On Fri, Jan 29, 2021 at 04:43:49PM +0100, Richard Biener wrote:
> 2021-01-29 Richard Biener <rguent...@suse.de>
>
> PR rtl-optimization/98863
> * config/i386/i386-features.c (remove_partial_avx_dependency):
> Do not perform DF analysis.
> (pass_data_remove_partial_avx_dependency): Remove
> TODO_df_finish.
> ---
> gcc/config/i386/i386-features.c | 17 +++++++----------
> 1 file changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/gcc/config/i386/i386-features.c b/gcc/config/i386/i386-features.c
> index ef4f9406102..c845ba90caf 100644
> --- a/gcc/config/i386/i386-features.c
> +++ b/gcc/config/i386/i386-features.c
> @@ -2272,6 +2272,9 @@ remove_partial_avx_dependency (void)
>
> auto_vec<rtx_insn *> control_flow_insns;
>
> + /* We create invalid RTL initially so defer rescans. */
> + df_set_flags (DF_DEFER_INSN_RESCAN);
> +
> FOR_EACH_BB_FN (bb, cfun)
> {
> FOR_BB_INSNS (bb, insn)
> @@ -2292,14 +2295,7 @@ remove_partial_avx_dependency (void)
> continue;
>
> if (!v4sf_const0)
> - {
> - calculate_dominance_info (CDI_DOMINATORS);
> - df_set_flags (DF_DEFER_INSN_RESCAN);
> - df_chain_add_problem (DF_DU_CHAIN | DF_UD_CHAIN);
> - df_md_add_problem ();
> - df_analyze ();
> - v4sf_const0 = gen_reg_rtx (V4SFmode);
> - }
> + v4sf_const0 = gen_reg_rtx (V4SFmode);
Can't you do that df_set_flags (DF_DEFER_INSN_RESCAN):
only here (when creating v4sf_const0)?
>
> /* Convert PARTIAL_XMM_UPDATE_TRUE insns, DF -> SF, SF -> DF,
> SI -> SF, SI -> DF, DI -> SF, DI -> DF, to vec_dup and
> @@ -2360,6 +2356,7 @@ remove_partial_avx_dependency (void)
> {
> /* (Re-)discover loops so that bb->loop_father can be used in the
> analysis below. */
> + calculate_dominance_info (CDI_DOMINATORS);
> loop_optimizer_init (AVOID_CFG_MODIFICATIONS);
>
> /* Generate a vxorps at entry of the nearest dominator for basic
> @@ -2391,7 +2388,6 @@ remove_partial_avx_dependency (void)
> set_insn = emit_insn_after (set,
> insn ? PREV_INSN (insn) : BB_END (bb));
> df_insn_rescan (set_insn);
> - df_process_deferred_rescans ();
And keep df_process_deferred_rescans (); here
> loop_optimizer_finalize ();
>
> if (!control_flow_insns.is_empty ())
> @@ -2412,6 +2408,7 @@ remove_partial_avx_dependency (void)
> }
> }
>
> + df_process_deferred_rescans ();
rather than here?
The pass these days does two separate optimizations, and only one of those
creates the use uninitialized pseudo and at the end initialize it.
The other optimization is replace_constant_pool_with_broadcast, which
doesn't do this but still calls validate_change -> df_insn_rescan.
> bitmap_obstack_release (NULL);
> BITMAP_FREE (convert_bbs);
>
> @@ -2441,7 +2438,7 @@ const pass_data pass_data_remove_partial_avx_dependency
> =
> 0, /* properties_provided */
> 0, /* properties_destroyed */
> 0, /* todo_flags_start */
> - TODO_df_finish, /* todo_flags_finish */
> + 0, /* todo_flags_finish */
> };
>
> class pass_remove_partial_avx_dependency : public rtl_opt_pass
> --
> 2.26.2
Otherwise LGTM if it works.
Jakub
