Change to use -O0 instead of -O1 in debug build. (#1949)

* Change to use -O0 instead of -O1 in debug build.

* Use -O1 for device code to avoid linking issue in debug build.

[ROCm/rccl commit: feee02ca61]

projects/rccl/CMakeLists.txt

@@ -886,6 +886,15 @@ foreach(file ${GENERATED_FILES})
   list(APPEND HIP_SOURCES ${file})
 endforeach()
 
+# Apply -O1 optimization for generated files in debug builds
+# This is needed for device object to not go over the stacksize limit at link time while allowing
+# -O0 for host code in debug build.
+if(CMAKE_BUILD_TYPE MATCHES "Debug" AND NOT DEFINED ENV{CXXFLAGS})
+  message(STATUS "Setting -O1 optimization for device code in ${GEN_DIR} (Debug build)")
+  set_source_files_properties(${GENERATED_FILES} PROPERTIES COMPILE_OPTIONS "-O1")
+endif()
+
+
 # Create an initial git_version.cpp file (that will be updated with latest git version)
 #==================================================================================================
 file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/git_version.cpp "")

projects/rccl/toolchain-linux.cmake

@@ -13,7 +13,7 @@ else()
 endif()
 
 if (NOT DEFINED ENV{CXXFLAGS})
-  set(CMAKE_CXX_FLAGS_DEBUG "-g -O1")
+  set(CMAKE_CXX_FLAGS_DEBUG "-g -O0")
   set(CMAKE_CXX_FLAGS_RELEASE "-O3")
 endif()
 
@@ -24,6 +24,6 @@ else()
 endif()
 
 if (NOT DEFINED ENV{CFLAGS})
-  set(CMAKE_C_FLAGS_DEBUG "-g -O1")
+  set(CMAKE_C_FLAGS_DEBUG "-g -O0")
   set(CMAKE_C_FLAGS_RELEASE "-O3")
 endif()