[PATCH] D128302: [AArch64][CostModel] Detects that ExtractElement at index is not free in AArch64 when result is used as integer.

[Mingming Liu via Phabricator via llvm-commits]

mingmingl added a comment.





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Comment at: llvm/include/llvm/Analysis/TargetTransformInfo.h:1155
 
   /// \return The expected cost of vector Insert and Extract.
   /// Use -1 to indicate that there is no information on the index value.
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davidxl wrote:
> Perhaps document this that this is used when the instruction is not available.
Done. Mention the typical use as provision vectorization/scalarization cost in vectorizer passes.


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Comment at: llvm/lib/Analysis/TargetTransformInfo.cpp:869
+  // callers, but never asserted upon.
+  assert((Opcode == Instruction::ExtractElement ||
+          Opcode == Instruction::InsertElement) &&
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davidxl wrote:
> probably submit this as a NFC patch seperately?
Sure. Will leave the FIXME inside this function, and the assert the newly added 'getVectorInstrCost'.


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Comment at: llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h:176
 
+  using BaseT::getVectorInstrCost;
   InstructionCost getVectorInstrCost(unsigned Opcode, Type *Val,
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davidxl wrote:
> what is the purpose of the using statement here?
Oh good catch. This is a mistake. 'using statement' is not needed for AArch64 since there is an override for new interface.


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  https://reviews.llvm.org/D128302/new/

https://reviews.llvm.org/D128302