[llvm] LV: Expand llvm.histogram intrinsic to support umax, umin, and uadd.sat operations (PR #127399)

[Florian Hahn via llvm-commits]

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@@ -5303,8 +5335,50 @@ LoopVectorizationCostModel::getInstructionCost(Instruction *I,
     return TTI.getCastInstrCost(Opcode, VectorTy, SrcVecTy, CCH,
                                 Config.CostKind, I);
   }
-  case Instruction::Call:
+  case Instruction::Call: {
+    // Check if this is a histogram update operation (intrinsic like uadd.sat,
+    // umax, umin used as histogram bucket update).
+    auto Info = Legal->getHistogramInfo(I);
+    if (Info && VF.isVector()) {
+      const HistogramInfo *HGram = Info.value();
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fhahn wrote:

is this code needed/tested? it looks like all tests also pass without it

https://github.com/llvm/llvm-project/pull/127399