[PATCH] D99718: [LoopVectorize] Simplify scalar cost calculation in getInstructionCost

[Christopher Tetreault via Phabricator via llvm-commits]

ctetreau added inline comments.


================
Comment at: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:7433
     SmallVector<const Value *, 4> Operands(I->operand_values());
-    unsigned N = isScalarAfterVectorization(I, VF) ? VF.getKnownMinValue() : 1;
-    return N * TTI.getArithmeticInstrCost(
-                   I->getOpcode(), VectorTy, CostKind,
-                   TargetTransformInfo::OK_AnyValue,
-                   Op2VK, TargetTransformInfo::OP_None, Op2VP, Operands, I);
+    return TTI.getArithmeticInstrCost(
+        I->getOpcode(), VectorTy, CostKind, TargetTransformInfo::OK_AnyValue,
----------------
I'd feel better if there was an assert here that verifies that the conditions you state in the commit message are true. Same with all the other places N is eliminated.

At the very least, a comment that explains inline that, even though conceptually there should be an N, because of [reasons], we don't need it.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D99718/new/

https://reviews.llvm.org/D99718