[llvm] [LV][VPlan] Extract the implementation of transform Recipe to EVLRecipe into a small function. NFC (PR #119510)

[Florian Hahn via llvm-commits]

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@@ -1438,13 +1438,105 @@ void VPlanTransforms::addActiveLaneMask(
     HeaderMask->replaceAllUsesWith(LaneMask);
 }
 
+// Convert each widen Recipe to a widen EVLRecipe in VectorLoopRegion.
+// \p HeaderMask  Header Mask.
+// \p CurRecipe   Recipe to be transform.
+// \p TypeInfo    VPlan-based type analysis.
+// \p AllOneMask  The vector mask parameter of vector-predication intrinsics.
+// \p EVL         The explicit vector length parameter of vector-predication
+// intrinsics.
+static VPRecipeBase *createEVLRecipe(VPValue *HeaderMask,
+                                     VPRecipeBase &CurRecipe,
+                                     VPTypeAnalysis &TypeInfo,
+                                     VPValue &AllOneMask, VPValue &EVL) {
+  using namespace llvm::VPlanPatternMatch;
+  auto GetNewMask = [&](VPValue *OrigMask) -> VPValue * {
+    assert(OrigMask && "Unmasked recipe when folding tail");
+    return HeaderMask == OrigMask ? nullptr : OrigMask;
+  };
+
+  return TypeSwitch<VPRecipeBase *, VPRecipeBase *>(&CurRecipe)
+      .Case<VPWidenLoadRecipe>([&](VPWidenLoadRecipe *L) {
+        VPValue *NewMask = GetNewMask(L->getMask());
+        return new VPWidenLoadEVLRecipe(*L, EVL, NewMask);
+      })
+      .Case<VPWidenStoreRecipe>([&](VPWidenStoreRecipe *S) {
+        VPValue *NewMask = GetNewMask(S->getMask());
+        return new VPWidenStoreEVLRecipe(*S, EVL, NewMask);
+      })
+      .Case<VPWidenRecipe>([&](VPWidenRecipe *W) -> VPRecipeBase * {
+        unsigned Opcode = W->getOpcode();
+        if (!Instruction::isBinaryOp(Opcode) && !Instruction::isUnaryOp(Opcode))
+          return nullptr;
+        return new VPWidenEVLRecipe(*W, EVL);
+      })
+      .Case<VPReductionRecipe>([&](VPReductionRecipe *Red) {
+        VPValue *NewMask = GetNewMask(Red->getCondOp());
+        return new VPReductionEVLRecipe(*Red, EVL, NewMask);
+      })
+      .Case<VPWidenIntrinsicRecipe>(
+          [&](VPWidenIntrinsicRecipe *CInst) -> VPRecipeBase * {
+            auto *CI = dyn_cast<CallInst>(CInst->getUnderlyingInstr());
+            Intrinsic::ID VPID = VPIntrinsic::getForIntrinsic(
+                CI->getCalledFunction()->getIntrinsicID());
+            assert(VPID != Intrinsic::not_intrinsic && "Expected VP intrinsic");
+            assert(VPIntrinsic::getMaskParamPos(VPID) &&
+                   VPIntrinsic::getVectorLengthParamPos(VPID) &&
+                   "Expected VP intrinsic");
+
+            SmallVector<VPValue *> Ops(CInst->operands());
+            Ops.push_back(&AllOneMask);
+            Ops.push_back(&EVL);
+            return new VPWidenIntrinsicRecipe(*CI, VPID, Ops,
+                                              TypeInfo.inferScalarType(CInst),
+                                              CInst->getDebugLoc());
+          })
+      .Case<VPWidenCastRecipe>([&](VPWidenCastRecipe *CInst) -> VPRecipeBase * {
+        auto *CI = dyn_cast<CastInst>(CInst->getUnderlyingInstr());
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fhahn wrote:

Just noticing this here, but this should use the opcode from the recipe, not from the underlying instruction.

Also is using `dyn_cast` ,but never checking if the result is non-null?

Can we share most of the logic/asserts with the `VPWidenIntrinsicRecipe` case?

https://github.com/llvm/llvm-project/pull/119510