[PATCH] D9284: Avoid double branch / conditional move for promoted cttz

[Marcin Kościelnicki via llvm-commits]

koriakin added a subscriber: koriakin.
koriakin added a comment.

Looks good, but there's room for a minor improvement still - see inline comment.


================
Comment at: lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:4051
@@ +4050,3 @@
+    if (Node->getOpcode() == ISD::CTTZ) {
+      Tmp1 = DAG.getNode(ISD::OR, dl, NVT, Tmp1, DAG.getConstant(1 << OVT.getSizeInBits(), NVT));
+    }
----------------
Another trick that can be added here: operation can now be safely changed to CTTZ_UNDEF.


http://reviews.llvm.org/D9284