[llvm] [NFC][AMDGPU] print more info when debugging InsertWaitCnts pass (PR #144629)

[Sameer Sahasrabuddhe via llvm-commits]

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@@ -1265,10 +1272,15 @@ bool WaitcntGeneratorPreGFX12::applyPreexistingWaitcnt(
   MachineInstr *WaitcntInstr = nullptr;
   MachineInstr *WaitcntVsCntInstr = nullptr;
 
+  LLVM_DEBUG(dbgs() << "PreGFX12::applyPreexistingWaitcnt at: " << *It << "\n");
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ssahasra wrote:

That newline puts helpful whitespace ahead of the "pre-existing iter" lines that come next. Sometimes *It is so long that it wraps into multiple lines.

https://github.com/llvm/llvm-project/pull/144629