Ping [PATCH] Change the behavior of predicate check failure on cbranchcc4 operand0 in prepare_cmp_insn

[HAO CHEN GUI <guihaoc@linux.ibm.com>]

Hi,
   Gentle ping this:
https://gcc.gnu.org/pipermail/gcc-patches/2022-November/607083.html
Thanks
Gui Haochen

在 2022/11/23 10:54, HAO CHEN GUI 写道:
> Hi,
>   I want to enable "have_cbranchcc4" on rs6000. But not all combinations of
> comparison codes and sub CC modes are benefited to generate cbranchcc4 insns
> on rs6000. There is an predicate for operand0 of cbranchcc4 to bypass
> some combinations. It gets assertion failure in prepare_cmp_insn. I think
> we shouldn't suppose that all comparison codes and sub CC modes are supported
> and throw an assertion failure in prepare_cmp_insn. It might check the
> predicate and go to fail if the predicate can't be satisfied. This patch
> changes the behavior of those codes.
> 
>   Bootstrapped and tested on powerpc64-linux BE/LE and x86 with no regressions.
> Is this okay for trunk? Any recommendations? Thanks a lot.
> 
> 
> ChangeLog
> 2022-11-23  Haochen Gui <guihaoc@linux.ibm.com>
> 
> gcc/
> 	* optabs.cc (prepare_cmp_insn): Go to fail other than assert it when
> 	predicate check of "cbranchcc4" operand[0] fails.
> 
> patch.diff
> diff --git a/gcc/optabs.cc b/gcc/optabs.cc
> index 165f8d1fa22..3ec8f6b17ba 100644
> --- a/gcc/optabs.cc
> +++ b/gcc/optabs.cc
> @@ -4484,8 +4484,9 @@ prepare_cmp_insn (rtx x, rtx y, enum rtx_code comparison, rtx size,
>      {
>        enum insn_code icode = optab_handler (cbranch_optab, CCmode);
>        test = gen_rtx_fmt_ee (comparison, VOIDmode, x, y);
> -      gcc_assert (icode != CODE_FOR_nothing
> -                  && insn_operand_matches (icode, 0, test));
> +      gcc_assert (icode != CODE_FOR_nothing);
> +      if (!insn_operand_matches (icode, 0, test))
> +	goto fail;
>        *ptest = test;
>        return;
>      }