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* [Bug c++/49988] New: constexpr on ctor invokes improper initialization
@ 2011-08-05 12:27 faisalv at yahoo dot com
2011-08-05 14:00 ` [Bug c++/49988] " faisalv at yahoo dot com
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: faisalv at yahoo dot com @ 2011-08-05 12:27 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49988
Summary: constexpr on ctor invokes improper initialization
Product: gcc
Version: 4.6.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: faisalv@yahoo.com
CC: jason@gcc.gnu.org
The following code compiles fine, but displays incorrect (or at the very least
inconsistent) behavior if constexpr is applied to A's ctor:
template<int ... I> struct X { };
struct A {
char data[3];
template<int ... I>
constexpr // works if you comment this constexpr out
A(const char (&s)[3], X<I...> x) : data{ s[I]...} { }
// above also works if you leave constexpr in but replace
// const char (&s)[3] with const char* s.
};
struct B {
A a;
B(const char (&s)[3]) : a{s,X<0,1,2>{}} { }
};
int main()
{
B b{"12"};
assert(b.a.data[0] == '1'); // assertion fails at run time
}
Compiled with gcc4.6.1 with *JUST* the following recent patch MANUALLY applied:
http://gcc.gnu.org/viewcvs/branches/gcc-4_6-branch/gcc/cp/semantics.c?r1=177188&r2=177187&pathrev=177188
(please refer to PR c++/49924 for details)
i.e gcc -v still reads (compared to PR c++/49924):
Using built-in specs.
COLLECT_GCC=g++-4.6.1
COLLECT_LTO_WRAPPER=/usr/local/gcc4.6.1/libexec/gcc/i686-pc-linux-gnu/4.6.1/lto-wrapper
Target: i686-pc-linux-gnu
Configured with: ../gcc-4.6.1/configure --prefix=/usr/local/gcc4.6.1
--enable-generated-files-in-srcdir --enable-threads=posix --with-system-zlib
--enable-__cxa_atexit --disable-checking --disable-nls --enable-bootstrap
--with-gcc --with-gnu-as --with-gnu-ld --disable-multilib
Thread model: posix
gcc version 4.6.1 (GCC)
I wonder if just applying that one patch manually, while fixing one bug, could
have introduced another?
Thanks
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/49988] constexpr on ctor invokes improper initialization
2011-08-05 12:27 [Bug c++/49988] New: constexpr on ctor invokes improper initialization faisalv at yahoo dot com
@ 2011-08-05 14:00 ` faisalv at yahoo dot com
2011-08-05 19:54 ` jason at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: faisalv at yahoo dot com @ 2011-08-05 14:00 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49988
--- Comment #1 from Faisal Vali <faisalv at yahoo dot com> 2011-08-05 13:59:55 UTC ---
Also, changing the parameter to a pointer to an array makes the code work
correctly:
struct A {
char data[3];
template<int ... I>
constexpr
// NOTE: now it is a pointer to an array - not just a pointer to char
A(const char (*s)[3], X<I...> x) : data{ (*s)[I]...} { }
};
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/49988] constexpr on ctor invokes improper initialization
2011-08-05 12:27 [Bug c++/49988] New: constexpr on ctor invokes improper initialization faisalv at yahoo dot com
2011-08-05 14:00 ` [Bug c++/49988] " faisalv at yahoo dot com
@ 2011-08-05 19:54 ` jason at gcc dot gnu.org
2011-08-06 4:34 ` jason at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: jason at gcc dot gnu.org @ 2011-08-05 19:54 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49988
Jason Merrill <jason at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2011.08.05 19:53:43
AssignedTo|unassigned at gcc dot |jason at gcc dot gnu.org
|gnu.org |
Ever Confirmed|0 |1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/49988] constexpr on ctor invokes improper initialization
2011-08-05 12:27 [Bug c++/49988] New: constexpr on ctor invokes improper initialization faisalv at yahoo dot com
2011-08-05 14:00 ` [Bug c++/49988] " faisalv at yahoo dot com
2011-08-05 19:54 ` jason at gcc dot gnu.org
@ 2011-08-06 4:34 ` jason at gcc dot gnu.org
2011-08-06 4:39 ` jason at gcc dot gnu.org
2011-08-06 22:25 ` jason at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: jason at gcc dot gnu.org @ 2011-08-06 4:34 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49988
--- Comment #2 from Jason Merrill <jason at gcc dot gnu.org> 2011-08-06 04:34:25 UTC ---
Author: jason
Date: Sat Aug 6 04:34:21 2011
New Revision: 177496
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=177496
Log:
PR c++/49988
* semantics.c (cxx_eval_array_reference): Handle failure to
reduce the array operand to something we can work with.
Added:
trunk/gcc/testsuite/g++.dg/cpp0x/constexpr-non-const-arg3.C
Modified:
trunk/gcc/cp/ChangeLog
trunk/gcc/cp/semantics.c
trunk/gcc/testsuite/ChangeLog
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/49988] constexpr on ctor invokes improper initialization
2011-08-05 12:27 [Bug c++/49988] New: constexpr on ctor invokes improper initialization faisalv at yahoo dot com
` (2 preceding siblings ...)
2011-08-06 4:34 ` jason at gcc dot gnu.org
@ 2011-08-06 4:39 ` jason at gcc dot gnu.org
2011-08-06 22:25 ` jason at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: jason at gcc dot gnu.org @ 2011-08-06 4:39 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49988
--- Comment #3 from Jason Merrill <jason at gcc dot gnu.org> 2011-08-06 04:38:11 UTC ---
Author: jason
Date: Sat Aug 6 04:38:08 2011
New Revision: 177500
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=177500
Log:
PR c++/49988
* semantics.c (cxx_eval_array_reference): Handle failure to
reduce the array operand to something we can work with.
Added:
branches/gcc-4_6-branch/gcc/testsuite/g++.dg/cpp0x/constexpr-non-const-arg3.C
Modified:
branches/gcc-4_6-branch/gcc/cp/ChangeLog
branches/gcc-4_6-branch/gcc/cp/semantics.c
branches/gcc-4_6-branch/gcc/testsuite/ChangeLog
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/49988] constexpr on ctor invokes improper initialization
2011-08-05 12:27 [Bug c++/49988] New: constexpr on ctor invokes improper initialization faisalv at yahoo dot com
` (3 preceding siblings ...)
2011-08-06 4:39 ` jason at gcc dot gnu.org
@ 2011-08-06 22:25 ` jason at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: jason at gcc dot gnu.org @ 2011-08-06 22:25 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49988
Jason Merrill <jason at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
Target Milestone|--- |4.6.2
--- Comment #4 from Jason Merrill <jason at gcc dot gnu.org> 2011-08-06 22:24:03 UTC ---
Fixed for 4.6.2.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2011-08-06 22:25 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2011-08-05 12:27 [Bug c++/49988] New: constexpr on ctor invokes improper initialization faisalv at yahoo dot com
2011-08-05 14:00 ` [Bug c++/49988] " faisalv at yahoo dot com
2011-08-05 19:54 ` jason at gcc dot gnu.org
2011-08-06 4:34 ` jason at gcc dot gnu.org
2011-08-06 4:39 ` jason at gcc dot gnu.org
2011-08-06 22:25 ` jason at gcc dot gnu.org
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