tree-core: clarify clobber comments

It came up on the mailing list that OBJECT_BEGIN/END are described as
marking object lifetime, but mark the beginning of the constructor and end
of the destructor, whereas the C++ notion of lifetime is between the end of
the constructor and beginning of the destructor.  So let's fix the comments.

gcc/ChangeLog:

	* tree-core.h (enum clobber_kind): Clarify CLOBBER_OBJECT_*
	comments.

diff --git a/gcc/tree-core.h b/gcc/tree-core.h
index d529712306d9a0592d8326077e20da70a58fefe6..a74fbdf75b4b451faece866ce895d96db3bb0846 100644 (file)
--- a/gcc/tree-core.h
+++ b/gcc/tree-core.h
@@ -993,9 +993,11 @@ enum clobber_kind {
   CLOBBER_UNDEF,
   /* Beginning of storage duration, e.g. malloc.  */
   CLOBBER_STORAGE_BEGIN,
-  /* Beginning of object lifetime, e.g. C++ constructor.  */
+  /* Beginning of object data, e.g. start of C++ constructor.  This differs
+     from C++ 'lifetime', which starts when initialization is complete; a
+     clobber there would discard the initialization.  */
   CLOBBER_OBJECT_BEGIN,
-  /* End of object lifetime, e.g. C++ destructor.  */
+  /* End of object data, e.g. end of C++ destructor.  */
   CLOBBER_OBJECT_END,
   /* End of storage duration, e.g. free.  */
   CLOBBER_STORAGE_END,