re PR rtl-optimization/25600 (unsigned>>31?-1:0 should be optimized to int>>31)

re PR rtl-optimization/25600 (unsigned>>31?-1:0  should be optimized to int>>31)

	PR middle-end/25600
	* fold-const.c (fold_binary): Fold (X >> C) != 0 into X < 0 when
	C is one less than the width of X (and related transformations).
	* simplify_rtx.c (simplify_unary_operation_1): Transform
	(neg (lt x 0)) into either (ashiftrt X C) or (lshiftrt X C)
	depending on STORE_FLAG_VALUE, were C is one less then the
	width of X.

From-SVN: r111226