diff --git a/src/cmd/compile/internal/gc/racewalk.go b/src/cmd/compile/internal/gc/racewalk.go
index 9df85adf62..5392d809ae 100644
--- a/src/cmd/compile/internal/gc/racewalk.go
+++ b/src/cmd/compile/internal/gc/racewalk.go
@@ -461,7 +461,7 @@ func callinstr(np **Node, init *Nodes, wr, skip bool) {
 				name = "msanwrite"
 			}
 			f = mkcall(name, nil, init, uintptraddr(n), nodintconst(w))
-		} else if flag_race && t.NumComponents() > 1 {
+		} else if flag_race && t.NumComponents(types.CountBlankFields) > 1 {
 			// for composite objects we have to write every address
 			// because a write might happen to any subobject.
 			// composites with only one element don't have subobjects, though.
diff --git a/src/cmd/compile/internal/gc/walk.go b/src/cmd/compile/internal/gc/walk.go
index d392d567ca..1f2f5c68c2 100644
--- a/src/cmd/compile/internal/gc/walk.go
+++ b/src/cmd/compile/internal/gc/walk.go
@@ -3298,7 +3298,7 @@ func walkcompare(n *Node, init *Nodes) *Node {
 		// We can compare several elements at once with 2/4/8 byte integer compares
 		inline = t.NumElem() <= 1 || (issimple[t.Elem().Etype] && (t.NumElem() <= 4 || t.Elem().Width*t.NumElem() <= maxcmpsize))
 	case TSTRUCT:
-		inline = t.NumComponents() <= 4
+		inline = t.NumComponents(types.IgnoreBlankFields) <= 4
 	}
 
 	cmpl := n.Left
diff --git a/src/cmd/compile/internal/types/type.go b/src/cmd/compile/internal/types/type.go
index 87623a2cc3..f5e9237b81 100644
--- a/src/cmd/compile/internal/types/type.go
+++ b/src/cmd/compile/internal/types/type.go
@@ -1325,7 +1325,20 @@ func (t *Type) SetNumElem(n int64) {
 	at.Bound = n
 }
 
-func (t *Type) NumComponents() int64 {
+type componentsIncludeBlankFields bool
+
+const (
+	IgnoreBlankFields componentsIncludeBlankFields = false
+	CountBlankFields  componentsIncludeBlankFields = true
+)
+
+// NumComponents returns the number of primitive elements that compose t.
+// Struct and array types are flattened for the purpose of counting.
+// All other types (including string, slice, and interface types) count as one element.
+// If countBlank is IgnoreBlankFields, then blank struct fields
+// (and their comprised elements) are excluded from the count.
+// struct { x, y [3]int } has six components; [10]struct{ x, y string } has twenty.
+func (t *Type) NumComponents(countBlank componentsIncludeBlankFields) int64 {
 	switch t.Etype {
 	case TSTRUCT:
 		if t.IsFuncArgStruct() {
@@ -1333,11 +1346,14 @@ func (t *Type) NumComponents() int64 {
 		}
 		var n int64
 		for _, f := range t.FieldSlice() {
-			n += f.Type.NumComponents()
+			if countBlank == IgnoreBlankFields && f.Sym.IsBlank() {
+				continue
+			}
+			n += f.Type.NumComponents(countBlank)
 		}
 		return n
 	case TARRAY:
-		return t.NumElem() * t.Elem().NumComponents()
+		return t.NumElem() * t.Elem().NumComponents(countBlank)
 	}
 	return 1
 }