[llvm] [RemoveDIs][DebugInfo] Handle DPVAssign in most transforms (PR #78986)

[Stephen Tozer via llvm-commits]

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@@ -1761,6 +1761,11 @@ bool SimplifyCFGOpt::hoistSuccIdenticalTerminatorToSwitchOrIf(
       OtherSuccTI->replaceAllUsesWith(NT);
     NT->takeName(I1);
   }
+  // Also clone DPValues from the existing terminator, and all others (to
+  // duplicate existing hoisting behaviour).
+  NT->cloneDebugInfoFrom(I1);
+  for (Instruction *OtherSuccTI : OtherSuccTIs)
+    NT->cloneDebugInfoFrom(OtherSuccTI);
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SLTozer wrote:

This should probably be split out of here - I think this is a general DPValue bug that I found while validating the assignment tracking patches; I'll create a separate patch with a reduced reproducer as the test case.

https://github.com/llvm/llvm-project/pull/78986