[polly] [RemoveDI][Polly] Migrate to adapt to the new DebugRecord format in more areas (PR #135935)

[Orlando Cazalet-Hyams via llvm-commits]

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@@ -1384,7 +1384,7 @@ void RegionGenerator::copyPHIInstruction(ScopStmt &Stmt, PHINode *PHI,
   unsigned NumIncoming = PHI->getNumIncomingValues();
   PHINode *PHICopy =
       Builder.CreatePHI(PHI->getType(), NumIncoming, "polly." + PHI->getName());
-  PHICopy->moveBefore(PHICopy->getParent()->getFirstNonPHIIt());
+  PHICopy->moveBeforePreserving(PHICopy->getParent()->getFirstNonPHIIt());
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OCHyams wrote:

Is this change needed?  It doesn't look like `PHICopy` will ever have dbg records attached to it (as 1. it has just been created and 2. PHI nodes are not allowed to have DbgRecords attached), so I don't think there's a difference between `moveBefore` and `moveBeforePreserving` in this instance.

https://github.com/llvm/llvm-project/pull/135935