[PATCH] D105432: [Analysis] Add simple cost model for strict (in-order) reductions

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


================
Comment at: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:7262
+  InstructionCost BaseCost = TTI.getArithmeticReductionCost(
+      RdxDesc.getOpcode(), VectorTy, RdxDesc.getFastMathFlags(), CostKind);
 
----------------
Aren't the calls to TTI.getArithmeticReductionCost the same?
```
InstructionCost BaseCost = TTI.getArithmeticReductionCost(
      RdxDesc.getOpcode(), VectorTy, RdxDesc.getFastMathFlags(), CostKind);

if (useOrderedReductions(RdxDesc))
  return BaseCost;
```


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D105432/new/

https://reviews.llvm.org/D105432