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<p class="MsoNormal">Hello everyone.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I would like to introduce new intrinsics for memory comparison:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">memcmp - an equivalent of libc' memcmp,<o:p></o:p></p>
<p class="MsoNormal">bcmp - an equivalent of libc' bcmp,<o:p></o:p></p>
<p class="MsoNormal">memcmp.element.unordered.atomic - an element atomic version of memcmp,<o:p></o:p></p>
<p class="MsoNormal">bcmp.element.unordered.atomic - an element atomic version of bcmp.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Currently there exist some optimizations for memcmp/bcmp libc calls.<o:p></o:p></p>
<p class="MsoNormal">We would like to have these optimizations for element atomic comparisons (atomicity permitted).<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I suggest we rewrite the existing optimizations to work with on new intrinsics and transform<o:p></o:p></p>
<p class="MsoNormal">memcmp/bcmp libc calls to the corresponding intrinsics. This is similar to what we do with<o:p></o:p></p>
<p class="MsoNormal">memcpy library calls.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Having these optimizations work on intrinsics and not on recognized libc calls<o:p></o:p></p>
<p class="MsoNormal">will allow us to share some existing transforms between atomic and non-atomic variants.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I propose the following plan for introducing the new intrinsics:<o:p></o:p></p>
<p class="MsoNormal">1. Introduce non-atomic memcmp and bcmp intrinsics.<o:p></o:p></p>
<p class="MsoNormal">2. Reimplement existing transforms for non-atomic memcmp intrinsic,<o:p></o:p></p>
<p class="MsoNormal">the same way as it's done for memcpy.<o:p></o:p></p>
<p class="MsoNormal">3. Introduce atomic intrinsics and reuse the optimizations.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Please express your concerns about this.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Dmitry<o:p></o:p></p>
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