diff --git a/config/unix-clang.cmake b/config/unix-clang.cmake
index 704de0ddc..bd01a9723 100644
--- a/config/unix-clang.cmake
+++ b/config/unix-clang.cmake
@@ -62,7 +62,8 @@ if(NOT CXX_FLAGS_INITIALIZED)
 
   # OneAPI on trinitite reports itself as "LLVM" and parses this file.  The Intel optimizer needs
   # these options to maintain IEEE 754 compliance.
-  if(CMAKE_CXX_COMPILER_WRAPPER STREQUAL CrayPrgEnv AND INTEL_COMPILER_TYPE STREQUAL "ONEAPI")
+  if(DEFINED CMAKE_CXX_COMPILER_WRAPPER AND CMAKE_CXX_COMPILER_WRAPPER STREQUAL CrayPrgEnv AND
+      DEFINED ENV{INTEL_COMPILER_TYPE} AND "$ENV{INTEL_COMPILER_TYPE}" STREQUAL "ONEAPI")
     string(APPEND CMAKE_C_FLAGS_RELEASE " -fp-model=precise")
     string(APPEND CMAKE_C_FLAGS_RELWITHDEBINFO " -fp-model=precise")
   endif()