1 files changed, 73 insertions, 0 deletions
diff --git a/gcc/tree.c b/gcc/tree.c
index d68f08e9b6f..f48512fceeb 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -9460,5 +9460,78 @@ list_equal_p (const_tree t1, const_tree t2)
   return !t1 && !t2;
 }
 
+/* Return true iff conversion in EXP generates no instruction.  Mark
+   it inline so that we fully inline into the stripping functions even
+   though we have two uses of this function.  */
+
+static inline bool
+tree_nop_conversion (const_tree exp)
+{
+  tree outer_type, inner_type;
+
+  if (!CONVERT_EXPR_P (exp)
+      && TREE_CODE (exp) != NON_LVALUE_EXPR)
+    return false;
+  if (TREE_OPERAND (exp, 0) == error_mark_node)
+    return false;
+
+  outer_type = TREE_TYPE (exp);
+  inner_type = TREE_TYPE (TREE_OPERAND (exp, 0));
+
+  /* Use precision rather then machine mode when we can, which gives
+     the correct answer even for submode (bit-field) types.  */
+  if ((INTEGRAL_TYPE_P (outer_type)
+       || POINTER_TYPE_P (outer_type)
+       || TREE_CODE (outer_type) == OFFSET_TYPE)
+      && (INTEGRAL_TYPE_P (inner_type)
+	  || POINTER_TYPE_P (inner_type)
+	  || TREE_CODE (inner_type) == OFFSET_TYPE))
+    return TYPE_PRECISION (outer_type) == TYPE_PRECISION (inner_type);
+
+  /* Otherwise fall back on comparing machine modes (e.g. for
+     aggregate types, floats).  */
+  return TYPE_MODE (outer_type) == TYPE_MODE (inner_type);
+}
+
+/* Return true iff conversion in EXP generates no instruction.  Don't
+   consider conversions changing the signedness.  */
+
+static bool
+tree_sign_nop_conversion (const_tree exp)
+{
+  tree outer_type, inner_type;
+
+  if (!tree_nop_conversion (exp))
+    return false;
+
+  outer_type = TREE_TYPE (exp);
+  inner_type = TREE_TYPE (TREE_OPERAND (exp, 0));
+
+  return (TYPE_UNSIGNED (outer_type) == TYPE_UNSIGNED (inner_type)
+	  && POINTER_TYPE_P (outer_type) == POINTER_TYPE_P (inner_type));
+}
+
+/* Strip conversions from EXP according to tree_nop_conversion and
+   return the resulting expression.  */
+
+tree
+tree_strip_nop_conversions (tree exp)
+{
+  while (tree_nop_conversion (exp))
+    exp = TREE_OPERAND (exp, 0);
+  return exp;
+}
+
+/* Strip conversions from EXP according to tree_sign_nop_conversion
+   and return the resulting expression.  */
+
+tree
+tree_strip_sign_nop_conversions (tree exp)
+{
+  while (tree_sign_nop_conversion (exp))
+    exp = TREE_OPERAND (exp, 0);
+  return exp;
+}
+
 
 #include "gt-tree.h"