RE: [PATCH v4 51/51] tcg/optimize: Propagate sign info for shifting

[Luis Fernando Fujita Pires]

From: Richard Henderson <richard.henderson@linaro.org>
> 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.
> 
> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  tcg/optimize.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++--
> -
>  1 file changed, 47 insertions(+), 3 deletions(-)

Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>

--
Luis Pires
Instituto de Pesquisas ELDORADO
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