PR rtl-optimization/56178
	* cse.c (cse_insn): Do not create a REG_EQUAL note if the source is a
	SUBREG of a register.  Tidy up related block of code.
	* fwprop.c (forward_propagate_and_simplify): Do not create a REG_EQUAL
	note if the source is a register or a SUBREG of a register.

From-SVN: r195841