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

Elena Demikhovsky via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Mon Jul 24 05:55:10 PDT 2017

delena added a comment.

I dug into the performance degradation and found that isExtLoad() reduces cost of a loop, as a result the loop is being unrolled. Unrolling this loop causes performance degradation.
But the load + zext cost is correct and it is 1 Op. I'll work more with our architects in order to understand what parameter is incorrect on X86.



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