Re: [PATCH 5/8] decodetree: Allow group covering the entire insn space

[Peter Maydell]

On Mon, 18 May 2020 at 17:41, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> This is an edge case for sure, but the logic that disallowed
> this case was faulty.  Further, a few fixes scattered about
> can allow this to work.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  ...est1.decode => succ_pattern_group_nest2.decode} |  2 +-
>  scripts/decodetree.py                              | 14 +++++++++++---
>  2 files changed, 12 insertions(+), 4 deletions(-)
>  rename tests/decode/{err_pattern_group_nest1.decode => 
> succ_pattern_group_nest2.decode} (85%)

> @@ -978,6 +980,12 @@ def build_tree(pats, outerbits, outermask):
>          innermask &= i.fixedmask
>
>      if innermask == 0:
> +        # Edge condition: One pattern covers the entire insnmask
> +        if len(pats) == 1:
> +            t = Tree(outermask, innermask)
> +            t.subs.append((0, pats[0]))
> +            return t
> +
>          text = 'overlapping patterns:'
>          for p in pats:
>              text += '\n' + p.file + ':' + str(p.lineno) + ': ' + str(p)

I don't really understand this code, but does the similar
looking build_size_tree() also need a change to handle a
length-one pats ?

thanks
-- PMM