diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 64211b69d74..35f823cabf3 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,7 @@
+2010-05-08  Pierre Muller  <muller@ics.u-strasbg.fr>
+
+	* p-exp.y (exp : SIZEOF '(' exp ')'): New rule.
+
 2010-05-08  Jan Kratochvil  <jan.kratochvil@redhat.com>
 
 	* dwarf2read.c (typename_concat): Use (char *) NULL terminated stdarg
diff --git a/gdb/p-exp.y b/gdb/p-exp.y
index fce3fc79665..2aec487463c 100644
--- a/gdb/p-exp.y
+++ b/gdb/p-exp.y
@@ -525,6 +525,9 @@ exp	:	SIZEOF '(' type ')'	%prec UNARY
 			  write_exp_elt_opcode (OP_LONG); }
 	;
 
+exp	:	SIZEOF  '(' exp ')'      %prec UNARY
+			{ write_exp_elt_opcode (UNOP_SIZEOF); }
+	
 exp	:	STRING
 			{ /* C strings are converted into array constants with
 			     an explicit null byte added at the end.  Thus