Bug#538647: marked as done (g++-4.3: g++ examines second value to "?" always if it is a template)
Your message dated Sun, 26 Jul 2009 08:59:22 +0200
with message-id <87tz100w1h@mid.deneb.enyo.de>
and subject line Re: Bug#538647: g++-4.3: g++ examines second value to "?"
always if it is a template
has caused the Debian Bug report #538647,
regarding g++-4.3: g++ examines second value to "?" always if it is a template
to be marked as done.
This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.
(NB: If you are a system administrator and have no idea what this
message is talking about, this may indicate a serious mail system
misconfiguration somewhere. Please contact ow...@bugs.debian.org
immediately.)
--
538647: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=538647
Debian Bug Tracking System
Contact ow...@bugs.debian.org with problems
--- Begin Message ---
Package: g++-4.3
Version: 4.3.2-1.1
Severity: important
Let an example do the talking
template< unsigned int result, unsigned int wanted, unsigned int guess >
struct log2_calculator;
// Specialisation that ends recursion.
template< unsigned int result, unsigned int wanted >
struct log2_calculator< result, wanted, 0>
{
enum { value = 0 }; // Invalid.
};
template< unsigned int result, unsigned int wanted, unsigned int guess >
struct log2_calculator
{
typedef log2_calculator< result+1, wanted, guess << 1 > next_value_type;
/*HERE*/enum { value = (wanted <= guess) ? result : next_value_type::value };
};
The intention of this code is to work out log2(a) at compile time, lacking
some other mechanism.
This allows...
enum { is3 = log2_calculator< 0, 8, 1 >::value };
enum { is4 = log2_calculator< 0, 16, 1 >::value };
enum { is6 = log2_calculator< 0, 64, 1 >::value };
something that's more obviously useful inside templates.
enum { isX = log2_calculator< 0, sizeof(N)*8, 1 >::value };
Anyway, the problem becomes obvious when you omit the specialisation from the
above - g++ reaches it's template nesting limit because it's instantiating
the template that's the second value to "?" even though the conditional is
true.
I've marked the line above with /*HERE*/.
-- System Information:
Debian Release: 5.0.2
APT prefers stable
APT policy: (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 2.6.26-2-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_IE.UTF-8, LC_CTYPE=en_IE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
Versions of packages g++-4.3 depends on:
ii gcc-4.3 4.3.2-1.1 The GNU C compiler
ii gcc-4.3-base 4.3.2-1.1 The GNU Compiler Collection (base
ii libc6 2.7-18 GNU C Library: Shared libraries
ii libgmp3c2 2:4.2.2+dfsg-3 Multiprecision arithmetic library
ii libmpfr1ldbl 2.3.1.dfsg.1-2 multiple precision floating-point
ii libstdc++6-4.3-dev4.3.2-1.1 The GNU Standard C++ Library v3 (d
g++-4.3 recommends no packages.
Versions of packages g++-4.3 suggests:
ii g++-4.3-multilib 4.3.2-1.1 The GNU C++ compiler (multilib fil
ii gcc-4.3-doc 4.3.2.nf1-1 documentation for the GNU compiler
pn libstdc++6-4.3-dbg (no description available)
-- no debconf information
--- End Message ---
--- Begin Message ---
* Philip Ashmore:
> /*HERE*/enum { value = (wanted <= guess) ? result : next_value_type::value };
Not a bug. You need to implement your own conditional operator at the
template level to make this work. The version with ?: is not valid
C++.
--- End Message ---
gnat-4.4_4.4.0-1_amd64.changes ACCEPTED
Accepted: gnat-4.4-base_4.4.0-1_amd64.deb to pool/main/g/gnat-4.4/gnat-4.4-base_4.4.0-1_amd64.deb gnat-4.4_4.4.0-1.diff.gz to pool/main/g/gnat-4.4/gnat-4.4_4.4.0-1.diff.gz gnat-4.4_4.4.0-1.dsc to pool/main/g/gnat-4.4/gnat-4.4_4.4.0-1.dsc gnat-4.4_4.4.0-1_amd64.deb to pool/main/g/gnat-4.4/gnat-4.4_4.4.0-1_amd64.deb gnat-4.4_4.4.0.orig.tar.gz to pool/main/g/gnat-4.4/gnat-4.4_4.4.0.orig.tar.gz libgnat-4.4-dbg_4.4.0-1_amd64.deb to pool/main/g/gnat-4.4/libgnat-4.4-dbg_4.4.0-1_amd64.deb libgnat-4.4_4.4.0-1_amd64.deb to pool/main/g/gnat-4.4/libgnat-4.4_4.4.0-1_amd64.deb libgnatprj4.4-dbg_4.4.0-1_amd64.deb to pool/main/g/gnat-4.4/libgnatprj4.4-dbg_4.4.0-1_amd64.deb libgnatprj4.4-dev_4.4.0-1_amd64.deb to pool/main/g/gnat-4.4/libgnatprj4.4-dev_4.4.0-1_amd64.deb libgnatprj4.4_4.4.0-1_amd64.deb to pool/main/g/gnat-4.4/libgnatprj4.4_4.4.0-1_amd64.deb libgnatvsn4.4-dbg_4.4.0-1_amd64.deb to pool/main/g/gnat-4.4/libgnatvsn4.4-dbg_4.4.0-1_amd64.deb libgnatvsn4.4-dev_4.4.0-1_amd64.deb to pool/main/g/gnat-4.4/libgnatvsn4.4-dev_4.4.0-1_amd64.deb libgnatvsn4.4_4.4.0-1_amd64.deb to pool/main/g/gnat-4.4/libgnatvsn4.4_4.4.0-1_amd64.deb Override entries for your package: gnat-4.4-base_4.4.0-1_amd64.deb - optional libs gnat-4.4_4.4.0-1.dsc - optional devel gnat-4.4_4.4.0-1_amd64.deb - optional devel libgnat-4.4-dbg_4.4.0-1_amd64.deb - extra debug libgnat-4.4_4.4.0-1_amd64.deb - optional libs libgnatprj4.4-dbg_4.4.0-1_amd64.deb - extra debug libgnatprj4.4-dev_4.4.0-1_amd64.deb - optional libdevel libgnatprj4.4_4.4.0-1_amd64.deb - optional libs libgnatvsn4.4-dbg_4.4.0-1_amd64.deb - extra debug libgnatvsn4.4-dev_4.4.0-1_amd64.deb - optional libdevel libgnatvsn4.4_4.4.0-1_amd64.deb - optional libs Announcing to debian-devel-chan...@lists.debian.org Thank you for your contribution to Debian. -- To UNSUBSCRIBE, email to debian-gcc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
[Bug libgcj/40859] [4.4/4.5 regression] regressions in libjava testsuite on arm-linux
--- Comment #1 from mikpe at it dot uu dot se 2009-07-26 12:54 --- Looks like fallout from revision 144323. As far as I can tell the "warning" is informational (ABI change from 4.3) so should be suppressed or ignored in the test suite. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40859 --- You are receiving this mail because: --- You reported the bug, or are watching the reporter. -- To UNSUBSCRIBE, email to debian-gcc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
Bug#538647: closed by Florian Weimer (Re: Bug#538647: g++-4.3: g++ examines second value to "?" always if it is a template)
* Philip Ashmore:
/*HERE*/enum { value = (wanted <= guess) ? result : next_value_type::value };
Not a bug. You need to implement your own conditional operator at the
template level to make this work. The version with ?: is not valid
C++
Not valid C++ ? My C++ compiler (g++) disagrees.
Think of
enum { big_int = (sizeof(int) > 4) ? true : false };
Have you tried compiling the example?
I don't remember reading anything about "conditional operator at the template
level" in
Stroustrup's "C++ programming language (third edition).
Could you elaborate?
Philip
[Bug bootstrap/37739] [4.4 Regression] bootstrap broken with core gcc > gcc-4.2.x
--- Comment #29 from giffordj at la dot twcbc dot com 2009-07-26 20:28 --- STAGE1_CFLAGS="-g -O2" is a workaround, -O1 gave failure later in the build. -O2 built GCC all the way through, with only one unexpected testsuite failure. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37739 --- You are receiving this mail because: --- You are on the CC list for the bug, or are watching someone who is. -- To UNSUBSCRIBE, email to debian-gcc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
