[PATCH] D74495: [VectorCombine] try to form vector binop to eliminate an extract element

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added inline comments.


================
Comment at: llvm/lib/Transforms/Vectorize/VectorCombine.cpp:103
+  // TODO: Relax the one-use constraints by adjusting the cost calc.
+  if (Ext0 != Ext1 && (!Ext0->hasOneUse() || !Ext1->hasOneUse()))
+    return false;
----------------
But even if it's the same extract, do we not care whether it will go away or not,
unlike the case with two different extracts?
I.e. for now i'd expect
```
  if (!(Ext0 == Ext1 && Ext0->hasNUses(2)) &&
      !(Ext0->hasOneUse() && Ext1->hasOneUse()))
    return false;
```


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  https://reviews.llvm.org/D74495/new/

https://reviews.llvm.org/D74495