[PATCH 2/2] Get rid of all float-int special cases in validate_subreg.

Richard Biener richard.guenther@gmail.com
Tue Aug 31 11:57:34 GMT 2021


On Tue, Aug 31, 2021 at 1:17 PM liuhongt <hongtao.liu@intel.com> wrote:
>
> gcc/ChangeLog:

OK.

Thanks,
Richard.

>         * emit-rtl.c (validate_subreg): Get rid of all float-int
>         special cases.
> ---
>  gcc/emit-rtl.c | 40 ----------------------------------------
>  1 file changed, 40 deletions(-)
>
> diff --git a/gcc/emit-rtl.c b/gcc/emit-rtl.c
> index ff3b4449b37..77ea8948ee8 100644
> --- a/gcc/emit-rtl.c
> +++ b/gcc/emit-rtl.c
> @@ -922,46 +922,6 @@ validate_subreg (machine_mode omode, machine_mode imode,
>
>    poly_uint64 regsize = REGMODE_NATURAL_SIZE (imode);
>
> -  /* ??? This should not be here.  Temporarily continue to allow word_mode
> -     subregs of anything.  The most common offender is (subreg:SI (reg:DF)).
> -     Generally, backends are doing something sketchy but it'll take time to
> -     fix them all.  */
> -  if (omode == word_mode)
> -    ;
> -  /* ??? Similarly, e.g. with (subreg:DF (reg:TI)).  Though store_bit_field
> -     is the culprit here, and not the backends.  */
> -  else if (known_ge (osize, regsize) && known_ge (isize, osize))
> -    ;
> -  /* Allow component subregs of complex and vector.  Though given the below
> -     extraction rules, it's not always clear what that means.  */
> -  else if ((COMPLEX_MODE_P (imode) || VECTOR_MODE_P (imode))
> -          && GET_MODE_INNER (imode) == omode)
> -    ;
> -  /* ??? x86 sse code makes heavy use of *paradoxical* vector subregs,
> -     i.e. (subreg:V4SF (reg:SF) 0) or (subreg:V4SF (reg:V2SF) 0).  This
> -     surely isn't the cleanest way to represent this.  It's questionable
> -     if this ought to be represented at all -- why can't this all be hidden
> -     in post-reload splitters that make arbitrarily mode changes to the
> -     registers themselves.  */
> -  else if (VECTOR_MODE_P (omode)
> -          && GET_MODE_INNER (omode) == GET_MODE_INNER (imode))
> -    ;
> -  /* Subregs involving floating point modes are not allowed to
> -     change size.  Therefore (subreg:DI (reg:DF) 0) is fine, but
> -     (subreg:SI (reg:DF) 0) isn't.  */
> -  else if (FLOAT_MODE_P (imode) || FLOAT_MODE_P (omode))
> -    {
> -      if (! (known_eq (isize, osize)
> -            /* LRA can use subreg to store a floating point value in
> -               an integer mode.  Although the floating point and the
> -               integer modes need the same number of hard registers,
> -               the size of floating point mode can be less than the
> -               integer mode.  LRA also uses subregs for a register
> -               should be used in different mode in on insn.  */
> -            || lra_in_progress))
> -       return false;
> -    }
> -
>    /* Paradoxical subregs must have offset zero.  */
>    if (maybe_gt (osize, isize))
>      return known_eq (offset, 0U);
> --
> 2.27.0
>


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