[all-commits] [llvm/llvm-project] c7593b: [ARM] Fix rewrite of frame index in Thumb2's addre...

[Victor Campos via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: c7593b0f0d28f6b7f9fa4557ce73197a49b37799
      https://github.com/llvm/llvm-project/commit/c7593b0f0d28f6b7f9fa4557ce73197a49b37799
  Author: Victor Campos <victor.campos at arm.com>
  Date:   2020-05-27 (Wed, 27 May 2020)

  Changed paths:
    M llvm/lib/Target/ARM/Thumb2InstrInfo.cpp
    A llvm/test/CodeGen/Thumb2/frame-index-addrmode-t2i8s4.mir

  Log Message:
  -----------
  [ARM] Fix rewrite of frame index in Thumb2's address mode i8s4

Summary:
In Thumb2's frame index rewriting process, the address mode i8s4, which
is used by LDRD and STRD instructions, is handled by taking the
immediate offset operand and multiplying it by 4.

This behaviour is wrong, however. In this specific address mode, the
MachineInstr's immediate operand is already in the expected form. By
consequence of that, multiplying it once more by 4 yields a flawed
offset value, four times greater than it should be.

Differential Revision: https://reviews.llvm.org/D80557