> The middle-end treats conversions between integral types that differ > in TYPE_MIN/MAX_VALUE but not in TYPE_PRECISION or signedness as useless. > This is inconsistent with VRP extracting range information from such > types (and it is not clear how NOP conversions behave here anyway).
IIRC we agreed, by the time I fixed the Ada compiler, that the IL shouldn't contain types with non-canonical bounds, except for constructs that don't generate code like the TYPE_DOMAIN of arrays. My understanding is that this has been the case (modulo bugs) for some time now, so I don't understand your remark about NOP conversions. > The following patch thus simply removes VRPs looking at TYPE_MIN/MAX_VALUE > in favor of using a canonical min/max value based on signedness and > precision. This exposes a latent bug in upper_bound_in_type and > lower_bound_in_type which do not properly sign-extend sizetype constants. Wouldn't it be better performance-wise to keep using TYPE_MIN/MAX_VALUE and add an appropriate check for non-standard types at the end of gimplification? -- Eric Botcazou
