pushl %ebp
movl %esp, %ebp
cmpl $0, 8(%ebp)
movl $1, %eax
cmove v, %eax ; load (maybe)
movl %eax, v ; store (always)
popl %ebp
ret
How is this even an optimization? It looks SLOWER to me. The
conditional read wastes memory bandwidth sometimes, if the condition is
true, and v isn't already in the cache. The unconditional write wastes
memory bandwidth ALL the time, and dirties/flushes caches, in addition
to not being thread safe.
This SHOULD be using a conditional write instead of a conditional read
and an unconditional write.
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