[all-commits] [llvm/llvm-project] d8ec2b: [RISCV] Fix the calculation of the offset of Zvlss...

[Kai Wang via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: d8ec2b183e9243366e3a0cd1116dbe879856b333
      https://github.com/llvm/llvm-project/commit/d8ec2b183e9243366e3a0cd1116dbe879856b333
  Author: Hsiangkai Wang <kai.wang at sifive.com>
  Date:   2021-05-11 (Tue, 11 May 2021)

  Changed paths:
    M llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp
    A llvm/test/CodeGen/RISCV/rvv/zvlsseg-spill.mir

  Log Message:
  -----------
  [RISCV] Fix the calculation of the offset of Zvlsseg spilling.

For Zvlsseg spilling, we need to convert the pseudo instructions
into multiple vector load/store instructions with appropriate offsets.
For example, for PseudoVSPILL3_M2, we need to convert it to

VS2R %v2, %base
ADDI %base, %base, (vlenb x 2)
VS2R %v4, %base
ADDI %base, %base, (vlenb x 2)
VS2R %v6, %base

We need to keep the size of the offset in the pseudo spilling instructions.
In this case, it is (vlenb x 2).

In the original implementation, we use the size of frame objects divide the
number of vectors in zvlsseg types. The size of frame objects is not
necessary exactly the same as the spilling data. It may be larger than
it. So, we change it to (VLENB x LMUL) in this patch. The calculation is
more direct and easy to understand.

Differential Revision: https://reviews.llvm.org/D101869