Minor fixes for nullptr checking

Change-Id: I82f38e0cf7c376b56ed37be51346b6ca914e75c1

Author: paigeale

visa/GraphColor.cpp

@@ -5133,9 +5133,11 @@ void GraphColor::createLiveRanges(unsigned reserveSpillSize)
         }
         if (dcl->getIsPartialDcl())
         {
-            G4_Declare * parentDcl = this->gra.getSplittedDeclare(dcl);
-            lrs[var->getId()]->setParentLRID(parentDcl->getRegVar()->getId());
-            lrs[var->getId()]->setIsPartialDcl();
+            if (G4_Declare * parentDcl = this->gra.getSplittedDeclare(dcl))
+            {
+                lrs[var->getId()]->setParentLRID(parentDcl->getRegVar()->getId());
+                lrs[var->getId()]->setIsPartialDcl();
+            }
         }
         if (dcl->getIsSplittedDcl())
         {
@@ -5700,19 +5702,22 @@ bool GraphColor::assignColors(ColorHeuristic colorHeuristicGRF, bool doBankConfl
                 if (varSplitPass.isPartialDcl(lr->getDcl()))
                 {
                     parentDcl = varSplitPass.getParentDcl(lr->getDcl());
-                    auto parentGRF = parentDcl->getRegVar()->getPhyReg();
-                    if (!parentGRF && parentDcl->getRegVar()->isRegAllocPartaker())
-                    {
-                        parentGRF = lrs[parentDcl->getRegVar()->getId()]->getPhyReg();
-                    }
-                    if (parentGRF)
+                    if (parentDcl)
                     {
-                        auto siblingNum = varSplitPass.getSiblingNum(lr->getDcl());
-                        auto parentGRFNum = parentGRF->asGreg()->getRegNum();
-                        auto forbiddenStart = parentGRFNum + ((siblingNum + 1) * lr->getDcl()->getNumRows());
-                        auto forbiddenEnd = parentGRFNum + parentDcl->getNumRows();
-                        lr->markForbidden(forbiddenStart, forbiddenEnd - forbiddenStart);
-                        skipParentIntf = true;
+                        auto parentGRF = parentDcl->getRegVar()->getPhyReg();
+                        if (!parentGRF && parentDcl->getRegVar()->isRegAllocPartaker())
+                        {
+                            parentGRF = lrs[parentDcl->getRegVar()->getId()]->getPhyReg();
+                        }
+                        if (parentGRF)
+                        {
+                            auto siblingNum = varSplitPass.getSiblingNum(lr->getDcl());
+                            auto parentGRFNum = parentGRF->asGreg()->getRegNum();
+                            auto forbiddenStart = parentGRFNum + ((siblingNum + 1) * lr->getDcl()->getNumRows());
+                            auto forbiddenEnd = parentGRFNum + parentDcl->getNumRows();
+                            lr->markForbidden(forbiddenStart, forbiddenEnd - forbiddenStart);
+                            skipParentIntf = true;
+                        }
                     }
                 }
             }

visa/LocalRA.cpp

@@ -2592,6 +2592,9 @@ void LinearScan::expireSplitParent(LocalLiveRange* lr)
     // lr is a partial dcl
     auto parentDcl = varSplit->getParentDcl(lr->getTopDcl());
 
+    if (parentDcl == nullptr)
+        return;
+
     // Now check whether parent in in active set
     LocalLiveRange* parentLR = nullptr;
     for (auto activeLR : active)

visa/VarSplit.cpp

@@ -506,21 +506,23 @@ void VarSplitPass::writeHints(G4_Declare* dcl, LiveRange** lrs)
     else if (isChild)
     {
         // Write hint to parent if its empty
-        auto parentDcl = getParentDcl(dcl);
-        auto idealParentGRF = getIdealAllocation(parentDcl, lrs);
-
-        if (idealParentGRF != 0 && parentDcl->getRegVar()->isRegAllocPartaker())
+        if (auto parentDcl = getParentDcl(dcl))
         {
-            lrs[parentDcl->getRegVar()->getId()]->setAllocHint(idealParentGRF);
-            auto children = getChildren(getParentDcl(dcl));
-            unsigned int i = 0;
-            for (auto child : *children)
+            auto idealParentGRF = getIdealAllocation(parentDcl, lrs);
+
+            if (idealParentGRF != 0 && parentDcl->getRegVar()->isRegAllocPartaker())
             {
-                if (child->getRegVar()->isRegAllocPartaker())
+                lrs[parentDcl->getRegVar()->getId()]->setAllocHint(idealParentGRF);
+                auto children = getChildren(getParentDcl(dcl));
+                unsigned int i = 0;
+                for (auto child : *children)
                 {
-                    lrs[child->getRegVar()->getId()]->setAllocHint(idealParentGRF + (i * child->getNumRows()));
+                    if (child->getRegVar()->isRegAllocPartaker())
+                    {
+                        lrs[child->getRegVar()->getId()]->setAllocHint(idealParentGRF + (i * child->getNumRows()));
+                    }
+                    i++;
                 }
-                i++;
             }
         }
     }
@@ -605,6 +607,10 @@ bool VarSplitPass::reallocParent(G4_Declare* child, LiveRange** lrs)
         return false;
 
     auto parent = getParentDcl(child);
+
+    if (parent == nullptr)
+        return false;
+
     auto children = getChildren(parent);
 
     auto baseRegNum = 0;