[PATCH] D34458: [TTI] Refine the cost of EXT in getUserCost()

Haicheng Wu via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Thu Jul 20 06:08:12 PDT 2017


haicheng added inline comments.


================
Comment at: llvm/trunk/include/llvm/CodeGen/BasicTTIImpl.h:167
+
+    return TargetTransformInfo::TCC_Basic;
+  }
----------------
delena wrote:
> At this point we should call to getOperationCost() and ask the target about the cost of Ext for the given type.
Sorry about the performance regression.

I think isExtFree(I) above checks isZExtFree() with its types.  The part that can affect x86 is isExtLoad().  Do you want me to add a target hook to choose use refined ext cost?


Repository:
  rL LLVM

https://reviews.llvm.org/D34458





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