https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93281
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by David Malcolm <dmalc...@gcc.gnu.org>: https://gcc.gnu.org/g:5f0303833d542b273da33e4b149974e739d350e5 commit r10-6039-g5f0303833d542b273da33e4b149974e739d350e5 Author: David Malcolm <dmalc...@redhat.com> Date: Wed Jan 15 15:55:11 2020 -0500 analyzer: fix handling of negative byte offsets (v2) (PR 93281) Various 32-bit targets show failures in gcc.dg/analyzer/data-model-1.c with tests of the form: __analyzer_eval (q[-2].x == 107024); /* { dg-warning "TRUE" } */ __analyzer_eval (q[-2].y == 107025); /* { dg-warning "TRUE" } */ where they emit UNKNOWN instead. The root cause is that gimple has a byte-based twos-complement offset of -16 expressed like this: _55 = q_92 + 4294967280; (32-bit) or: _55 = q_92 + 18446744073709551600; (64-bit) Within region_model::convert_byte_offset_to_array_index that unsigned offset was being divided by the element size to get an offset within an array. This happened to work on 64-bit target and host, but not elsewhere; the offset needs to be converted to a signed type before the division is meaningful. This patch does so, fixing the failures. gcc/analyzer/ChangeLog: PR analyzer/93281 * region-model.cc (region_model::convert_byte_offset_to_array_index): Convert to ssizetype before dividing by byte_size. Use fold_binary rather than fold_build2 to avoid needlessly constructing a tree for the non-const case.