Add Pre-RA register pressure stat

Author: jfuentes

visa/JitterDataStruct.cpp

@@ -23,6 +23,7 @@ llvm::json::Value toJSON(const PERF_STATS &p) {
     {"numGRFSpillFill", p.numGRFSpillFillWeighted},
     {"GRFSpillSize", p.spillMemUsed},
     {"numCycles", p.numCycles},
+    {"maxGRFPressurePreRA", p.maxGRFPressurePreRA},
     {"maxGRFPressure", p.maxGRFPressure}
   };
 }

visa/Optimizer.h

@@ -168,7 +168,7 @@ class Optimizer {
       Sched.run(KernelPressure);
     }
     // Update Jit info for max register pressure
-    kernel.fg.builder->getJitInfo()->stats.maxGRFPressure = KernelPressure;
+    kernel.fg.builder->getJitInfo()->stats.maxGRFPressurePreRA = KernelPressure;
   }
   void localSchedule() {
     LocalScheduler lSched(kernel.fg);

visa/include/JitterDataStruct.h

@@ -69,6 +69,9 @@ struct PERF_STATS {
   // Unweighted cycles count estimated by the scheduler.
   uint32_t numCycles = 0;
 
+  // Max register pressure before RA, used for GRF selection
+  uint32_t maxGRFPressurePreRA = 0;
+  // Final max register pressure
   uint32_t maxGRFPressure = 0;
 
   // These fields are currently used by IGC.