[OpenMP][libomp] Allow unused-but-set warnings

[jlpeyton]

Summary

Only a few remaining which are taken care of by this patch.

[hbae]

LGTM

openmp/runtime/cmake/LibompHandleFlags.cmake

function(libomp_get_cxxflags cxxflags)
   libomp_append(flags_local -Wno-class-memaccess LIBOMP_HAVE_WNO_CLASS_MEMACCESS_FLAG)
   libomp_append(flags_local -Wno-covered-switch-default LIBOMP_HAVE_WNO_COVERED_SWITCH_DEFAULT_FLAG)
   libomp_append(flags_local -Wno-frame-address LIBOMP_HAVE_WNO_FRAME_ADDRESS_FLAG)
   libomp_append(flags_local -Wno-strict-aliasing LIBOMP_HAVE_WNO_STRICT_ALIASING_FLAG)
   libomp_append(flags_local -Wstringop-overflow=0 LIBOMP_HAVE_WSTRINGOP_OVERFLOW_FLAG)
   libomp_append(flags_local -Wno-stringop-truncation LIBOMP_HAVE_WNO_STRINGOP_TRUNCATION_FLAG)
   libomp_append(flags_local -Wno-switch LIBOMP_HAVE_WNO_SWITCH_FLAG)
   libomp_append(flags_local -Wno-uninitialized LIBOMP_HAVE_WNO_UNINITIALIZED_FLAG)
-  libomp_append(flags_local -Wno-unused-but-set-variable LIBOMP_HAVE_WNO_UNUSED_BUT_SET_VARIABLE_FLAG)
   libomp_append(flags_local -Wno-return-type-c-linkage LIBOMP_HAVE_WNO_RETURN_TYPE_C_LINKAGE_FLAG)
   libomp_append(flags_local -Wno-cast-qual LIBOMP_HAVE_WNO_CAST_QUAL_FLAG)
   libomp_append(flags_local -Wno-int-to-void-pointer-cast LIBOMP_HAVE_WNO_INT_TO_VOID_POINTER_CAST_FLAG)
   # libomp_append(flags_local -Wconversion LIBOMP_HAVE_WCONVERSION_FLAG)
   libomp_append(flags_local /GS LIBOMP_HAVE_GS_FLAG)
   libomp_append(flags_local /EHsc LIBOMP_HAVE_EHSC_FLAG)
   libomp_append(flags_local /Oy- LIBOMP_HAVE_OY__FLAG)
   libomp_append(flags_local -mrtm LIBOMP_HAVE_MRTM_FLAG)

openmp/runtime/cmake/config-ix.cmake

 check_cxx_compiler_flag(-Wno-class-memaccess LIBOMP_HAVE_WNO_CLASS_MEMACCESS_FLAG)
 check_cxx_compiler_flag(-Wno-covered-switch-default LIBOMP_HAVE_WNO_COVERED_SWITCH_DEFAULT_FLAG)
 check_cxx_compiler_flag(-Wno-frame-address LIBOMP_HAVE_WNO_FRAME_ADDRESS_FLAG)
 check_cxx_compiler_flag(-Wno-strict-aliasing LIBOMP_HAVE_WNO_STRICT_ALIASING_FLAG)
 check_cxx_compiler_flag(-Wstringop-overflow=0 LIBOMP_HAVE_WSTRINGOP_OVERFLOW_FLAG)
 check_cxx_compiler_flag(-Wno-stringop-truncation LIBOMP_HAVE_WNO_STRINGOP_TRUNCATION_FLAG)
 check_cxx_compiler_flag(-Wno-switch LIBOMP_HAVE_WNO_SWITCH_FLAG)
 check_cxx_compiler_flag(-Wno-uninitialized LIBOMP_HAVE_WNO_UNINITIALIZED_FLAG)
-check_cxx_compiler_flag(-Wno-unused-but-set-variable LIBOMP_HAVE_WNO_UNUSED_BUT_SET_VARIABLE_FLAG)
 check_cxx_compiler_flag(-Wno-return-type-c-linkage LIBOMP_HAVE_WNO_RETURN_TYPE_C_LINKAGE_FLAG)
 check_cxx_compiler_flag(-Wno-cast-qual LIBOMP_HAVE_WNO_CAST_QUAL_FLAG)
 check_cxx_compiler_flag(-Wno-int-to-void-pointer-cast LIBOMP_HAVE_WNO_INT_TO_VOID_POINTER_CAST_FLAG)
 # check_cxx_compiler_flag(-Wconversion LIBOMP_HAVE_WCONVERSION_FLAG)
 check_cxx_compiler_flag(-msse2 LIBOMP_HAVE_MSSE2_FLAG)
 check_cxx_compiler_flag(-ftls-model=initial-exec LIBOMP_HAVE_FTLS_MODEL_FLAG)
 libomp_check_architecture_flag(-mmic LIBOMP_HAVE_MMIC_FLAG)
 libomp_check_architecture_flag(-m32 LIBOMP_HAVE_M32_FLAG)

openmp/runtime/src/kmp_affinity.cpp

#endif // KMP_MIC && REDUCE_TEAM_SIZE
   KMP_ASSERT(depth > 0);
 
   // Construct the data structure that is to be returned.
   __kmp_topology = kmp_topology_t::allocate(num_avail, depth, types);
 
   for (i = 0; i < num_avail; ++i) {
     unsigned os = threadInfo[i][osIdIndex];
     int src_index;
-    int dst_index = 0;
     kmp_hw_thread_t &hw_thread = __kmp_topology->at(i);
     hw_thread.clear();
     hw_thread.os_id = os;
 
     idx = 0;
     for (src_index = maxIndex; src_index >= threadIdIndex; src_index--) {
       if (!inMap[src_index]) {
         continue;
       }
       if (src_index == pkgIdIndex) {
         hw_thread.ids[pkgLevel] = threadInfo[i][src_index];
       } else if (src_index == coreIdIndex) {
         hw_thread.ids[coreLevel] = threadInfo[i][src_index];
       } else if (src_index == threadIdIndex) {
         hw_thread.ids[threadLevel] = threadInfo[i][src_index];
       }
-      dst_index++;
     }
   }
 
   __kmp_free(inMap);
   __kmp_free(lastId);
   __kmp_free(totals);
   __kmp_free(maxCt);
   __kmp_free(counts);

openmp/runtime/src/z_Linux_util.cpp

int __kmp_get_load_balance(int max) {
   DIR *task_dir = NULL; // Handle of "/proc/<pid>/task/<tid>/" directory.
   struct dirent *task_entry = NULL;
   int task_path_fixed_len;
 
   kmp_str_buf_t stat_path; // "/proc/<pid>/task/<tid>/stat" path.
   int stat_file = -1;
   int stat_path_fixed_len;
 
+#ifdef KMP_DEBUG
   int total_processes = 0; // Total number of processes in system.
-  int total_threads = 0; // Total number of threads in system.
+#endif
 
   double call_time = 0.0;
 
   __kmp_str_buf_init(&task_path);
   __kmp_str_buf_init(&stat_path);
 
   __kmp_elapsed(&call_time);
 
#endif
   task_path_fixed_len = task_path.used; // Remember number of used characters.
 
   proc_entry = readdir(proc_dir);
   while (proc_entry != NULL) {
     // Proc entry is a directory and name starts with a digit. Assume it is a
     // process' directory.
     if (proc_entry->d_type == DT_DIR && isdigit(proc_entry->d_name[0])) {
 
+#ifdef KMP_DEBUG
       ++total_processes;
+#endif
       // Make sure init process is the very first in "/proc", so we can replace
       // strcmp( proc_entry->d_name, "1" ) == 0 with simpler total_processes ==
       // 1. We are going to check that total_processes == 1 => d_name == "1" is
       // true (where "=>" is implication). Since C++ does not have => operator,
       // let us replace it with its equivalent: a => b == ! a || b.
       KMP_DEBUG_ASSERT(total_processes != 1 ||
                        strcmp(proc_entry->d_name, "1") == 0);
 
#endif
         __kmp_str_buf_cat(&stat_path, task_path.str, task_path.used);
         __kmp_str_buf_cat(&stat_path, "/", 1);
         stat_path_fixed_len = stat_path.used;
 
         task_entry = readdir(task_dir);
         while (task_entry != NULL) {
           // It is a directory and name starts with a digit.
           if (proc_entry->d_type == DT_DIR && isdigit(task_entry->d_name[0])) {
-            ++total_threads;
 
             // Construct complete stat file path. Easiest way would be:
             //  __kmp_str_buf_print( & stat_path, "%s/%s/stat", task_path.str,
             //  task_entry->d_name );
             // but seriae of __kmp_str_buf_cat works a bit faster.
             stat_path.used =
                 stat_path_fixed_len; // Reset stat path to its fixed part.
             __kmp_str_buf_cat(&stat_path, task_entry->d_name,