[llvm] [AMDGPU] Add flag to control VGPR pressure limits (PR #203797)

[Lucas Ramirez via llvm-commits]

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@@ -154,12 +182,31 @@ void GCNSchedStrategy::initialize(ScheduleDAGMI *DAG) {
     VGPRBudget = std::max(VGPRBudget, Granule);
     VGPRCriticalLimit = std::min(VGPRBudget, VGPRExcessLimit);
   }
+  // Apply VGPR excess threshold percentage if specified.
+  if (VGPRExcessThresholdPercentOpt > 0) {
+    [[maybe_unused]] unsigned OriginalVGPRExcessLimit = VGPRExcessLimit;
+    [[maybe_unused]] unsigned OriginalVGPRCriticalLimit = VGPRCriticalLimit;
+    VGPRExcessLimit =
+        (VGPRExcessThresholdPercentOpt * VGPRExcessLimit + 99) / 100;
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lucas-rami wrote:

Same as `std::ceil((VGPRExcessThresholdPercentOpt * VGPRExcessLimit) / 100)`? If yes I find it clearer

https://github.com/llvm/llvm-project/pull/203797