[PATCH] D96399: [X86][CodeGenPrepare] Try to reuse IV's incremented value instead of adding the offset

[Max Kazantsev via Phabricator via llvm-commits]

mkazantsev added inline comments.


================
Comment at: llvm/lib/CodeGen/CodeGenPrepare.cpp:3848
+    if (!IVInc || !L->contains(IVInc->getParent()))
+      return None;
+    ConstantInt *Step;
----------------
reames wrote:
> You really should be able to factor out some common code here with the isIVIncrement function above.  Maybe time for a getIVIncrement function?  
> 
> Hm, though there appears to be a bug in this copy.  The "incr" you identify doesn't appear to be tied to the PN.  
`IVInc` is the incoming value of the Phi node from the backedge which has the same phi node as argument thru matcher. That makes it tied, no?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D96399/new/

https://reviews.llvm.org/D96399