https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98255
--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> --- (In reply to Richard Biener from comment #9) > (In reply to Jakub Jelinek from comment #8) > > 503 poly_offset_int woffset > > 504 = wi::sext (wi::to_poly_offset (index) > > 505 - wi::to_poly_offset (low_bound), > > 506 TYPE_PRECISION (TREE_TYPE (index))); > > in get_ref_base_and_extent indeed looks incorrect to me, for precisions > > smaller than precision of pointer (or is that sizetype) I think we need to > > sign or zero extend based on whether index has signed or unsigned type. > > For arrays with zero low_bound I think what get_inner_reference does is > > right, in particular: > > offset = size_binop (PLUS_EXPR, offset, > > size_binop (MULT_EXPR, > > fold_convert (sizetype, index), > > unit_size)); > > For non-zero low_bound, it does: > > if (! integer_zerop (low_bound)) > > index = fold_build2 (MINUS_EXPR, TREE_TYPE (index), > > index, low_bound); > > before that and I'm surprised that it assumes index and low_bound will be > > compatible types. But perhaps they are in the languages that do support > > non-zero low bounds. > > Note all the above "mess" is due to FEs behaving oddly, notably different > from just interpreting the index as-is (appropriately sign or zero-extending > it to sizetype for the sizetype offset compute). The odd sign-extension > is from gb48e22b2bd02 Possibly wi::sext(..., TYPE_PRECISION (sizetype)) is what we want.
