Hello,
this is more out of curiosity than anything else. When looking at the generated assembly code for a tight loop that polls an atomic state member until it has a certain value, I see that the read of the atomic variable is translated by the compiler (gcc 5.2.0 x64) into 3 identical loads (as shown by the assmbly view in vTune). So:
while (m_state == TS_BUSY_WAITING) { ASM_PAUSE; }
turns into
Block 7:
pause
movl 0x3c(%rdi), %eax
movl 0x3c(%rdi), %eax
movl 0x3c(%rdi), %eax
cmp $0x3, %eax
jz 0x1b5af88 <Block 7>
Notice the 3 identical movl operations.
What is the cause behind this translation? I see a similar translation also in other places where tbb::atomic is being used.
