[Bug libstdc++/21951] [4.0 only] std::vector.reserve() unusable with -Werror -Wall -O -fno-exceptions

[Bug libstdc++/21951] [4.0 only] std::vector.reserve() unusable with -Werror -Wall -O -fno-exceptions

[pinskia at gcc dot gnu dot org]

------- Comment #16 from pinskia at gcc dot gnu dot org  2005-10-24 01:31 -------
*** Bug 24498 has been marked as a duplicate of this bug. ***


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pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |yuri at tsoft dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21951

[Bug libstdc++/21951] [4.0 only] std::vector.reserve() unusable with -Werror -Wall -O -fno-exceptions

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-07-16 21:00 -------
Fixed by:
2005-07-08 Geoffrey Keating  <geoffk@apple.com>

        * tree-inline.c (expand_call_inline): Prevent 'may reach end'
        warning in system headers.
        

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21951

[Bug libstdc++/21951] [4.0 only] std::vector.reserve() unusable with -Werror -Wall -O -fno-exceptions

[dank at kegel dot com]

------- Additional Comments From dank at kegel dot com  2005-07-01 19:42 -------
That's certainly prettier than my header changes.  
I'll give it a shot.  Thanks!

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21951

[Bug libstdc++/21951] [4.0 only] std::vector.reserve() unusable with -Werror -Wall -O -fno-exceptions

[geoffk at gcc dot gnu dot org]

------- Additional Comments From geoffk at gcc dot gnu dot org  2005-07-01 19:10 -------
I have a patch for the compiler here:

http://gcc.gnu.org/ml/gcc-patches/2005-07/msg00049.html

which will fix this problem.

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           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |geoffk at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2005-06-12 15:02:26         |2005-07-01 19:10:02
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21951

[Bug libstdc++/21951] [4.0 only] std::vector.reserve() unusable with -Werror -Wall -O -fno-exceptions

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2005-06-12 15:02:26
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21951

[Bug libstdc++/21951] [4.0 only] std::vector.reserve() unusable with -Werror -Wall -O -fno-exceptions

[dank at kegel dot com]

------- Additional Comments From dank at kegel dot com  2005-06-11 19:29 -------
Created an attachment (id=9071)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=9071&action=view)
proposed workaround


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21951

[Bug libstdc++/21951] [4.0 only] std::vector.reserve() unusable with -Werror -Wall -O -fno-exceptions

[dank at kegel dot com]

------- Additional Comments From dank at kegel dot com  2005-06-11 11:25 -------
OK, I'm testing a patch now.

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21951

[Bug libstdc++/21951] [4.0 only] std::vector.reserve() unusable with -Werror -Wall -O -fno-exceptions

[bkoz at gcc dot gnu dot org]

------- Additional Comments From bkoz at gcc dot gnu dot org  2005-06-08 19:16 -------

This is a compiler bug. If they don't fix it in 4.0.x, then we'll have to work
around it in libstdc++ 4.0 sources only. 

People have suggested a patch to add a dummy return. If that's posted, it seems
to be perfectly acceptable to me. I suggest that be posted...

-benjamin

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21951

[Bug libstdc++/21951] [4.0 only] std::vector.reserve() unusable with -Werror -Wall -O -fno-exceptions

[veksler at il dot ibm dot com]

------- Additional Comments From veksler at il dot ibm dot com  2005-06-08 14:43 -------
(In reply to comment #7)
> It sure as hell is for those shops that require -Werror.
>
> But ok, I'll be happy if it's fixed for 4.0.2.

I think that your argument (as phrased) does not hold.
Maybe you meant "It sure as hell is for those shops that require -Werror, 
in this particular instance".
(Pardon my language, I just quoted the original ;-)

Consider:
1. 1: int main()
   2: {
   3:   int a;
   4:   never_return(); // the halting problem
   5:   return a;       // Uninitialized variable?
   6: }
   This is perfectly valid code and well defined, yet -Wall -Werror
   will reject it. No compiler will ever be able to determine if
   line 5 is ever reached.

2. 1: int main()
   2: {
   3:    int a;
   4:    if(foo())
   5:      a= bar();
   6:    if(foo())
   7:      return a;  // Uninitialized variable?
   8:    return 0;
   9: }

   Again, no compiler will be able to prove that a nontrivial foo() does
   not change over time (unless declared const/pure/whatever).
   And as a result, -Wall -Werror will reject valid code.

In both examples, the user has a simple work-around, initialize 'a'.
Adding initialization will make the code more stable, as foo() is
no longer constrained to be const/pure (forgive me for not remembering if
it is called pure or const).

In contrast (as mentioned in comment #4), this PR and PR 21183 do not
give the user the tools to shut this specific diagnostic instance up.

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21951

[Bug libstdc++/21951] [4.0 only] std::vector.reserve() unusable with -Werror -Wall -O -fno-exceptions

[veksler at il dot ibm dot com]

------- Additional Comments From veksler at il dot ibm dot com  2005-06-08 14:11 -------
(In reply to comment #6)
> Note Mark has said in the past (and in a private mail which was supposed to be
a public one too) that 
> warnings cannot cause this to be a rejects valid.


For the same reason, PR 21183 should be reopened or merged with this PR:

> When compiling a C++ program with -Wall, I get the following compiler warning
>
>/usr/local/bin/../lib/gcc/i686-pc-linux-gnu/4.0.0/../../../../include/c++/4.0.0/bits/stl_uninitialized.h:113:
>warning: control may reach end of non-void function '_ForwardIterator
> std::__uninitialized_copy_aux(_InputIterator, _InputIterator, 
...
> The problem seems to be in __uninitialized_copy_aux() in stl_uninitialized.h
>
> The catch statement block beginning on line 89 merely exits the routine without 
> actually returning a value.



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21951

[Bug libstdc++/21951] [4.0 only] std::vector.reserve() unusable with -Werror -Wall -O -fno-exceptions

[dank at kegel dot com]

------- Additional Comments From dank at kegel dot com  2005-06-08 13:57 -------
It sure as hell is for those shops that require -Werror.

But ok, I'll be happy if it's fixed for 4.0.2.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21951

[Bug libstdc++/21951] [4.0 only] std::vector.reserve() unusable with -Werror -Wall -O -fno-exceptions

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-06-08 13:20 -------
Note Mark has said in the past (and in a private mail which was supposed to be a public one too) that 
warnings cannot cause this to be a rejects valid.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic
            Summary|[gcc-4.0 regression,        |[4.0 only]
                   |rejects-valid]              |std::vector.reserve()
                   |std::vector.reserve()       |unusable with -Werror -Wall
                   |unusable with -Werror -Wall |-O -fno-exceptions
                   |-O -fno-exceptions          |
   Target Milestone|---                         |4.0.2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21951