[PATCH] D104187: [DAGCombine] reduceBuildVecToShuffle(): sort input vectors by decreasing size

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In D104187#2815568 <https://reviews.llvm.org/D104187#2815568>, @RKSimon wrote:

> A few nits but the premise seems sound



> did you encounter real world cases that led you to this?

Not particularly, was just looking at the shuffle handling code and saw this.



================
Comment at: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:19270
+  return std::distance(Range.begin(), I);
+}
+
----------------
RKSimon wrote:
> Move this inside reduceBuildVecToShuffle?
I actually want to pull this into STLExtras or something,
this seems like a common patter.


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https://reviews.llvm.org/D104187