Bug#931921: clutter's autopkgtests hang when ran with a libglib2.0-0 built with gcc-9

[Matthias Klose <doko@debian.org>]

Control: tags -1 + upstream moreinfo

now https://gcc.gnu.org/PR91491

On 02.08.19 23:27, Simon McVittie wrote:
> On Fri, 02 Aug 2019 at 19:49:20 +0100, Simon McVittie wrote:
>> If you compile test_run_seed() with -O1, and the rest of gtestutils.c
>> with -O2, the clutter test hangs.

so building this all with -O2, and with the flags above, it both fails?

> Binary-searching through the extra optimizations enabled by -O2 [1]
> led me to the minimal change being: if you modify test_run_seed() to add
> 
>     __attribute__((optimize("no-tree-pre")))
> 
> then the clutter test passes. Without that attribute it fails.
> 
> I have no idea why.
> 
>     smcv
> 
> [1] gcc-9 -Q -O2 --help=optimizers > O2
>     gcc-9 -Q -O1 --help=optimizers > O1
>     diff -u O1 O2
> 

can you tell where exactly the test case loops?

can you outline how you did setup your test case for that?

can you have a look at the search script in
https://gcc.gnu.org/viewcvs/gcc/branches/gcc-9-branch/gcc/dbgcnt.def?view=markup
and run 'gcc "-fdbg-cnt=treepre_insert:$lb:$ub"' in $cmd? so the whole $cmd
should rebuild gtestutils, perform the link steps and run the test.