PR c/48418
	* c-common.c (c_fully_fold_internal): Warn for LSHIFT_EXPR and
	RSHIFT_EXPR, if orig_op1 isn't INTEGER_CST, op1 is INTEGER_CST
	and is either negative or bigger or equal to type precision
	of the first operand.

	* typeck.c (cp_build_binary_op): For LSHIFT_EXPR and RSHIFT_EXPR,
	call maybe_constant_value for the negative or too big shift
	count warnings.

	* c-c++-common/pr48418.c: New test.

From-SVN: r195051