PR c/11449
	* fold-const.c (sign_bit_p): Return EXP if VAL is the sign bit
	of HOST_WIDE_INT.
	(fold_single_bit_test): If sign_bit_p() fails, assume that the
	bit being tested is not a sign bit.

	PR c/11449
	* gcc.c-torture/compile/20030707-1.c: New.
	* config/h8300/h8300.md (a peephole2): New.

From-SVN: r69184