[Bug tree-optimization/58039] New: -ftree-vectorizer make a loop crash on non-aligned memory

[bar at mariadb dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58039

            Bug ID: 58039
           Summary: -ftree-vectorizer make a loop crash on non-aligned
                    memory
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bar at mariadb dot org

Created attachment 30578
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30578&action=edit
The program that repeats the report crash

If I compile the attached program using:

gcc -Wall -O2 -fno-inline -ftree-vectorize -ftree-vectorizer-verbose=2 a.c

it crashes with "segmentation fault".


$ gcc --version
gcc (GCC) 4.7.2 20120921 (Red Hat 4.7.2-2)

Processor: Intel® Core™ i7-3520M CPU @ 2.90GHz × 4


The program is a minimal extract from the MariaDB-10.0 sources
that reproduces the crash.

The GCC flags that are actually used in the debug build of MariaDB are:
gcc -Wall -O3 -fno-inline a.c

but after tracking it down we noticed that the actually reason is
-ftree-vectorize.