Hi, On Mon, 16 May 2011, Richard Guenther wrote:
> We can't use a test for BOOLEAN_TYPE as the middle-end considers a > INTEGER_TYPE with same precision/signedness as compatible and thus may > propagate a variable of INTEGER_TYPE there. I don't understand why > promoting bools to boolean_type_node during gimplification does not work > (it might be slightly undesirable as it might introduce conversions from > one boolean type to another). > > So, to relax the above check to allow any of the boolean types we'd need > a way to enumerate them. Or make conversions to/from BOOLEAN_TYPEs not > useless. I think conversion _to_ BOOLEAN_TYPE shouldn't be useless, on the grounds that it requires booleanization (at least conceptually), i.e. conversion to a set of two values (no matter the precision or size) based on the outcome of comparing the RHS value with false_pre_image(TREE_TYPE(RHS)). Conversion _from_ BOOLEAN_TYPE can be regarded as useless, as the conversions from false or true into false_pre_image or true_pre_image always is simply an embedding of 0 or 1/-1 (depending on target type signedness). And if the BOOLEAN_TYPE and the LHS have same signedness the bit representation of boolean_true_type is (or should be) the same as the one converted to LHS (namely either 1 or -1). Ciao, Michael.
