diff --git a/llvm/include/llvm/IR/IRBuilder.h b/llvm/include/llvm/IR/IRBuilder.h
--- a/llvm/include/llvm/IR/IRBuilder.h
+++ b/llvm/include/llvm/IR/IRBuilder.h
@@ -697,12 +697,16 @@
       MDNode *TBAAStructTag = nullptr, MDNode *ScopeTag = nullptr,
       MDNode *NoAliasTag = nullptr);
 
-  /// Create a vector fadd reduction intrinsic of the source vector.
-  /// The first parameter is a scalar accumulator value for ordered reductions.
+  /// Create a sequential vector fadd reduction intrinsic of the source vector.
+  /// The first parameter is a scalar accumulator value. An unordered reduction
+  /// can be created by adding the reassoc fast-math flag to the resulting
+  /// sequential reduction.
   CallInst *CreateFAddReduce(Value *Acc, Value *Src);
 
-  /// Create a vector fmul reduction intrinsic of the source vector.
-  /// The first parameter is a scalar accumulator value for ordered reductions.
+  /// Create a sequential vector fmul reduction intrinsic of the source vector.
+  /// The first parameter is a scalar accumulator value. An unordered reduction
+  /// can be created by adding the reassoc fast-math flag to the resulting
+  /// sequential reduction.
   CallInst *CreateFMulReduce(Value *Acc, Value *Src);
 
   /// Create a vector int add reduction intrinsic of the source vector.