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<p class="MsoNormal">Nobody is currently working on this, as far as I know. If you’re interested in looking into it, I’ll try to answer any questions.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">-Eli<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b>From:</b> llvm-dev <llvm-dev-bounces@lists.llvm.org> <b>On Behalf Of
</b>Phipps, Alan via llvm-dev<br>
<b>Sent:</b> Wednesday, September 23, 2020 7:34 AM<br>
<b>To:</b> llvm-dev@lists.llvm.org<br>
<b>Subject:</b> [EXT] [llvm-dev] Improved jump-threading in LLVM for finite state automata<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">It is my understanding that the implementation for jump-threading in LLVM is not presently able to effectively optimize code containing a state-machine implemented using a loop + switch. This is the case, for example, with the Coremark
benchmark function core_state_transition(). Bug 42313 was filed to address this in 2019:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><a href="https://bugs.llvm.org/show_bug.cgi?id=42313">https://bugs.llvm.org/show_bug.cgi?id=42313</a><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">It appears that GCC improved support for jump threading in 2015 along the same lines:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54742">https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54742</a><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Is anyone aware of any plan to do improve LLVM jump-threading along the same lines for LLVM?<o:p></o:p></p>
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<p class="MsoNormal">Thanks!<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Alan Phipps<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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