LNV bug fix

Lvn bug fix

Author: bcheng0127

visa/Passes/LVN.cpp

@@ -200,6 +200,11 @@ bool LVN::canReplaceUses(INST_LIST_ITER inst_it, UseList &uses,
       break;
     }
 
+    if (opndNum == Opnd_pred || opndNum == Opnd_condMod) {
+      canReplace = false;
+      break;
+    }
+
     if (!bb->isAllLaneActive()) {
       auto defCoversUseEmask =
           defInst->getMaskOffset() <= useInst->getMaskOffset() &&
@@ -1430,6 +1435,10 @@ void LVN::addUse(G4_DstRegRegion *dst, G4_INST *use, unsigned int srcIndex) {
     srcPos = Opnd_src1;
   } else if (srcIndex == 2) {
     srcPos = Opnd_src2;
+  } else if (srcIndex == 3) {
+    srcPos = Opnd_pred;
+  } else if (srcIndex == 4) {
+    srcPos = Opnd_condMod;
   }
 
   UseInfo useInst = {use, srcPos};
@@ -1443,6 +1452,10 @@ void LVN::addUse(G4_DstRegRegion *dst, G4_INST *use, unsigned int srcIndex) {
     (*it).second.push_back(useInst);
   }
 
+  if (srcIndex > 3) {
+    return;
+  }
+
   auto srcOpnd = use->getSrc(srcIndex);
   auto itUD = useDef.find(srcOpnd);
   if (itUD == useDef.end()) {
@@ -1465,6 +1478,16 @@ void LVN::removeAddrTaken(G4_AddrExp *opnd) {
   }
 }
 
+void LVN::removeFlag(G4_Declare *topDcl) {
+  auto range_it = activeDefs.equal_range(topDcl->getDeclId());
+  for (auto it = range_it.first; it != range_it.second;) {
+    auto prev_it = it;
+    (*prev_it).second.second->getInst()->removeAllUses();
+    it++;
+    activeDefs.erase(prev_it);
+  }
+}
+
 void LVN::populateDuTable(INST_LIST_ITER inst_it) {
   duTablePopulated = true;
   // Populate duTable from inst_it position
@@ -1612,6 +1635,48 @@ void LVN::populateDuTable(INST_LIST_ITER inst_it) {
         }
       }
     }
+    G4_CondMod *condMod = curInst->getCondMod();
+    if (condMod && condMod->getBase() && condMod->getBase()->isRegVar()) {
+      G4_Declare *condDcl = condMod->getTopDcl();
+      if (condDcl && condDcl->getRegVar()->isFlag()) {
+        auto range_it = activeDefs.equal_range(condDcl->getDeclId());
+        if (range_it.first != range_it.second) {
+          auto start_it = range_it.second;
+          start_it--;
+          for (auto it = start_it;;) {
+            G4_DstRegRegion *activeDst = (*it).second.second;
+            addUse(activeDst, curInst, 4);
+            if (it == range_it.first) {
+              // Last match reached
+              break;
+            }
+            it--;
+          }
+        }
+        removeFlag(condDcl);
+      }
+    }
+
+    G4_Predicate *predicate = curInst->getPredicate();
+    if (predicate && predicate->getBase() && predicate->getBase()->isRegVar()) {
+      G4_Declare *predDcl = predicate->getTopDcl();
+      if (predDcl && predDcl->getRegVar()->isFlag()) {
+        auto range_it = activeDefs.equal_range(predDcl->getDeclId());
+        if (range_it.first != range_it.second) {
+          auto start_it = range_it.second;
+          start_it--;
+          for (auto it = start_it;;) {
+            G4_DstRegRegion *activeDst = (*it).second.second;
+            addUse(activeDst, curInst, 3);
+            if (it == range_it.first) {
+              // Last match reached
+              break;
+            }
+            it--;
+          }
+        }
+      }
+    }
 
     inst_it++;
   }

visa/Passes/LVN.hpp

@@ -120,6 +120,7 @@ class LVN {
 
   void populateDuTable(INST_LIST_ITER inst_it);
   void removeAddrTaken(G4_AddrExp *opnd);
+  void removeFlag(G4_Declare *topDck);
   void addUse(G4_DstRegRegion *dst, G4_INST *use, unsigned int srcIndex);
   void addValueToTable(G4_INST *inst, Value &oldValue);
   LVNItemInfo *isValueInTable(Value &value, bool negate);