I was wondering if something needs to be done about the gcc.dg/guality tests.

There are two main issues I see with these tests, one is that they are often
not run during testing and so failures do not show up.  I looked into this
and found that, at least on my ubuntu 16.04 system, the kernel parameter
kernel.yama.ptrace_scope is set to 1 by default.  This limits the use of
ptrace to direct child processes and causes the guality tests to not run
on my system.  They also don't show up as failures, all you get is a message
in the test log that says 'gdb: took too long to attach'.  After changing this
to 0, the guality tests do get run.

The second problem is that many of the tests fail when they are run.
For example, looking at some August test runs:

x86_64 failures:  https://gcc.gnu.org/ml/gcc-testresults/2017-08/msg00651.html
aarch64 failures: https://gcc.gnu.org/ml/gcc-testresults/2017-08/msg00603.html
mips64 failures:  https://gcc.gnu.org/ml/gcc-testresults/2017-08/msg00527.html
s390x failures:   https://gcc.gnu.org/ml/gcc-testresults/2017-08/msg00509.html

These all show many failures in gcc.dg/guality.  Most of the failures
are related to using the '-O2 -flto' or '-O3' options.  If I remove those
option runs I get 15 failures involving 5 tests on my aarch64 system:

        gcc.dg/guality/pr36728-1.c
        gcc.dg/guality/pr41447-1.c
        gcc.dg/guality/pr54200.c
        gcc.dg/guality/pr54693-2.c
        gcc.dg/guality/vla-1.c

So I guess there are number of questions:  Are these tests worth runnning?
Do they make sense with -O3 and/or -O2 -flto?   If they make sense and 
should be run do we need to fix GCC to clean up the failures?  Or should
we continue to just ignore them?

Steve Ellcey
sell...@cavium.com

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