[llvm] [CostModel][AArch64] Make extractelement, with fmul user, free whenev… (PR #111479)

[David Green via llvm-commits]

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@@ -1282,12 +1281,24 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
     return 1;
   }
 
-  InstructionCost getVectorInstrCost(unsigned Opcode, Type *Val,
-                                     TTI::TargetCostKind CostKind,
-                                     unsigned Index, Value *Op0, Value *Op1) {
+  virtual InstructionCost getVectorInstrCost(unsigned Opcode, Type *Val,
+                                             TTI::TargetCostKind CostKind,
+                                             unsigned Index, Value *Op0,
+                                             Value *Op1) {
     return getRegUsageForType(Val->getScalarType());
   }
 
+  /// \param ScalarUserAndIdx encodes the information about extracts from a
+  /// vector with 'Scalar' being the value being extracted,'User' being the user
+  /// of the extract(nullptr if user is not known before vectorization) and
+  /// 'Idx' being the extract lane.
+  InstructionCost getVectorInstrCost(
+      unsigned Opcode, Type *Val, TTI::TargetCostKind CostKind, unsigned Index,
+      Value *Scalar,
+      ArrayRef<std::tuple<Value *, User *, int>> ScalarUserAndIdx) {
+    return getVectorInstrCost(Opcode, Val, CostKind, Index, nullptr, nullptr);
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davemgreen wrote:

return thisT()->getVectorInstrCost(..)

https://github.com/llvm/llvm-project/pull/111479