re PR tree-optimization/54877 (ICE: tree check: expected ssa_name, have real_cst in copy_ssa_name_fn, at tree-ssanames.c:335)

	PR tree-optimization/54877
	* tree-vect-loop.c (vect_is_simple_reduction_1): For MINUS_EXPR
	use make_ssa_name instead of copy_ssa_name.

	* gcc.dg/torture/pr54877.c: New test.

From-SVN: r192322