1 files changed, 51 insertions, 0 deletions
diff --git a/gcc/tree.c b/gcc/tree.c
index 5ed55c1d372..92f16e7a88f 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -5696,6 +5696,57 @@ build_range_type (tree type, tree lowval, tree highval)
     return itype;
 }
 
+/* Return true if the debug information for TYPE, a subtype, should be emitted
+   as a subrange type.  If so, set LOWVAL to the low bound and HIGHVAL to the
+   high bound, respectively.  Sometimes doing so unnecessarily obfuscates the
+   debug info and doesn't reflect the source code.  */
+
+bool
+subrange_type_for_debug_p (const_tree type, tree *lowval, tree *highval)
+{
+  tree base_type = TREE_TYPE (type), low, high;
+
+  /* Subrange types have a base type which is an integral type.  */
+  if (!INTEGRAL_TYPE_P (base_type))
+    return false;
+
+  /* Get the real bounds of the subtype.  */
+  if (lang_hooks.types.get_subrange_bounds)
+    lang_hooks.types.get_subrange_bounds (type, &low, &high);
+  else
+    {
+      low = TYPE_MIN_VALUE (type);
+      high = TYPE_MAX_VALUE (type);
+    }
+
+  /* If the type and its base type have the same representation and the same
+     name, then the type is not a subrange but a copy of the base type.  */
+  if ((TREE_CODE (base_type) == INTEGER_TYPE
+       || TREE_CODE (base_type) == BOOLEAN_TYPE)
+      && int_size_in_bytes (type) == int_size_in_bytes (base_type)
+      && tree_int_cst_equal (low, TYPE_MIN_VALUE (base_type))
+      && tree_int_cst_equal (high, TYPE_MAX_VALUE (base_type)))
+    {
+      tree type_name = TYPE_NAME (type);
+      tree base_type_name = TYPE_NAME (base_type);
+
+      if (type_name && TREE_CODE (type_name) == TYPE_DECL)
+	type_name = DECL_NAME (type_name);
+
+      if (base_type_name && TREE_CODE (base_type_name) == TYPE_DECL)
+	base_type_name = DECL_NAME (base_type_name);
+
+      if (type_name == base_type_name)
+	return false;
+    }
+
+  if (lowval)
+    *lowval = low;
+  if (highval)
+    *highval = high;
+  return true;
+}
+
 /* Just like build_index_type, but takes lowval and highval instead
    of just highval (maxval).  */