Re: [PATCH] RISC-V: Allow unaligned accesses in cpymemsi expansion

[Kito Cheng <kito.cheng@gmail.com>]

Hi Christoph:

Generally LGTM, only 1 minor comment.

> @@ -3292,8 +3294,17 @@ riscv_expand_block_move (rtx dest, rtx src, rtx length)
>        unsigned HOST_WIDE_INT hwi_length = UINTVAL (length);
>        unsigned HOST_WIDE_INT factor, align;
>
> -      align = MIN (MIN (MEM_ALIGN (src), MEM_ALIGN (dest)), BITS_PER_WORD);
> -      factor = BITS_PER_WORD / align;
> +      if (riscv_slow_unaligned_access_p)
> +       {
> +         align = MIN (MIN (MEM_ALIGN (src), MEM_ALIGN (dest)), BITS_PER_WORD);
> +         factor = BITS_PER_WORD / align;
> +       }
> +      else
> +       {
> +         /* Assume data to be aligned.  */
> +         align = hwi_length * BITS_PER_UNIT;

Either the variable should be renamed or just set to BITS_PER_WORD?
e.g hwi_length = 15, then align =15 * 8 = 120

Although that still generated the result since mode_for_size still
returns DI for rv64 and SI for rv32.

> +         factor = 1;

I would prefer keep factor = BITS_PER_WORD / align; and then pull it
outside like that:

```c
     if (riscv_slow_unaligned_access_p)
       align = MIN (MIN (MEM_ALIGN (src), MEM_ALIGN (dest)), BITS_PER_WORD);
     else
       align =  BITS_PER_WORD;

    factor = BITS_PER_WORD / align;
```