diff --git a/cranelift/codegen/src/isa/constraints.rs b/cranelift/codegen/src/isa/constraints.rs
index d6e809738599..ce1d2a5fe166 100644
--- a/cranelift/codegen/src/isa/constraints.rs
+++ b/cranelift/codegen/src/isa/constraints.rs
@@ -105,13 +105,13 @@ pub struct RecipeConstraints {
     /// constraints must be derived from the calling convention ABI.
     pub outs: &'static [OperandConstraint],
 
-    /// Are any of the input constraints `FixedReg`?
+    /// Are any of the input constraints `FixedReg` or `FixedTied`?
     pub fixed_ins: bool,
 
-    /// Are any of the output constraints `FixedReg`?
+    /// Are any of the output constraints `FixedReg` or `FixedTied`?
     pub fixed_outs: bool,
 
-    /// Are there any tied operands?
+    /// Are any of the input/output constraints `Tied` (but not `FixedTied`)?
     pub tied_ops: bool,
 
     /// Does this instruction clobber the CPU flags?