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<p class="MsoNormal">Hi all,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">GVN currently iterates until it can do no more, then performs PRE. There’s a FIXME, saying we should try GVN again if PRE made changes.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">This patch changes GVN to do this, motivated by the attached testcase (reduced from SPEC) where GVN currently leaves a redundant load.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The FIXME mentions memory dependence checking, but it looks to me like the memory dependence updating got implemented after the FIXME was written, so it’s out of date.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’ve tested this for compile time and there are no non-noise regressions (in fact, the geomean was a 5% speedup, interestingly).<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">What do you think?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Cheers,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">James<o:p></o:p></p>
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