On Mon, Dec 5, 2022 at 4:08 AM HAO CHEN GUI <guih...@linux.ibm.com> wrote:
>
> Hi,
> It gets an assertion failure when targers don't support cbranchcc4 or
> predicate check fails in prepare_cmp_insn. prepare_cmp_insn is a help
> function to generate compare rtx, so it should not assume that cbranchcc4
> is existing or all sub-CC modes are supported on one target. I think it
> should return the NULL rtx when cbranchcc4 is not supported or predicate check
> fails, as its callers already check if the return value is null or not for CC
> mode. This patch just does the change.
>
> Bootstrapped and tested on powerpc64-linux BE/LE and x86 with no
> regressions.
> Is this okay for trunk? Any recommendations? Thanks a lot.
I wonder if you have a testcase you can add showing this change is
worthwhile and
fixes a bug?
OK.
Thanks,
Richard.
>
> ChangeLog
> 2022-12-05 Haochen Gui <guih...@linux.ibm.com>
>
> gcc/
> * optabs.cc (prepare_cmp_insn): Return a NULL rtx other than assertion
> failure when targets don't have cbranch optab or predicate check
> fails.
>
> patch.diff
> diff --git a/gcc/optabs.cc b/gcc/optabs.cc
> index 165f8d1fa22..f6d3242479b 100644
> --- a/gcc/optabs.cc
> +++ b/gcc/optabs.cc
> @@ -4484,10 +4484,14 @@ 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));
> - *ptest = test;
> - return;
> + if (icode != CODE_FOR_nothing
> + && insn_operand_matches (icode, 0, test))
> + {
> + *ptest = test;
> + return;
> + }
> + else
> + goto fail;
> }
>
> mclass = GET_MODE_CLASS (mode);
