[llvm] [AMDGPU] Optionally Use GCNRPTrackers during scheduling (PR #93090)

[Pierre van Houtryve via llvm-commits]

================
@@ -294,8 +330,16 @@ void GCNSchedStrategy::pickNodeFromQueue(SchedBoundary &Zone,
   unsigned SGPRPressure = 0;
   unsigned VGPRPressure = 0;
   if (DAG->isTrackingPressure()) {
-    SGPRPressure = Pressure[AMDGPU::RegisterPressureSets::SReg_32];
-    VGPRPressure = Pressure[AMDGPU::RegisterPressureSets::VGPR_32];
+    if (!GCNTrackers) {
+      SGPRPressure = Pressure[AMDGPU::RegisterPressureSets::SReg_32];
+      VGPRPressure = Pressure[AMDGPU::RegisterPressureSets::VGPR_32];
+    } else {
+      GCNRPTracker *T = &UpwardTracker;
+      if (Zone.isTop())
+        T = &DownwardTracker;
----------------
Pierre-vh wrote:

```suggestion
      GCNRPTracker *T = Zone.isTop() ? &DownwardTracke : &UpwardTracker;
```

https://github.com/llvm/llvm-project/pull/93090