[Bug c++/49165] New: ICE on for-loop/throw combination

[Bug c++/49165] New: ICE on for-loop/throw combination

[gcc at portuosus dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

           Summary: ICE on for-loop/throw combination
           Product: gcc
           Version: 4.5.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: gcc@portuosus.com


Source file /tmp/redux.cc:

#include <iostream>
#include <string>

int main(int argc,char**argv)
{
  std::string str;
  for ( int field(0);
        (field<10) && ((std::cin>>str)?true:(throw std::string("failure")));
        field++ );
}

produces:

/tmp/redux.cc: In function ‘int main(int, char**)’:
/tmp/redux.cc:7:3: internal compiler error: in fold_convert_loc, at
fold-const.c:2670

[Bug c++/49165] ICE on for-loop/throw combination

[gcc at portuosus dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

--- Comment #1 from Vijay Rao <gcc at portuosus dot com> 2011-05-25 18:34:31 UTC ---
/tmp/redux.cc

#include <iostream>
#include <string>

int main(int argc,char**argv)
{
  std::string str;
  for ( int field(0);
        (field<10) && ((std::cin>>str)? 1 :(throw std::string("failure")));
        field++ );
}

g++ /tmp/redux.cc 
/tmp/redux.cc: In function ‘int main(int, char**)’:
/tmp/redux.cc:8:65: error: void value not ignored as it ought to be

This bug looks a lot like what I reported some years ago:

This:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14083

shows that it should be accepted by the compiler.

[Bug c++/49165] [4.3/4.4/4.5/4.6/4.7 Regression] ICE on for-loop/throw combination

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2011.05.25 18:43:15
                 CC|                            |jakub at gcc dot gnu.org
         Depends on|14083                       |
            Summary|ICE on for-loop/throw       |[4.3/4.4/4.5/4.6/4.7
                   |combination                 |Regression] ICE on
                   |                            |for-loop/throw combination
     Ever Confirmed|0                           |1

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-05-25 18:43:15 UTC ---
Shorter testcase:
int
foo (bool x, int y)
{
  if (y < 10 && (x ? true : throw 1))
    y++;
  return y;
}

ICE started between r112000 and r113000, before that it failed to compile with
error: void value not ignored as it ought to be error.
The ICE is during gimple_boolify, throw has void_type_node and fold_convert to
boolean_type_node ICEs.

[Bug c++/49165] [4.3/4.4/4.5/4.6/4.7 Regression] ICE on for-loop/throw combination

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jason at gcc dot gnu.org

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-05-25 19:47:52 UTC ---
--- gimplify.c (revision 174199)
+++ gimplify.c (working copy)
@@ -2848,7 +2848,7 @@
     default:
       /* Other expressions that get here must have boolean values, but
          might need to be converted to the appropriate mode.  */
-      if (type == boolean_type_node)
+      if (type == boolean_type_node || type == void_type_node)
         return expr;
       return fold_convert_loc (loc, boolean_type_node, expr);
     }
fixes the ICE, but we error out then still during gimplification:
error: using result of function returning ‘void’
I think the only problematic case is when one COND_EXPR arm is THROW_EXPR (i.e.
void_type_node) and the other one has gimple reg type.  Either the FE
(genericization or during gimplification) should replace THROW_EXPR with
COMPOUND_EXPR <THROW_EXPR, <fold_convert <type, integer_zero_node>>>, or
gimplifier needs to special case it in some places.  Is the only possibility to
create COND_EXPR in C++ with void_type_node on one arm and some other type on
the other arm and COND_EXPR itself a throw?

[Bug c++/49165] [4.3/4.4/4.5/4.6/4.7 Regression] ICE on for-loop/throw combination

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

--- Comment #4 from Jason Merrill <jason at gcc dot gnu.org> 2011-05-25 20:04:47 UTC ---
Yes, that's right.  5.16/2:

If either the second or the third operand has type (possibly cv-qualified)
void, then the lvalue-to-rvalue (4.1), array-to-pointer (4.2), and
function-to-pointer (4.3) standard conversions are performed on the second and
third operands, and one of the following shall hold:
— The second or the third operand (but not both) is a throw-expression (15.1);
the result is of the type of the other and is a prvalue.
— Both the second and the third operands have type void; the result is of type
void and is a prvalue. [ Note: This includes the case where both operands are
throw-expressions. — end note ]

[Bug c++/49165] [4.3/4.4/4.5/4.6/4.7 Regression] ICE on for-loop/throw combination

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
         AssignedTo|unassigned at gcc dot       |jakub at gcc dot gnu.org
                   |gnu.org                     |

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-05-26 07:27:45 UTC ---
Created attachment 24361
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24361
gcc46-pr49165.patch

Fix.  Will commit after bootstrap/regtest.

[Bug c++/49165] [4.3/4.4/4.5/4.6/4.7 Regression] ICE on for-loop/throw combination

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

--- Comment #6 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-05-26 08:25:26 UTC ---
       && !VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (pred, 1)))
2578        && !VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (pred, 2))))

shouldn't either none or both arms be VOID_TYPE_P?  So,

           && (!VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (pred, 1)))
               || !VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (pred, 2))))
       {
         gcc[_checking]_assert (!VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (pred,
1))))
&& !VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (pred, 2))))
...

would be better?

[Bug c++/49165] [4.3/4.4/4.5/4.6/4.7 Regression] ICE on for-loop/throw combination

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-05-26 08:47:36 UTC ---
No.
Both arms shouldn't be VOID_TYPE_P, otherwise the COND_EXPR would be
VOID_TYPE_P too and we really shouldn't be using the COND_EXPR's value.
The problem is that the C++ FE gives us
COND_EXPR with bool type (or some other type), with one arm the same type and
the other arm THROW_EXPR (i.e. VOID_TYPE_P).
The gimplifier is already aware of this and handles it right:
      /* Build the new then clause, `tmp = then_;'.  But don't build the
         assignment if the value is void; in C++ it can be if it's a throw.  */
      if (!VOID_TYPE_P (TREE_TYPE (then_)))
        TREE_OPERAND (expr, 1) = build2 (MODIFY_EXPR, type, tmp, then_);

      /* Similarly, build the new else clause, `tmp = else_;'.  */
      if (!VOID_TYPE_P (TREE_TYPE (else_)))
        TREE_OPERAND (expr, 2) = build2 (MODIFY_EXPR, type, tmp, else_);
just shortcut_cond_r didn't handle it well (it created
COND_EXPR with void type throw ? goto L1 : goto L2).

[Bug c++/49165] [4.3/4.4/4.5/4.6/4.7 Regression] ICE on for-loop/throw combination

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-05-26 10:25:23 UTC ---
Author: jakub
Date: Thu May 26 10:25:21 2011
New Revision: 174273

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=174273
Log:
    PR c++/49165
    * gimplify.c (shortcut_cond_r): Don't special case
    COND_EXPRs if they have void type on one of their arms.

    * g++.dg/eh/cond5.C: New test.

Added:
    trunk/gcc/testsuite/g++.dg/eh/cond5.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/gimplify.c
    trunk/gcc/testsuite/ChangeLog

[Bug c++/49165] [4.3/4.4/4.5/4.6/4.7 Regression] ICE on for-loop/throw combination

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-05-26 10:27:59 UTC ---
Author: jakub
Date: Thu May 26 10:27:57 2011
New Revision: 174274

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=174274
Log:
    PR c++/49165
    * gimplify.c (shortcut_cond_r): Don't special case
    COND_EXPRs if they have void type on one of their arms.

    * g++.dg/eh/cond5.C: New test.

Added:
    branches/gcc-4_6-branch/gcc/testsuite/g++.dg/eh/cond5.C
Modified:
    branches/gcc-4_6-branch/gcc/ChangeLog
    branches/gcc-4_6-branch/gcc/gimplify.c
    branches/gcc-4_6-branch/gcc/testsuite/ChangeLog

[Bug c++/49165] [4.3/4.4/4.5 Regression] ICE on for-loop/throw combination

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.3.6
            Summary|[4.3/4.4/4.5/4.6/4.7        |[4.3/4.4/4.5 Regression]
                   |Regression] ICE on          |ICE on for-loop/throw
                   |for-loop/throw combination  |combination

--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-05-26 10:46:40 UTC ---
Fixed for 4.6+ so far.

[Bug c++/49165] [4.3/4.4/4.5 Regression] ICE on for-loop/throw combination

[gcc at portuosus dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

--- Comment #11 from Vijay Rao <gcc at portuosus dot com> 2011-05-27 07:58:25 UTC ---
Does this fix the situation when the 2nd operand of the conditional operator is
of type int? 

extern "C" void abort ();

int bar (bool x, int y)
{
  if (y < 10 && (x ? 1 : throw 1))
    y++;
  if (y > 20 || (x ? 1 : throw 2))
    y++;
  return y;
}

int main ()
{
  if (bar (true, 0) != 2
      || bar (true, 10) != 11
      || bar (false, 30) != 31)
    abort ();
  try
    {
      bar (false, 0);
      abort ();
    }
  catch (int i)
    {
      if (i != 1)
        abort ();
    }
  try
    {
      bar (false, 10);
      abort ();
    }
  catch (int i)
    {
      if (i != 2)
        abort ();
    }
}

[Bug c++/49165] [4.3/4.4/4.5 Regression] ICE on for-loop/throw combination

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

--- Comment #12 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-05-27 12:30:29 UTC ---
Created attachment 24369
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24369
gcc46-pr49165.patch

Indeed, c_common_truthvalue_conversion needs to be aware of it too.

[Bug c++/49165] [4.3/4.4/4.5 Regression] ICE on for-loop/throw combination

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

--- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-05-27 19:19:39 UTC ---
Author: jakub
Date: Fri May 27 19:19:36 2011
New Revision: 174350

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=174350
Log:
    PR c++/49165
    * c-common.c (c_common_truthvalue_conversion) <case COND_EXPR>: For
    C++ don't call c_common_truthvalue_conversion on void type arms.

    * g++.dg/eh/cond6.C: New test.

Added:
    trunk/gcc/testsuite/g++.dg/eh/cond6.C
Modified:
    trunk/gcc/c-family/ChangeLog
    trunk/gcc/c-family/c-common.c
    trunk/gcc/testsuite/ChangeLog

[Bug c++/49165] [4.3/4.4/4.5 Regression] ICE on for-loop/throw combination

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

--- Comment #14 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-05-27 19:23:49 UTC ---
Author: jakub
Date: Fri May 27 19:23:46 2011
New Revision: 174351

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=174351
Log:
    PR c++/49165
    * c-common.c (c_common_truthvalue_conversion) <case COND_EXPR>: For
    C++ don't call c_common_truthvalue_conversion on void type arms.

    * g++.dg/eh/cond6.C: New test.

Added:
    branches/gcc-4_6-branch/gcc/testsuite/g++.dg/eh/cond6.C
Modified:
    branches/gcc-4_6-branch/gcc/c-family/ChangeLog
    branches/gcc-4_6-branch/gcc/c-family/c-common.c
    branches/gcc-4_6-branch/gcc/testsuite/ChangeLog

[Bug c++/49165] [4.3/4.4/4.5 Regression] ICE on for-loop/throw combination

[gcc at portuosus dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

--- Comment #15 from Vijay Rao <gcc at portuosus dot com> 2011-05-27 22:19:00 UTC ---
Ok, thanks for this. While using 4.5.1 I'm also stuck in a toolchain using
3.4.6 for which the latter doesn't fail when one of the conditional args is of
type bool but does give the "void value not ignored as it ought to be" error
when one of the args is of int type which I wasn't getting while using 3.3.2. I
was getting an ICE when using bool for one of the conditional args in 3.3.2
(reported in 14083).

I was wondering whether to try a compiler version > 3.3.2 and < 3.4.6 but if
both issues are going to be covered then it'll be worth the effort, ceteris
paribus, of introducing a version 4 compiler in the toolchain. 

Just goofing around with test cases code:

template<typename R, typename Y, typename C>
struct X 
{
  R f(int x, Y y);
};

template<typename R, typename Y>
struct X<R,Y,bool> 
{
  R f(int x, Y y) {
    return y && (x<2?true:throw 14);
  }
};

template<typename R, typename Y>
struct X<R,Y,int> 
{
  R f(int x, Y y) {
    return y && (x<2? 1 :throw 14);
  }
};

int main(int argc,char**argv)
{
  int x(2);
  try {
    int j(X<int,int,int>()
          .f(x,
             X<int,int,bool>()
             .f(x,
                X<int,bool,int>()
                .f(x,
                   X<bool,bool,bool>()
                   .f(x,
                      X<bool,bool,int>()
                      .f(x,
                         X<bool,int,int>()
                         .f(x, x)
                         )
                      )
                   )
                )
             )
          );
  } catch ( int e ) { if (e!=14) throw; }

  x=argc;
  int k(X<int,int,int>()
        .f(x,
           X<int,int,bool>()
           .f(x,
              X<int,bool,int>()
              .f(x,
                 X<bool,bool,bool>()
                 .f(x,
                    X<bool,bool,int>()
                    .f(x,
                       X<bool,int,int>()
                       .f(x, x)
                       )
                    )
                 )
              )
           )
        );
}

[Bug c++/49165] [4.3/4.4/4.5 Regression] ICE on for-loop/throw combination

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

[Bug c++/49165] [4.3/4.4/4.5 Regression] ICE on for-loop/throw combination

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.3.6                       |4.4.7

--- Comment #16 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-06-27 12:13:28 UTC ---
4.3 branch is being closed, moving to 4.4.7 target.

[Bug c++/49165] [4.4/4.5 Regression] ICE on for-loop/throw combination

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

--- Comment #17 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-07-19 12:54:37 UTC ---
Author: jakub
Date: Tue Jul 19 12:54:34 2011
New Revision: 176452

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=176452
Log:
    Backport from mainline
    2011-05-26  Jakub Jelinek  <jakub@redhat.com>

    PR c++/49165
    * gimplify.c (shortcut_cond_r): Don't special case
    COND_EXPRs if they have void type on one of their arms.

    * g++.dg/eh/cond5.C: New test.

Added:
    branches/gcc-4_5-branch/gcc/testsuite/g++.dg/eh/cond5.C
Modified:
    branches/gcc-4_5-branch/gcc/ChangeLog
    branches/gcc-4_5-branch/gcc/gimplify.c
    branches/gcc-4_5-branch/gcc/testsuite/ChangeLog

[Bug c++/49165] [4.4/4.5 Regression] ICE on for-loop/throw combination

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

--- Comment #18 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-07-19 12:56:50 UTC ---
Author: jakub
Date: Tue Jul 19 12:56:48 2011
New Revision: 176453

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=176453
Log:
    Backport from mainline
    2011-05-27  Jakub Jelinek  <jakub@redhat.com>

    PR c++/49165
    * c-common.c (c_common_truthvalue_conversion) <case COND_EXPR>: For
    C++ don't call c_common_truthvalue_conversion on void type arms.

    * g++.dg/eh/cond6.C: New test.

Added:
    branches/gcc-4_5-branch/gcc/testsuite/g++.dg/eh/cond6.C
Modified:
    branches/gcc-4_5-branch/gcc/ChangeLog
    branches/gcc-4_5-branch/gcc/c-common.c
    branches/gcc-4_5-branch/gcc/testsuite/ChangeLog

[Bug c++/49165] [4.4/4.5 Regression] ICE on for-loop/throw combination

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

--- Comment #19 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-07-19 19:30:01 UTC ---
Author: jakub
Date: Tue Jul 19 19:29:57 2011
New Revision: 176483

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=176483
Log:
    Backport from mainline
    2011-05-26  Jakub Jelinek  <jakub@redhat.com>

    PR c++/49165
    * gimplify.c (shortcut_cond_r): Don't special case
    COND_EXPRs if they have void type on one of their arms.

    * g++.dg/eh/cond5.C: New test.

Added:
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/eh/cond5.C
Modified:
    branches/gcc-4_4-branch/gcc/ChangeLog
    branches/gcc-4_4-branch/gcc/gimplify.c
    branches/gcc-4_4-branch/gcc/testsuite/ChangeLog

[Bug c++/49165] [4.4/4.5 Regression] ICE on for-loop/throw combination

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

--- Comment #20 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-07-19 19:31:04 UTC ---
Author: jakub
Date: Tue Jul 19 19:31:01 2011
New Revision: 176484

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=176484
Log:
    Backport from mainline
    2011-05-27  Jakub Jelinek  <jakub@redhat.com>

    PR c++/49165
    * c-common.c (c_common_truthvalue_conversion) <case COND_EXPR>: For
    C++ don't call c_common_truthvalue_conversion on void type arms.

    * g++.dg/eh/cond6.C: New test.

Added:
    branches/gcc-4_4-branch/gcc/testsuite/g++.dg/eh/cond6.C
Modified:
    branches/gcc-4_4-branch/gcc/ChangeLog
    branches/gcc-4_4-branch/gcc/c-common.c
    branches/gcc-4_4-branch/gcc/testsuite/ChangeLog

[Bug c++/49165] [4.4/4.5 Regression] ICE on for-loop/throw combination

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49165

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

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

--- Comment #21 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-07-19 19:50:57 UTC ---
Fixed.