[PATCH] D134605: [SLP] Add ScalarizationOverheadBuilder helper to track vector extractions

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


================
Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:6115
       }
-      Cost -= TTIRef.getVectorInstrCost(*EE, EE->getVectorOperandType(), Idx);
-    }
-    // Add a cost for subvector extracts/inserts if required.
-    for (const auto &Data : ExtractVectorsTys) {
-      auto *EEVTy = cast<FixedVectorType>(Data.first->getType());
-      unsigned NumElts = VecTy->getNumElements();
-      if (Data.second % NumElts == 0)
-        continue;
-      if (TTIRef.getNumberOfParts(EEVTy) > TTIRef.getNumberOfParts(VecTy)) {
-        unsigned Idx = (Data.second / NumElts) * NumElts;
-        unsigned EENumElts = EEVTy->getNumElements();
-        if (Idx + NumElts <= EENumElts) {
-          Cost +=
-              TTIRef.getShuffleCost(TargetTransformInfo::SK_ExtractSubvector,
-                                    EEVTy, None, CostKind, Idx, VecTy);
-        } else {
-          // Need to round up the subvector type vectorization factor to avoid a
-          // crash in cost model functions. Make SubVT so that Idx + VF of SubVT
-          // <= EENumElts.
-          auto *SubVT =
-              FixedVectorType::get(VecTy->getElementType(), EENumElts - Idx);
-          Cost +=
-              TTIRef.getShuffleCost(TargetTransformInfo::SK_ExtractSubvector,
-                                    EEVTy, None, CostKind, Idx, SubVT);
-        }
-      } else {
-        Cost += TTIRef.getShuffleCost(TargetTransformInfo::SK_InsertSubvector,
-                                      VecTy, None, CostKind, 0, EEVTy);
-      }
+      ScalarizationCost.addExtract(EE->getVectorOperand(), Idx);
     }
----------------
ABataev wrote:
> Does it support extract subvector?
getScalarizationOverhead should handle it there - however the getExtractWithExtendCost case doesn't handle subvectors yet - I really want to replace getExtractWithExtendCost with a getScalarizationOverhead equivalent tbh as this is the only user of it.


Repository:
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  https://reviews.llvm.org/D134605/new/

https://reviews.llvm.org/D134605