Hi Richard, Catherine, Matthew

On Thu, 2017-03-02 14:40:46 +0100, Richard Biener <rguenther@suse.de> wrote:
[...]
> On IRC we decided to wait&see for the TREE_NO_WARNING issue.  So the
> following is what I committed.
> 
> Bootstrapped / tested on x86_64-unknown-linux-gnu.
[...]
> 2017-03-02  Richard Biener  <rguenther@suse.de>
> 
> 	PR tree-optimization/79345
> 	PR c++/42000
> 	* tree-ssa-alias.c (walk_aliased_vdefs_1): Take a limit
> 	param and abort the walk, returning -1 if it is hit.
> 	(walk_aliased_vdefs): Take a limit param and pass it on.
> 	* tree-ssa-alias.h (walk_aliased_vdefs): Add a limit param,
> 	defaulting to 0 and return a signed int.
> 	* tree-ssa-uninit.c (struct check_defs_data): New struct.
> 	(check_defs): New helper.
> 	(warn_uninitialized_vars): Use walk_aliased_vdefs to warn
> 	about uninitialized memory.
> 
> 	* fixed-value.c (fixed_from_string): Use ulow/uhigh to avoid
> 	bogus uninitialized warning.
> 	(fixed_convert_from_real): Likewise.
> 
> 	* g++.dg/warn/Wuninitialized-7.C: New testcase.
> 	* c-c++-common/ubsan/bounds-2.c: Add -Wno-uninitialized.
> 	* gcc.dg/uninit-pr19430-2.c: Add expected warning.

When building with config-list.mk, it seems to break for all of the
listed MIPS targets, but not on any other architecture:

[...]
g++ -fno-PIE -c   -g -O2 -DIN_GCC  -DCROSS_DIRECTORY_STRUCTURE   -fno-exceptions -fno-rtti -fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrite-strings -Wcast-qual -Wmissing-format-attribute -Woverloaded-virtual -pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings -Werror -fno-common  -DHAVE_CONFIG_H -I. -I. -I/scratch/4/jbglaw/configlist/repos/gcc/gcc -I/scratch/4/jbglaw/configlist/repos/gcc/gcc/. -I/scratch/4/jbglaw/configlist/repos/gcc/gcc/../include -I/scratch/4/jbglaw/configlist/repos/gcc/gcc/../libcpp/include -I/opt/cfarm/mpc/include  -I/scratch/4/jbglaw/configlist/repos/gcc/gcc/../libdecnumber -I/scratch/4/jbglaw/configlist/repos/gcc/gcc/../libdecnumber/dpd -I../libdecnumber -I/scratch/4/jbglaw/configlist/repos/gcc/gcc/../libbacktrace   -o mips.o -MT mips.o -MMD -MP -MF ./.deps/mips.TPo /scratch/4/jbglaw/configlist/repos/gcc/gcc/config/mips/mips.c
In file included from /scratch/4/jbglaw/configlist/repos/gcc/gcc/hash-table.h:236:0,
                 from /scratch/4/jbglaw/configlist/repos/gcc/gcc/coretypes.h:369,
                 from /scratch/4/jbglaw/configlist/repos/gcc/gcc/config/mips/mips.c:26:
/scratch/4/jbglaw/configlist/repos/gcc/gcc/vec.h: In function ‘mips_multi_member* mips_multi_add()’:
/scratch/4/jbglaw/configlist/repos/gcc/gcc/vec.h:865:3: error: ‘empty’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
   *slot = obj;
   ^
/scratch/4/jbglaw/configlist/repos/gcc/gcc/vec.h: In function ‘void mips_process_sync_loop(rtx_insn*, rtx_def**)’:
/scratch/4/jbglaw/configlist/repos/gcc/gcc/vec.h:865:3: error: ‘empty’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
   *slot = obj;
   ^
/scratch/4/jbglaw/configlist/repos/gcc/gcc/vec.h:865:3: error: ‘empty’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
   *slot = obj;
   ^
/scratch/4/jbglaw/configlist/repos/gcc/gcc/vec.h:865:3: error: ‘empty’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
   *slot = obj;
   ^
/scratch/4/jbglaw/configlist/repos/gcc/gcc/config/mips/mips.c: In function ‘bool mips_expand_vec_perm_const(rtx_def**)’:
/scratch/4/jbglaw/configlist/repos/gcc/gcc/config/mips/mips.c:21362:10: error: ‘orig_perm’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
   memcpy (d.perm, orig_perm, MAX_VECT_LEN);
   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1plus: all warnings being treated as errors
make[2]: *** [mips.o] Error 1


See eg. all the most recent builds:
mips64el-st-linux-gnu:	http://toolchain.lug-owl.de/buildbot/show_build_details.php?id=699675
mips64orion-elf:	http://toolchain.lug-owl.de/buildbot/show_build_details.php?id=699678
mipsisa32r2-linux-gnu:	http://toolchain.lug-owl.de/buildbot/show_build_details.php?id=699702
mipsisa32-elfoabi:	http://toolchain.lug-owl.de/buildbot/show_build_details.php?id=699701
mipsisa64sb1-elf:	http://toolchain.lug-owl.de/buildbot/show_build_details.php?id=699724
mipsisa64sr71k-elf:	http://toolchain.lug-owl.de/buildbot/show_build_details.php?id=699726
mips-netbsd:		http://toolchain.lug-owl.de/buildbot/show_build_details.php?id=699750

MfG, JBG

-- 
      Jan-Benedict Glaw      jbglaw@lug-owl.de              +49-172-7608481
Signature of:             God put me on earth to accomplish a certain number of
the second  :            things. Right now I am so far behind I will never die.