[all-commits] [llvm/llvm-project] 6b17cf: [RISCV][P-ext] Support packed SSHLSAT with non-con...

[Craig Topper via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 6b17cf8d11ce2d8b37b5770a0b9f6082a3fc63e2
      https://github.com/llvm/llvm-project/commit/6b17cf8d11ce2d8b37b5770a0b9f6082a3fc63e2
  Author: Craig Topper <craig.topper at sifive.com>
  Date:   2026-05-26 (Tue, 26 May 2026)

  Changed paths:
    M llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    M llvm/lib/Target/RISCV/RISCVInstrInfoP.td
    M llvm/test/CodeGen/RISCV/rvp-simd-32.ll
    M llvm/test/CodeGen/RISCV/rvp-simd-64.ll

  Log Message:
  -----------
  [RISCV][P-ext] Support packed SSHLSAT with non-constant splat shift amount. (#198937)

We can use the pssha instructions. These instructions look at the lower
8-bits of the shift amount and treat positive values as a left shift and
a negative value as a right shift.

Since out of bound shift amounts for SSHLSAT are poison, we can directly
pass the shift amount to the instruction.



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