diff --git a/libc/cmake/modules/prepare_libc_gpu_build.cmake b/libc/cmake/modules/prepare_libc_gpu_build.cmake
--- a/libc/cmake/modules/prepare_libc_gpu_build.cmake
+++ b/libc/cmake/modules/prepare_libc_gpu_build.cmake
@@ -42,6 +42,25 @@
                       "build")
 endif()
 
+set(LIBC_GPU_TEST_ARCHITECTURE "" CACHE STRING "Architecture for the GPU tests")
+if(LIBC_GPU_TEST_ARCHITECTURE)
+  message(STATUS "Using user-specified GPU architecture for testing "
+                 "'${LIBC_GPU_TARGET_ARCHITECTURE}'")
+  if("${LIBC_GPU_TARGET_ARCHITECTURE}" IN_LIST all_amdgpu_architectures)
+    set(LIBC_GPU_TARGET_ARCHITECTURE_IS_AMDGPU TRUE)
+    set(LIBC_GPU_TARGET_TRIPLE "amdgcn-amd-amdhsa")
+    set(LIBC_GPU_TARGET_ARCHITECTURE "${LIBC_GPU_TEST_ARCHITECTURE}")
+  elseif("${LIBC_GPU_TARGET_ARCHITECTURE}" IN_LIST all_nvptx_architectures)
+    set(LIBC_GPU_TARGET_ARCHITECTURE_IS_NVPTX TRUE)
+    set(LIBC_GPU_TARGET_TRIPLE "nvptx64-nvidia-cuda")
+    set(LIBC_GPU_TARGET_ARCHITECTURE "${LIBC_GPU_TEST_ARCHITECTURE}")
+  else()
+    message(FATAL_ERROR 
+            "Unknown GPU architecture '${LIBC_GPU_TARGET_ARCHITECTURE}'")
+  endif()
+  return()
+endif()
+
 # Identify any locally installed AMD GPUs on the system to use for testing.
 find_program(LIBC_AMDGPU_ARCH
              NAMES amdgpu-arch