diff --git a/src/cmd/compile/internal/ssagen/ssa.go b/src/cmd/compile/internal/ssagen/ssa.go
index dd16169103cd5036eb765e8e73202318e819dcc7..c02f5f51291d47f9f1e008d1f53a4d29832f651c 100644
--- a/src/cmd/compile/internal/ssagen/ssa.go
+++ b/src/cmd/compile/internal/ssagen/ssa.go
@@ -4215,12 +4215,10 @@ type intrinsicKey struct {
 func InitTables() {
 	intrinsics = map[intrinsicKey]intrinsicBuilder{}
 
-	var all []*sys.Arch
 	var p4 []*sys.Arch
 	var p8 []*sys.Arch
 	var lwatomics []*sys.Arch
-	for _, a := range &sys.Archs {
-		all = append(all, a)
+	for _, a := range sys.Archs {
 		if a.PtrSize == 4 {
 			p4 = append(p4, a)
 		} else {
@@ -4230,6 +4228,7 @@ func InitTables() {
 			lwatomics = append(lwatomics, a)
 		}
 	}
+	all := sys.Archs[:]
 
 	// add adds the intrinsic b for pkg.fn for the given list of architectures.
 	add := func(pkg, fn string, b intrinsicBuilder, archs ...*sys.Arch) {
@@ -4239,15 +4238,8 @@ func InitTables() {
 	}
 	// addF does the same as add but operates on architecture families.
 	addF := func(pkg, fn string, b intrinsicBuilder, archFamilies ...sys.ArchFamily) {
-		m := 0
-		for _, f := range archFamilies {
-			if f >= 32 {
-				panic("too many architecture families")
-			}
-			m |= 1 << uint(f)
-		}
-		for _, a := range all {
-			if m>>uint(a.Family)&1 != 0 {
+		for _, a := range sys.Archs {
+			if a.InFamily(archFamilies...) {
 				intrinsics[intrinsicKey{a, pkg, fn}] = b
 			}
 		}
diff --git a/src/cmd/internal/sys/arch_test.go b/src/cmd/internal/sys/arch_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..011d0923d587e0dceed8374e239e5ca67d0d4450
--- /dev/null
+++ b/src/cmd/internal/sys/arch_test.go
@@ -0,0 +1,24 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package sys
+
+import (
+	"testing"
+)
+
+func TestArchInFamily(t *testing.T) {
+	if got, want := ArchPPC64LE.InFamily(AMD64), false; got != want {
+		t.Errorf("Got ArchPPC64LE.InFamily(AMD64) = %v, want %v", got, want)
+	}
+	if got, want := ArchPPC64LE.InFamily(PPC64), true; got != want {
+		t.Errorf("Got ArchPPC64LE.InFamily(PPC64) = %v, want %v", got, want)
+	}
+	if got, want := ArchPPC64LE.InFamily(AMD64, RISCV64), false; got != want {
+		t.Errorf("Got ArchPPC64LE.InFamily(AMD64, RISCV64) = %v, want %v", got, want)
+	}
+	if got, want := ArchPPC64LE.InFamily(AMD64, PPC64), true; got != want {
+		t.Errorf("Got ArchPPC64LE.InFamily(AMD64, PPC64) = %v, want %v", got, want)
+	}
+}