Document MULT_HIGHPART_EXPR

From-SVN: r189054

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4e327763ce82e590b7396bbc986328e80fe4b7cf..29ecf36f707414903cb9b4d69ea9855aa7da02ee 100644 (file)
--- 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 e99366fb28d0ad0a3fe7b3aa31732d1532420f38..c48b663a0335cd18b908b0a2e91c3aef3b66b2cc 100644 (file)
--- 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.