PR middle-end/29749
	* fold-const.c (fold_binary) <case BIT_AND_EXPR>: Optimize
	(X << C1) & C2 into (X << C1) & (C2 | ((1 << C1) - 1))
	and (X >> C1) & C2 into (X >> C1) & (C2 | ~((type) -1 >> C1)).
	(fold_binary) <case LSHIFT_EXPR, case RSHIFT_EXPR>: Optimize
	(X & C2) << C1 into (X << C1) & (C2 << C1) and
	(X & C2) >> C1 into (X >> C1) & (C2 >> C1) if that allows further
	optimizations.

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

From-SVN: r130589