[Bug tree-optimization/77550] [6/7 Regression] std::deque with -O3 has infinite std::distance

[bernd.edlinger at hotmail dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77550

--- Comment #12 from Bernd Edlinger <bernd.edlinger at hotmail dot de> ---
(In reply to Markus Trippelsdorf from comment #11)
> (In reply to Bernd Edlinger from comment #9)
> > I'm unable to reduce the test case...
> 
> Creduce is running and hopefully I will have a small testcase tomorrow
> morning.
> 
> 

good luck.

here is a hacky patch, test case passes, but I don't know
if it is going design-wise in the right direction:


--- tree-vect-stmts.c   2016-09-11 19:53:01.841182370 +0200
+++ tree-vect-stmts.c   2016-09-11 19:34:15.691171637 +0200
@@ -5482,6 +5483,7 @@
   gimple *new_stmt;
   int vf;
   vec_load_store_type vls_type;
+  bool alias_p = false;

   if (!STMT_VINFO_RELEVANT_P (stmt_info) && !bb_vinfo)
     return false;
@@ -5740,6 +5742,16 @@
       first_stmt = GROUP_FIRST_ELEMENT (stmt_info);
       first_dr = STMT_VINFO_DATA_REF (vinfo_for_stmt (first_stmt));
       group_size = GROUP_SIZE (vinfo_for_stmt (first_stmt));
+      next_stmt = GROUP_NEXT_ELEMENT (vinfo_for_stmt (first_stmt));
+      for (i = 1; i < group_size; i++)
+       {
+         struct data_reference *next_dr
+           = STMT_VINFO_DATA_REF (vinfo_for_stmt (next_stmt));
+         if (get_alias_set (DR_REF (first_dr))
+             != get_alias_set (DR_REF (next_dr)))
+           alias_p = true;
+         next_stmt = GROUP_NEXT_ELEMENT (vinfo_for_stmt (next_stmt));
+       }

       GROUP_STORE_COUNT (vinfo_for_stmt (first_stmt))++;

@@ -6174,8 +6188,10 @@
                                      dataref_ptr,
                                      dataref_offset
                                      ? dataref_offset
-                                     : build_int_cst (reference_alias_ptr_type
-                                                      (DR_REF (first_dr)),
0));
+                                     : build_int_cst (alias_p
+                                                      ? ptr_type_node
+                                                      :
reference_alias_ptr_type
+                                                        (DR_REF (first_dr)),
0));
              align = TYPE_ALIGN_UNIT (vectype);
              if (aligned_access_p (first_dr))
                misalign = 0;