<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Hi Daniel,</div><div><br></div><div>Maybe my commit message was not clear. The idea is that the SelectionDAG store vectorizer can only handle pairs. So, the number three means "more than a pair". </div><div><br></div><div>Thanks,</div><div>Nadav<br><br>Sent from my iPhone</div><div><br>On Jul 26, 2013, at 17:48, Daniel Berlin <<a href="mailto:dberlin@dberlin.org">dberlin@dberlin.org</a>> wrote:<br><br></div><blockquote type="cite"><div><div dir="ltr">Hey Nadav,<div>I'd humbly suggest that rather than use 3 directly, you should add a shared constant between these two passes, so when one changes, the other doesn't need to be updated. It would also ensure this bit of info about what needs to be updated isn't only contained in the comments.. </div>
<div class="gmail_extra"><br><div class="gmail_quote">On Fri, Jul 26, 2013 at 4:07 PM, Nadav Rotem <span dir="ltr"><<a href="mailto:nrotem@apple.com" target="_blank">nrotem@apple.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span style="font-family:arial,sans-serif;font-size:13px">Author: nadav</span><br style="font-family:arial,sans-serif;font-size:13px">
<span style="font-family:arial,sans-serif;font-size:13px">Date: Fri Jul 26 18:07:55 2013</span><br style="font-family:arial,sans-serif;font-size:13px"><span style="font-family:arial,sans-serif;font-size:13px">New Revision: 187267</span><br style="font-family:arial,sans-serif;font-size:13px">
<br style="font-family:arial,sans-serif;font-size:13px"><span style="font-family:arial,sans-serif;font-size:13px">URL: </span><a href="http://llvm.org/viewvc/llvm-project?rev=187267&view=rev" target="_blank" style="font-family:arial,sans-serif;font-size:13px">http://llvm.org/viewvc/llvm-project?rev=187267&view=rev</a><br style="font-family:arial,sans-serif;font-size:13px">
<span style="font-family:arial,sans-serif;font-size:13px">Log:</span><br style="font-family:arial,sans-serif;font-size:13px"><span class="" style="font-family:arial,sans-serif;font-size:13px">SLP</span><span style="font-family:arial,sans-serif;font-size:13px"> Vectorier: Don't </span><span class="" style="font-family:arial,sans-serif;font-size:13px">vectorize</span><span style="font-family:arial,sans-serif;font-size:13px"> really short chains because they are already handled by the SelectionDAG store-</span><span class="" style="font-family:arial,sans-serif;font-size:13px">vectorizer</span><span style="font-family:arial,sans-serif;font-size:13px">, which does a better job in deciding when to </span><span class="" style="font-family:arial,sans-serif;font-size:13px">vectorize</span><span style="font-family:arial,sans-serif;font-size:13px">.</span></blockquote>
<div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><br>
Modified: llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp?rev=187267&r1=187266&r2=187267&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp?rev=187267&r1=187266&r2=187267&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp (original)<br>
+++ llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp Fri Jul 26 18:07:55 2013<br>
@@ -898,8 +898,12 @@ int BoUpSLP::getTreeCost() {<br>
DEBUG(dbgs() << "SLP: Calculating cost for tree of size " <<<br>
VectorizableTree.size() << ".\n");<br>
<br>
- if (!VectorizableTree.size()) {<br>
- assert(!ExternalUses.size() && "We should not have any external users");<br>
+ // Don't vectorize tiny trees. Small load/store chains or consecutive stores<br>
+ // of constants will be vectoried in SelectionDAG in MergeConsecutiveStores.<br>
+ if (VectorizableTree.size() < 3) {<br>
+ if (!VectorizableTree.size()) {<br>
+ assert(!ExternalUses.size() && "We should not have any external users");<br>
+ }<br>
return 0;<br>
}<br>
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