diff --git a/compiler-rt/cmake/config-ix.cmake b/compiler-rt/cmake/config-ix.cmake
--- a/compiler-rt/cmake/config-ix.cmake
+++ b/compiler-rt/cmake/config-ix.cmake
@@ -271,6 +271,9 @@
 # specific architecture.  When cross-compiling, this is controled via
 # COMPILER_RT_TEST_COMPILER and COMPILER_RT_TEST_COMPILER_CFLAGS.
 macro(get_test_cc_for_arch arch cc_out cflags_out)
+  if (NOT ${ARGC} EQUAL 3)
+    message(FATAL_ERROR "got too many args. expected 3, got ${ARGC} (namely: ${ARGV})")
+  endif()
   if(ANDROID OR (NOT APPLE AND ${arch} MATCHES "arm|aarch64|riscv32|riscv64"))
     # This is only true if we are cross-compiling.
     # Build all tests with host compiler and use host tools.