i386: Fix up the vzeroupper REG_DEAD/REG_UNUSED note workaround [PR114190]

When writing the rest_of_handle_insert_vzeroupper workaround to manually
remove all the REG_DEAD/REG_UNUSED notes from the IL, I've missed that
there is a df_analyze () call right after it and that the problems added
earlier in the pass, like df_note_add_problem () done during mode switching,
doesn't affect just the next df_analyze () call right after it, but all
other df_analyze () calls until the end of the current pass where
df_finish_pass removes the optional problems.

So, as can be seen on the following patch, the workaround doesn't actually
work there, because while rest_of_handle_insert_vzeroupper carefully removes
all REG_DEAD/REG_UNUSED notes, the df_analyze () call at the end of the
function immediately adds them in again (so, I must say I have no idea
why the workaround worked on the earlier testcases).

Now, I could move the df_analyze () call just before the REG_DEAD/REG_UNUSED
note removal loop, but I think the following patch is better, because
the df_analyze () call doesn't have to recompute the problem when we don't
care about it and will actively strip all traces of it away.

2024-03-06  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/114190
	* config/i386/i386-features.cc (rest_of_handle_insert_vzeroupper):
	Call df_remove_problem for df_note before calling df_analyze.

	* gcc.target/i386/avx-pr114190.c: New test.

0 files changed, 0 insertions, 0 deletions