diff --git a/src/runtime/alg.go b/src/runtime/alg.go
index d8789b4b5f..5a0656513d 100644
--- a/src/runtime/alg.go
+++ b/src/runtime/alg.go
@@ -160,7 +160,15 @@ func nilinterhash(p unsafe.Pointer, h uintptr) uintptr {
 // maps generated by reflect.MapOf (reflect_typehash, below).
 func typehash(t *_type, p unsafe.Pointer, h uintptr) uintptr {
 	if t.tflag&tflagRegularMemory != 0 {
-		return memhash(p, h, t.size)
+		// Handle ptr sizes specially, see issue 37086.
+		switch t.size {
+		case 4:
+			return memhash32(p, h)
+		case 8:
+			return memhash64(p, h)
+		default:
+			return memhash(p, h, t.size)
+		}
 	}
 	switch t.kind & kindMask {
 	case kindFloat32: