diff --git a/mlir/lib/Analysis/AffineStructures.cpp b/mlir/lib/Analysis/AffineStructures.cpp
--- a/mlir/lib/Analysis/AffineStructures.cpp
+++ b/mlir/lib/Analysis/AffineStructures.cpp
@@ -1114,9 +1114,10 @@
 }
 
 /// Let this set be S. If S is bounded then we directly call into the GBR
-/// sampling algorithm. Otherwise, if there are some unbounded directions,
-/// vectors v such that S extends to infininty along v or -v, then a different
-/// algorithm is used:
+/// sampling algorithm. Otherwise, there are some unbounded directions, i.e.,
+/// vectors v such that S extends to infininty along v or -v. In this case we
+/// use an algorithm described in the integer set library (isl) manual and used
+/// by the isl_set_sample function in that library. The algorithm is:
 ///
 /// 1) Apply an invertible transform T to S to obtain S*T, such that all
 /// dimensions in which S*T is bounded lie in the linear span of a prefix of the