[llvm] [ValueLattice] Support constant vectors in mergeIn() (PR #99466)

[Nikita Popov via llvm-commits]

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@@ -426,6 +431,16 @@ class ValueLatticeElement {
         return false;
       if (RHS.isUndef())
         return false;
+      // If the constant is a vector of integers, try to treat it as a range.
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nikic wrote:

For plain integers, constants get converted into constant range on construction. For vectors this doesn't happen as it's a lossy operation. So I think there was just never a need for it before.

https://github.com/llvm/llvm-project/pull/99466