Red Hat Bugzilla – Bug 57467
gcc 3.1-0.10 miscompiles qmake
Last modified: 2008-05-01 11:38:01 EDT
Description of Problem:
Using qmake (Qt's makefile generator) after compiling it with gcc
3.1-0.10 produces broken Makefiles. The same version of qt/qmake works
perfectly with 2.96-101.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Install qt 3.0.1 sources
2. Attempt to build
Build fails because tools/designer/designer/Makefile gets weird rules:
$(UIC) dbconnections.ui -o dbconnections\.ui
The Makefile has the correct rule, such as the one I'm getting when
building qmake with gcc 2.96 or 3.0.2:
$(UIC) dbconnections.ui -o dbconnections.h
qmake compiles without any warnings even with gcc 3.1 -Wall, so it's
probably not some newly enforced standards compliance.
Happens even at -O0
It's even weirder:
qmake is usually compiled with out any -O flags because it has to support
pretty much all compilers out there.
Adding -O2 to the CFLAGS actually fixes the problem.
So qmake is miscompiled at -O0 only (guess that's the first time I've had to
_increase_ the optimization level to work around compiler bugs ;) ).
Reducing priority after finding a workaround.
Reduced to makefile.o (if it is compiled with -O0, it doesn't work, if -O1
and above, it works). Will need to debug where things change...
As it does go away if makefile.cc is compiled with -fno-inline, I guess this
is just the result of bogus change from 2001-11-15 which caused tree inlining
to happen without optimizations too.
This was fixed on 2001-12-13 in CVS.