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* [Bug c++/54059] New: g++ silently omits code that creates a std::chrono::millisecond temporary
@ 2012-07-20 23:08 jason at cornsyrup dot org
2012-07-20 23:11 ` [Bug c++/54059] " jason at cornsyrup dot org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: jason at cornsyrup dot org @ 2012-07-20 23:08 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54059
Bug #: 54059
Summary: g++ silently omits code that creates a
std::chrono::millisecond temporary
Classification: Unclassified
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: jason@cornsyrup.org
jason@ps027 ~/bug$ g++-4.7 -std=c++11 bug.cc
jason@ps027 ~/bug$ ./a.out
got 100
jason@ps027 ~/bug$ cat bug.cc
#include <chrono>
#include <iostream>
struct foo {
foo(std::chrono::milliseconds ms) {
std::cout << "got " << ms.count() << "\n";
}
};
int main() {
foo f1(std::chrono::milliseconds(100));
unsigned int a = 200;
foo f2(std::chrono::milliseconds(a));
return 0;
}
jason@ps027 ~/bug$ g++-4.7 -v
Using built-in specs.
COLLECT_GCC=g++-4.7
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.7/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro
4.7.1-4+ub1' --with-bugurl=file:///usr/share/doc/gcc-4.7/README.Bugs
--enable-languages=c,c++,go,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.7 --enable-shared --enable-linker-build-id
--with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.7
--libdir=/usr/lib --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-gnu-unique-object --enable-plugin
--enable-objc-gc --disable-werror --with-arch-32=i586 --with-tune=generic
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
Thread model: posix
gcc version 4.7.1 (Ubuntu/Linaro 4.7.1-4+ub1)
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/54059] g++ silently omits code that creates a std::chrono::millisecond temporary
2012-07-20 23:08 [Bug c++/54059] New: g++ silently omits code that creates a std::chrono::millisecond temporary jason at cornsyrup dot org
@ 2012-07-20 23:11 ` jason at cornsyrup dot org
2012-07-20 23:12 ` pinskia at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: jason at cornsyrup dot org @ 2012-07-20 23:11 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54059
--- Comment #1 from Jason Toffaletti <jason at cornsyrup dot org> 2012-07-20 23:11:37 UTC ---
$ g++-4.7 -c -g -Wa,-alh -std=c++11 bug.cc
<snip>
155 .LEHE0:
13:bug.cc **** unsigned int a = 200;
156 .loc 2 13 0 discriminator 1
157 0035 C745ECC8 movl $200, -20(%rbp)
157 000000
14:bug.cc **** foo f2(std::chrono::milliseconds(a));
15:bug.cc **** return 0;
158 .loc 2 15 0 discriminator 1
159 003c B8000000 movl $0, %eax
159 00
160 0041 EB08 jmp .L9
161 .L8:
162 0043 4889C7 movq %rax, %rdi
163 .LEHB1:
164 0046 E8000000 call _Unwind_Resume
164 00
165 .LEHE1:
166 .L9:
167 .LBE4:
16:bug.cc **** }
<snip>
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/54059] g++ silently omits code that creates a std::chrono::millisecond temporary
2012-07-20 23:08 [Bug c++/54059] New: g++ silently omits code that creates a std::chrono::millisecond temporary jason at cornsyrup dot org
2012-07-20 23:11 ` [Bug c++/54059] " jason at cornsyrup dot org
@ 2012-07-20 23:12 ` pinskia at gcc dot gnu.org
2012-07-20 23:14 ` redi at gcc dot gnu.org
2012-07-20 23:17 ` jason at cornsyrup dot org
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2012-07-20 23:12 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54059
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |INVALID
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-07-20 23:12:23 UTC ---
> foo f2(std::chrono::milliseconds(a));
This is a function declaration and not a variable definition ...
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/54059] g++ silently omits code that creates a std::chrono::millisecond temporary
2012-07-20 23:08 [Bug c++/54059] New: g++ silently omits code that creates a std::chrono::millisecond temporary jason at cornsyrup dot org
2012-07-20 23:11 ` [Bug c++/54059] " jason at cornsyrup dot org
2012-07-20 23:12 ` pinskia at gcc dot gnu.org
@ 2012-07-20 23:14 ` redi at gcc dot gnu.org
2012-07-20 23:17 ` jason at cornsyrup dot org
3 siblings, 0 replies; 5+ messages in thread
From: redi at gcc dot gnu.org @ 2012-07-20 23:14 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54059
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-07-20 23:14:09 UTC ---
This is http://en.wikipedia.org/wiki/Most_vexing_parse
The declaration f2 declares a function, it is not a variables definition.
To convince yourself, try taking its address:
foo* p = &f2;
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/54059] g++ silently omits code that creates a std::chrono::millisecond temporary
2012-07-20 23:08 [Bug c++/54059] New: g++ silently omits code that creates a std::chrono::millisecond temporary jason at cornsyrup dot org
` (2 preceding siblings ...)
2012-07-20 23:14 ` redi at gcc dot gnu.org
@ 2012-07-20 23:17 ` jason at cornsyrup dot org
3 siblings, 0 replies; 5+ messages in thread
From: jason at cornsyrup dot org @ 2012-07-20 23:17 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54059
--- Comment #4 from Jason Toffaletti <jason at cornsyrup dot org> 2012-07-20 23:16:56 UTC ---
I knew there was something familiar about this, thanks for the reminder.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2012-07-20 23:17 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2012-07-20 23:08 [Bug c++/54059] New: g++ silently omits code that creates a std::chrono::millisecond temporary jason at cornsyrup dot org
2012-07-20 23:11 ` [Bug c++/54059] " jason at cornsyrup dot org
2012-07-20 23:12 ` pinskia at gcc dot gnu.org
2012-07-20 23:14 ` redi at gcc dot gnu.org
2012-07-20 23:17 ` jason at cornsyrup dot org
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