Re: Fix twolf -funroll-loops -O3 miscompilation (a semi-latent web.c bug)

[Steven Bosscher <stevenb.gcc@gmail.com>]

On Tue, Nov 27, 2012 at 3:25 PM, Dominique Dhumieres <dominiq@lps.ens.fr> wrote:
>> And more band-aid, ...
>
> The gcc_assert triggers at bootstrap when compiling gcc/ada/ali.adb:
>
> +===========================GNAT BUG DETECTED==============================+
> | 4.8.0 20121127 (experimental) [trunk revision 193848p10] (x86_64-apple-darwin10.8.0) GCC error:|
> | in df_remove_dead_eq_notes, at df-problems.c:2917                        |
> | Error detected around ../../work/gcc/ada/ali.adb:2682:8                  |
> | Please submit a bug report; see http://gcc.gnu.org/bugs.html.            |
> | Use a subject line meaningful to you and us to track the bug.            |
> | Include the entire contents of this bug box in the report.               |
> | Include the exact gcc or gnatmake command that you entered.              |
> | Also include sources listed below in gnatchop format                     |
> | (concatenated together with no headers between files).                   |
> +==========================================================================+

Yes, I found that one already, too.

And, oh joy, we have pseudos in REG_EQUAL notes after LRA! (Probably
also after reload, btw.).  In the ICE I got, a pseudo's live range got
split and an inheritance move is injected, but REG_EQUAL notes were
not updated or removed. Finding and removing the notes is hard in IRA
and LRA because they don't use the DF caches.

Ciao!
Steven