Re: lambda-switch regression

2017-11-15 Thread Martin Sebor

On 11/15/2017 10:38 AM, David Malcolm wrote:

On Wed, 2017-11-15 at 12:25 -0500, David Malcolm wrote:

On Wed, 2017-11-15 at 12:06 -0500, David Malcolm wrote:

On Wed, 2017-11-15 at 08:03 -0500, Nathan Sidwell wrote:

g++.dg/lambda/lambda-switch.C Has recently regressed.


g++.dg/cpp0x/lambda/lambda-switch.C


It appears the
location of a warning message has moved.

  l = []()  // { dg-warning "statement will never
be executed" }
{
case 3: // { dg-error "case" }
  break;// { dg-error "break" }
};  <--- warning now here

We seem to be diagnosing the last line of the statement, not the
first.
That seems not a useful.

I've not investigated what patch may have caused this, on the
chance
someone might already know?

nathan


The warning was added in r236597 (aka
1398da0f786e120bb0b407e84f412aa9fc6d80ee):

+2016-05-23  Marek Polacek  
+
+   PR c/49859
+   * common.opt (Wswitch-unreachable): New option.
+   * doc/invoke.texi: Document -Wswitch-unreachable.
+   * gimplify.c (gimplify_switch_expr): Implement the
-Wswitch-
unreachable
+   warning.

which had it at there (23:7).

r244705 (aka 3ef7eab185e1463c7dbfa2a8d1af5d0120cf9f76) moved the
warning from 23:7 up to the "[] ()" at 19:6 in:

+2017-01-20  Marek Polacek  
+
+   PR c/64279
[...snip...]
+   * g++.dg/cpp0x/lambda/lambda-switch.C: Move dg-warning.

I tried it with some working copies I have to hand:
- works for me with r254387 (2017-11-03)
- fails for me with r254700 (2017-11-13)

so hopefully that helps track it down.

Dave


Searching in the November archives of the gcc-regression ML for
"lambda-switch.c":

https://gcc.gnu.org/cgi-bin/search.cgi?wm=wrd=extended=all=D
=lambda-switch.c=%2Fml%2Fgcc-regression%2F2017-11%2F%25

showed e.g.:
  https://gcc.gnu.org/ml/gcc-regression/2017-11/msg00173.html
   "Regressions on trunk at revision 254648 vs revision 254623"

which says this is a new failure somewhere in that range; so it
presumably happened sometime on 2017-11-10 after r254623 and up to
(maybe ==) r254648.

Looking at:
   svn log -r r254623:r254648 |less
nothing jumps out at me as being related.

Hope this is helpful
Dave


Actually, https://gcc.gnu.org/ml/gcc-regression/2017-11/msg00157.html
has a tighter range: r254628 vs r254635.

Looking at:
  svn log -r r254628:r254635 |less
I see msebor's r254630 ("PR c/81117 - Improve buffer overflow checking
in strncpy") has:

* gimple.c (gimple_build_call_from_tree): Set call location.

with:
+  gimple_set_location (call, EXPR_LOCATION (t));

Maybe that's it?  (nothing else in that commit range seems to affect
locations).


Yes, that's it.  Before the change there would be no location
associated with a GIMPLE call seen in gimple-fold.  The location
would only get added later, after folding.

The purpose of the lambda-switch.C test is to verify GCC doesn't
ICE on the ill-formed code.  The warning is incidental to the test
case so I've adjusted it to filter it out.

Martin



Re: lambda-switch regression

2017-11-15 Thread David Malcolm
On Wed, 2017-11-15 at 12:25 -0500, David Malcolm wrote:
> On Wed, 2017-11-15 at 12:06 -0500, David Malcolm wrote:
> > On Wed, 2017-11-15 at 08:03 -0500, Nathan Sidwell wrote:
> > > g++.dg/lambda/lambda-switch.C Has recently regressed.  
> > 
> > g++.dg/cpp0x/lambda/lambda-switch.C
> > 
> > > It appears the 
> > > location of a warning message has moved.
> > > 
> > > l = []()  // { dg-warning "statement will never
> > > be executed" }
> > >   {
> > >   case 3: // { dg-error "case" }
> > > break;// { dg-error "break" }
> > >   };  <--- warning now here
> > > 
> > > We seem to be diagnosing the last line of the statement, not the
> > > first. 
> > > That seems not a useful.
> > > 
> > > I've not investigated what patch may have caused this, on the
> > > chance 
> > > someone might already know?
> > > 
> > > nathan
> > 
> > The warning was added in r236597 (aka
> > 1398da0f786e120bb0b407e84f412aa9fc6d80ee):
> > 
> > +2016-05-23  Marek Polacek  
> > +
> > +   PR c/49859
> > +   * common.opt (Wswitch-unreachable): New option.
> > +   * doc/invoke.texi: Document -Wswitch-unreachable.
> > +   * gimplify.c (gimplify_switch_expr): Implement the
> > -Wswitch-
> > unreachable
> > +   warning.
> > 
> > which had it at there (23:7).
> > 
> > r244705 (aka 3ef7eab185e1463c7dbfa2a8d1af5d0120cf9f76) moved the
> > warning from 23:7 up to the "[] ()" at 19:6 in:
> > 
> > +2017-01-20  Marek Polacek  
> > +
> > +   PR c/64279
> > [...snip...]
> > +   * g++.dg/cpp0x/lambda/lambda-switch.C: Move dg-warning.
> > 
> > I tried it with some working copies I have to hand:
> > - works for me with r254387 (2017-11-03)
> > - fails for me with r254700 (2017-11-13)
> > 
> > so hopefully that helps track it down.
> > 
> > Dave
> 
> Searching in the November archives of the gcc-regression ML for
> "lambda-switch.c":
> 
> https://gcc.gnu.org/cgi-bin/search.cgi?wm=wrd=extended=all=D
> =lambda-switch.c=%2Fml%2Fgcc-regression%2F2017-11%2F%25
> 
> showed e.g.:
>   https://gcc.gnu.org/ml/gcc-regression/2017-11/msg00173.html
>"Regressions on trunk at revision 254648 vs revision 254623"
> 
> which says this is a new failure somewhere in that range; so it
> presumably happened sometime on 2017-11-10 after r254623 and up to
> (maybe ==) r254648.
> 
> Looking at:
>svn log -r r254623:r254648 |less
> nothing jumps out at me as being related.
> 
> Hope this is helpful
> Dave

Actually, https://gcc.gnu.org/ml/gcc-regression/2017-11/msg00157.html
has a tighter range: r254628 vs r254635.

Looking at:
  svn log -r r254628:r254635 |less
I see msebor's r254630 ("PR c/81117 - Improve buffer overflow checking
in strncpy") has:

* gimple.c (gimple_build_call_from_tree): Set call location.

with:
+  gimple_set_location (call, EXPR_LOCATION (t));

Maybe that's it?  (nothing else in that commit range seems to affect
locations).

Dave


Re: lambda-switch regression

2017-11-15 Thread Martin Sebor

On 11/15/2017 06:03 AM, Nathan Sidwell wrote:

g++.dg/lambda/lambda-switch.C Has recently regressed.  It appears the
location of a warning message has moved.

  l = []()// { dg-warning "statement will never be executed" }
{
case 3:// { dg-error "case" }
  break;// { dg-error "break" }
};  <--- warning now here

We seem to be diagnosing the last line of the statement, not the first.
That seems not a useful.

I've not investigated what patch may have caused this, on the chance
someone might already know?


Bug 82988 points to my r254630 as the commit that triggered it.
I haven't yet looked into it.  There some small chance that it
was caused by bug 82977 that Jakub just fixed.

Martin



Re: lambda-switch regression

2017-11-15 Thread David Malcolm
On Wed, 2017-11-15 at 12:06 -0500, David Malcolm wrote:
> On Wed, 2017-11-15 at 08:03 -0500, Nathan Sidwell wrote:
> > g++.dg/lambda/lambda-switch.C Has recently regressed.  
> 
> g++.dg/cpp0x/lambda/lambda-switch.C
> 
> > It appears the 
> > location of a warning message has moved.
> > 
> >   l = []()  // { dg-warning "statement will never
> > be executed" }
> > {
> > case 3: // { dg-error "case" }
> >   break;// { dg-error "break" }
> > };  <--- warning now here
> > 
> > We seem to be diagnosing the last line of the statement, not the
> > first. 
> > That seems not a useful.
> > 
> > I've not investigated what patch may have caused this, on the
> > chance 
> > someone might already know?
> > 
> > nathan
> 
> The warning was added in r236597 (aka
> 1398da0f786e120bb0b407e84f412aa9fc6d80ee):
> 
> +2016-05-23  Marek Polacek  
> +
> +   PR c/49859
> +   * common.opt (Wswitch-unreachable): New option.
> +   * doc/invoke.texi: Document -Wswitch-unreachable.
> +   * gimplify.c (gimplify_switch_expr): Implement the -Wswitch-
> unreachable
> +   warning.
> 
> which had it at there (23:7).
> 
> r244705 (aka 3ef7eab185e1463c7dbfa2a8d1af5d0120cf9f76) moved the
> warning from 23:7 up to the "[] ()" at 19:6 in:
> 
> +2017-01-20  Marek Polacek  
> +
> +   PR c/64279
> [...snip...]
> +   * g++.dg/cpp0x/lambda/lambda-switch.C: Move dg-warning.
> 
> I tried it with some working copies I have to hand:
> - works for me with r254387 (2017-11-03)
> - fails for me with r254700 (2017-11-13)
> 
> so hopefully that helps track it down.
> 
> Dave

Searching in the November archives of the gcc-regression ML for
"lambda-switch.c":

https://gcc.gnu.org/cgi-bin/search.cgi?wm=wrd=extended=all=D=lambda-switch.c=%2Fml%2Fgcc-regression%2F2017-11%2F%25

showed e.g.:
  https://gcc.gnu.org/ml/gcc-regression/2017-11/msg00173.html
   "Regressions on trunk at revision 254648 vs revision 254623"

which says this is a new failure somewhere in that range; so it
presumably happened sometime on 2017-11-10 after r254623 and up to
(maybe ==) r254648.

Looking at:
   svn log -r r254623:r254648 |less
nothing jumps out at me as being related.

Hope this is helpful
Dave


Re: lambda-switch regression

2017-11-15 Thread David Malcolm
On Wed, 2017-11-15 at 08:03 -0500, Nathan Sidwell wrote:
> g++.dg/lambda/lambda-switch.C Has recently regressed.  

g++.dg/cpp0x/lambda/lambda-switch.C

> It appears the 
> location of a warning message has moved.
> 
> l = []()  // { dg-warning "statement will never
> be executed" }
>   {
>   case 3: // { dg-error "case" }
> break;// { dg-error "break" }
>   };  <--- warning now here
> 
> We seem to be diagnosing the last line of the statement, not the
> first. 
> That seems not a useful.
> 
> I've not investigated what patch may have caused this, on the chance 
> someone might already know?
> 
> nathan

The warning was added in r236597 (aka
1398da0f786e120bb0b407e84f412aa9fc6d80ee):

+2016-05-23  Marek Polacek  
+
+   PR c/49859
+   * common.opt (Wswitch-unreachable): New option.
+   * doc/invoke.texi: Document -Wswitch-unreachable.
+   * gimplify.c (gimplify_switch_expr): Implement the -Wswitch-unreachable
+   warning.

which had it at there (23:7).

r244705 (aka 3ef7eab185e1463c7dbfa2a8d1af5d0120cf9f76) moved the
warning from 23:7 up to the "[] ()" at 19:6 in:

+2017-01-20  Marek Polacek  
+
+   PR c/64279
[...snip...]
+   * g++.dg/cpp0x/lambda/lambda-switch.C: Move dg-warning.

I tried it with some working copies I have to hand:
- works for me with r254387 (2017-11-03)
- fails for me with r254700 (2017-11-13)

so hopefully that helps track it down.

Dave


lambda-switch regression

2017-11-15 Thread Nathan Sidwell
g++.dg/lambda/lambda-switch.C Has recently regressed.  It appears the 
location of a warning message has moved.


  l = []()  // { dg-warning "statement will never be 
executed" }
{
case 3: // { dg-error "case" }
  break;// { dg-error "break" }
};  <--- warning now here

We seem to be diagnosing the last line of the statement, not the first. 
That seems not a useful.


I've not investigated what patch may have caused this, on the chance 
someone might already know?


nathan
--
Nathan Sidwell