[PATCH] D32563: Improve code placement algorithm in Reassociate pass.

[Daniel Berlin via Phabricator via llvm-commits]

dberlin added inline comments.


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Comment at: lib/Transforms/Scalar/Reassociate.cpp:1697
+                       return DT.dominates(ia, ib);
+                     });
     Value *V = EmitAddTreeOfValues(I, NewMulOps);
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efriedma wrote:
> dominates() isn't a strict weak ordering in general.  But maybe you don't actually hit those cases because of the way NewMulOps is constructed?  In any case, needs a explanation.
> 
> Also, this could be kind of slow: dominates() will iterate over the basic block if ia and ib have the same parent.

You should use the global and local dominance dfs numbers to do this


https://reviews.llvm.org/D32563