Re: Ping: Re: [PATCH 1/2] gcc: Remove unneeded global flag.

[Andrew Burgess <andrew.burgess@embecosm.com>]

* Jeff Law <law@redhat.com> [2016-11-29 10:35:50 -0700]:

> On 11/29/2016 07:02 AM, Andrew Burgess wrote:
> > * Jeff Law <law@redhat.com> [2016-11-28 15:08:46 -0700]:
> > 
> > > On 11/24/2016 02:40 PM, Andrew Burgess wrote:
> > > > * Christophe Lyon <christophe.lyon@linaro.org> [2016-11-21 13:47:09 +0100]:
> > > > 
> > > > > On 20 November 2016 at 18:27, Mike Stump <mikestump@comcast.net> wrote:
> > > > > > On Nov 19, 2016, at 1:59 PM, Andrew Burgess <andrew.burgess@embecosm.com> wrote:
> > > > > > > > So, your new test fails on arm* targets:
> > > > > > > 
> > > > > > > After a little digging I think the problem might be that
> > > > > > > -freorder-blocks-and-partition is not supported on arm.
> > > > > > > 
> > > > > > > This should be detected as the new tests include:
> > > > > > > 
> > > > > > >    /* { dg-require-effective-target freorder } */
> > > > > > > 
> > > > > > > however this test passed on arm as -freorder-blocks-and-partition does
> > > > > > > not issue any warning unless -fprofile-use is also passed.
> > > > > > > 
> > > > > > > The patch below extends check_effective_target_freorder to check using
> > > > > > > -fprofile-use.  With this change in place the tests are skipped on
> > > > > > > arm.
> > > > > > 
> > > > > > > All feedback welcome,
> > > > > > 
> > > > > > Seems reasonable, unless a -freorder-blocks-and-partition/-fprofile-use person thinks this is the wrong solution.
> > > > > > 
> > > > > 
> > > > > Hi,
> > > > > 
> > > > > As promised, I tested this patch: it makes
> > > > > gcc.dg/tree-prof/section-attr-[123].c
> > > > > unsupported on arm*, and thus they are not failing anymore :-)
> > > > > 
> > > > > However, it also makes other tests unsupported, while they used to pass:
> > > > > 
> > > > >   gcc.dg/pr33648.c
> > > > >   gcc.dg/pr46685.c
> > > > >   gcc.dg/tree-prof/20041218-1.c
> > > > >   gcc.dg/tree-prof/bb-reorg.c
> > > > >   gcc.dg/tree-prof/cold_partition_label.c
> > > > >   gcc.dg/tree-prof/comp-goto-1.c
> > > > >   gcc.dg/tree-prof/pr34999.c
> > > > >   gcc.dg/tree-prof/pr45354.c
> > > > >   gcc.dg/tree-prof/pr50907.c
> > > > >   gcc.dg/tree-prof/pr52027.c
> > > > >   gcc.dg/tree-prof/va-arg-pack-1.c
> > > > > 
> > > > > and failures are now unsupported:
> > > > >   gcc.dg/tree-prof/cold_partition_label.c
> > > > >   gcc.dg/tree-prof/section-attr-1.c
> > > > >   gcc.dg/tree-prof/section-attr-2.c
> > > > >   gcc.dg/tree-prof/section-attr-3.c
> > > > > 
> > > > > So, maybe this patch is too strong?
> > > > 
> > > > In all of the cases that used to pass the tests are compile only tests
> > > > (except for cold_partition_label, which I discuss below).
> > > > 
> > > > On ARM passing -fprofile-use and -freorder-blocks-and-partition
> > > > results in a warning, and the -freorder-blocks-and-partition flag is
> > > > ignored.  However, disabling -freorder-blocks-and-partition doesn't
> > > > stop any of the tests compiling, hence the passes.
> > > > 
> > > > All the tests include:
> > > > 
> > > >   /* { dg-require-effective-target freorder } */
> > > > 
> > > > which I understand to mean, the tests requires the 'freorder' feature
> > > > to be supported (which corresponds to -freorder-blocks-and-partition).
> > > > 
> > > > For cold_partition_label and my new tests it's seems clear that the
> > > > lack of support for -freorder-blocks-and-partition on ARM is the cause
> > > > of the test failures.
> > > > 
> > > > So, is it reasonable to give up the other tests as "unsupported"?  I'd
> > > > be inclined to say yes, but I happy to rework the patch if anyone has
> > > > a suggestion for an alternative approach.
> > > It is reasonable.  It's not uncommon to have to drop various tests to
> > > UNSUPPORTED, particularly things which depend on assembler/linker
> > > capabilities, the target runtime system, etc.
> > 
> > OK, I'm going to take that as approval for my patch[1].  I'll wait a
> > couple of days to give people a chance to correct me, then I'll push
> > the change.  This should resolve the test regressions I introduced for
> > ARM.
> I'll just go ahead and explicitly ACK this.

Committed as r243009.

Thanks,
Andrew