Remove unused variables (intel#2044)

- remove unused variables,
- add compiler flag to prevent this in the future

Author: Silv3S

.github/workflows/_linux_build.yml

@@ -94,6 +94,7 @@ jobs:
       - name: Build Pytorch on ${{ needs.runner.outputs.hostname }}
         run: |
           export USE_XCCL=1
+          export IS_XPU_CI=1
           # only build pvc for CI
           if [ "${{ github.event_name }}" == "pull_request" ];then
             export TORCH_XPU_ARCH_LIST='pvc'

CMakeLists.txt

@@ -25,6 +25,9 @@ set(PROJECT_VERSION "2.3.0")
 # Avoid SYCL compiler error
 if(NOT WIN32)
   string(APPEND CMAKE_CXX_FLAGS " -Wno-error")
+  if("$ENV{IS_XPU_CI}" STREQUAL "1")
+    string(APPEND CMAKE_CXX_FLAGS " -Werror=unused-variable")
+  endif()
 endif()
 
 cmake_policy(SET CMP0048 NEW)

src/ATen/native/xpu/sycl/LayerNormKernels.cpp

@@ -1103,9 +1103,6 @@ void _layer_norm_backward_kernel(
     // affecting performance and behavior.
     const scalar_t* dY_data = dY.const_data_ptr<scalar_t>();
     const scalar_t* X_data = X.const_data_ptr<scalar_t>();
-    weight_t* dg_data =
-        dgamma.defined() ? dgamma.data_ptr<weight_t>() : nullptr;
-    weight_t* db_data = dbeta.defined() ? dbeta.data_ptr<weight_t>() : nullptr;
     Tensor dgamma_blocks;
     Tensor dbeta_blocks;
     weight_t* dgamma_blocks_ptr = nullptr;

src/ATen/native/xpu/sycl/RoiAlignKernels.cpp

@@ -440,7 +440,6 @@ Tensor roi_align_kernel(
 
   at::Tensor output = at::zeros(
       {num_rois, channels, pooled_height, pooled_width}, input.options());
-  auto output_size = num_rois * pooled_height * pooled_width * channels;
 
   if (output.numel() == 0) {
     return output;