JIT: Support delegate GDV guards in loop cloning

* Support cloning loops based on delegate GDV guards
* Do flow-graph opts directly in loop cloning instead of relying on RBO
  to clean it up (for both type and delegate GDV)

src/coreclr/jit/compiler.h

@@ -7413,17 +7413,17 @@ class Compiler
         Statement*        stmt;
         const unsigned    loopNum;
         const bool        cloneForArrayBounds;
-        const bool        cloneForTypeTests;
+        const bool        cloneForGDVTests;
         LoopCloneVisitorInfo(LoopCloneContext* context,
                              unsigned          loopNum,
                              Statement*        stmt,
                              bool              cloneForArrayBounds,
-                             bool              cloneForTypeTests)
+                             bool              cloneForGDVTests)
             : context(context)
             , stmt(nullptr)
             , loopNum(loopNum)
             , cloneForArrayBounds(cloneForArrayBounds)
-            , cloneForTypeTests(cloneForTypeTests)
+            , cloneForGDVTests(cloneForGDVTests)
         {
         }
     };
@@ -7437,13 +7437,16 @@ class Compiler
     fgWalkResult optCanOptimizeByLoopCloning(GenTree* tree, LoopCloneVisitorInfo* info);
     bool optObtainLoopCloningOpts(LoopCloneContext* context);
     bool optIsLoopClonable(unsigned loopInd);
+    bool optCheckLoopCloningGDVTestProfitable(GenTreeOp* guard, LoopCloneVisitorInfo* info);
+    bool optIsHandleOrIndirOfHandle(GenTree* tree, GenTreeFlags handleType);
 
     bool optLoopCloningEnabled();
 
 #ifdef DEBUG
     void optDebugLogLoopCloning(BasicBlock* block, Statement* insertBefore);
 #endif
     void optPerformStaticOptimizations(unsigned loopNum, LoopCloneContext* context DEBUGARG(bool fastPath));
+    void optPerformFlowGraphOptimizations(unsigned loopNum, LoopCloneContext* context);
     bool optComputeDerefConditions(unsigned loopNum, LoopCloneContext* context);
     bool optDeriveLoopCloningConditions(unsigned loopNum, LoopCloneContext* context);
     BasicBlock* optInsertLoopChoiceConditions(LoopCloneContext* context,

src/coreclr/jit/indirectcalltransformer.cpp

@@ -546,7 +546,8 @@ class IndirectCallTransformer
             // Create temp for this if the tree is costly.
             if (thisTree->IsLocal())
             {
-                thisTree = compiler->gtCloneExpr(thisTree);
+                thisTree       = compiler->gtCloneExpr(thisTree);
+                LclVarDsc* dsc = compiler->lvaGetDesc(thisTree->AsLclVarCommon());
             }
             else
             {
@@ -594,7 +595,7 @@ class IndirectCallTransformer
                 // TODO-GDV: Consider duplicating the store at the end of the
                 // cold case for the previous GDV. Then we can reuse the target
                 // if the second check of a chained GDV fails.
-                bool reuseTarget = (origCall->gtCallMoreFlags & GTF_CALL_M_GUARDED_DEVIRT_CHAIN) == 0;
+                bool reuseTarget = false; //(origCall->gtCallMoreFlags & GTF_CALL_M_GUARDED_DEVIRT_CHAIN) == 0;
                 if (origCall->IsVirtualVtable())
                 {
                     GenTree* tarTree = compiler->fgExpandVirtualVtableCallTarget(origCall);

src/coreclr/jit/jitconfigvalues.h

@@ -41,8 +41,8 @@ CONFIG_INTEGER(JitBreakOnBadCode, W("JitBreakOnBadCode"), 0)
 CONFIG_INTEGER(JitBreakOnMinOpts, W("JITBreakOnMinOpts"), 0) // Halt if jit switches to MinOpts
 CONFIG_INTEGER(JitBreakOnUnsafeCode, W("JitBreakOnUnsafeCode"), 0)
 CONFIG_INTEGER(JitCloneLoops, W("JitCloneLoops"), 1) // If 0, don't clone. Otherwise clone loops for optimizations.
-CONFIG_INTEGER(JitCloneLoopsWithTypeTests, W("JitCloneLoopsWithTypeTests"), 1) // If 0, don't clone loops based on
-                                                                               // invariant type tests
+CONFIG_INTEGER(JitCloneLoopsWithGdvTests, W("JitCloneLoopsWithGdvTests"), 1) // If 0, don't clone loops based on
+                                                                             // invariant type/method address tests
 CONFIG_INTEGER(JitDebugLogLoopCloning, W("JitDebugLogLoopCloning"), 0) // In debug builds log places where loop cloning
                                                                        // optimizations are performed on the fast path.
 CONFIG_INTEGER(JitDefaultFill, W("JitDefaultFill"), 0xdd) // In debug builds, initialize the memory allocated by the nra