[libc-commits] [libc] 2dc60b4 - [libc] Use LTO for AMDGPU compilation and linking

[Joseph Huber via libc-commits]

Author: Joseph Huber
Date: 2023-03-29T14:20:44-05:00
New Revision: 2dc60b4ea4f1a3f321ea93055038d711f0af4c49

URL: https://github.com/llvm/llvm-project/commit/2dc60b4ea4f1a3f321ea93055038d711f0af4c49
DIFF: https://github.com/llvm/llvm-project/commit/2dc60b4ea4f1a3f321ea93055038d711f0af4c49.diff

LOG: [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.

Added: 
    

Modified: 
    libc/cmake/modules/LLVMLibCObjectRules.cmake
    libc/cmake/modules/LLVMLibCTestRules.cmake

Removed: 
    


################################################################################
diff  --git a/libc/cmake/modules/LLVMLibCObjectRules.cmake b/libc/cmake/modules/LLVMLibCObjectRules.cmake
index b3503a986efa..289612bc32a3 100644
--- 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
index 4e1a63dc3765..0e1b9f1f6efd 100644
--- 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