From 99651574134ba16dc5256f70b2dcf13473f7e497 Mon Sep 17 00:00:00 2001
From: Richard Henderson <rth@redhat.com>
Date: Thu, 28 Jun 2012 12:01:28 -0700
Subject: [PATCH] Document MULT_HIGHPART_EXPR

From-SVN: r189054
---
 gcc/ChangeLog        | 4 ++++
 gcc/doc/generic.texi | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4e327763ce82..29ecf36f7074 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2012-06-28  Richard Henderson  <rth@redhat.com>
+
+	* doc/generic.texi (MULT_HIGHPART_EXPR): Document it.
+
 2012-06-28  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/51581
diff --git a/gcc/doc/generic.texi b/gcc/doc/generic.texi
index e99366fb28d0..c48b663a0335 100644
--- a/gcc/doc/generic.texi
+++ b/gcc/doc/generic.texi
@@ -1235,6 +1235,7 @@ the byte offset of the field, but should not be used directly; call
 @tindex PLUS_EXPR
 @tindex MINUS_EXPR
 @tindex MULT_EXPR
+@tindex MULT_HIGHPART_EXPR
 @tindex RDIV_EXPR
 @tindex TRUNC_DIV_EXPR
 @tindex FLOOR_DIV_EXPR
@@ -1433,6 +1434,11 @@ one operand is of floating type and the other is of integral type.
 The behavior of these operations on signed arithmetic overflow is
 controlled by the @code{flag_wrapv} and @code{flag_trapv} variables.
 
+@item MULT_HIGHPART_EXPR
+This node represents the ``high-part'' of a widening multiplication.
+For an integral type with @var{b} bits of precision, the result is
+the most significant @var{b} bits of the full @math{2@var{b}} product.
+
 @item RDIV_EXPR
 This node represents a floating point division operation.