Re: Probably minor bug

[Dr . Jürgen Sauermann]

Hi Chris, this warning is haunting us for quite a while now. I have written a README-11-bogus-compiler-warnings with work-arounds. Unfortunately the loop below is not entirely bogus (what happens is that for some r the uninitialized value other.rho[r] is being copied to the never-used value rho[r]). Unfortunately the obvious fix for the warning has shown to cause significant perfomance impacts because it prevents loop unrolling (and there was a separate trouble report concerning that performance drop on bug-apl). At that time I filed a gcc trouble report: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94905 asking to fix this, but I am afraid that this may take some time. My bug report was merged into a meta-bug which is open since 2005: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=24639 Best Regards, Jürgen On 6/27/20 5:01 PM, Chris Moller wrote: Shape.hh: In member function 'Shape Shape::insert_axis(Axis, ShapeItem) const': Shape.hh:69:46: error: ''target_mem_ref' not supported by dump_expr<_expression_ error>' may be used uninitialized in this function [-Werror=maybe-uninitialized]    69 |      loop(r, MAX_RANK)   rho[r] = other.rho[r];       |                                   ~~~~~~~~~~~^ Just to finish the build, I patched around the bug by editing out the Wall and the Werror in the Makefile, so: [moller@hpbox]~tinkering/gnuapl/trunk% apl -v                                                                       10:47:53 BUILDTAG: ---------     Project:        GNU APL     Version / SVN:  1.8 / 1210     Build Date:     2019-12-19 17:09:01 UTC     Build OS:       Linux 4.19.3-200.fc28.x86_64 x86_64     config.status:  'PKG_CONFIG_PATH=/usr/local/lib64/pkgconfig:/usr/local/lib/pkgconfig:/usr/lib64/pkgconfig:/usr/lib/pkgconfig'     Archive SVN:    1161 [moller@hpbox]~tinkering/gnuapl/trunk% gcc --version                                                                10:49:35 gcc (GCC) 10.1.1 20200507 (Red Hat 10.1.1-1) [moller@hpbox]~tinkering/gnuapl/trunk% cat /etc/redhat-release                                                      10:51:45 Fedora release 32 (Thirty Two) [moller@hpbox]~tinkering/gnuapl/trunk% uname -a                                                                     10:52:29 Linux hpbox 5.6.19-300.fc32.x86_64 #1 SMP Wed Jun 17 16:10:48 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux