On 12/19/24 20:10, Richard Henderson wrote:
> Simply or'ing the an input s_mask with the mask implied by
> the sign extension operation may leave disconnected bits
> to the right. Use smask_from_smask to canonicalize.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
> tcg/optimize.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/tcg/optimize.c b/tcg/optimize.c
> index d0a9ea1ee4..8735dc0c9c 100644
> --- a/tcg/optimize.c
> +++ b/tcg/optimize.c
> @@ -1827,6 +1827,7 @@ static bool fold_exts(OptContext *ctx, TCGOp *op)
> g_assert_not_reached();
> }
> s_mask |= sign << 1;
> + s_mask = smask_from_smask(s_mask);
>
> if (!type_change && fold_affected_mask(ctx, op, s_mask & ~s_mask_old)) {
> return true;
> @@ -2534,8 +2535,13 @@ static bool fold_sextract(OptContext *ctx, TCGOp *op)
> }
>
> s_mask_old = t1->s_mask;
> + /*
> + * Use the sign mask from the input, force the repetitons from
> + * the sign extension operation, and canonicalize the result.
> + */
> s_mask = sextract64(s_mask_old, pos, len);
> s_mask |= MAKE_64BIT_MASK(len, 64 - len);
> + s_mask = smask_from_smask(s_mask);
>
> if (pos == 0 && fold_affected_mask(ctx, op, s_mask & ~s_mask_old)) {
> return true;
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>