Statements which are live but not relevant need marking to ensure they are
vectorized.

Live statements which are simple and all uses of them are invariant do not
need
to be vectorized.

This patch adds a check to make sure those stmts which pass both the above
checks are not vectorized and then discarded.

Tested on x86 and aarch64.


gcc/
        *tree-vect-stmts.c (vect_stmt_relevant_p): Do not vectorize non
live
        relevant stmts which are simple and invariant.

        testsuite/
        * gcc.dg/vect/vect-live-slp-5.c: Remove dg check.



Alan.