Re: Ping: [PATCH] Fix PR112419

[Martin Uecker <uecker@tugraz.at>]

Am Montag, dem 27.11.2023 um 08:36 -0700 schrieb Jeff Law:
> 
> On 11/23/23 10:05, Hans-Peter Nilsson wrote:
> > > From: Hans-Peter Nilsson <hp@axis.com>
> > > Date: Thu, 16 Nov 2023 05:24:06 +0100
> > > 
> > > > From: Martin Uecker <uecker@tugraz.at>
> > > > Date: Tue, 07 Nov 2023 06:56:25 +0100
> > > 
> > > > Am Montag, dem 06.11.2023 um 21:01 -0700 schrieb Jeff Law:
> > > > > 
> > > > > On 11/6/23 20:58, Hans-Peter Nilsson wrote:
> > > > > > This patch caused a testsuite regression: there's now an
> > > > > > "excess error" failure for gcc.dg/Wnonnull-4.c for 32-bit
> > > > > > targets (and 64-bit targets testing with a "-m32" option)
> > > > > > after your r14-5115-g6e9ee44d96e5.  It's logged as PR112419.
> > > > > It caused failures for just about every target ;(  Presumably it worked
> > > > > on x86_64...
> > > > 
> > > > I do not think this is a true regression
> > > > just a problem with the test on 32-bit which somehow surfaced
> > > > due to the change.
> > > > 
> > > > The excess error is:
> > > > 
> > > > FAIL: gcc.dg/Wnonnull-4.c (test for excess errors)
> > > > Excess errors:
> > > > /home/tcwg-buildslave/workspace/tcwg_gnu_6/abe/snapshots/gcc.git~master/gcc/testsuite/gcc.dg/Wnonnull-4.c:144:3: warning: 'fda_n_5' specified size 4294967256 exceeds maximum object size
> > > > 2147483647 [-Wstringop-overflow=]
> > > > 
> > > > I think the warning was suppressed before due to the other (nonnull)
> > > > warning which I removed in this case.
> > > > 
> > > > I think the simple fix might be to to turn off -Wstringop-overflow.
> > > 
> > > No, that trigs many of the dg-warnings that are tested.
> > > 
> > > (I didn't pay attention to the actual warning messages and
> > > tried to pursue that at first.)
> > > 
> > > Maybe think it's best to actually expect the warning, like
> > > so.
> > > 
> > > Maintainers of 16-bit targets will have to address their
> > > concerns separately.  For example, they may choose to not
> > > run the test at all.
> > > 
> > > Ok to commit?
> > > 
> > > Subject: [PATCH] gcc.dg/Wnonnull-4.c: Handle new overflow warning for 32-bit targets [PR112419]
> > > 
> > > 	PR testsuite/112419
> > > 	* gcc.dg/Wnonnull-4.c (test_fda_n_5): Expect warning for exceeding
> > > 	maximum object size for 32-bit targets.
> > > ---
> > >   gcc/testsuite/gcc.dg/Wnonnull-4.c | 1 +
> > >   1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/gcc/testsuite/gcc.dg/Wnonnull-4.c b/gcc/testsuite/gcc.dg/Wnonnull-4.c
> > > index 1f14fbba45df..d63e76da70a2 100644
> > > --- a/gcc/testsuite/gcc.dg/Wnonnull-4.c
> > > +++ b/gcc/testsuite/gcc.dg/Wnonnull-4.c
> > > @@ -142,6 +142,7 @@ void test_fda_n_5 (int r_m1)
> > >     T (  1);          // { dg-bogus "argument 2 of variable length array 'double\\\[n]\\\[5]' is null but the corresponding bound argument 1 value is 1" }
> > >     T (  9);          // { dg-bogus "argument 2 of variable length array 'double\\\[n]\\\[5]' is null but the corresponding bound argument 1 value is 9" }
> > >     T (max);          // { dg-bogus "argument 2 of variable length array 'double\\\[n]\\\[5]' is null but the corresponding bound argument 1 value is \\d+" }
> > > +// { dg-warning "size 4294967256 exceeds maximum object size" "" { target ilp32 } .-1 }
> > >   }
> Unfortunately I think we need to go back to the original issue that 
> Martin (I think) dismissed.
> 
> Specifically, this is a regression.  It's very clear that prior to the 
> patch in question there was no diagnostic about the size of the 
> requested memory allocation and after the patch in question we get the 
> "exceeds maximum object size" diagnostic.
> 
> Now one explanation could be that the diagnostic is warranted and it was 
> a bug that the diagnostic hadn't been emitted prior to Martin's patch. 
> In this case some kind of dg-blah is warranted, but I don't think anyone 
> has made this argument.
> 
I believe the warning is correct but was suppressed before.


My plan was to split up the test case in one which is for
-Wstringop-overflow and one which is for -Wnonnull and then
one could turn off the -Wstringop-overflow for the tests
which are actually for -Wnonnull.  But adding the dg-blah
would certainly be simpler.


Martin