PR middle-end/38250
        * tree-loop-distribution.c (build_size_arg): New function.
        (generate_memset_zero): Checks if DR_STEP(de) is NULL.
        Reorganized generating of stmts.
        * testsuite/gcc.dg/tree-ssa/pr38250.c: New file.
        * tree-data-ref.c (dr_analyze_innermost): Returns bool.
        Indicate if analysis succeed.
        * tree-data-ref.h (dr_analyze_innermost): Returns bool.
        * tree-predcom.c (valid_initializer_p, find_looparound_phi):
        Uses new definition of dr_analyze_innermost.

From-SVN: r142394