[llvm] [CostModel] Add type-based cost model for get.active.lane.mask intrinsic (PR #130132)

[Ricardo Jesus via llvm-commits]

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@@ -2394,6 +2374,28 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
           thisT()->getArithmeticInstrCost(BinaryOperator::And, RetTy, CostKind);
       return Cost;
     }
+    case Intrinsic::get_active_lane_mask: {
+      Type *ArgTy = ICA.getArgTypes()[0];
+      EVT ResVT = getTLI()->getValueType(DL, RetTy, true);
+      EVT ArgVT = getTLI()->getValueType(DL, ArgTy, true);
+
+      // If we're not expanding the intrinsic then we assume this is cheap
+      // to implement.
+      if (!getTLI()->shouldExpandGetActiveLaneMask(ResVT, ArgVT))
+        return getTypeLegalizationCost(RetTy).first;
+
+      // Create the expanded types that will be used to calculate the uadd_sat
+      // operation.
+      Type *ExpRetTy =
+          VectorType::get(ArgTy, cast<VectorType>(RetTy)->getElementCount());
+      IntrinsicCostAttributes Attrs(Intrinsic::uadd_sat, ExpRetTy, {},
+                                    FastMathFlags());
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rj-jesus wrote:

Could this reuse `FMF` declared above?

https://github.com/llvm/llvm-project/pull/130132