re PR tree-optimization/47005 (ACATS c62002a is miscompiled at -O2)

	PR tree-optimization/47005
	* tree-sra.c (struct access): Add 'non_addressable' bit.
	(create_access): Set it for a DECL_NONADDRESSABLE_P field.
	(decide_one_param_reduction): Return 0 if the parameter is passed by
	reference and one of the accesses in the group is non_addressable.

From-SVN: r168508

1 files changed, 13 insertions, 1 deletions

diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c
index 14fef47..c2ec204 100644
--- a/gcc/tree-sra.c
+++ b/gcc/tree-sra.c
@@ -173,6 +173,9 @@ struct access
      entirely? */
   unsigned total_scalarization : 1;
 
+  /* Is this access an access to a non-addressable field? */
+  unsigned non_addressable : 1;
+
   /* Is this access currently in the work queue?  */
   unsigned grp_queued : 1;
 
@@ -816,6 +819,10 @@ create_access (tree expr, gimple stmt, bool write)
   access->grp_unscalarizable_region = unscalarizable_region;
   access->stmt = stmt;
 
+  if (TREE_CODE (expr) == COMPONENT_REF
+      && DECL_NONADDRESSABLE_P (TREE_OPERAND (expr, 1)))
+    access->non_addressable = 1;
+
   return access;
 }
 
@@ -3666,13 +3673,18 @@ decide_one_param_reduction (struct access *repr)
   for (; repr; repr = repr->next_grp)
     {
       gcc_assert (parm == repr->base);
-      new_param_count++;
+
+      /* Taking the address of a non-addressable field is verboten.  */
+      if (by_ref && repr->non_addressable)
+	return 0;
 
       if (!by_ref || (!repr->grp_maybe_modified
 		      && !repr->grp_not_necessarilly_dereferenced))
 	total_size += repr->size;
       else
 	total_size += cur_parm_size;
+
+      new_param_count++;
     }
 
   gcc_assert (new_param_count > 0);