On Sat, Jan 30, 2021 at 10:46:17AM +0100, Jakub Jelinek via Gcc-patches wrote:
> On Sat, Jan 30, 2021 at 09:17:45AM +0100, Richard Biener wrote:
> > >The following patch fixes it, ok for trunk if it passes
> > >bootstrap/regtest?
> >
> > Hmm, that's odd. Who relies on deferred rescan being the default? Finish
> > pass, via processing deferred insns also resets it back. Or is this
> > documented somewhere?
>
> Ifcvt clearly relies on non-deferred rescanning.
> And yes, df_finish_pass clears df->changeable_flags, but we don't do that
> for this pass anymore (removal of TODO_df_finish), as that pass didn't call
> df_analyze either.
> df_process_deferred_rescans temporarily clears DF_DEFER_INSN_RESCAN
> flag, but restores it to the previous state at the end.
>
> So, I think we either need what I posted (which passed bootstrap/regtest
> on x86_64-linux and i686-linux), or we need to restore TODO_df_finish
> for the pass.
> Given that the pass previously did call df_analyze () only conditionally,
> not at all in many functions, and had TODO_df_finish unconditionally,
> perhaps that needs to work even if it wasn't meant to be used that way.
The following works too, can bootstrap/regtest it if you prefer it that way:
2021-01-29 Jakub Jelinek <ja...@redhat.com>
* config/i386/i386-features.c (remove_partial_avx_dependency): Don't
call df_process_deferred_rescans.
(pass_data_remove_partial_avx_dependency): Readd TODO_df_finish.
* gcc.target/i386/20051216-1.c: New test.
--- gcc/config/i386/i386-features.c.jj 2021-01-30 10:48:09.788800773 +0100
+++ gcc/config/i386/i386-features.c 2021-01-30 11:42:35.660376111 +0100
@@ -2408,7 +2408,6 @@ remove_partial_avx_dependency (void)
}
}
- df_process_deferred_rescans ();
bitmap_obstack_release (NULL);
BITMAP_FREE (convert_bbs);
@@ -2438,7 +2437,7 @@ const pass_data pass_data_remove_partial
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- 0, /* todo_flags_finish */
+ TODO_df_finish, /* todo_flags_finish */
};
class pass_remove_partial_avx_dependency : public rtl_opt_pass
--- gcc/testsuite/gcc.target/i386/20051216-1.c.jj 2021-01-30
11:41:15.558293070 +0100
+++ gcc/testsuite/gcc.target/i386/20051216-1.c 2021-01-30 11:41:15.558293070
+0100
@@ -0,0 +1,5 @@
+/* PR rtl-optimization/25432 */
+/* { dg-do compile } */
+/* { dg-options "-O1 -march=cascadelake" } */
+
+#include "../../gcc.c-torture/compile/20051216-1.c"
Jakub
