https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91373
--- Comment #7 from Qiang <qiang.fu at verisilicon dot com> --- Sorry to be a bother and thanks all of you. '-fsanitize=undefined' & '-fwrapv' are new item to me. '-fsanitize=undefined' is helpful to me to find out the similar issue in our code. '-fwrapv' may hide other potential issue. I'll do more check later follow the following instructions before reporting a bug: 'Before reporting that GCC compiles your code incorrectly, compile it with gcc -Wall -Wextra and see whether this shows anything wrong with your code. Similarly, if compiling with -fno-strict-aliasing -fwrapv -fno-aggressive-loop-optimizations makes a difference, or if compiling with -fsanitize=undefined produces any run-time errors, then your code is probably not correct.'
