1 files changed, 53 insertions, 0 deletions
diff --git a/gcc/tree.c b/gcc/tree.c
index 62d9d78..910fb06 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -10273,6 +10273,59 @@ uniform_integer_cst_p (tree t)
   return NULL_TREE;
 }
 
+/* Checks to see if T is a constant or a constant vector and if each element E
+   adheres to ~E + 1 == pow2 then return ~E otherwise NULL_TREE.  */
+
+tree
+bitmask_inv_cst_vector_p (tree t)
+{
+
+  tree_code code = TREE_CODE (t);
+  tree type = TREE_TYPE (t);
+
+  if (!INTEGRAL_TYPE_P (type)
+      && !VECTOR_INTEGER_TYPE_P (type))
+    return NULL_TREE;
+
+  unsigned HOST_WIDE_INT nelts = 1;
+  tree cst;
+  unsigned int idx = 0;
+  bool uniform = uniform_integer_cst_p (t);
+  tree newtype = unsigned_type_for (type);
+  tree_vector_builder builder;
+  if (code == INTEGER_CST)
+    cst = t;
+  else
+    {
+      if (!VECTOR_CST_NELTS (t).is_constant (&nelts))
+	return NULL_TREE;
+
+      cst = vector_cst_elt (t, 0);
+      builder.new_vector (newtype, nelts, 1);
+    }
+
+  tree ty = unsigned_type_for (TREE_TYPE (cst));
+
+  do {
+    if (idx > 0)
+      cst = vector_cst_elt (t, idx);
+    wide_int icst = wi::to_wide (cst);
+    wide_int inv =  wi::bit_not (icst);
+    icst = wi::add (1, inv);
+    if (wi::popcount (icst) != 1)
+      return NULL_TREE;
+
+    tree newcst = wide_int_to_tree (ty, inv);
+
+    if (uniform)
+      return build_uniform_cst (newtype, newcst);
+
+    builder.quick_push (newcst);
+  } while (++idx < nelts);
+
+  return builder.build ();
+}
+
 /* If VECTOR_CST T has a single nonzero element, return the index of that
    element, otherwise return -1.  */