diff --git a/gcc/doc/generic.texi b/gcc/doc/generic.texi
index 3f52d30..4e8f131 100644
--- a/gcc/doc/generic.texi
+++ b/gcc/doc/generic.texi
@@ -1826,6 +1826,7 @@ a value from @code{enum annot_expr_kind}, the third is an @code{INTEGER_CST}.
 @tindex VEC_PACK_FIX_TRUNC_EXPR
 @tindex VEC_PACK_FLOAT_EXPR
 @tindex VEC_COND_EXPR
+@tindex VEC_PERM_EXPR
 @tindex SAD_EXPR
 
 @table @code
@@ -1967,6 +1968,27 @@ any other value currently, but optimizations should not rely on that
 property. In contrast with a @code{COND_EXPR}, all operands are always
 evaluated.
 
+@item VEC_PERM_EXPR
+This node represents a vector permute/blend operation.  The three operands
+must be vectors of the same number of elements.  The first and second
+operands must be vectors of the same type as the entire expression, and
+the third operand, @dfn{selector}, must be an integral vector type.
+
+The input elements are numbered from 0 in operand 1 through
+@math{2*@var{N}-1} in operand 2.  The elements of the selector are
+interpreted modulo @math{2*@var{N}}.
+
+The expression
+@code{@var{out} = VEC_PERM_EXPR<@var{v0}, @var{v1}, @var{selector}>}, 
+where @var{v0}, @var{v1} and @var{selector} have @var{N} elements, means
+@smallexample
+  for (int i = 0; i < N; i++)
+    @{
+      int j = selector[i] % (2*N);
+      out[i] = j < N ? v0[j] : v1[j-N];
+    @}
+@end smallexample
+
 @item SAD_EXPR
 This node represents the Sum of Absolute Differences operation.  The three
 operands must be vectors of integral types.  The first and second operand