JIT: enable cloning of try regions

src/coreclr/jit/compiler.h

@@ -2232,8 +2232,8 @@ class FlowGraphNaturalLoop
 
     bool HasDef(unsigned lclNum);
 
-    bool CanDuplicate(INDEBUG(const char** reason));
-    void Duplicate(BasicBlock** insertAfter, BlockToBlockMap* map, weight_t weightScale);
+    bool CanDuplicate(bool allowEH DEBUGARG(const char** reason));
+    void Duplicate(BasicBlock** insertAfter, BlockToBlockMap* map, weight_t weightScale, bool allowEH);
 
     bool MayExecuteBlockMultipleTimesPerIteration(BasicBlock* block);
 
@@ -3001,7 +3001,7 @@ class Compiler
 
     void fgRemoveEHTableEntry(unsigned XTnum);
 
-    EHblkDsc* fgAddEHTableEntry(unsigned XTnum);
+    EHblkDsc* fgTryAddEHTableEntries(unsigned XTnum, unsigned count = 1, bool deferAdding = false);
 
     void fgSortEHTable();
 
@@ -5358,6 +5358,23 @@ class Compiler
 
     PhaseStatus fgCloneFinally();
 
+    struct CloneTryInfo
+    {
+        CloneTryInfo(BitVecTraits& traits, BitVec& visited) : Traits(traits), Visited(visited) {}
+        BitVecTraits Traits;
+        BitVec& Visited;
+        BlockToBlockMap* Map = nullptr;
+        jitstd::vector<BasicBlock*>* BlocksToClone = nullptr;
+        weight_t ProfileScale = 0.0;
+        unsigned EHIndexShift = 0;
+        bool AddEdges = false;
+        bool ScaleOriginalBlockProfile = false;
+    };
+
+    bool fgCanCloneTryRegion(BasicBlock* tryEntry);
+
+    BasicBlock* fgCloneTryRegion(BasicBlock* tryEntry, CloneTryInfo& info, BasicBlock** insertAfter = nullptr);
+
     void fgCleanupContinuation(BasicBlock* continuation);
 
     PhaseStatus fgTailMergeThrows();
@@ -12260,6 +12277,13 @@ class EHClauses
         assert((m_begin != nullptr) || (m_begin == m_end));
     }
 
+    EHClauses(Compiler* comp, EHblkDsc* begin)
+        : m_begin(begin)
+        , m_end(comp->compHndBBtab + comp->compHndBBtabCount)
+    {
+        assert((m_begin != nullptr) || (m_begin == m_end));
+    }
+
     iterator begin() const
     {
         return iterator(m_begin);

src/coreclr/jit/compmemkind.h

@@ -65,6 +65,7 @@ CompMemKindMacro(EarlyProp)
 CompMemKindMacro(ZeroInit)
 CompMemKindMacro(Pgo)
 CompMemKindMacro(MaskConversionOpt)
+CompMemKindMacro(TryRegionClone)
 //clang-format on
 
 #undef CompMemKindMacro