On Fri, Oct 8, 2021 at 1:31 PM Stefan Schulze Frielinghaus via
Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
>
> gcc/ChangeLog:
>
> * regcprop.c (maybe_mode_change): Determine offset relative to
> high or low part depending on endianness.
>
> Bootstrapped and regtested on IBM Z. Ok for mainline and gcc-{11,10,9}?
Is there a testcase to add?
> ---
> gcc/regcprop.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/gcc/regcprop.c b/gcc/regcprop.c
> index d2a01130fe1..0e1ac12458a 100644
> --- a/gcc/regcprop.c
> +++ b/gcc/regcprop.c
> @@ -414,9 +414,14 @@ maybe_mode_change (machine_mode orig_mode, machine_mode
> copy_mode,
> copy_nregs, &bytes_per_reg))
> return NULL_RTX;
> poly_uint64 copy_offset = bytes_per_reg * (copy_nregs - use_nregs);
> - poly_uint64 offset
> - = subreg_size_lowpart_offset (GET_MODE_SIZE (new_mode) + copy_offset,
> - GET_MODE_SIZE (orig_mode));
> + poly_uint64 offset =
> +#if WORDS_BIG_ENDIAN
> + subreg_size_highpart_offset
> +#else
> + subreg_size_lowpart_offset
> +#endif
> + (GET_MODE_SIZE (new_mode) + copy_offset,
> + GET_MODE_SIZE (orig_mode));
> regno += subreg_regno_offset (regno, orig_mode, offset, new_mode);
> if (targetm.hard_regno_mode_ok (regno, new_mode))
> return gen_raw_REG (new_mode, regno);
> --
> 2.31.1
>
