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* [Bug c++/14035] New: Compiler generates spurious temporary
@ 2004-02-05 23:12 austern at apple dot com
2004-02-14 20:11 ` [Bug c++/14035] " pinskia at gcc dot gnu dot org
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: austern at apple dot com @ 2004-02-05 23:12 UTC (permalink / raw)
To: gcc-bugs
Consider the following test case:
#include <stdio.h>
struct Blob {
int x, y;
Blob() { }
Blob(const Blob &b) { printf("Copying %p to %p!!\n", &b, this); }
};
struct Blobby : public Blob { };
struct Wooly {
operator const Blobby & ()
{
printf("Conversion operator yields: %p\n", &myBlobby);
return myBlobby;
}
Blobby myBlobby;
};
void catcher(const Blob &blo)
{ printf("catcher: %p\n", &blo); }
int main()
{
Wooly wooly;
catcher((const Blob &)wooly); // <-- generates a copy
}
Compiling and running this gives the following output:
[tmp]$ ./a.out
Conversion operator yields: 0xbffffd50
Copying 0xbffffd50 to 0xbffffd60!!
catcher: 0xbffffd60
[tmp]$
This is wrong. The conversion operator yields a const Blobby&, and we're asking for a const Blob&. All
we need to do is perform the derived-to-base standard conversion. Instead, for no apparent reason,
the compiler invokes Blob's copy constructor and creates a temporary.
Note that this test case really does need the explicit cast of wooly to const Blob&. Without the explicit
cast we don't get a temporary.
--
Summary: Compiler generates spurious temporary
Product: gcc
Version: 3.5.0
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: austern at apple dot com
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: powerpc-apple-darwin
GCC host triplet: powerpc-apple-darwin
GCC target triplet: powerpc-apple-darwin6.6
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14035
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/14035] Compiler generates spurious temporary
2004-02-05 23:12 [Bug c++/14035] New: Compiler generates spurious temporary austern at apple dot com
@ 2004-02-14 20:11 ` pinskia at gcc dot gnu dot org
2004-10-13 14:59 ` pinskia at gcc dot gnu dot org
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-02-14 20:11 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2004-02-14 20:11 -------
Confirmed, related to 14140.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed| |1
Keywords| |rejects-valid, wrong-code
Last reconfirmed|0000-00-00 00:00:00 |2004-02-14 20:11:20
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14035
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/14035] [3.3/3.4/4.0 Regression] Compiler generates spurious temporary
2004-02-05 23:12 [Bug c++/14035] New: Compiler generates spurious temporary austern at apple dot com
2004-02-14 20:11 ` [Bug c++/14035] " pinskia at gcc dot gnu dot org
2004-10-13 14:59 ` pinskia at gcc dot gnu dot org
@ 2004-10-13 14:59 ` pinskia at gcc dot gnu dot org
2004-10-15 21:27 ` mmitchel at gcc dot gnu dot org
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-10-13 14:59 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
Known to fail| |3.4.0 4.0.0
Known to work| |2.95.3
Summary|Compiler generates spurious |[3.3/3.4/4.0 Regression]
|temporary |Compiler generates spurious
| |temporary
Target Milestone|--- |3.4.3
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14035
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/14035] Compiler generates spurious temporary
2004-02-05 23:12 [Bug c++/14035] New: Compiler generates spurious temporary austern at apple dot com
2004-02-14 20:11 ` [Bug c++/14035] " pinskia at gcc dot gnu dot org
@ 2004-10-13 14:59 ` pinskia at gcc dot gnu dot org
2004-10-13 14:59 ` [Bug c++/14035] [3.3/3.4/4.0 Regression] " pinskia at gcc dot gnu dot org
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-10-13 14:59 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2004-10-13 14:59 -------
*** Bug 14140 has been marked as a duplicate of this bug. ***
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |christian dot engstrom at
| |glindra dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14035
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/14035] [3.3/3.4/4.0 Regression] Compiler generates spurious temporary
2004-02-05 23:12 [Bug c++/14035] New: Compiler generates spurious temporary austern at apple dot com
` (2 preceding siblings ...)
2004-10-13 14:59 ` [Bug c++/14035] [3.3/3.4/4.0 Regression] " pinskia at gcc dot gnu dot org
@ 2004-10-15 21:27 ` mmitchel at gcc dot gnu dot org
2004-10-19 23:30 ` mmitchel at gcc dot gnu dot org
2004-10-19 23:37 ` pinskia at gcc dot gnu dot org
5 siblings, 0 replies; 7+ messages in thread
From: mmitchel at gcc dot gnu dot org @ 2004-10-15 21:27 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|unassigned at gcc dot gnu |mark at codesourcery dot com
|dot org |
Status|NEW |ASSIGNED
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14035
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/14035] [3.3/3.4/4.0 Regression] Compiler generates spurious temporary
2004-02-05 23:12 [Bug c++/14035] New: Compiler generates spurious temporary austern at apple dot com
` (3 preceding siblings ...)
2004-10-15 21:27 ` mmitchel at gcc dot gnu dot org
@ 2004-10-19 23:30 ` mmitchel at gcc dot gnu dot org
2004-10-19 23:37 ` pinskia at gcc dot gnu dot org
5 siblings, 0 replies; 7+ messages in thread
From: mmitchel at gcc dot gnu dot org @ 2004-10-19 23:30 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From mmitchel at gcc dot gnu dot org 2004-10-19 23:30 -------
Fixed in GCC 4.0.
Will not be fixed in GCC 3.4.x.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14035
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/14035] [3.3/3.4/4.0 Regression] Compiler generates spurious temporary
2004-02-05 23:12 [Bug c++/14035] New: Compiler generates spurious temporary austern at apple dot com
` (4 preceding siblings ...)
2004-10-19 23:30 ` mmitchel at gcc dot gnu dot org
@ 2004-10-19 23:37 ` pinskia at gcc dot gnu dot org
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-10-19 23:37 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|3.4.3 |4.0.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14035
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2004-10-19 23:37 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
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2004-02-05 23:12 [Bug c++/14035] New: Compiler generates spurious temporary austern at apple dot com
2004-02-14 20:11 ` [Bug c++/14035] " pinskia at gcc dot gnu dot org
2004-10-13 14:59 ` pinskia at gcc dot gnu dot org
2004-10-13 14:59 ` [Bug c++/14035] [3.3/3.4/4.0 Regression] " pinskia at gcc dot gnu dot org
2004-10-15 21:27 ` mmitchel at gcc dot gnu dot org
2004-10-19 23:30 ` mmitchel at gcc dot gnu dot org
2004-10-19 23:37 ` pinskia at gcc dot gnu dot org
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