re PR middle-end/62263 (Good codegen for bitwise rotate requires code that is technically undefined behavior)

	PR middle-end/62263
	PR middle-end/82498
	* tree-ssa-phiopt.c (value_replacement): Comment fix.  Handle
	up to 2 preparation statements for ASSIGN in MIDDLE_BB.

	* c-c++-common/rotate-8.c: Expect no PHIs in optimized dump.

From-SVN: r253761