[llvm] [AMDGPU] Use range-based for loops. NFC. (PR #99047)

[Jay Foad via llvm-commits]

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@@ -344,6 +342,8 @@ void SIMachineFunctionInfo::shiftSpillPhysVGPRsToLowestRange(
       MBB.removeLiveIn(Reg);
       MBB.sortUniqueLiveIns();
     }
+
+    Reg = NewReg;
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jayfoad wrote:

I find this a bit subtle. It updates the entry in SpillPhysVGPRs. I don't know if there's a good way to make this more obvious to the reader.

https://github.com/llvm/llvm-project/pull/99047