On Fri, Jan 26, 2024 at 9:17 AM Robin Dapp <rdapp....@gmail.com> wrote:
>
> Hi,
>
> init_all_optabs initializes > 10000 patterns for riscv targets. This
> leads to pathological situations in dataflow analysis (which can occur
> with many adjacent stores).
> To alleviate this this patch makes genopinit split the init_all_optabs
> function into several init_optabs_xx functions that each initialize 1000
> patterns.
>
> With this change insn-opinit.cc's compilation time is reduced from 4+
> minutes to 1:30 and memory consumption decreases from 1.2G to 630M.
>
> Bootstrapped and regtested on x86 and aarch64 (where we do split) and
> on power10 (where we don't). Regtested on riscv.
OK.
Thanks,
Richard.
> Regards
> Robin
>
> gcc/ChangeLog:
>
> PR other/113575
>
> * genopinit.cc (main): Split init_all_optabs into functions
> of 1000 patterns each.
> ---
> gcc/genopinit.cc | 43 ++++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 38 insertions(+), 5 deletions(-)
>
> diff --git a/gcc/genopinit.cc b/gcc/genopinit.cc
> index 88ccafa5b2c..d8682b2a9ad 100644
> --- a/gcc/genopinit.cc
> +++ b/gcc/genopinit.cc
> @@ -367,11 +367,44 @@ main (int argc, const char **argv)
> fprintf (s_file, " { %#08x, CODE_FOR_%s },\n", p->sort_num, p->name);
> fprintf (s_file, "};\n\n");
>
> - fprintf (s_file, "void\ninit_all_optabs (struct target_optabs
> *optabs)\n{\n");
> - fprintf (s_file, " bool *ena = optabs->pat_enable;\n");
> - for (i = 0; patterns.iterate (i, &p); ++i)
> - fprintf (s_file, " ena[%u] = HAVE_%s;\n", i, p->name);
> - fprintf (s_file, "}\n\n");
> + /* Some targets like riscv have a large number of patterns. In order to
> + prevent pathological situations in dataflow analysis split the init
> + function into separate ones that initialize 1000 patterns each. */
> +
> + const int patterns_per_function = 1000;
> +
> + if (patterns.length () > patterns_per_function)
> + {
> + unsigned num_init_functions
> + = patterns.length () / patterns_per_function + 1;
> + for (i = 0; i < num_init_functions; i++)
> + {
> + fprintf (s_file, "static void\ninit_optabs_%02d "
> + "(struct target_optabs *optabs)\n{\n", i);
> + fprintf (s_file, " bool *ena = optabs->pat_enable;\n");
> + unsigned start = i * patterns_per_function;
> + unsigned end = MIN (patterns.length (),
> + (i + 1) * patterns_per_function);
> + for (j = start; j < end; ++j)
> + fprintf (s_file, " ena[%u] = HAVE_%s;\n", j, patterns[j].name);
> + fprintf (s_file, "}\n\n");
> + }
> +
> + fprintf (s_file, "void\ninit_all_optabs "
> + "(struct target_optabs *optabs)\n{\n");
> + for (i = 0; i < num_init_functions; ++i)
> + fprintf (s_file, " init_optabs_%02d (optabs);\n", i);
> + fprintf (s_file, "}\n\n");
> + }
> + else
> + {
> + fprintf (s_file, "void\ninit_all_optabs "
> + "(struct target_optabs *optabs)\n{\n");
> + fprintf (s_file, " bool *ena = optabs->pat_enable;\n");
> + for (i = 0; patterns.iterate (i, &p); ++i)
> + fprintf (s_file, " ena[%u] = HAVE_%s;\n", i, p->name);
> + fprintf (s_file, "}\n\n");
> + }
>
> fprintf (s_file,
> "/* Returns TRUE if the target supports any of the partial
> vector\n"
> --
> 2.43.0
