[PATCH] D33391: [DAGCombine] fold (add/uaddo (xor a, -1), 1) -> (sub 0, a)

Eli Friedman via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Mon May 22 14:53:59 PDT 2017


efriedma added inline comments.


================
Comment at: lib/CodeGen/SelectionDAG/DAGCombiner.cpp:2095
+    return DAG.getNode(ISD::USUBO, DL, N->getVTList(),
+                       DAG.getConstant(0, DL, VT), N0.getOperand(0));
+
----------------
Are you sure this sets the overflow bit correctly?


https://reviews.llvm.org/D33391





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