Compiler Memory Fences

The compiler optimizes the generated executable code to some extent, resulting in out-of-order execution or even execution omission.

The following instruction can solve the memory access disorder caused by optimization in the compilation phase.

• Code on x86:

  // GCC ensures in-order execution of write and read operations issued before and after the following instruction.
  __asm__ __volatile__("" : : : "memory");

• Alternative for Kunpeng processors:

  __asm__ __volatile__ ("dmb ish" ::: "memory");