Re: [PATCH IRA] update_equiv_regs fails to set EQUIV reg-note for pseudo with more than one definition

[Jeff Law <law@redhat.com>]

On 09/23/14 04:51, Felix Yang wrote:
> Hi,
>
>      Ignore the previous message.
>      Attached please find the updated patch.
>      Bootstrapped on x86_64-suse-linux. Please apply this patch if OK for trunk.
>
> Index: gcc/ChangeLog
> ===================================================================
> --- gcc/ChangeLog    (revision 215500)
> +++ gcc/ChangeLog    (working copy)
> @@ -1,3 +1,8 @@
> +2014-09-23  Felix Yang  <felix.yang@huawei.com>
> +
> +    * ira.c (update_equiv_regs): Check all definitions for a multiple-set
> +    register to make sure that the RHS have the same value.
> +
>   2014-09-23  Ilya Enkovich  <ilya.enkovich@intel.com>
>
>       * cfgcleanup.c (try_optimize_cfg): Do not remove label
> Index: gcc/ira.c
> ===================================================================
> --- gcc/ira.c    (revision 215500)
> +++ gcc/ira.c    (working copy)
> @@ -3467,16 +3467,43 @@ update_equiv_regs (void)
>         if (note && GET_CODE (XEXP (note, 0)) == EXPR_LIST)
>           note = NULL_RTX;
>
> -      if (DF_REG_DEF_COUNT (regno) != 1
> -          && (! note
> +      if (DF_REG_DEF_COUNT (regno) != 1)
> +        {
> +          rtx list;
This should probably be "rtx_insn_list list".

> +          list = reg_equiv[regno].init_insns;
> +          for (; list; list = XEXP (list, 1))
Please use the next/insn member functions of the rtx_insn_list rather 
than the old style XEXP accessor macros.


> +        {
> +          rtx note_tmp, insn_tmp;
> +          insn_tmp = XEXP (list, 0);
> +          note_tmp = find_reg_note (insn_tmp, REG_EQUAL, NULL_RTX);
> +
> +          if (note_tmp == 0
> +              || ! rtx_equal_p (XEXP (note, 0), XEXP (note_tmp, 0)))
Under what conditions did you find an insn on this list that did not 
have a note?  There's a deeper question I'm getting to, but let's start 
here.

Rather than use "== 0", if you have an RTX use "== NULL_RTX".  That 
applies to the note_tmp == 0 test above.


Can you make the edits noted above & answer the question WRT insns on 
the reg_equiv[].init_insns list without notes and repost?

Thanks,
Jeff