Re-schedule only when option ForceGRFModeUp is set.

Author: jfuentes

visa/G4_Kernel.cpp

@@ -2178,8 +2178,7 @@ GRFMode::GRFMode(const TARGET_PLATFORM platform, Options *op) : options(op) {
 unsigned GRFMode::setModeByRegPressure(unsigned maxRP, unsigned largestInputReg,
                                        bool forceGRFModeUp) {
   unsigned size = configs.size(), i = 0;
-  bool spillAllowed = 0;
-  spillAllowed = options->getuInt32Option(vISA_SpillAllowed) > 256;
+  bool spillAllowed = options->getuInt32Option(vISA_SpillAllowed) > 256;
   // find appropiate GRF based on reg pressure
   for (; i < size; i++) {
     if (configs[i].VRTEnable && configs[i].numGRF >= lowerBoundGRF &&

visa/Optimizer.h

@@ -159,8 +159,11 @@ class Optimizer {
     if (kernel.useAutoGRFSelection()) {
       unsigned InitialGRFNumber = kernel.getNumRegTotal();
       Sched.runWithGRFSelection(KernelPressure);
-      if (InitialGRFNumber != kernel.getNumRegTotal())
+      if (kernel.getuInt32Option(vISA_ForceGRFModeUp) > 0 &&
+          InitialGRFNumber != kernel.getNumRegTotal()) {
+        // Only re-schedule when ForceGRFModeUP is set
         Sched.run(KernelPressure);
+      }
     } else {
       Sched.run(KernelPressure);
     }