan 2021)

  Changed paths:
    M llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    M llvm/test/CodeGen/RISCV/mul.ll

  Log Message:
  -----------
  [RISCV] Optimize multiplication with constant

1. Break MUL with specific constant to a SLLI and an ADD/SUB on riscv32
   with the M extension.
2. Break MUL with specific constant to two SLLI and an ADD/SUB, if the
   constant needs a pair of LUI/ADDI to construct.

Reviewed by: craig.topper

Differential Revision: https://reviews.llvm.org/D93619