Bug fix (eclipse-openj9#19947)

A crash was occuring in Unsafe.get/put() case (6) when trying to modify
the CFG to include the newly generated directAccessBlock. To avoid this,
we can simply append the directAccessTreeTop onto the previous block
(beforeCallBlock), which elimiates the need to update the CFG, since no
new blocks are added. Additionally, without this commit, these two blocks
(in addition to the one after the directAccessBlock, joinBlock), would
get merged during block simplication anyways: so this fix eliminates the
need to perform that optimization later down the line.

Signed-off-by: midronij <[email protected]>

runtime/compiler/optimizer/InlinerTempForJ9.cpp

@@ -1065,17 +1065,8 @@ TR_J9InlinerPolicy::genCodeForUnsafeGetPut(TR::Node* unsafeAddress,
       //SPECIAL CASE
       if (!directAccessWithConversionTreeTop && conversionNeeded)
          {
-         //Generating block for arrayDirectAccess (direct access with conversion)
-         arrayDirectAccessBlock = TR::Block::createEmptyBlock(callNodeTreeTop->getNode(), comp(),
-                                                              joinBlock->getFrequency());
-         arrayDirectAccessBlock->append(arrayDirectAccessTreeTop);
-         beforeCallBlock->getExit()->insertTreeTopsAfterMe(arrayDirectAccessBlock->getEntry(), arrayDirectAccessBlock->getExit());
-
-         //add arrayDirectAccessBlock to cfg
-         cfg->addNode(arrayDirectAccessBlock);
-         cfg->addEdge(TR::CFGEdge::createEdge(beforeCallBlock, arrayDirectAccessBlock, trMemory()));
-         cfg->addEdge(TR::CFGEdge::createEdge(arrayDirectAccessBlock, joinBlock, trMemory()));
-         cfg->removeEdge(beforeCallBlock, joinBlock);
+         //Since no runtime tests are being performed, we can simply append the arrayDirectAccessTreeTop to beforeCallBlock
+         beforeCallBlock->append(arrayDirectAccessTreeTop);
          }
       else
          {
@@ -1093,17 +1084,8 @@ TR_J9InlinerPolicy::genCodeForUnsafeGetPut(TR::Node* unsafeAddress,
       }
    else // CASE (6)
       {
-      //Generating block for direct access
-      directAccessBlock = TR::Block::createEmptyBlock(callNodeTreeTop->getNode(), comp(),
-                                                      joinBlock->getFrequency());
-      directAccessBlock->append(directAccessTreeTop);
-      beforeCallBlock->getExit()->insertTreeTopsAfterMe(directAccessBlock->getEntry(), directAccessBlock->getExit());
-
-      //add directAccessBlock to cfg
-      cfg->addNode(directAccessBlock);
-      cfg->addEdge(TR::CFGEdge::createEdge(beforeCallBlock, directAccessBlock, trMemory()));
-      cfg->addEdge(TR::CFGEdge::createEdge(directAccessBlock, joinBlock, trMemory()));
-      cfg->removeEdge(beforeCallBlock, joinBlock);
+      //Since no runtime tests are being performed, we can simply append the directAccessTreeTop to beforeCallBlock
+      beforeCallBlock->append(directAccessTreeTop);
       }
 
    if (directAccessBlock)