gcc/

[pf3gnuchains/gcc-fork.git] / gcc / doc / rtl.texi

diff --git a/gcc/doc/rtl.texi b/gcc/doc/rtl.texi
index ea30e38..0d348dc 100644 (file)
--- a/gcc/doc/rtl.texi
+++ b/gcc/doc/rtl.texi
@@ -413,11 +413,17 @@ object associated with the reference.
 @item MEM_OFFSET (@var{x})
 The offset from the start of @code{MEM_EXPR} as a @code{CONST_INT} rtx.
 
+@findex MEM_SIZE_KNOWN_P
+@item MEM_SIZE_KNOWN_P (@var{x})
+True if the size of the memory reference is known.
+@samp{MEM_SIZE (@var{x})} provides its size if so.
+
 @findex MEM_SIZE
 @item MEM_SIZE (@var{x})
-The size in bytes of the memory reference as a @code{CONST_INT} rtx.
+The size in bytes of the memory reference.
 This is mostly relevant for @code{BLKmode} references as otherwise
-the size is implied by the mode.
+the size is implied by the mode.  The value is only valid if
+@samp{MEM_SIZE_KNOWN_P (@var{x})} is true.
 
 @findex MEM_ALIGN
 @item MEM_ALIGN (@var{x})