[llvm] [regalloc][basic] Change spill weight for optsize funcs (PR #112960)

[Ellis Hoag via llvm-commits]

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@@ -113,14 +114,18 @@ class LiveIntervals {
   ~LiveIntervals();
 
   /// Calculate the spill weight to assign to a single instruction.
+  /// If \p PSI is provided the calculation is altered for optsize functions.
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ellishg wrote:

I understand that this may be confusing, but I thought it was less disruptive than adding a separate `ConsiderOptSize` parameter

https://github.com/llvm/llvm-project/pull/112960