On Wed, 1 Feb 2017, Jakub Jelinek wrote: > On Wed, Feb 01, 2017 at 11:07:18AM +0100, Richard Biener wrote: > > > On Wed, Feb 01, 2017 at 10:58:29AM +0100, Richard Biener wrote: > > > > > > +/* Nonzero if TYPE represents a (scalar) boolean type or type > > > > > > + in the middle-end compatible with it. */ > > > > > > + > > > > > > +#define INTEGRAL_BOOLEAN_TYPE_P(TYPE) \ > > > > > > + (TREE_CODE (TYPE) == BOOLEAN_TYPE \ > > > > > > + || ((TREE_CODE (TYPE) == INTEGER_TYPE \ > > > > > > + || TREE_CODE (TYPE) == ENUMERAL_TYPE) \ > > > > > > + && TYPE_PRECISION (TYPE) == 1 \ > > > > > > + && TYPE_UNSIGNED (TYPE))) > > > > > > > > > > > > (just to quote what you proposed). > > > > > > > > > > So would it help to use > > > > > (TREE_CODE (TYPE) == BOOLEAN_TYPE > > > > > || (INTEGRAL_TYPE_P (TYPE) > > > > > && useless_type_conversion_p (boolean_type_node, TYPE))) > > > > > It would be much slower than the above, but would be less dependent > > > > > on useless_type_conversion_p details. > > > > > > > > For the vectorizer it likely would break the larger logical type > > > > handling? > > > > > > Why? It is the same thing as the earlier macro above. > > > Any kind of boolean, plus anything that could be initially boolean > > > and the middle-end might have replaced it with. > > > > boolean_type_node is QImode but logical(8) is DImode for example. > > Both have precision == 1 but they are not types_compatible_p > > (you probably missed the mode check in useless_type_conversion_p). > > Then the earlier macro should have used also a TYPE_MODE check. > The latter macro is what I've been looking for in the patch, except that > I thought it is too expensive (plus might actually not DTRT if > boolean_type_node has > 1 precision, but some unsigned precision 1 > BOOLEAN_TYPE exists too; as Fortran has changed, now it is only Ada that > doesn't have precision 1 boolean_type_node, but then it likely doesn't > have any precision 1 BOOLEAN_TYPEs). > > > > > The question is really what the vectorizer and other places are looking > > > > for -- which isually is a 1-bit precision, eventually unsigned, > > > > integral type. > > > > > > It is looking for any type where the only valid values are 0 (false) and 1 > > > (true), so that it can actually vectorize it as a bitmask, or vector of > > > integers with -1 and 0 values. > > > > That's INTEGRAL_TYPE_P && TYPE_PRECISION == 1 && TYPE_UNSIGNED. The > > Ada types do not fall under this category as far as I understand as > > the exceptional values may exist in memory(?) > > But the exceptional values are undefined behavior I believe. > Anyway, we've been vectorizing not just the 1-bit precision BOOLEAN_TYPEs > but other BOOLEAN_TYPEs (Ada and especially Fortran) for a couple of years > this way already and I'm not aware of issues with that. > > So suddenly stopping doing that because we want to fix a bug related > to the fact that for 1-bit precision unsigned QImode BOOLEAN_TYPE the > middle-end considers other types to be compatible with those is strange > and very risky, especially at this point in GCC 7 development.
I agree. But this means we should look for a vectorizer-local fix without a new global predicate then (there seem to be subtly different needs and coming up with good names for all of them sounds difficult...). Richard.
