Fixed null dereference errors in SimdCF passes

Fixed null dereference errors in GenXSimdCFConformance and GenXSimdCFRegion

Author: fveselov

IGC/VectorCompiler/lib/GenXCodeGen/GenXSimdCFConformance.cpp

@@ -4130,11 +4130,12 @@ void GenXLateSimdCFConformance::hoistExtractEMInstructions() {
       else {
         ToRemove.push_back(V);
         V->replaceAllUsesWith(It->second);
-        V->eraseFromParent();
       }
     }
-  for (auto &&V : ToRemove)
+  for (auto &&V : ToRemove) {
     removeFromEMRMVals(V);
+    V->eraseFromParent();
+  }
 }
 
 /***********************************************************************

IGC/VectorCompiler/lib/GenXCodeGen/GenXSimdCFRegion.cpp

@@ -1180,11 +1180,11 @@ void GenXPredToSimdCF::insertIfGotoJoin(SimdCFIfRegion *R) {
   if (R->hasElse()) {
     auto *ElseExit = R->getIfThenRegion()->getExit();
     Br = cast<BranchInst>(ElseExit->getTerminator());
+    auto *IfEndBB = IfThenExitBr->getSuccessor(1);
     // 1-th: generate goto(EM, zeroinitializer, zeroinitializer) in the end of
     // then-block
     generateThenGoto(Br, JoinBlock);
 
-    auto *IfEndBB = IfThenExitBr->getSuccessor(1);
     for (auto &PHI : IfEndBB->phis()) {
       PHI.replaceIncomingBlockWith(IfThenExit, JoinBlock);
     }