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</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hi Lang,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The attached patch addresses a FIXME in RegAllocPBQP.cpp, in the Interference class when building the graph.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>This indeed improves compilation time when building llvm+clang+lldb.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>However, I wonder if this check+continue for an already seen edge should exist at all.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I may have missed something in my reading / understanding of Interference::apply(), but I do not think the algorithm can exhibit such a case --- or it would be an error, which we should trap with an assert, either in Interference::apply, or even better in Graph::addEdge. I replaced the continue statement with an llvm_unreachable, and it never triggered while building llvm+clang+lldb (granted, this is not a proof, just an hint). Removing this check+continue brings yet another nice speedup, making pbqp build llvm+clang+lldb slightly faster than the default allocator in release mode.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=FR>Cheers,<o:p></o:p></span></p><p class=MsoNormal><span lang=FR style='mso-fareast-language:EN-GB'>--<o:p></o:p></span></p><p class=MsoNormal><span lang=FR style='mso-fareast-language:EN-GB'>Arnaud A. de Grandmaison<o:p></o:p></span></p><p class=MsoNormal><span lang=FR><o:p> </o:p></span></p></div></body></html>