[llvm] [InstCombine] Skip redundant demanded element queries in insert chains (PR #205948)

[Yingwei Zheng via llvm-commits]

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@@ -1607,6 +1665,11 @@ Value *InstCombinerImpl::SimplifyDemandedVectorElts(Value *V,
     break;
   }
   case Instruction::InsertElement: {
+    auto *IE = cast<InsertElementInst>(I);
+    if (Depth == 0 && DemandedElts.isAllOnes() &&
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dtcxzyw wrote:

I'd prefer to move the check into `visitInsertElementInst`:
https://github.com/llvm/llvm-project/blob/92f01b267efe262a096baa433665c169cd53ff2c/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp#L1836-L1846

https://github.com/llvm/llvm-project/pull/205948