[Bug target/56858] alpha looks for NOTE_INSN_EH_REGION notes that cannot exist

["stevenb.gcc at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56858

--- Comment #10 from stevenb.gcc at gmail dot com <stevenb.gcc at gmail dot com> 2013-04-08 19:42:51 UTC ---
> Sure.  Do you know any package that combines C++ EH with IEEE exceptions?
> I don't.  In fact, I don't actually know of a package that wants to enable
> trapping fp math at all.

I barely know a thing about EH, or IEEE exceptions, let alone a
combination or two. I'm a doc^Wn aerospace engineer, not a computer
scientist.

> Do you believe that you're going to be able to delete the notes entirely,
> and that it's only Alpha that's keeping them alive?  That's certainly not
> true, I assure you.

Removing the notes entirely is the goal eventually, but I'd settle for
making them local to final.c for now.

What besides alpha and final are keeping these notes alive? You've
probably seen my grep results, and at least from passes.c there
doesn't seem to be anything between pass_convert_to_eh_region_ranges
and pass_final that would use the INSN_NOTEs:

          NEXT_PASS (pass_convert_to_eh_region_ranges);
          NEXT_PASS (pass_shorten_branches);
          NEXT_PASS (pass_set_nothrow_function_flags);
          NEXT_PASS (pass_dwarf2_frame);
          NEXT_PASS (pass_final);

AFAIU the only code transformations done in these passes are in
shorten_branches that shouldn't care whether it's dealing with the
REG_EH_REGION notes or the NOTE_INSN_EH_REGION notes.

But my U in AFAIU is obviously no-where near your U when it comes to
EH, so if you can explain a bit, I'd really appreciate it! :-)

(On the topic of notes: note to self, kill NOTE_EH_CONTEXT.)