[Bug bootstrap/113132] New: [14 regression] --enable-checking=release build fails: tree-vect-loop.cc:6221:34: error: ‘vec_stmts.vec<gimple*, va_heap, vl_ptr>::m_vec’ may be used uninitialized [-Werror=maybe-uninitialized]

[Bug bootstrap/113132] New: [14 regression] --enable-checking=release build fails: tree-vect-loop.cc:6221:34: error: ‘vec_stmts.vec<gimple*, va_heap, vl_ptr>::m_vec’ may be used uninitialized [-Werror=maybe-uninitialized]

[slyfox at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113132

            Bug ID: 113132
           Summary: [14 regression] --enable-checking=release build fails:
                    tree-vect-loop.cc:6221:34: error:
                    ‘vec_stmts.vec<gimple*, va_heap, vl_ptr>::m_vec’ may
                    be used uninitialized [-Werror=maybe-uninitialized]
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: bootstrap
          Assignee: unassigned at gcc dot gnu.org
          Reporter: slyfox at gcc dot gnu.org
  Target Milestone: ---

Noticed on today's build of master r14-6828-g0beeddd6b1b1cb :

$ ../gcc/configure --disable-multilib --enable-checking=release
$ make
...
/tmp/gb/./prev-gcc/xg++ -B/tmp/gb/./prev-gcc/
-B/usr/local/x86_64-pc-linux-gnu/bin/ -nostdinc++
-B/tmp/gb/prev-x86_64-pc-linux-gnu/libstdc++-v3/src/.libs
-B/tmp/gb/prev-x86_64-pc-linux-gnu/libstdc++-v3/libsupc++/.libs 
-I/tmp/gb/prev-x86_64-pc-linux-gnu/libstdc++-v3/include/x86_64-pc-linux-gnu 
-I/tmp/gb/prev-x86_64-pc-linux-gnu/libstdc++-v3/include 
-I/home/slyfox/dev/git/gcc/libstdc++-v3/libsupc++
-L/tmp/gb/prev-x86_64-pc-linux-gnu/libstdc++-v3/src/.libs
-L/tmp/gb/prev-x86_64-pc-linux-gnu/libstdc++-v3/libsupc++/.libs  -fno-PIE -c  
-g -O2 -fno-checking -gtoggle -DIN_GCC    -fno-exceptions -fno-rtti
-fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrite-strings
-Wcast-qual -Wmissing-format-attribute -Wconditionally-supported
-Woverloaded-virtual -pedantic -Wno-long-long -Wno-variadic-macros
-Wno-overlength-strings -Werror   -DHAVE_CONFIG_H -fno-PIE -I. -I.
-I/home/slyfox/dev/git/gcc/gcc -I/home/slyfox/dev/git/gcc/gcc/.
-I/home/slyfox/dev/git/gcc/gcc/../include 
-I/home/slyfox/dev/git/gcc/gcc/../libcpp/include
-I/home/slyfox/dev/git/gcc/gcc/../libcody 
-I/home/slyfox/dev/git/gcc/gcc/../libdecnumber
-I/home/slyfox/dev/git/gcc/gcc/../libdecnumber/bid -I../libdecnumber
-I/home/slyfox/dev/git/gcc/gcc/../libbacktrace   -o tree-vect-loop.o -MT
tree-vect-loop.o -MMD -MP -MF ./.deps/tree-vect-loop.TPo
/home/slyfox/dev/git/gcc/gcc/tree-vect-loop.cc
/home/slyfox/dev/git/gcc/gcc/tree-vect-loop.cc: In function 'void
vect_create_epilog_for_reduction(loop_vec_info, stmt_vec_info, slp_tree,
slp_instance, edge)':
/home/slyfox/dev/git/gcc/gcc/tree-vect-loop.cc:6221:34: error:
'vec_stmts.vec<gimple*, va_heap, vl_ptr>::m_vec' may be used uninitialized
[-Werror=maybe-uninitialized]
 6221 |             def = gimple_get_lhs (vec_stmts[j]);
      |                   ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~
/home/slyfox/dev/git/gcc/gcc/tree-vect-loop.cc:6210:18: note:
'vec_stmts.vec<gimple*, va_heap, vl_ptr>::m_vec' was declared here
 6210 |   vec <gimple *> vec_stmts;
      |                  ^~~~~~~~~
cc1plus: all warnings being treated as errors
make[3]: *** [Makefile:1198: tree-vect-loop.o] Error 1
make[3]: Leaving directory '/tmp/gb/gcc'
make[2]: *** [Makefile:5094: all-stage2-gcc] Error 2
make[2]: Leaving directory '/tmp/gb'
make[1]: *** [Makefile:26393: stage2-bubble] Error 2
make[1]: Leaving directory '/tmp/gb'
make: *** [Makefile:1096: all] Error 2

$ ./gcc/xgcc -v
Using built-in specs.
COLLECT_GCC=./gcc/xgcc
Target: x86_64-pc-linux-gnu
Configured with: /home/slyfox/dev/git/gcc/configure --disable-multilib
--enable-checking=release
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 14.0.0 20231225 (experimental) (GCC)

[Bug bootstrap/113132] [14 regression] --enable-checking=release build fails: tree-vect-loop.cc:6221:34: error: ‘vec_stmts.vec<gimple*, va_heap, vl_ptr>::m_vec’ may be used uninitialized [-Werror=maybe-uninitialized]

[slyfox at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113132

Sergei Trofimovich <slyfox at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tamar.christina at arm dot com

--- Comment #1 from Sergei Trofimovich <slyfox at gcc dot gnu.org> ---
Might be exposed by r14-6822-g01f4251b8775c8 "middle-end: Support vectorization
of loops with multiple exits."

[Bug bootstrap/113132] [14 regression] --enable-checking=release build fails: tree-vect-loop.cc:6221:34: error: ‘vec_stmts.vec<gimple*, va_heap, vl_ptr>::m_vec’ may be used uninitialized [-Werror=maybe-uninitialized]

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113132

--- Comment #2 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Tamar Christina <tnfchris@gcc.gnu.org>:

https://gcc.gnu.org/g:fd032cce216e003d58b2394f7e61b03dee27e81a

commit r14-6830-gfd032cce216e003d58b2394f7e61b03dee27e81a
Author: Tamar Christina <tamar.christina@arm.com>
Date:   Mon Dec 25 10:58:40 2023 +0000

    middle-end: explicitly initialize vec_stmts [PR113132]

    when configured with --enable-checking=release we get a false
    positive on the use of vec_stmts as the compiler seems unable
    to notice it gets initialized through the pass-by-reference.

    This explicitly initializes the local.

    gcc/ChangeLog:

            PR bootstrap/113132
            * tree-vect-loop.cc (vect_create_epilog_for_reduction): Initialize
vec_stmts;

[Bug bootstrap/113132] [14 regression] --enable-checking=release build fails: tree-vect-loop.cc:6221:34: error: ‘vec_stmts.vec<gimple*, va_heap, vl_ptr>::m_vec’ may be used uninitialized [-Werror=maybe-uninitialized]

[tnfchris at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113132

Tamar Christina <tnfchris at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |tnfchris at gcc dot gnu.org

--- Comment #3 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
fixed, thanks