[llvm] [DebugInfo][NewGVN] Fix debug value loss (PR #147634)

[Orlando Cazalet-Hyams via llvm-commits]

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@@ -0,0 +1,43 @@
+; RUN: opt -S -passes=newgvn %s | FileCheck %s
+
+; Check that eliminateInstruction() salvages the debug value of `Def` (`DefI`)
+; which is marked for deletion.
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OCHyams wrote:

The comment has a chance of going stale, referring to the LLVM source. I think function name is ok but instead of LLVM source variables, it's probably better to describe what's happening in terms of the IR in the test.

https://github.com/llvm/llvm-project/pull/147634