[PATCH] D114716: [DAGCombiner] When combining REM ensure optimized div nodes are unique

[Paul Walker via Phabricator via llvm-commits]

paulwalker-arm accepted this revision.
paulwalker-arm added inline comments.
This revision is now accepted and ready to land.


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Comment at: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:4439
         isSigned ? visitSDIVLike(N0, N1, N) : visitUDIVLike(N0, N1, N);
-    if (OptimizedDiv.getNode()) {
+    if (OptimizedDiv.getNode() && OptimizedDiv.getNode() != N) {
       // If the equivalent Div node also exists, update its users.
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bsmith wrote:
> paulwalker-arm wrote:
> > Can you just use `if (OptimizedDiv.getNode() != N)` here?
> Presumably not? If `OptimizedDiv` is `SDValue()`, then `getNode()` will return `nullptr` which is `!= N`, hence this check would pass, whereas currently it would fail.
Are yes, I see what you mean.  I guess this hasn't been hit before because the code is protected by `TLI.isIntDivCheap` which is the only other time `N` is returned untouched.


Repository:
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  https://reviews.llvm.org/D114716/new/

https://reviews.llvm.org/D114716