[llvm] [RISCV][TTI] Scale the cost of FP-Int conversion with LMUL (PR #87506)

[Shih-Po Hung via llvm-commits]

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@@ -1099,34 +1099,90 @@ InstructionCost RISCVTTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst,
     return Cost;
   }
   case ISD::FP_TO_SINT:
-  case ISD::FP_TO_UINT:
-    // For fp vector to mask, we use:
-    // vfncvt.rtz.x.f.w v9, v8
-    // vand.vi v8, v9, 1
-    // vmsne.vi v0, v8, 0
-    if (Dst->getScalarSizeInBits() == 1)
-      return 3;
-
-    if (std::abs(PowDiff) <= 1)
-      return 1;
+  case ISD::FP_TO_UINT: {
+    unsigned IsSigned = ISD == ISD::FP_TO_SINT;
+    unsigned FCVT = IsSigned ? RISCV::VFCVT_RTZ_X_F_V : RISCV::VFCVT_RTZ_XU_F_V;
+    unsigned FWCVT =
+        IsSigned ? RISCV::VFWCVT_RTZ_X_F_V : RISCV::VFWCVT_RTZ_XU_F_V;
+    unsigned FNCVT =
+        IsSigned ? RISCV::VFNCVT_RTZ_X_F_W : RISCV::VFNCVT_RTZ_XU_F_W;
+    unsigned SrcEltSize = Src->getScalarSizeInBits();
+    unsigned DstEltSize = Dst->getScalarSizeInBits();
+    InstructionCost Cost = 0;
+    if ((SrcEltSize == 16) &&
+        (!ST->hasVInstructionsF16() || ((DstEltSize >> 1) > SrcEltSize))) {
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arcbbb wrote:

Fixed. Thanks!

https://github.com/llvm/llvm-project/pull/87506