[Bug target/122872] New: [UBSAN] tree-vect-loop.cc:4518:10: runtime error: signed integer overflow: 1703712 * 65528 cannot be represented in type 'int'

[dcb314 at hotmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122872

            Bug ID: 122872
           Summary: [UBSAN] tree-vect-loop.cc:4518:10: runtime error:
                    signed integer overflow: 1703712 * 65528 cannot be
                    represented in type 'int'
           Product: gcc
           Version: 16.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

For the Ada test suite file gnat.dg/unroll4.adb,
compiled with an UBSAN version of today's trunk Ada compiler,
does this:

testsuite $ ~/gcc/results.20251126/bin/gcc -c   -O2    ./gnat.dg/unroll4.adb
../../trunk/gcc/tree-vect-loop.cc:4518:10: runtime error: signed integer
overflow: 1572752 * 65532 cannot be represented in type 'int'
../../trunk/gcc/tree-vect-loop.cc:4594:6: runtime error: signed integer
overflow: 1572816 * 65532 cannot be represented in type 'int'


Compiler is

testsuite $ ~/gcc/results.20251126/bin/gcc -v
Using built-in specs.
COLLECT_GCC=/home/dcb42/gcc/results.20251126/bin/gcc
COLLECT_LTO_WRAPPER=/home/dcb42/gcc/results.20251126/libexec/gcc/x86_64-pc-linux-gnu/16.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../trunk/configure --prefix=/home/dcb42/gcc/results.20251126
--disable-doc --disable-multilib --disable-werror --enable-checking=yes
--enable-languages=c,c++,fortran,ada,cobol --with-build-config=bootstrap-ubsan
--with-pkgversion=a0b8cc4a473e1e87
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 16.0.0 20251126 (experimental) (a0b8cc4a473e1e87) 
testsuite $