fix CUDA architectures cmake logic

Author: GaetanLepage

transformer_engine/common/CMakeLists.txt

@@ -36,7 +36,11 @@ if(NOT DEFINED CMAKE_CUDA_ARCHITECTURES)
   endif()
 endif()
 
-# Process CMAKE_CUDA_ARCHITECTURES to separate generic and specific architectures
+# Process CMAKE_CUDA_ARCHITECTURES to separate standard, generic, and specific architectures.
+# - NVTE_STANDARD_ARCHS: pre-Blackwell archs (e.g. 75, 80, 89, 90). Applied to all CUDA sources.
+# - NVTE_GENERIC_ARCHS: Blackwell family heads (e.g. 100, 120). Applied to non-arch-specific sources only.
+# - NVTE_SPECIFIC_ARCHS: Blackwell specific targets (e.g. 100a, 120f). Applied to arch-specific sources only.
+set(NVTE_STANDARD_ARCHS)
 set(NVTE_GENERIC_ARCHS)
 set(NVTE_SPECIFIC_ARCHS)
 
@@ -79,6 +83,10 @@ if(NOT arch_120_index EQUAL -1)
   endif()
 endif()
 
+# Move remaining standard (pre-Blackwell) architectures into NVTE_STANDARD_ARCHS.
+# These are applied to all CUDA sources (both generic and arch-specific).
+set(NVTE_STANDARD_ARCHS ${CMAKE_CUDA_ARCHITECTURES})
+
 # cuDNN frontend API
 set(CUDNN_FRONTEND_INCLUDE_DIR
     "${CMAKE_CURRENT_SOURCE_DIR}/../../3rdparty/cudnn-frontend/include")
@@ -192,9 +200,13 @@ list(APPEND transformer_engine_SOURCES ${transformer_engine_cuda_arch_specific_s
                                        ${transformer_engine_cuda_sources}
                                        ${transformer_engine_cpp_sources})
 
-# Set compile options for CUDA sources with generic architectures
+# Set compile options for CUDA sources with generic architectures.
+# These get standard archs (pre-Blackwell) + generic Blackwell family heads.
 foreach(cuda_source IN LISTS transformer_engine_cuda_sources)
   set(arch_compile_options)
+  foreach(arch IN LISTS NVTE_STANDARD_ARCHS)
+    list(APPEND arch_compile_options "--generate-code=arch=compute_${arch},code=sm_${arch}")
+  endforeach()
   foreach(arch IN LISTS NVTE_GENERIC_ARCHS)
     list(APPEND arch_compile_options "--generate-code=arch=compute_${arch},code=sm_${arch}")
   endforeach()
@@ -209,9 +221,14 @@ foreach(cuda_source IN LISTS transformer_engine_cuda_sources)
   endif()
 endforeach()
 
-# Set compile options for CUDA sources with specific architectures
+# Set compile options for CUDA sources with arch-specific features.
+# These get standard archs (pre-Blackwell) + Blackwell specific targets (a/f suffix).
+# They must NOT get generic Blackwell archs, as they use family/arch-specific PTX features.
 foreach(cuda_source IN LISTS transformer_engine_cuda_arch_specific_sources)
   set(arch_compile_options)
+  foreach(arch IN LISTS NVTE_STANDARD_ARCHS)
+    list(APPEND arch_compile_options "--generate-code=arch=compute_${arch},code=sm_${arch}")
+  endforeach()
   foreach(arch IN LISTS NVTE_SPECIFIC_ARCHS)
     list(APPEND arch_compile_options "--generate-code=arch=compute_${arch},code=sm_${arch}")
   endforeach()
@@ -232,6 +249,10 @@ list(APPEND transformer_engine_SOURCES
 endif()
 
 add_library(transformer_engine SHARED ${transformer_engine_SOURCES})
+# Disable CMake's automatic architecture flag injection.
+# All architectures are handled explicitly via per-source COMPILE_OPTIONS
+# using NVTE_STANDARD_ARCHS, NVTE_GENERIC_ARCHS, and NVTE_SPECIFIC_ARCHS above.
+set_target_properties(transformer_engine PROPERTIES CUDA_ARCHITECTURES OFF)
 target_include_directories(transformer_engine PUBLIC
                            "${CMAKE_CURRENT_SOURCE_DIR}/include")