[llvm] [LLVM][ConstProp] Enable intrinsic simplifications for vector ConstantInt based operands. (PR #159358)

[Paul Walker via llvm-commits]

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@@ -2165,7 +2165,7 @@ Constant *constantFoldVectorReduce(Intrinsic::ID IID, Constant *Op) {
     return PoisonValue::get(VT->getElementType());
 
   // TODO: Handle undef.
-  if (!isa<ConstantVector>(Op) && !isa<ConstantDataVector>(Op))
+  if (!isa<ConstantVector, ConstantDataVector, ConstantInt>(Op))
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paulwalker-arm wrote:

Looking at `getAggregateElement` there is a "bad" path for scalable vectors, but swapping the following `dyn_cast` with `dyn_cast_or_null` should account for that, so yes.

https://github.com/llvm/llvm-project/pull/159358