https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120941
--- Comment #22 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Filip Kastl from comment #21)
> Oh, ok. I misunderstood.
>
> Well, you have SPEC CPU 2017, right? Then setting
>
No, I don't. Please extract a small testcase.
> OPTIMIZE = -Ofast -march=znver2 -mtune=znver2 -g -flto -fdump-rtl-all
>
> should work.
>
> Perhaps you'll also need
>
> COPTIMIZE = -fpermissive -std=gnu17
>
> Use GCC at commit r16-1644-gaba3b9d3a48a07 plus the rrvl dumping:
>
> diff --git a/gcc/config/i386/i386-features.cc
> b/gcc/config/i386/i386-features.cc
> index 36878aab968..29893e52439 100644
> --- a/gcc/config/i386/i386-features.cc
> +++ b/gcc/config/i386/i386-features.cc
> @@ -3424,11 +3426,22 @@ replace_vector_const (machine_mode vector_mode, rtx
> vector_const,
> replace = gen_rtx_SUBREG (mode, vector_const, 0);
> }
>
> + if (dump_file)
> + {
> + fprintf (dump_file, "\nReplace:\n\n");
> + print_rtl_single (dump_file, insn);
> + }
> SET_SRC (set) = replace;
> /* Drop possible dead definitions. */
> PATTERN (insn) = set;
> INSN_CODE (insn) = -1;
> recog_memoized (insn);
> + if (dump_file)
> + {
> + fprintf (dump_file, "\nwith:\n\n");
> + print_rtl_single (dump_file, insn);
> + fprintf (dump_file, "\n");
> + }
> df_insn_rescan (insn);
> }
> }
>
> and you should see the replacement I mention in comment 17 in file
> lbm_r.ltrans0.ltrans.310r.rrvl.
