https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106019
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Richard Sandiford <rsand...@gcc.gnu.org>: https://gcc.gnu.org/g:038b077689bb5310386b04d40a2cea234f01e6aa commit r13-1203-g038b077689bb5310386b04d40a2cea234f01e6aa Author: Richard Sandiford <richard.sandif...@arm.com> Date: Wed Jun 22 11:27:15 2022 +0100 data-ref: Improve non-loop disambiguation [PR106019] When dr_may_alias_p is called without a loop context, it tries to use the tree-affine interface to calculate the difference between the two addresses and use that difference to check whether the gap between the accesses is known at compile time. However, as the example in the PR shows, this doesn't expand SSA_NAMEs and so can easily be defeated by things like reassociation. One fix would have been to use aff_combination_expand to expand the SSA_NAMEs, but we'd then need some way of maintaining the associated cache. This patch instead reuses the innermost_loop_behavior fields (which exist even when no loop context is provided). It might still be useful to do the aff_combination_expand thing too, if an example turns out to need it. gcc/ PR tree-optimization/106019 * tree-data-ref.cc (dr_may_alias_p): Try using the innermost_loop_behavior to disambiguate non-loop queries. gcc/testsuite/ PR tree-optimization/106019 * gcc.dg/vect/bb-slp-pr106019.c: New test.
