Add fixit hint for -Wlogical-not-parentheses

[David Malcolm]

On Mon, 2016-08-29 at 13:44 +0200, Marek Polacek wrote:
> On Mon, Aug 29, 2016 at 12:35:38PM +0200, Marek Polacek wrote:
> > On Mon, Aug 29, 2016 at 11:16:25AM +0200, Andreas Schwab wrote:
> > > On Aug 25 2016, Marek Polacek <polacek@redhat.com> wrote:
> > > 
> > > > 	* c-c++-common/Wlogical-not-parentheses-2.c: New test.
> > > 
> > > FAIL: c-c++-common/Wlogical-not-parentheses-2.c  -std=gnu++11 
> > >  expected multiline pattern lines 13-17 not found: "\s*r \+= !aaa
> > > == bbb;.*\n             \^~\n   r \+= !aaa == bbb;.*\n       
> > >  \^~~~\n        \(   \).*\n"
> > > FAIL: c-c++-common/Wlogical-not-parentheses-2.c  -std=gnu++11
> > > (test for excess errors)
> > > Excess errors:
> > >    r += !aaa == bbb; /* { dg-warning "logical not is only
> > > applied" } */
> > >              ^~
> > >    r += !aaa == bbb; /* { dg-warning "logical not is only
> > > applied" } */
> > >         ^~~~
> > 
> > This has regressed with David's
> > 
> > commit 367964faf71a99ebd511dffb81075b58bff345a1
> > Author: dmalcolm <dmalcolm@138bc75d-0d04-0410-961f-82ee72b054a4>
> > Date:   Fri Aug 26 21:25:41 2016 +0000
> > 
> >     Add validation and consolidation of fix-it hints
> >     
> > I don't know yet what exactly went wrong here.
> 
> So we reject printing fix-it hint because in reject_impossible_fixit:
> 
> 2187   if (where <= LINE_MAP_MAX_LOCATION_WITH_COLS)
> 2188     /* WHERE is a reasonable location for a fix-it; don't reject
> it.  */
> 2189     return false;
> 
> (gdb) p where
> $1 = 2147483652
> (gdb) p LINE_MAP_MAX_LOCATION_WITH_COLS
> $2 = 1610612736
> 
> so we set m_seen_impossible_fixit.
> 
> David, why is that happening?

Sorry about this; I believe I did my testing of my patch against a tree
that didn't yet have your change.

(gdb) p /x 2147483652
$2 = 0x80000004

so "where", the insertion-point, is an ad-hoc location (describing a
range), and it looks like I somehow forgot to deal with that case in
the validation code.

I'm working on a fix.  Sorry again.

Dave