[PATCH] D141665: [DAGCombine][AArch64][ARM] Combine abd(sub(x, y)) to abd if the sub is nsw

[Dave Green via Phabricator via llvm-commits]

dmgreen added inline comments.


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Comment at: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:10120
+        TLI.isOperationLegalOrCustom(ISD::ABDS, VT))
+      return DAG.getNode(ISD::ABDS, SDLoc(N), VT, Op0, Op1);
     return SDValue();
----------------
RKSimon wrote:
> You can probably hoist this before the sext/zext test?
The idea is that if we have a sext/zext pair then is better to use them in the abd, creating the smaller type. We use the wrapping flags if that fails.


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  https://reviews.llvm.org/D141665/new/

https://reviews.llvm.org/D141665