On Fri, Sep 10, 2021 at 2:58 PM liuhongt <hongtao....@intel.com> wrote:
>
> gcc/ChangeLog:
>
> * expmed.c (extract_bit_field_using_extv): validate_subreg
> before call gen_lowpart.
> ---
> gcc/expmed.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/expmed.c b/gcc/expmed.c
> index 3143f38e057..10d62d857a8 100644
> --- a/gcc/expmed.c
> +++ b/gcc/expmed.c
> @@ -1571,12 +1571,16 @@ extract_bit_field_using_extv (const extraction_insn
> *extv, rtx op0,
>
> if (GET_MODE (target) != ext_mode)
> {
> + machine_mode tmode = GET_MODE (target);
> /* Don't use LHS paradoxical subreg if explicit truncation is needed
> between the mode of the extraction (word_mode) and the target
> mode. Instead, create a temporary and use convert_move to set
> the target. */
> if (REG_P (target)
> - && TRULY_NOOP_TRUNCATION_MODES_P (GET_MODE (target), ext_mode))
> + && TRULY_NOOP_TRUNCATION_MODES_P (tmode, ext_mode)
> + && validate_subreg (ext_mode, tmode,
> + target,
> + subreg_lowpart_offset (ext_mode, tmode)))
> {
> target = gen_lowpart (ext_mode, target);
That would be equivalent to use gen_lowpart_if_possible?
> if (partial_subreg_p (GET_MODE (spec_target), ext_mode))
> --
> 2.27.0
>
