gimplify.c (gimplify_modify_expr_rhs): Handle the case when we are assigning…

gimplify.c (gimplify_modify_expr_rhs): Handle the case when we are assigning from a constant constructor.

        * gimplify.c (gimplify_modify_expr_rhs): Handle the case when we
        are assigning from a constant constructor.
        Fix wrapping in function comment.

From-SVN: r130788

gcc/ChangeLog

+2007-12-12  Aldy Hernandez  <aldyh@redhat.com>
+
+	PR tree-optimization/32901
+	* gimplify.c (gimplify_modify_expr_rhs): Handle the case when we
+	are assigning from a constant constructor.
+	Fix wrapping in function comment.
+
 2007-12-12  Andreas Krebbel  <krebbel1@de.ibm.com>
 
 	* config/s390/s390.c (s390_O_constraint_str): Limit the range

gcc/gimplify.c

@@ -3470,8 +3470,9 @@ fold_indirect_ref_rhs (tree t)
   return NULL_TREE;
 }
 
-/* Subroutine of gimplify_modify_expr to do simplifications of MODIFY_EXPRs
-   based on the code of the RHS.  We loop for as long as something changes.  */
+/* Subroutine of gimplify_modify_expr to do simplifications of
+   MODIFY_EXPRs based on the code of the RHS.  We loop for as long as
+   something changes.  */
 
 static enum gimplify_status
 gimplify_modify_expr_rhs (tree *expr_p, tree *from_p, tree *to_p, tree *pre_p,
@@ -3482,6 +3483,18 @@ gimplify_modify_expr_rhs (tree *expr_p, tree *from_p, tree *to_p, tree *pre_p,
   while (ret != GS_UNHANDLED)
     switch (TREE_CODE (*from_p))
       {
+      case VAR_DECL:
+	/* If we're assigning from a constant constructor, move the
+	   constructor expression to the RHS of the MODIFY_EXPR.  */
+	if (DECL_INITIAL (*from_p)
+	    && TYPE_READONLY (TREE_TYPE (*from_p))
+	    && TREE_CODE (DECL_INITIAL (*from_p)) == CONSTRUCTOR)
+	  {
+	    *from_p = DECL_INITIAL (*from_p);
+	    ret = GS_OK;
+	  }
+	ret = GS_UNHANDLED;
+	break;
       case INDIRECT_REF:
 	{
 	  /* If we have code like 

gcc/testsuite/gcc.dg/tree-ssa/pr32901.c

+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-gimple" } */
+
+struct foo {
+        unsigned a1: 1;
+        unsigned a2: 3;
+        unsigned : 4;
+};
+
+extern struct foo thefoo;
+
+void setup_foo(void)
+{
+        const struct foo init = {
+                .a1 = 1,
+                .a2 = 5,
+        };
+        thefoo = init;
+}
+
+/* { dg-final { scan-tree-dump-times "thefoo.0 = \{\}" 1 "gimple"} } */
+/* { dg-final { scan-tree-dump-times "thefoo.0.a1 = 1" 1 "gimple"} } */
+/* { dg-final { scan-tree-dump-times "thefoo.0.a2 = 5" 1 "gimple"} } */
+/* { dg-final { cleanup-tree-dump "gimple" } } */