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
@@ -29,18 +29,20 @@
                       "GPU.")
 endif()
 
+# Identify any locally installed GPUs to use for testing.
 find_program(LIBC_AMDGPU_ARCH
              NAMES amdgpu-arch
              PATHS ${LLVM_BINARY_DIR}/bin /opt/rocm/llvm/bin/)
-if (LIBC_AMDGPU_ARCH)
+if(LIBC_AMDGPU_ARCH)
   execute_process(COMMAND ${LIBC_AMDGPU_ARCH}
                   OUTPUT_VARIABLE LIBC_AMDGPU_ARCH_OUTPUT
                   OUTPUT_STRIP_TRAILING_WHITESPACE)
-  string(REPLACE "\n" ";" LIBC_AMDGPU_ARCH_OUTPUT "${LIBC_AMDGPU_ARCH_OUTPUT}")
-
-  list(LENGTH "${LIBC_AMDGPU_ARCH_OUTPUT}" LEN)
-  message(WARNING ${LEN})
-  message(WARNING ${LIBC_AMDGPU_ARCH_OUTPUT})
-  list(POP_BACK ${LIBC_AMDGPU_ARCH_OUTPUT} OUT)
-  message(WARNING ${OUT})
+  string(FIND "${LIBC_AMDGPU_ARCH_OUTPUT}" "\n" first_arch_string)
+  string(SUBSTRING "${LIBC_AMDGPU_ARCH_OUTPUT}" 0 ${first_arch_string}
+         arch_string)
+  if(arch_string)
+    set(LIBC_GPU_TARGET_TRIPLE "amdgcn-amd-amdhsa")
+    set(LIBC_GPU_TARGET_ARCHITECTURE "${arch_string}")
+  endif()
 endif()
+# TODO: Check for Nvidia GPUs.