[Bug preprocessor/53463] New: [4.8 Regression]: system header not recognized, yielding warnings about long long preprocessor constant

[Bug preprocessor/53463] New: [4.8 Regression]: system header not recognized, yielding warnings about long long preprocessor constant

[hp at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53463

             Bug #: 53463
           Summary: [4.8 Regression]: system header not recognized,
                    yielding warnings about long long preprocessor
                    constant
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Keywords: diagnostic, rejects-valid
          Severity: normal
          Priority: P3
         Component: preprocessor
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: hp@gcc.gnu.org
                CC: dodji@gcc.gnu.org
              Host: x86_64-unknown-linux-gnu
            Target: cris-axis-elf


Created attachment 27483
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27483
First test-case failing, preprocessed.

These below tests previously passed, now they fails.
The svn revision r187587 exposed or caused these regressions.  Since then they
fail as follows:

Running /tmp/bad0516b/gcc/gcc/testsuite/gcc.dg/cpp/cpp.exp ...
FAIL: gcc.dg/cpp/19990407-1.c (test for excess errors)
WARNING: gcc.dg/cpp/19990407-1.c compilation failed to produce executable
FAIL: gcc.dg/cpp/paste12.c (test for excess errors)
FAIL: gcc.dg/cpp/strp1.c (test for excess errors)
WARNING: gcc.dg/cpp/strp1.c compilation failed to produce executable
FAIL: gcc.dg/cpp/strp2.c (test for excess errors)
WARNING: gcc.dg/cpp/strp2.c compilation failed to produce executable
...
Running /tmp/bad0516b/gcc/gcc/testsuite/gcc.dg/dg.exp ...
...
FAIL: gcc.dg/struct-ret-libc.c (test for excess errors)
WARNING: gcc.dg/struct-ret-libc.c compilation failed to produce executable
...
Running /tmp/bad0516b/gcc/gcc/testsuite/g++.dg/dg.exp ...
...
FAIL: g++.dg/warn/format1.C -std=gnu++98 (test for excess errors)
FAIL: g++.dg/warn/format1.C -std=gnu++11 (test for excess errors)
FAIL: g++.dg/warn/huge-val1.C -std=gnu++98 (test for excess errors)
...
Running /tmp/bad0516b/gcc/gcc/testsuite/gfortran.dg/dg.exp ...
FAIL: gfortran.dg/bind_c_usage_16.f03  -O0  (test for excess errors)
WARNING: gfortran.dg/bind_c_usage_16.f03  -O0  compilation failed to produce
executable
FAIL: gfortran.dg/bind_c_usage_16.f03  -O1  (test for excess errors)
WARNING: gfortran.dg/bind_c_usage_16.f03  -O1  compilation failed to produce
executable
FAIL: gfortran.dg/bind_c_usage_16.f03  -O2  (test for excess errors)
WARNING: gfortran.dg/bind_c_usage_16.f03  -O2  compilation failed to produce
executable
FAIL: gfortran.dg/bind_c_usage_16.f03  -O3 -fomit-frame-pointer  (test for
excess errors)
WARNING: gfortran.dg/bind_c_usage_16.f03  -O3 -fomit-frame-pointer  compilation
failed to produce executable
FAIL: gfortran.dg/bind_c_usage_16.f03  -O3 -fomit-frame-pointer -funroll-loops 
(test for excess errors)
WARNING: gfortran.dg/bind_c_usage_16.f03  -O3 -fomit-frame-pointer
-funroll-loops  compilation failed to produce execut\
able
FAIL: gfortran.dg/bind_c_usage_16.f03  -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions  (test for excess\
 errors)
WARNING: gfortran.dg/bind_c_usage_16.f03  -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions  compilation f\
ailed to produce executable
FAIL: gfortran.dg/bind_c_usage_16.f03  -O3 -g  (test for excess errors)
WARNING: gfortran.dg/bind_c_usage_16.f03  -O3 -g  compilation failed to produce
executable
FAIL: gfortran.dg/bind_c_usage_16.f03  -Os  (test for excess errors)
WARNING: gfortran.dg/bind_c_usage_16.f03  -Os  compilation failed to produce
executable
FAIL: gfortran.dg/bind_c_usage_24.f90  -O0  (test for excess errors)
WARNING: gfortran.dg/bind_c_usage_24.f90  -O0  compilation failed to produce
executable
FAIL: gfortran.dg/bind_c_usage_24.f90  -O1  (test for excess errors)
WARNING: gfortran.dg/bind_c_usage_24.f90  -O1  compilation failed to produce
executable
FAIL: gfortran.dg/bind_c_usage_24.f90  -O2  (test for excess errors)
WARNING: gfortran.dg/bind_c_usage_24.f90  -O2  compilation failed to produce
executable
FAIL: gfortran.dg/bind_c_usage_24.f90  -O3 -fomit-frame-pointer  (test for
excess errors)
WARNING: gfortran.dg/bind_c_usage_24.f90  -O3 -fomit-frame-pointer  compilation
failed to produce executable
FAIL: gfortran.dg/bind_c_usage_24.f90  -O3 -fomit-frame-pointer -funroll-loops 
(test for excess errors)
WARNING: gfortran.dg/bind_c_usage_24.f90  -O3 -fomit-frame-pointer
-funroll-loops  compilation failed to produce execut\
able
FAIL: gfortran.dg/bind_c_usage_24.f90  -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions  (test for excess\
 errors)
WARNING: gfortran.dg/bind_c_usage_24.f90  -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions  compilation f\
ailed to produce executable
FAIL: gfortran.dg/bind_c_usage_24.f90  -O3 -g  (test for excess errors)
WARNING: gfortran.dg/bind_c_usage_24.f90  -O3 -g  compilation failed to produce
executable
FAIL: gfortran.dg/bind_c_usage_24.f90  -Os  (test for excess errors)
WARNING: gfortran.dg/bind_c_usage_24.f90  -Os  compilation failed to produce
executable
FAIL: gfortran.dg/c_funloc_tests_3.f03  -O0  (test for excess errors)
WARNING: gfortran.dg/c_funloc_tests_3.f03  -O0  compilation failed to produce
executable
FAIL: gfortran.dg/c_funloc_tests_3.f03  -O1  (test for excess errors)
WARNING: gfortran.dg/c_funloc_tests_3.f03  -O1  compilation failed to produce
executable
FAIL: gfortran.dg/c_funloc_tests_3.f03  -O2  (test for excess errors)
WARNING: gfortran.dg/c_funloc_tests_3.f03  -O2  compilation failed to produce
executable
FAIL: gfortran.dg/c_funloc_tests_3.f03  -O3 -fomit-frame-pointer  (test for
excess errors)
WARNING: gfortran.dg/c_funloc_tests_3.f03  -O3 -fomit-frame-pointer 
compilation failed to produce executable
FAIL: gfortran.dg/c_funloc_tests_3.f03  -O3 -fomit-frame-pointer -funroll-loops
 (test for excess errors)
WARNING: gfortran.dg/c_funloc_tests_3.f03  -O3 -fomit-frame-pointer
-funroll-loops  compilation failed to produce execu\
table
FAIL: gfortran.dg/c_funloc_tests_3.f03  -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions  (test for exces\
s errors)
WARNING: gfortran.dg/c_funloc_tests_3.f03  -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions  compilation \
failed to produce executable
FAIL: gfortran.dg/c_funloc_tests_3.f03  -O3 -g  (test for excess errors)
WARNING: gfortran.dg/c_funloc_tests_3.f03  -O3 -g  compilation failed to
produce executable
FAIL: gfortran.dg/c_funloc_tests_3.f03  -Os  (test for excess errors)
WARNING: gfortran.dg/c_funloc_tests_3.f03  -Os  compilation failed to produce
executable
FAIL: gfortran.dg/c_funloc_tests_4.f03  -O0  (test for excess errors)
WARNING: gfortran.dg/c_funloc_tests_4.f03  -O0  compilation failed to produce
executable
FAIL: gfortran.dg/c_funloc_tests_4.f03  -O1  (test for excess errors)
WARNING: gfortran.dg/c_funloc_tests_4.f03  -O1  compilation failed to produce
executable
FAIL: gfortran.dg/c_funloc_tests_4.f03  -O2  (test for excess errors)
WARNING: gfortran.dg/c_funloc_tests_4.f03  -O2  compilation failed to produce
executable
FAIL: gfortran.dg/c_funloc_tests_4.f03  -O3 -fomit-frame-pointer  (test for
excess errors)
WARNING: gfortran.dg/c_funloc_tests_4.f03  -O3 -fomit-frame-pointer 
compilation failed to produce executable
FAIL: gfortran.dg/c_funloc_tests_4.f03  -O3 -fomit-frame-pointer -funroll-loops
 (test for excess errors)
WARNING: gfortran.dg/c_funloc_tests_4.f03  -O3 -fomit-frame-pointer
-funroll-loops  compilation failed to produce execu\
table
FAIL: gfortran.dg/c_funloc_tests_4.f03  -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions  (test for exces\
s errors)
WARNING: gfortran.dg/c_funloc_tests_4.f03  -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions  compilation \
failed to produce executable
FAIL: gfortran.dg/c_funloc_tests_4.f03  -O3 -g  (test for excess errors)
WARNING: gfortran.dg/c_funloc_tests_4.f03  -O3 -g  compilation failed to
produce executable
FAIL: gfortran.dg/c_funloc_tests_4.f03  -Os  (test for excess errors)
WARNING: gfortran.dg/c_funloc_tests_4.f03  -Os  compilation failed to produce
executable
FAIL: gfortran.dg/c_ptr_tests_8.f03  -O0  (test for excess errors)
WARNING: gfortran.dg/c_ptr_tests_8.f03  -O0  compilation failed to produce
executable
FAIL: gfortran.dg/c_ptr_tests_8.f03  -O1  (test for excess errors)
WARNING: gfortran.dg/c_ptr_tests_8.f03  -O1  compilation failed to produce
executable
FAIL: gfortran.dg/c_ptr_tests_8.f03  -O2  (test for excess errors)
WARNING: gfortran.dg/c_ptr_tests_8.f03  -O2  compilation failed to produce
executable
FAIL: gfortran.dg/c_ptr_tests_8.f03  -O3 -fomit-frame-pointer  (test for excess
errors)
WARNING: gfortran.dg/c_ptr_tests_8.f03  -O3 -fomit-frame-pointer  compilation
failed to produce executable
FAIL: gfortran.dg/c_ptr_tests_8.f03  -O3 -fomit-frame-pointer -funroll-loops 
(test for excess errors)
WARNING: gfortran.dg/c_ptr_tests_8.f03  -O3 -fomit-frame-pointer -funroll-loops
 compilation failed to produce executab\
le
FAIL: gfortran.dg/c_ptr_tests_8.f03  -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions  (test for excess e\
rrors)
WARNING: gfortran.dg/c_ptr_tests_8.f03  -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions  compilation fai\
led to produce executable
FAIL: gfortran.dg/c_ptr_tests_8.f03  -O3 -g  (test for excess errors)
WARNING: gfortran.dg/c_ptr_tests_8.f03  -O3 -g  compilation failed to produce
executable
FAIL: gfortran.dg/c_ptr_tests_8.f03  -Os  (test for excess errors)
WARNING: gfortran.dg/c_ptr_tests_8.f03  -Os  compilation failed to produce
executable
FAIL: gfortran.dg/c_size_t_test.f03  -O0  (test for excess errors)
WARNING: gfortran.dg/c_size_t_test.f03  -O0  compilation failed to produce
executable
FAIL: gfortran.dg/c_size_t_test.f03  -O1  (test for excess errors)
WARNING: gfortran.dg/c_size_t_test.f03  -O1  compilation failed to produce
executable
FAIL: gfortran.dg/c_size_t_test.f03  -O2  (test for excess errors)
WARNING: gfortran.dg/c_size_t_test.f03  -O2  compilation failed to produce
executable
FAIL: gfortran.dg/c_size_t_test.f03  -O3 -fomit-frame-pointer  (test for excess
errors)
WARNING: gfortran.dg/c_size_t_test.f03  -O3 -fomit-frame-pointer  compilation
failed to produce executable
FAIL: gfortran.dg/c_size_t_test.f03  -O3 -fomit-frame-pointer -funroll-loops 
(test for excess errors)
WARNING: gfortran.dg/c_size_t_test.f03  -O3 -fomit-frame-pointer -funroll-loops
 compilation failed to produce executab\
le
FAIL: gfortran.dg/c_size_t_test.f03  -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions  (test for excess e\
rrors)
WARNING: gfortran.dg/c_size_t_test.f03  -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions  compilation fai\
led to produce executable
FAIL: gfortran.dg/c_size_t_test.f03  -O3 -g  (test for excess errors)
WARNING: gfortran.dg/c_size_t_test.f03  -O3 -g  compilation failed to produce
executable
FAIL: gfortran.dg/c_size_t_test.f03  -Os  (test for excess errors)
WARNING: gfortran.dg/c_size_t_test.f03  -Os  compilation failed to produce
executable

The messages in the logfiles are similar:
Executing on host: /tmp/bad0516b/gccobj/gcc/xgcc -B/tmp/bad0516b/gccobj/gcc/
/tmp/bad0516b/gcc/gcc/testsuite/gcc.dg/cpp/19990407-1.c 
-fno-diagnostics-show-caret    -ansi -pedantic-errors   -isystem
/tmp/bad0516b/gccobj/cris-elf/./newlib/targ-include -isystem
/tmp/bad0516b/gcc/newlib/libc/include
-B/tmp/bad0516b/gccobj/cris-elf/./libgloss/cris/
-L/tmp/bad0516b/gccobj/cris-elf/./libgloss/cris
-L/tmp/bad0516b/gcc/libgloss/cris  -B/tmp/bad0516b/gccobj/cris-elf/./newlib/
-L/tmp/bad0516b/gccobj/cris-elf/./newlib -sim3  -lm   -o ./19990407-1.exe   
(timeout = 300)
/tmp/bad0516b/gcc/newlib/libc/include/machine/_default_types.h:98:39: error:
use of C99 long long integer constant [-Wlong-long]^M
compiler exited with status 1
output is:
/tmp/bad0516b/gcc/newlib/libc/include/machine/_default_types.h:98:39: error:
use of C99 long long integer constant [-Wlong-long]^M

FAIL: gcc.dg/cpp/19990407-1.c (test for excess errors)
Excess errors:
/tmp/bad0516b/gcc/newlib/libc/include/machine/_default_types.h:98:39: error:
use of C99 long long integer constant [-Wlong-long]

WARNING: gcc.dg/cpp/19990407-1.c compilation failed to produce executable

I'm attaching 19990407-1.i and _default_types.h.  From what I can see, the
latter is considered a system header by the preprocessor just as before, still
a warning is now emitted that wasn't before.  A -Wno-system-headers has no
effect.

According to -v, the preprocessor is invoked as "/tmp/bad0516b/gccobj/gcc/cc1
-E -quiet -v -iprefix /tmp/bad0516b/gccobj/gcc/../lib/gcc/cris-elf/4.8.0/
-isystem /tmp/bad0516b/gccobj/gcc/include -isystem
/tmp/bad0516b/gccobj/gcc/include-fixed -isystem
/tmp/bad0516b/gccobj/cris-elf/./newlib/targ-include -isystem
/tmp/bad0516b/gcc/newlib/libc/include
/tmp/bad0516b/gcc/gcc/testsuite/gcc.dg/cpp/19990407-1.c -melf -ansi
-pedantic-errors -fno-diagnostics-show-caret -fpch-preprocess -o 19990407-1.i"
which yields:

ignoring nonexistent directory
"/tmp/bad0516b/gccobj/gcc/../lib/gcc/cris-elf/4.8.0/include"
ignoring nonexistent directory
"/tmp/bad0516b/gccobj/gcc/../lib/gcc/cris-elf/4.8.0/include-fixed"
ignoring nonexistent directory
"/tmp/bad0516b/gccobj/gcc/../lib/gcc/cris-elf/4.8.0/../../../../cris-elf/sys-include"
ignoring nonexistent directory
"/tmp/bad0516b/gccobj/gcc/../lib/gcc/cris-elf/4.8.0/../../../../cris-elf/include"
ignoring nonexistent directory
"/tmp/bad0516b/gccobj/gcc/../lib/gcc/../../lib/gcc/cris-elf/4.8.0/include"
ignoring nonexistent directory
"/tmp/bad0516b/gccobj/gcc/../lib/gcc/../../lib/gcc/cris-elf/4.8.0/include-fixed"
ignoring nonexistent directory
"/tmp/bad0516b/gccobj/gcc/../lib/gcc/../../lib/gcc/cris-elf/4.8.0/../../../../cris-elf/sys-include"
ignoring nonexistent directory
"/tmp/bad0516b/gccobj/gcc/../lib/gcc/../../lib/gcc/cris-elf/4.8.0/../../../../cris-elf/include"
#include "..." search starts here:
#include <...> search starts here:
 /tmp/bad0516b/gccobj/gcc/include
 /tmp/bad0516b/gccobj/gcc/include-fixed
 /tmp/bad0516b/gccobj/cris-elf/./newlib/targ-include
 /tmp/bad0516b/gcc/newlib/libc/include
End of search list.
/tmp/bad0516b/gcc/newlib/libc/include/machine/_default_types.h:98:39: error:
use of C99 long long integer constant [-Wlong-long]

Author of the patch in that revision is CC:ed.

[Bug preprocessor/53463] [4.8 Regression]: system header not recognized, yielding warnings about long long preprocessor constant

[hp at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53463

--- Comment #1 from Hans-Peter Nilsson <hp at gcc dot gnu.org> 2012-05-23 20:21:01 UTC ---
Created attachment 27484
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27484
The offending system header _default_types.h, fresh from newlib.

A brief look in gcc-testresults archives expectedly shows this regression for
other newlib targets too.

[Bug preprocessor/53463] [4.8 Regression]: system header not recognized, yielding warnings about long long preprocessor constant

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53463

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.8.0

[Bug preprocessor/53463] [4.8 Regression]: system header not recognized, yielding warnings about long long preprocessor constant

[Greta.Yorsh at arm dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53463

Greta Yorsh <Greta.Yorsh at arm dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |Greta.Yorsh at arm dot com

--- Comment #2 from Greta Yorsh <Greta.Yorsh at arm dot com> 2012-05-24 13:08:57 UTC ---
The following tests fail on arm-none-eabi:

FAIL: gcc.dg/cpp/19990407-1.c (test for excess errors)
FAIL: gcc.dg/cpp/paste12.c (test for excess errors)
FAIL: gcc.dg/cpp/strp1.c (test for excess errors)
FAIL: gcc.dg/cpp/strp2.c (test for excess errors)
FAIL: gcc.dg/struct-ret-libc.c (test for excess errors)

For example:

/work/builds/a9-may/install/bin/arm-none-eabi-gcc
/work/local-checkouts/gcc-fsf/gcc/testsuite/gcc.dg/cpp/19990407-1.c
-mcpu=cortex-a9 -mfloat-abi=softfp -mfpu=neon -fno-diagnostics-show-caret
-pedantic-errors -o 19990407-1.exe
/work/builds/a9-may/install/arm-none-eabi/include/machine/_default_types.h:98:39:
error: use of C99 long long integer constant [-Wlong-long]

[Bug preprocessor/53463] [4.8 Regression]: system header not recognized, yielding warnings about long long preprocessor constant

[dodji at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53463

Dodji Seketeli <dodji at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2012-05-25
         AssignedTo|unassigned at gcc dot       |dodji at gcc dot gnu.org
                   |gnu.org                     |
     Ever Confirmed|0                           |1

[Bug preprocessor/53463] [4.8 Regression]: system header not recognized, yielding warnings about long long preprocessor constant

[dodji at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53463

--- Comment #3 from Dodji Seketeli <dodji at gcc dot gnu.org> 2012-05-25 09:58:42 UTC ---
It seems to me that this issue is dealt with by the patch I have proposed at
http://gcc.gnu.org/ml/gcc-patches/2012-05/msg01389.html.  The discussion on
that patch is still going on.

Could you please try that patch and reply to the discussion there to say if it
address the issue on your target?

Thanks.

[Bug preprocessor/53463] [4.8 Regression]: system header not recognized, yielding warnings about long long preprocessor constant

[hp at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53463

--- Comment #4 from Hans-Peter Nilsson <hp at gcc dot gnu.org> 2012-05-26 01:50:09 UTC ---
(In reply to comment #3)
> Could you please try that patch and reply to the discussion there to say if it
> address the issue on your target?

It does thanks, see the reply.

[Bug preprocessor/53463] [4.8 Regression]: system header not recognized, yielding warnings about long long preprocessor constant

[Greta.Yorsh at arm dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53463

--- Comment #5 from Greta Yorsh <Greta.Yorsh at arm dot com> 2012-05-28 15:28:16 UTC ---
(In reply to comment #3)
> It seems to me that this issue is dealt with by the patch I have proposed at
> http://gcc.gnu.org/ml/gcc-patches/2012-05/msg01389.html.  The discussion on
> that patch is still going on.
> 
> Could you please try that patch and reply to the discussion there to say if it
> address the issue on your target?
> 
> Thanks.

This patch fixes the regressions observed for arm-none-eabi.

[Bug preprocessor/53463] [4.8 Regression]: system header not recognized, yielding warnings about long long preprocessor constant

[dodji at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53463

--- Comment #6 from Dodji Seketeli <dodji at gcc dot gnu.org> 2012-06-04 19:20:16 UTC ---
Author: dodji
Date: Mon Jun  4 19:19:58 2012
New Revision: 188203

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=188203
Log:
PR preprocessor/53463 - Fix system header detection for built-in macro tokens

The location for a built-in macro token is BUILTIN_LOCATION.  When we
see that location value, we cannot know if that token was used in a
system header or not.  And that can trigger some unwanted warnings on
e.g, the use of __LONG_LONG_MAX__ built-in macro in system headers
when we compile with -pedantic, like in the test case accompanying
this patch.

In that case, I think we ought to step-up to see where the built-in
macro has been expanded, until we see a location that is not for a
built-in macro.  Then we can check if the resulting location is in a
system header or not.

Now that we step up to the location of first non-built-in-macro token,
it appeared that for
testsuite/c-c++-common/dfp/convert-int-saturate.c, G++ then fails to
emit the warning in:

    volatile unsigned int usi;
    int
    main ()
    {
      usi = DEC32_MAX;  /* { dg-warning "overflow in implicit constant
conversion" } */
     ...
    }

Because DEC32_MAX is defined in the system header float.h as a
built-in macro:

    #define DEC32_MAX    __DEC32_MAX__

And during the parsing of the assignment expression that should have
led to the warning above, input_location is set to the location for
the DEC32_MAX, which is actually the location for the built-in
__DECL32_MAX_EXP.

A possible fix is to use the location of the "=" operator as the
default location for assignment expressions.  This is what the patch
does.

I had to adjust a couple of tests to arrange for this.

Bootstrapped and tested on x86_64-unknown-linux-gnu against trunk.

libcpp/

    PR preprocessor/53463
    * line-map.c (linemap_location_in_system_header_p): For built-in
    macro tokens, check the first expansion point location for that is
    not for a token coming from a built-in macro.

gcc/cp/

    PR preprocessor/53463
    * parser.c (cp_parser_assignment_expression): Use the location
    for the LHS as the default location for the expression.

gcc/testsuite/

    PR preprocessor/53463
    * g++.dg/cpp/limits.C: New test.
    * g++.dg/parse/error19.C: Adjust.
    * g++.dg/warn/Wconversion-real-integer2.C: Likewise.
    * g++.dg/warn/pr35635.C: Likewise.
    * g++.old-deja/g++.pt/assign1.C: Likewise.

Added:
    trunk/gcc/testsuite/g++.dg/cpp/limits.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cp/parser.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/g++.dg/parse/error19.C
    trunk/gcc/testsuite/g++.dg/warn/Wconversion-real-integer2.C
    trunk/gcc/testsuite/g++.dg/warn/pr35635.C
    trunk/gcc/testsuite/g++.old-deja/g++.pt/assign1.C
    trunk/libcpp/ChangeLog
    trunk/libcpp/line-map.c

[Bug preprocessor/53463] [4.8 Regression]: system header not recognized, yielding warnings about long long preprocessor constant

[dodji at seketeli dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53463

--- Comment #7 from dodji at seketeli dot org <dodji at seketeli dot org> 2012-06-04 19:57:31 UTC ---
Hans-Peter and Greta,

Could you please test trunk and, if the commit above fixes the issue for
you, close the bug please?

Thank you in advance.

[Bug preprocessor/53463] [4.8 Regression]: system header not recognized, yielding warnings about long long preprocessor constant

[hp at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53463

Hans-Peter Nilsson <hp at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED

--- Comment #8 from Hans-Peter Nilsson <hp at gcc dot gnu.org> 2012-06-05 08:29:39 UTC ---
(In reply to comment #7)
> Hans-Peter and Greta,
> 
> Could you please test trunk and, if the commit above fixes the issue for
> you, close the bug please?

Yes, thanks. The witch is cooked (SCNR :)