PR optimization/5263
	* simplify-rtx.c (associative_constant_p): Delete.
	(simplify_associative_operation): Rewrite to linearize terms, and
	attempt to simplify new term against both left and right subterms.
	(simplify_binary_operation): Call swap_commutative_operands_p on
	op0 and op1, not trueop0 and trueop1.  Move the initialization of
	trueop0 and trueop1 down to where first needed.
	(simplify_relational_operation): Likewise.
	* rtlanal.c (commutative_operand_precedence): Also order constant
	operands using avoid_constant_pool_reference.

From-SVN: r76179