Make edgeWeightGRF faster

edgeWeightGRF() is a hot method as per VTune profile. For large
tests with subroutines, the function consumed about 8% of total compile time.

In this change, we breakup edgeWeightGRF() method so that static version in header is devoid of direct memory accesses on objects and can be easily inlined in simplification phase.

This brings ~3% reduction in total compile time for large tests.

Author: pratikashar

visa/GraphColor.cpp

@@ -5360,12 +5360,17 @@ void GraphColor::computeSpillCosts(bool useSplitLLRHeuristic, const RPE *rpe) {
 void GraphColor::relaxNeighborDegreeGRF(LiveRange *lr) {
   if (!(lr->getIsPseudoNode()) && !(lr->getIsPartialDcl())) {
     unsigned lr_id = lr->getVar()->getId();
+    bool lr2EvenAlign = gra.isEvenAligned(lr->getDcl());
+    unsigned lr2_nreg = lr->getNumRegNeeded();
 
     // relax degree between 2 nodes
     auto relaxDegree = [&](LiveRange *lr1) {
       if (lr1->getActive() && !lr1->getIsPseudoNode() &&
           !(lr1->getIsPartialDcl())) {
-        unsigned w = edgeWeightGRF(lr1, lr);
+        bool lr1EvenAlign = gra.isEvenAligned(lr1->getDcl());
+        unsigned lr1_nreg = lr1->getNumRegNeeded();
+        unsigned w =
+            edgeWeightGRF(lr1EvenAlign, lr2EvenAlign, lr1_nreg, lr2_nreg);
         VISA_DEBUG_VERBOSE({
           std::cout << "\t relax ";
           lr1->dump();
@@ -10623,23 +10628,11 @@ void GlobalRA::insertRestoreAddr(G4_BB *bb) {
 //
 unsigned GraphColor::edgeWeightGRF(const LiveRange *lr1, const LiveRange *lr2) {
   bool lr1EvenAlign = gra.isEvenAligned(lr1->getDcl());
+  bool lr2EvenAlign = gra.isEvenAligned(lr2->getDcl());
   unsigned lr1_nreg = lr1->getNumRegNeeded();
   unsigned lr2_nreg = lr2->getNumRegNeeded();
 
-  if (!lr1EvenAlign) {
-    return lr1_nreg + lr2_nreg - 1;
-  }
-
-  bool lr2EvenAlign = gra.isEvenAligned(lr2->getDcl());
-  if (!lr2EvenAlign) {
-    unsigned sum = lr1_nreg + lr2_nreg;
-    return sum + 1 - ((sum) % 2);
-  } else if (lr2EvenAlign) {
-    return lr1_nreg + lr2_nreg - 1 + (lr1_nreg % 2) + (lr2_nreg % 2);
-  } else {
-    vISA_ASSERT_UNREACHABLE("should be unreachable");
-    return 0;
-  }
+  return edgeWeightGRF(lr1EvenAlign, lr2EvenAlign, lr1_nreg, lr2_nreg);
 }
 
 unsigned GraphColor::edgeWeightARF(const LiveRange *lr1, const LiveRange *lr2) {

visa/GraphColor.h

@@ -887,6 +887,22 @@ class GraphColor {
 
   unsigned edgeWeightGRF(const LiveRange *lr1, const LiveRange *lr2);
   unsigned edgeWeightARF(const LiveRange *lr1, const LiveRange *lr2);
+  static unsigned edgeWeightGRF(bool lr1EvenAlign, bool lr2EvenAlign,
+                                unsigned lr1_nreg, unsigned lr2_nreg) {
+    if (!lr1EvenAlign) {
+      return lr1_nreg + lr2_nreg - 1;
+    }
+
+    if (!lr2EvenAlign) {
+      unsigned sum = lr1_nreg + lr2_nreg;
+      return sum + 1 - ((sum) % 2);
+    } else if (lr2EvenAlign) {
+      return lr1_nreg + lr2_nreg - 1 + (lr1_nreg % 2) + (lr2_nreg % 2);
+    } else {
+      vISA_ASSERT_UNREACHABLE("should be unreachable");
+      return 0;
+    }
+  }
 
   void computeDegreeForGRF();
   void computeDegreeForARF();