1 files changed, 58 insertions, 2 deletions

diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index 9452973..657d531 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -2846,6 +2846,62 @@ gimplify_init_constructor (tree *expr_p, tree *pre_p,
     return GS_ALL_DONE;
 }
 
+/* Given a pointer value OP0, return a simplified version of an
+   indirection through OP0, or NULL_TREE if no simplification is
+   possible.  This may only be applied to a rhs of an expression.
+   Note that the resulting type may be different from the type pointed
+   to in the sense that it is still compatible from the langhooks
+   point of view. */
+
+static tree
+fold_indirect_ref_rhs (tree t)
+{
+  tree type = TREE_TYPE (TREE_TYPE (t));
+  tree sub = t;
+  tree subtype;
+
+  STRIP_NOPS (sub);
+  subtype = TREE_TYPE (sub);
+  if (!POINTER_TYPE_P (subtype))
+    return NULL_TREE;
+
+  if (TREE_CODE (sub) == ADDR_EXPR)
+    {
+      tree op = TREE_OPERAND (sub, 0);
+      tree optype = TREE_TYPE (op);
+      /* *&p => p */
+      if (lang_hooks.types_compatible_p (type, optype))
+        return op;
+      /* *(foo *)&fooarray => fooarray[0] */
+      else if (TREE_CODE (optype) == ARRAY_TYPE
+	       && lang_hooks.types_compatible_p (type, TREE_TYPE (optype)))
+       {
+         tree type_domain = TYPE_DOMAIN (optype);
+         tree min_val = size_zero_node;
+         if (type_domain && TYPE_MIN_VALUE (type_domain))
+           min_val = TYPE_MIN_VALUE (type_domain);
+         return build4 (ARRAY_REF, type, op, min_val, NULL_TREE, NULL_TREE);
+       }
+    }
+
+  /* *(foo *)fooarrptr => (*fooarrptr)[0] */
+  if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE
+      && lang_hooks.types_compatible_p (type, TREE_TYPE (TREE_TYPE (subtype))))
+    {
+      tree type_domain;
+      tree min_val = size_zero_node;
+      sub = fold_indirect_ref_rhs (sub);
+      if (! sub)
+	sub = build1 (INDIRECT_REF, TREE_TYPE (subtype), sub);
+      type_domain = TYPE_DOMAIN (TREE_TYPE (sub));
+      if (type_domain && TYPE_MIN_VALUE (type_domain))
+        min_val = TYPE_MIN_VALUE (type_domain);
+      return build4 (ARRAY_REF, type, sub, min_val, NULL_TREE, NULL_TREE);
+    }
+
+  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.  */
 
@@ -2869,8 +2925,8 @@ gimplify_modify_expr_rhs (tree *expr_p, tree *from_p, tree *to_p, tree *pre_p,
 	     This kind of code arises in C++ when an object is bound
 	     to a const reference, and if "x" is a TARGET_EXPR we want
 	     to take advantage of the optimization below.  */
-	  tree t = fold_indirect_ref (*from_p);
-	  if (t != *from_p)
+	  tree t = fold_indirect_ref_rhs (TREE_OPERAND (*from_p, 0));
+	  if (t)
 	    {
 	      *from_p = t;
 	      ret = GS_OK;