* fold-const.c (fold_binary) <EQ_EXPR>: Fold "(X^C1) eq/ne C2" into
	"X eq/ne (C1^C2)".  Fold "(X^Z) eq/ne (Y^Z)" as "X eq/ne Y" when Z
	has no side-effects.  Fold "(X^C1) eq/ne (Y^C2)" as "(X^(C1^C2))
	eq/ne Y".

	* gcc.dg/fold-eqxor-4.c: New test case.

From-SVN: r120333