* fold-const.c (fold_unary) <NOP_EXPR>: Fold (T1)(~(T2)X) as
	~(T1)X, when T1 and T2 are integer types of the same precision
	and (T2)X isn't an extension.

	* gcc.dg/fold-convnotconv-1.c: New test case.

From-SVN: r112455