Re: [PATCH v3 48/48] tcg/optimize: Propagate sign info for shifting

[Alex Bennée]

Richard Henderson <richard.henderson@linaro.org> writes:

> For constant shifts, we can simply shift the s_mask.
>
> For variable shifts, we know that sar does not reduce
> the s_mask, which helps for sequences like
>
>     ext32s_i64  t, in
>     sar_i64     t, t, v
>     ext32s_i64  out, t
>
> allowing the final extend to be eliminated.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

-- 
Alex Bennée