diff --git a/var/spack/repos/builtin/packages/amrex/package.py b/var/spack/repos/builtin/packages/amrex/package.py
index 03be9f78e20..2b7a2d72491 100644
--- a/var/spack/repos/builtin/packages/amrex/package.py
+++ b/var/spack/repos/builtin/packages/amrex/package.py
@@ -65,6 +65,7 @@ class Amrex(CMakePackage):
     depends_on('mpi', when='+mpi')
     depends_on('python@2.7:', type='build')
     depends_on('cmake@3.5:',  type='build')
+    conflicts('%clang')
 
     def cmake_is_on(self, option):
         return 'ON' if option in self.spec else 'OFF'
diff --git a/var/spack/repos/builtin/packages/xsdk/package.py b/var/spack/repos/builtin/packages/xsdk/package.py
index 9b20a7e3746..415fd98c9ae 100644
--- a/var/spack/repos/builtin/packages/xsdk/package.py
+++ b/var/spack/repos/builtin/packages/xsdk/package.py
@@ -87,6 +87,11 @@ class Xsdk(Package):
     depends_on('magma@2.2.0', when='@0.3.0 +cuda')
     depends_on('magma@2.2.0', when='@develop +cuda')
 
+    depends_on('amrex@develop', when='@develop %gcc')
+    depends_on('amrex@develop', when='@develop %intel')
+
+    depends_on('slepc@develop', when='@develop')
+
     # xSDKTrilinos depends on the version of Trilinos built with
     # +tpetra which is turned off for faster xSDK
     # depends_on('xsdktrilinos@xsdk-0.2.0', when='@xsdk-0.2.0')