[Bug tree-optimization/96522] [9/10 Regression] Incorrect with with -O -fno-tree-pta

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96522

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #6)
> Hmm, picking the ref onto gcc-10 causes
> 
> FAIL: gcc.dg/vect/pr81410.c execution test
> 
> due to an unaligned access.

Looks like a latent issue.  The following on an unpatched tree is enough
to provoke the FAIL (but ptr-info should not affect correctness).

diff --git a/gcc/tree-vect-stmts.c b/gcc/tree-vect-stmts.c
index 9ace345fc5e..ea32b70a4f3 100644
--- a/gcc/tree-vect-stmts.c
+++ b/gcc/tree-vect-stmts.c
@@ -9565,10 +9567,12 @@ vectorizable_load (stmt_vec_info stmt_info,
gimple_stmt_iterator *gsi,
                      }
                    else
                      misalign = DR_MISALIGNMENT (first_dr_info);
+#if 0
                    if (dataref_offset == NULL_TREE
                        && TREE_CODE (dataref_ptr) == SSA_NAME)
                      set_ptr_info_alignment (get_ptr_info (dataref_ptr),
                                              align, misalign);
+#endif

                    if (final_mask)
                      {