https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70509
--- Comment #3 from Marc Glisse <glisse at gcc dot gnu.org> --- (In reply to Zdenek Sojka from comment #2) > (In reply to Zdenek Sojka from comment #0) > > First broken dump seems to be .forwprop, where is: > > .forwprop4 , that is. The problem might be that simplify_bitfield_ref() does: > tree-ssa-forwprop.c > ... > 1793: index = build_int_cst (TREE_TYPE (TREE_TYPE (m)), idx * size); > ... > > which builds the index of type "unsigned char", which wraps around from 256 > to 0. > Is there any reason to have index of type "TREE_TYPE (TREE_TYPE (m))" in > that statement? Rereading this a few years later, I have no idea why I used that type. bitsize_int would make more sense...