[LLVMdev] Bug in visitSIGN_EXTEND in DAGCombiner.cpp?

Relph, Richard Richard.Relph at amd.com
Tue Mar 12 09:35:50 PDT 2013

On Mar 11, 2013, at 11:27 AM, Nadav Rotem <nrotem at apple.com<mailto:nrotem at apple.com>>

Line 4501 in trunk DAGCombiner.cpp… I changed the ISD::SELECT to the VT.isVector() ? ISD::VSELECT : ISD::SELECT...

Thanks. From the commit message I think that we should only run this optimization on scalars.

I have tried making just that change… it definitely helps quite a bit. I submitted the simple patch to llvm-commits for approval.

It doesn't quite clear up ALL the asserts I see in my test runs… I'm still getting the assert in ExpandVSELECT in a few cases, but I suppose the custom lowering is the "easy" way to solve those, though I'm sure the TRUNCATE would do the trick as well.

Thanks for your help.

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