[Bug c++/59804] New: C++ front-end checking ends in an infinite loop on erroneous code

[Bug c++/59804] New: C++ front-end checking ends in an infinite loop on erroneous code

[jamborm at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59804

            Bug ID: 59804
           Summary: C++ front-end checking ends in an infinite loop on
                    erroneous code
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jamborm at gcc dot gnu.org

Created attachment 31831
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31831&action=edit
Testcase

I discovered this problem when multidelta-reducing a different PR.
Multidelta produced this invalid source that however causes the c++
front-end of an checking-enabled compiler to end up in an infinite
loop (or just takes incredible time to finish but I doubt that).

Release-checking g++ compains about errors and exits normally.

x86_64-linux, no compiler options necessary.

[Bug c++/59804] C++ front-end checking ends in an infinite loop on erroneous code

[manu at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59804

Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |error-recovery,
                   |                            |ice-checking
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-09-27
                 CC|                            |manu at gcc dot gnu.org
     Ever confirmed|0                           |1
      Known to fail|                            |4.9.0, 5.0

--- Comment #1 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
It is recursing here:
1396    #ifdef ENABLE_CHECKING
1397          if (USE_CANONICAL_TYPES)
1398            {
1399              bool result = structural_comptypes (t1, t2, strict);

so we get:

#0  comptypes (t1=0x7ffff6db4000, t2=0x7ffff6d59000, strict=<optimized out>) at
/home/manuel/test1/pristine/gcc/cp/typeck.c:1401
#1  0x00000000006f5e1e in structural_comptypes (t1=0x7ffff6db42a0,
t2=0x7ffff6d592a0, strict=0) at
/home/manuel/test1/pristine/gcc/cp/typeck.c:1341
#2  0x00000000006f7c88 in comptypes (t1=0x7ffff6db42a0, t2=0x7ffff6d592a0,
strict=<optimized out>) at /home/manuel/test1/pristine/gcc/cp/typeck.c:1399
#3  0x00000000006f5e1e in structural_comptypes (t1=0x7ffff6db4540,
t2=0x7ffff6d59540, strict=0) at
/home/manuel/test1/pristine/gcc/cp/typeck.c:1341
#4  0x00000000006f7c88 in comptypes (t1=0x7ffff6db4540, t2=0x7ffff6d59540,
strict=<optimized out>) at /home/manuel/test1/pristine/gcc/cp/typeck.c:1399
#5  0x00000000006f5e1e in structural_comptypes (t1=0x7ffff6db47e0,
t2=0x7ffff6d597e0, strict=0) at
/home/manuel/test1/pristine/gcc/cp/typeck.c:1341
#6  0x00000000006f7c88 in comptypes (t1=0x7ffff6db47e0, t2=0x7ffff6d597e0,
strict=<optimized out>) at /home/manuel/test1/pristine/gcc/cp/typeck.c:1399
#7  0x00000000006f5e1e in structural_comptypes (t1=0x7ffff6db4a80,
t2=0x7ffff6d59a80, strict=0) at
/home/manuel/test1/pristine/gcc/cp/typeck.c:1341
#8  0x00000000006f7c88 in comptypes (t1=0x7ffff6db4a80, t2=0x7ffff6d59a80,
strict=<optimized out>) at /home/manuel/test1/pristine/gcc/cp/typeck.c:1399
#9  0x00000000006f5e1e in structural_comptypes (t1=0x7ffff6db4d20,
t2=0x7ffff6d59d20, strict=0) at
/home/manuel/test1/pristine/gcc/cp/typeck.c:1341
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Subject: [Bug c++/16564] g++ seems to go into an infinite loop after errors
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=16564

--- Comment #22 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
(In reply to Volker Reichelt from comment #18)
> The first error message about exceeding the maximum template instantiation
> depth appears rather quickly. So maybe we could make the first error message
> a fatal one to avoid further processing of potentially bogus nested classes.

This is a patch doing exactly that:
https://gcc.gnu.org/ml/gcc-patches/2014-08/msg01709.html

However, I probably won't have time until the Christmas holidays to work on it,
so please anyone feel free to take it and get it reviewed and applied. Thanks!
>From gcc-bugs-return-462715-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Sat Sep 27 16:26:07 2014
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Subject: [Bug c++/63389] New: Wrong warning about 64 bit integer constant overflow
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idc389

            Bug ID: 63389
           Summary: Wrong warning about 64 bit integer constant overflow
           Product: gcc
           Version: 4.9.1
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ingo.josopait at gmx dot de

Declaring the following constant creates a warning. I don't think it should.
-2^63 is the largest negative 64 bit integer value. The same warning appears
when compiling C language.


long i = -9223372036854775808L;   // equals -2^63



The compiler output is:

test.cpp:1:11: warning: integer constant is so large that it is unsigned
 long i = -9223372036854775808L;
           ^
test.cpp:1:1: warning: this decimal constant is unsigned only in ISO C90
 long i = -9223372036854775808L;