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

gcc/ChangeLog

@@ -1,3 +1,11 @@
+2011-01-05  Eric Botcazou  <ebotcazou@adacore.com>
+
+	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.
+
 2011-01-04  Eric Botcazou  <ebotcazou@adacore.com>
 
 	PR tree-optimization/47056

gcc/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2011-01-05  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gnat.dg/opt14.adb: New test.
+
 2011-01-05  Thomas Koenig  <tkoenig@gcc.gnu.org>
 
 	PR fortran/46017

gcc/testsuite/gnat.dg/opt14.adb

@@ -0,0 +1,25 @@
+-- { dg-do run }
+-- { dg-options "-O2" }
+
+procedure Opt14 is
+
+  type Rec is record
+    I1, I2, I3 : Integer;
+  end record;
+
+  type Ptr is access Rec;
+
+  P : Ptr := new Rec'(0,0,0);
+
+  procedure Sub (R : In Out Rec) is
+  begin
+    R.I3 := R.I3 - 1;
+  end;
+
+begin
+  P.all := (1,2,3);
+  Sub (P.all);
+  if P.all /= (1,2,2) then
+    raise Program_Error;
+  end if;
+end;

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);