diff --git a/ryu.go b/ryu.go
index 5f31c34..bbedc43 100644
--- a/ryu.go
+++ b/ryu.go
@@ -158,7 +158,7 @@ func pow5Bits(e int32) int32 {
 	return int32((uint32(e)*1217359)>>19 + 1)
 }
 
-// FIXME(caleb): Document how these are optimized.
+// These boolToXxx all inline as a movzx.
 
 func boolToInt(b bool) int {
 	if b {
diff --git a/ryu64.go b/ryu64.go
index 5c6081a..9e93085 100644
--- a/ryu64.go
+++ b/ryu64.go
@@ -339,7 +339,6 @@ func shiftRight128(v uint128, shift int32) uint64 {
 	// Check this here in case a future change requires larger shift
 	// values. In this case this function needs to be adjusted.
 	assert(shift < 64, "shift < 64")
-	// FIXME: optimize
 	return (v.hi << uint64(64-shift)) | (v.lo >> uint(shift))
 }