https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66592
--- Comment #1 from kargl at gcc dot gnu.org --- This bug appears to be regression and it requires the -O2 and -ftree-vectorize options. gfortran -c -O2 -ftree-vectorize z.f z.f:1:0: subroutine calsvp(nkr,nkz) ^ internal compiler error: in vect_get_vec_def_for_operand, at tree-vect-stmts.c:1478 0xd6a2a9 vect_get_vec_def_for_operand(tree_node*, gimple_statement_base*, tree_node**) ../../gcc6/gcc/tree-vect-stmts.c:1478 0xd72a0d vectorizable_store ../../gcc6/gcc/tree-vect-stmts.c:5330 0xd7d6a6 vect_transform_stmt(gimple_statement_base*, gimple_stmt_iterator*, bool*, _slp_tree*, _slp_instance*) ../../gcc6/gcc/tree-vect-stmts.c:7496 0xd9a541 vect_schedule_slp_instance ../../gcc6/gcc/tree-vect-slp.c:3481 0xd9ab16 vect_schedule_slp(_loop_vec_info*, _bb_vec_info*) ../../gcc6/gcc/tree-vect-slp.c:3551 0xd82c17 vect_transform_loop(_loop_vec_info*) ../../gcc6/gcc/tree-vect-loop.c:6218 0xda0792 vectorize_loops() ../../gcc6/gcc/tree-vectorizer.c:495 Please submit a full bug report, with preprocessed source if appropriate. Please include the complete backtrace with any bug report. See <http://gcc.gnu.org/bugs.html> for instructions.