JIT: enable cloning of try regions (#110020)

Add a utility to clone a try region and all associated regions.

Test this by enabling duplication of loops with try regions.

src/coreclr/jit/compiler.h

@@ -2233,7 +2233,9 @@ class FlowGraphNaturalLoop
     bool HasDef(unsigned lclNum);
 
     bool CanDuplicate(INDEBUG(const char** reason));
+    bool CanDuplicateWithEH(INDEBUG(const char** reason));
     void Duplicate(BasicBlock** insertAfter, BlockToBlockMap* map, weight_t weightScale);
+    void DuplicateWithEH(BasicBlock** insertAfter, BlockToBlockMap* map, weight_t weightScale);
 
     bool MayExecuteBlockMultipleTimesPerIteration(BasicBlock* block);
 
@@ -2557,6 +2559,29 @@ struct RelopImplicationInfo
     bool reverseSense = false;
 };
 
+//------------------------------------------------------------------------
+// CloneTryInfo
+//
+// Describes information needed to clone a try region, and information
+// produced by cloning that region
+//
+struct CloneTryInfo
+{
+    CloneTryInfo(Compiler* comp);
+
+    // bbID based traits and vector
+    //
+    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;
+};
+
 /*
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 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
@@ -3001,7 +3026,7 @@ class Compiler
 
     void fgRemoveEHTableEntry(unsigned XTnum);
 
-    EHblkDsc* fgAddEHTableEntry(unsigned XTnum);
+    EHblkDsc* fgTryAddEHTableEntries(unsigned XTnum, unsigned count = 1, bool deferAdding = false);
 
     void fgSortEHTable();
 
@@ -5359,6 +5384,10 @@ class Compiler
 
     PhaseStatus fgCloneFinally();
 
+    bool fgCanCloneTryRegion(BasicBlock* tryEntry);
+
+    BasicBlock* fgCloneTryRegion(BasicBlock* tryEntry, CloneTryInfo& info, BasicBlock** insertAfter = nullptr);
+
     void fgUpdateACDsBeforeEHTableEntryRemoval(unsigned XTnum);
 
     void fgCleanupContinuation(BasicBlock* continuation);
@@ -12264,6 +12293,13 @@ 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