diff --git a/lib/spack/spack/compilers/__init__.py b/lib/spack/spack/compilers/__init__.py
index 8ce9d81120..88e5e7b998 100644
--- a/lib/spack/spack/compilers/__init__.py
+++ b/lib/spack/spack/compilers/__init__.py
@@ -220,10 +220,10 @@ def _compiler_config_from_external(config):
         operating_system = host_platform.operating_system("default_os")
         target = host_platform.target("default_target").microarchitecture
     else:
-        target = spec.target
+        target = spec.architecture.target
         if not target:
-            host_platform = spack.platforms.host()
-            target = host_platform.target("default_target").microarchitecture
+            target = spack.platforms.host().target("default_target")
+        target = target.microarchitecture
 
         operating_system = spec.os
         if not operating_system: