re PR rtl-optimization/67218 (Combine incorrectly folds (double) (float) (unsigned))

re PR rtl-optimization/67218 (Combine incorrectly folds (double) (float) (unsigned))

gcc/
	PR rtl-optimization/67218
	* simplify-rtx.c (exact_int_to_float_conversion_p): New function.
	(simplify_unary_operation_1): Use it.

gcc/testsuite/
	PR rtl-optimization/67218
	* gcc.c-torture/execute/ieee/pr67218.c,
	gcc.target/aarch64/fcvt_int_float_double1.c,
	gcc.target/aarch64/fcvt_int_float_double2.c,
	gcc.target/aarch64/fcvt_int_float_double3.c,
	gcc.target/aarch64/fcvt_int_float_double4.c,
	gcc.target/aarch64/fcvt_uint_float_double1.c,
	gcc.target/aarch64/fcvt_uint_float_double2.c,
	gcc.target/aarch64/fcvt_uint_float_double3.c,
	gcc.target/aarch64/fcvt_uint_float_double4.c: New tests.

From-SVN: r226987