Revert "[CMake] Disable more noisy GCC warnings (#159044)"

This reverts commit 984be7c.

Author: mstorsjo

llvm/cmake/modules/HandleLLVMOptions.cmake

@@ -911,22 +911,6 @@ if (LLVM_ENABLE_WARNINGS AND (LLVM_COMPILER_IS_GCC_COMPATIBLE OR CLANG_CL))
     endif()
   endif()
 
-  # Disable -Warray-bounds on GCC; this warning exists since a very long time,
-  # but since GCC 11, it produces a lot of very noisy, seemingly false positive
-  # warnings (potentially originating in libstdc++).
-  if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-    append("-Wno-array-bounds" CMAKE_CXX_FLAGS)
-  endif()
-
-  # Disable -Wstringop-overread on GCC; this warning produces a number of very
-  # noisy diagnostics when -Warray-bounds is disabled above; this option exists
-  # since GCC 11.
-  if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-    if (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 11.1)
-      append("-Wno-stringop-overread" CMAKE_CXX_FLAGS)
-    endif()
-  endif()
-
   # The LLVM libraries have no stable C++ API, so -Wnoexcept-type is not useful.
   append("-Wno-noexcept-type" CMAKE_CXX_FLAGS)