<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Oct 21, 2014 at 9:24 AM, Arnaud A. de Grandmaison <span dir="ltr"><<a href="mailto:arnaud.degrandmaison@arm.com" target="_blank">arnaud.degrandmaison@arm.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: aadg<br>
Date: Tue Oct 21 11:24:15 2014<br>
New Revision: 220302<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=220302&view=rev" target="_blank">http://llvm.org/viewvc/llvm-project?rev=220302&view=rev</a><br>
Log:<br>
[PBQP] Fix coalescing benefits<br>
<br>
As coalescing registers is a benefit, the cost should be improved (i.e. made smaller) when coalescing is possible.<br>
<br>
Modified:<br>
    llvm/trunk/lib/CodeGen/RegAllocPBQP.cpp<br>
<br>
Modified: llvm/trunk/lib/CodeGen/RegAllocPBQP.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/RegAllocPBQP.cpp?rev=220302&r1=220301&r2=220302&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/RegAllocPBQP.cpp?rev=220302&r1=220301&r2=220302&view=diff</a><br>
==============================================================================<br>
--- llvm/trunk/lib/CodeGen/RegAllocPBQP.cpp (original)<br>
+++ llvm/trunk/lib/CodeGen/RegAllocPBQP.cpp Tue Oct 21 11:24:15 2014<br>
@@ -350,7 +350,7 @@ public:<br>
<br>
           if (PRegOpt < Allowed.size()) {<br>
             PBQPRAGraph::RawVector NewCosts(G.getNodeCosts(NId));<br>
-            NewCosts[PRegOpt + 1] += CBenefit;<br>
+            NewCosts[PRegOpt + 1] -= CBenefit;<br></blockquote><div><br>Test coverage for this?<br> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
             G.setNodeCosts(NId, std::move(NewCosts));<br>
           }<br>
         } else {<br>
@@ -395,7 +395,7 @@ private:<br>
       for (unsigned J = 0; J != Allowed2.size(); ++J) {<br>
         unsigned PReg2 = Allowed2[J];<br>
         if (PReg1 == PReg2)<br>
-          CostMat[I + 1][J + 1] += -Benefit;<br>
+          CostMat[I + 1][J + 1] -= Benefit;<br>
       }<br>
     }<br>
   }<br>
<br>
<br>
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</blockquote></div><br></div></div>