[OpenMP] Change initialization of __kmp_global

There's no need to initialize variables with static storage duration
because they're implicitly initialized to zero. See
https://en.cppreference.com/w/c/language/initialization#Implicit_initialization

I think that's already relied upon because the supplied 0 only sets
'kmp_time_global_t g_time;' in 'struct kmp_base_global'. The other fields
are not set in the code, but implicitly initialized by the compiler.

Differential Revision: https://reviews.llvm.org/D66292

git-svn-id: https://llvm.org/svn/llvm-project/openmp/trunk@370943 91177308-0d34-0410-b5e6-96231b3b80d8

Author: hahnjo

runtime/cmake/LibompHandleFlags.cmake

@@ -30,7 +30,6 @@ 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-missing-braces LIBOMP_HAVE_WNO_MISSING_BRACES_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)

runtime/cmake/config-ix.cmake

@@ -51,7 +51,6 @@ check_cxx_compiler_flag(-fno-rtti LIBOMP_HAVE_FNO_RTTI_FLAG)
 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-missing-braces LIBOMP_HAVE_WNO_MISSING_BRACES_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)

runtime/src/kmp_global.cpp

@@ -431,7 +431,7 @@ std::atomic<int> __kmp_thread_pool_active_nth = ATOMIC_VAR_INIT(0);
 /* -------------------------------------------------
  * GLOBAL/ROOT STATE */
 KMP_ALIGN_CACHE
-kmp_global_t __kmp_global = {{0}};
+kmp_global_t __kmp_global;
 
 /* ----------------------------------------------- */
 /* GLOBAL SYNCHRONIZATION LOCKS */