[llvm] Greedy: Make eviction broken hint cost use CopyCost units (PR #160084)

[Philip Reames via llvm-commits]

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@@ -300,12 +300,14 @@ bool DefaultEvictionAdvisor::canEvictInterferenceBasedOnCost(
           return false;
         // We permit breaking cascades for urgent evictions. It should be the
         // last resort, though, so make it really expensive.
-        Cost.BrokenHints += 10;
+        Cost.BrokenHints += 10 * MRI->getRegClass(Intf->reg())->getCopyCost();
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preames wrote:

Or we should explicitly use saturating arithmetic here.  Either way, probably worth a revert and reapply with a fix.  

https://github.com/llvm/llvm-project/pull/160084