[llvm] [SandboxIR] Implement UndefValue (PR #107628)

[Sriraman Tallam via llvm-commits]

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@@ -642,6 +642,7 @@ define void @foo() {
   // Check classof() and creation.
   auto *Poison = cast<sandboxir::PoisonValue>(I0->getOperand(0));
   EXPECT_EQ(Poison->getType(), Int32Ty);
+  EXPECT_TRUE(isa<sandboxir::UndefValue>(Poison)); // Poison is Undef
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tmsri wrote:

LGTM, Poison value is an undef.

https://github.com/llvm/llvm-project/pull/107628