[llvm] [AMDGPU] Add mark last scratch load pass (PR #75512)

[Matt Arsenault via llvm-commits]

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@@ -1491,6 +1491,8 @@ void TargetPassConfig::addOptimizedRegAlloc() {
   addPass(&MachineSchedulerID);
 
   if (addRegAssignAndRewriteOptimized()) {
+    addPreStackSlotColoring();
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arsenm wrote:

I'd assume you could just put this in addRegAssignAndRewriteOptimized

https://github.com/llvm/llvm-project/pull/75512