Re: Strange asm generated by GCC...

On 12/19/2024 4:43 PM, Chris M. Thomasson wrote:

Why in the world would GCC use an XCHG instruction for the following code. The damn XCHG has an implied LOCK prefix! Yikes!
 https://godbolt.org/z/Thxchdcr8
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#include <atomic>
 int main()
{
      std::atomic<unsigned long> m_state = 0;
      m_state.store(std::memory_order_relaxed);

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Strange to me that this even compiled at all. I clearly forgot to put in a value. aka:
m_state.store(1, std::memory_order_release);
Sorry about that. ;^o
DOH!!!!!

      return 0;
}
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