gcc CVS mainline, 2005/01/23 12:10 PST
Configured with: /net/legless/scratch1/rwgk/gcc_cvs_head/configure --
prefix=/usr/local_cci/gcc_cvs_head_20050123 --enable-languages=c,c++
Red Hat Enterprise Linux WS release 3 (Taroon)
Boost CVS mainline, 2005/01/06 10:09 PST
The following piece of code works correctly only if CCTBX_GCC4_WORKAROUND is
defined:
rt_mx rt_mx::new_denominators(int r_den, int t_den) const
{
rt_mx result(*this);
#ifndef CCTBX_GCC4_WORKAROUND
if (r_den) result.r_ = result.r_.new_denominator(r_den);
#else
if (r_den) {
rot_mx r = result.r_.new_denominator(r_den);
result.r_ = r;
}
#endif
if (t_den) result.t_ = result.t_.new_denominator(t_den);
return result;
}
A reproducer is available here:
http://cci.lbl.gov/~rwgk/bugs/gcc_cvs_head_20050123/gcc4_debug.tar.gz
To build:
gunzip -c gcc4_debug.tar.gz | tar xf -
cd gcc4_debug
make
Expected output:
g++ -fPIC -ftemplate-depth-120 -w -DBOOST_DISABLE_THREADS -DNDEBUG -O3 -ffast-
math -I. -c gcc4_debug.cpp
g++ -fPIC -ftemplate-depth-120 -w -DBOOST_DISABLE_THREADS -DNDEBUG -O3 -ffast-
math -I. -c cctbx.cpp -o cctbx_normal.o
g++ -o normal gcc4_debug.o cctbx_normal.o
g++ -fPIC -ftemplate-depth-120 -w -DBOOST_DISABLE_THREADS -DNDEBUG -O3 -ffast-
math -I. -DCCTBX_GCC4_WORKAROUND -c cctbx.cpp -o cctbx_hacked.o
g++ -o hacked gcc4_debug.o cctbx_hacked.o
This will only take a few seconds to build the commands "normal" and "hacked".
The expected output is:
./normal
y,z,x
x,y,z
./hacked
y,z,x
y,z,x
The output of ./normal is wrong, the output of ./hacked is correct. The only
difference is the CCTBX_GCC4_WORKAROUND.
The same code works fine (without the workaround) with gcc 3.2.3 and many other
compilers.
I will try to attach the reproducer if possible. It still is 877kB in size,
starting from 15+MB, mainly because of the Boost headers. I spent several hours
stripping it down to this size. I hope you have tools to reduce the rest much
faster.
--
Summary: code generation error
Product: gcc
Version: 4.0.0
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: rwgk at yahoo dot com
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: i686-pc-linux-gnu
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19603
