[RISCV] Add cost model for vector.splice mask operation

[Jimerlife]

Summary

Vector.splice mask operation need additional two operand extend and truncate. So, I try to adjust cost model with adding extend and truncate cost.

[reames]

I'm a bit confused. It sounds like the sequence you're describing is inserted during legalization? If so, why is this not covered by the existing use of legalization cost?

Also, it would help me to understand your intent if you included the generated code for an example in the review description.

llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp

 
 InstructionCost RISCVTTIImpl::getSpliceCost(VectorType *Tp, int Index) {
   std::pair<InstructionCost, MVT> LT = TLI->getTypeLegalizationCost(DL, Tp);
 
   unsigned Cost = 2; // vslidedown+vslideup.
   // TODO: LMUL should increase cost.
   // TODO: Multiplying by LT.first implies this legalizes into multiple copies
   // of similar code, but I think we expand through memory.
+  if (Tp->getElementType()->isIntegerTy(1)) {
+    // Mask operation need additional two operands extend and result truncate.
+    Cost = Cost + 5;
+  }
   return Cost * LT.first;
 }
 
 InstructionCost RISCVTTIImpl::getShuffleCost(TTI::ShuffleKind Kind,
                                              VectorType *Tp, ArrayRef<int> Mask,
                                              int Index, VectorType *SubTp,
                                              ArrayRef<const Value *> Args) {
   if (isa<ScalableVectorType>(Tp)) {

llvm/test/Analysis/CostModel/RISCV/rvv-shuffle.ll

 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %splice_nxv2i16 = call <vscale x 2 x i16> @llvm.experimental.vector.splice.nxv2i16(<vscale x 2 x i16> zeroinitializer, <vscale x 2 x i16> zeroinitializer, i32 1)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %splice_nxv4i16 = call <vscale x 4 x i16> @llvm.experimental.vector.splice.nxv4i16(<vscale x 4 x i16> zeroinitializer, <vscale x 4 x i16> zeroinitializer, i32 1)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %splice_nxv8i16 = call <vscale x 8 x i16> @llvm.experimental.vector.splice.nxv8i16(<vscale x 8 x i16> zeroinitializer, <vscale x 8 x i16> zeroinitializer, i32 1)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %splice_nxv16i16 = call <vscale x 16 x i16> @llvm.experimental.vector.splice.nxv16i16(<vscale x 16 x i16> zeroinitializer, <vscale x 16 x i16> zeroinitializer, i32 1)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %splice_nxv4i32 = call <vscale x 4 x i32> @llvm.experimental.vector.splice.nxv4i32(<vscale x 4 x i32> zeroinitializer, <vscale x 4 x i32> zeroinitializer, i32 1)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %splice_nxv8i32 = call <vscale x 8 x i32> @llvm.experimental.vector.splice.nxv8i32(<vscale x 8 x i32> zeroinitializer, <vscale x 8 x i32> zeroinitializer, i32 1)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %splice_nxv2i64 = call <vscale x 2 x i64> @llvm.experimental.vector.splice.nxv2i64(<vscale x 2 x i64> zeroinitializer, <vscale x 2 x i64> zeroinitializer, i32 1)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %splice_nxv4i64 = call <vscale x 4 x i64> @llvm.experimental.vector.splice.nxv4i64(<vscale x 4 x i64> zeroinitializer, <vscale x 4 x i64> zeroinitializer, i32 1)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %splice_nxv16i1 = call <vscale x 16 x i1> @llvm.experimental.vector.splice.nxv16i1(<vscale x 16 x i1> zeroinitializer, <vscale x 16 x i1> zeroinitializer, i32 1)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %splice_nxv8i1 = call <vscale x 8 x i1> @llvm.experimental.vector.splice.nxv8i1(<vscale x 8 x i1> zeroinitializer, <vscale x 8 x i1> zeroinitializer, i32 1)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %splice_nxv4i1 = call <vscale x 4 x i1> @llvm.experimental.vector.splice.nxv4i1(<vscale x 4 x i1> zeroinitializer, <vscale x 4 x i1> zeroinitializer, i32 1)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %splice_nxv2i1 = call <vscale x 2 x i1> @llvm.experimental.vector.splice.nxv2i1(<vscale x 2 x i1> zeroinitializer, <vscale x 2 x i1> zeroinitializer, i32 1)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %splice_nxv16i1 = call <vscale x 16 x i1> @llvm.experimental.vector.splice.nxv16i1(<vscale x 16 x i1> zeroinitializer, <vscale x 16 x i1> zeroinitializer, i32 1)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %splice_nxv8i1 = call <vscale x 8 x i1> @llvm.experimental.vector.splice.nxv8i1(<vscale x 8 x i1> zeroinitializer, <vscale x 8 x i1> zeroinitializer, i32 1)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %splice_nxv4i1 = call <vscale x 4 x i1> @llvm.experimental.vector.splice.nxv4i1(<vscale x 4 x i1> zeroinitializer, <vscale x 4 x i1> zeroinitializer, i32 1)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %splice_nxv2i1 = call <vscale x 2 x i1> @llvm.experimental.vector.splice.nxv2i1(<vscale x 2 x i1> zeroinitializer, <vscale x 2 x i1> zeroinitializer, i32 1)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: ret void
 ;
   %splice_nxv16i8 = call <vscale x 16 x i8> @llvm.experimental.vector.splice.nxv16i8(<vscale x 16 x i8> zeroinitializer, <vscale x 16 x i8> zeroinitializer, i32 1)
   %splice_nxv32i8 = call <vscale x 32 x i8> @llvm.experimental.vector.splice.nxv32i8(<vscale x 32 x i8> zeroinitializer, <vscale x 32 x i8> zeroinitializer, i32 1)
   %splice_nxv2i16 = call <vscale x 2 x i16> @llvm.experimental.vector.splice.nxv2i16(<vscale x 2 x i16> zeroinitializer, <vscale x 2 x i16> zeroinitializer, i32 1)
   %splice_nxv4i16 = call <vscale x 4 x i16> @llvm.experimental.vector.splice.nxv4i16(<vscale x 4 x i16> zeroinitializer, <vscale x 4 x i16> zeroinitializer, i32 1)
   %splice_nxv8i16 = call <vscale x 8 x i16> @llvm.experimental.vector.splice.nxv8i16(<vscale x 8 x i16> zeroinitializer, <vscale x 8 x i16> zeroinitializer, i32 1)
   %splice_nxv16i16 = call <vscale x 16 x i16> @llvm.experimental.vector.splice.nxv16i16(<vscale x 16 x i16> zeroinitializer, <vscale x 16 x i16> zeroinitializer, i32 1)