[libc] Use LTO for AMDGPU compilation and linking

Summary: The AMDGPU ABI isn't stable or well defined. For that reson we prefer to rely on LTO to ensure that multiple files get linked correctly. Currently the internal targets used for testing mix LLVM-IR and assembly. We should be consistent here.
llvm · Mar 29, 2023 · 2dc60b4 · 2dc60b4
1 parent 389e93c
commit 2dc60b4
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Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/libc/cmake/modules/LLVMLibCObjectRules.cmake b/libc/cmake/modules/LLVMLibCObjectRules.cmake
@@ -193,7 +193,7 @@ function(_build_gpu_objects fq_target_name internal_target_name)
     target_compile_options(${internal_target_name} BEFORE PRIVATE
                            ${common_compile_options} --target=${LIBC_GPU_TARGET_TRIPLE})
     if(LIBC_GPU_TARGET_ARCHITECTURE_IS_AMDGPU)
-      target_compile_options(${internal_target_name} PRIVATE -mcpu=${LIBC_GPU_TARGET_ARCHITECTURE})
+      target_compile_options(${internal_target_name} PRIVATE -mcpu=${LIBC_GPU_TARGET_ARCHITECTURE} -flto)
     elseif(LIBC_GPU_TARGET_ARCHITECTURE_IS_NVPTX)
       target_compile_options(${internal_target_name} PRIVATE -march=${LIBC_GPU_TARGET_ARCHITECTURE})
     endif()

diff --git a/libc/cmake/modules/LLVMLibCTestRules.cmake b/libc/cmake/modules/LLVMLibCTestRules.cmake
@@ -503,7 +503,7 @@ function(add_integration_test test_name)
   # The GPU build requires overriding the default CMake triple and architecture.
   if(LIBC_GPU_TARGET_ARCHITECTURE_IS_AMDGPU)
     target_compile_options(${fq_build_target_name} PRIVATE
-                           -mcpu=${LIBC_GPU_TARGET_ARCHITECTURE} -emit-llvm
+                           -mcpu=${LIBC_GPU_TARGET_ARCHITECTURE} -flto
                            --target=${LIBC_GPU_TARGET_TRIPLE})
   elseif(LIBC_GPU_TARGET_ARCHITECTURE_IS_NVPTX)
     target_compile_options(${fq_build_target_name} PRIVATE