diff --git a/libc/startup/linux/CMakeLists.txt b/libc/startup/gpu/CMakeLists.txt
copy from libc/startup/linux/CMakeLists.txt
copy to libc/startup/gpu/CMakeLists.txt
--- a/libc/startup/linux/CMakeLists.txt
+++ b/libc/startup/gpu/CMakeLists.txt
@@ -37,7 +37,6 @@
     DEPENDS ${ADD_STARTUP_OBJECT_DEPENDS}
     COMPILE_OPTIONS ${ADD_STARTUP_OBJECT_COMPILE_OPTIONS}
   )
-
   set(objfile ${LIBC_BUILD_DIR}/lib/${name}.o)
   add_custom_command(
     OUTPUT ${objfile}
@@ -58,39 +57,37 @@
   )
 endfunction()
 
-if(NOT (EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_ARCHITECTURE}))
-  message(STATUS "Skipping startup for target architecture ${LIBC_TARGET_ARCHITECTURE}")
-  return()
-endif()
-
-add_subdirectory(${LIBC_TARGET_ARCHITECTURE})
-
-add_startup_object(
-  crt1
-  ALIAS
-  DEPENDS
-    .${LIBC_TARGET_ARCHITECTURE}.crt1
-)
+if(LIBC_GPU_TARGET_ARCHITECTURE_IS_AMDGPU)
+  add_subdirectory(amdgpu)
 
-add_startup_object(
-  crti
-  SRC
-    crti.cpp
-)
+  add_startup_object(
+    crt1
+    ALIAS
+    DEPENDS
+      libc.startup.gpu.amdgpu.crt1
+  )
+elseif(LIBC_GPU_TARGET_ARCHITECTURE_IS_NVPTX)
+  add_subdirectory(nvptx)
 
-add_startup_object(
-  crtn
-  SRC
-    crtn.cpp
-)
+  add_startup_object(
+    crt1
+    ALIAS
+    DEPENDS
+      .nvptx.crt1
+  )
+else()
+  # Skip building the startup code if there are no supported GPUs.
+  message(STATUS "Skipping startup for gpu target, no GPUs were detected")
+  return()
+endif()
 
 add_custom_target(libc-startup)
-set(startup_components crt1 crti crtn)
+set(startup_components crt1)
 foreach(target IN LISTS startup_components)
-  set(fq_target_name libc.startup.linux.${target})
+  set(fq_target_name libc.startup.gpu.${target})
   add_dependencies(libc-startup ${fq_target_name})
   get_target_property(startup_object ${fq_target_name} STARTUP_OBJECT)
   install(FILES ${startup_object}
           DESTINATION ${CMAKE_INSTALL_LIBDIR}
-          COMPONENT libc)
+          COMPONENT ${LIBC_COMPONENT})
 endforeach()
diff --git a/libc/startup/gpu/amdgpu/CMakeLists.txt b/libc/startup/gpu/amdgpu/CMakeLists.txt
new file mode 100644
--- /dev/null
+++ b/libc/startup/gpu/amdgpu/CMakeLists.txt
@@ -0,0 +1,14 @@
+add_startup_object(
+  crt1
+  SRC
+    start.cpp
+  COMPILE_OPTIONS
+    -ffreestanding # To avoid compiler warnings about calling the main function.
+    -fno-builtin
+    -nogpulib # Do not include any GPU vendor libraries.
+    -nogpuinc
+    -nostdinc
+    -mcpu=${LIBC_GPU_TARGET_ARCHITECTURE}
+    -emit-llvm # AMDGPU's intermediate object file format is bitcode.
+    --target=${LIBC_GPU_TARGET_TRIPLE}
+)
diff --git a/libc/startup/gpu/amdgpu/start.cpp b/libc/startup/gpu/amdgpu/start.cpp
new file mode 100644
--- /dev/null
+++ b/libc/startup/gpu/amdgpu/start.cpp
@@ -0,0 +1,14 @@
+//===-- Implementation of crt for amdgpu ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+extern "C" int main(int argc, char **argv);
+
+extern "C" [[gnu::visibility("protected"), clang::amdgpu_kernel]] void
+_start(int argc, char **argv, int *ret) {
+  __atomic_fetch_or(ret, main(argc, argv), __ATOMIC_RELAXED);
+}
diff --git a/libc/startup/gpu/nvptx/CMakeLists.txt b/libc/startup/gpu/nvptx/CMakeLists.txt
new file mode 100644
--- /dev/null
+++ b/libc/startup/gpu/nvptx/CMakeLists.txt
@@ -0,0 +1,14 @@
+add_startup_object(
+  crt1
+  SRC
+    start.cpp
+  COMPILE_OPTIONS
+    -ffreestanding # To avoid compiler warnings about calling the main function.
+    -fno-builtin
+    -nogpulib # Do not include any GPU vendor libraries.
+    -nogpuinc
+    -nostdinc
+    -x cuda # Use the CUDA toolchain to emit the `_start` kernel.
+    --offload-device-only
+    --offload-arch=${LIBC_GPU_TARGET_ARCHITECTURE}
+)
diff --git a/libc/startup/gpu/nvptx/start.cpp b/libc/startup/gpu/nvptx/start.cpp
new file mode 100644
--- /dev/null
+++ b/libc/startup/gpu/nvptx/start.cpp
@@ -0,0 +1,15 @@
+//===-- Implementation of crt for amdgpu ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+extern "C" __attribute__((device)) int main(int argc, char **argv);
+
+// TODO: We shouldn't need to use the CUDA language to emit a kernel for NVPTX.
+extern "C" [[gnu::visibility("protected")]] __attribute__((global)) void
+_start(int argc, char **argv, int *ret) {
+  __atomic_fetch_or(ret, main(argc, argv), __ATOMIC_RELAXED);
+}
diff --git a/libc/startup/linux/CMakeLists.txt b/libc/startup/linux/CMakeLists.txt
--- a/libc/startup/linux/CMakeLists.txt
+++ b/libc/startup/linux/CMakeLists.txt
@@ -37,7 +37,6 @@
     DEPENDS ${ADD_STARTUP_OBJECT_DEPENDS}
     COMPILE_OPTIONS ${ADD_STARTUP_OBJECT_COMPILE_OPTIONS}
   )
-
   set(objfile ${LIBC_BUILD_DIR}/lib/${name}.o)
   add_custom_command(
     OUTPUT ${objfile}