Do not recost and rethread trees inside optRemoveRangeCheck

src/coreclr/jit/compiler.h

@@ -5497,7 +5497,6 @@ class Compiler
     GenTree* fgInsertCommaFormTemp(GenTree** ppTree, CORINFO_CLASS_HANDLE structType = nullptr);
     GenTree* fgMakeMultiUse(GenTree** ppTree, CORINFO_CLASS_HANDLE structType = nullptr);
 
-private:
     //                  Recognize a bitwise rotation pattern and convert into a GT_ROL or a GT_ROR node.
     GenTree* fgRecognizeAndMorphBitwiseRotation(GenTree* tree);
     bool fgOperIsBitwiseRotationRoot(genTreeOps oper);
@@ -5509,8 +5508,11 @@ class Compiler
 #endif
 
     //-------- Determine the order in which the trees will be evaluated -------
-    GenTree* fgSetTreeSeq(GenTree* tree, bool isLIR = false);
+public:
     void fgSetStmtSeq(Statement* stmt);
+
+private:
+    GenTree* fgSetTreeSeq(GenTree* tree, bool isLIR = false);
     void fgSetBlockOrder(BasicBlock* block);
 
     //------------------------- Morphing --------------------------------------

src/coreclr/jit/optimizer.cpp

@@ -8107,10 +8107,12 @@ void Compiler::AddModifiedElemTypeAllContainingLoops(unsigned lnum, CORINFO_CLAS
 // Return Value:
 //    Rewritten "check" - no-op if it has no side effects or the tree that contains them.
 //
-// Assumptions:
-//    This method is capable of removing checks of two kinds: COMMA-based and standalone top-level ones.
-//    In case of a COMMA-based check, "check" must be a non-null first operand of a non-null COMMA.
-//    In case of a standalone check, "comma" must be null and "check" - "stmt"'s root.
+// Notes:
+//    This method is capable of removing checks of two kinds: COMMA-based and standalone top-level
+//    ones. In case of a COMMA-based check, "check" must be a non-null first operand of a non-null
+//    COMMA. In case of a standalone check, "comma" must be null and "check" - "stmt"'s root.
+//
+//    Does not keep costs or node threading up to date, but does update side effect flags.
 //
 GenTree* Compiler::optRemoveRangeCheck(GenTreeBoundsChk* check, GenTree* comma, Statement* stmt)
 {
@@ -8165,15 +8167,6 @@ GenTree* Compiler::optRemoveRangeCheck(GenTreeBoundsChk* check, GenTree* comma,
 
     gtUpdateSideEffects(stmt, tree);
 
-    // Recalculate the GetCostSz(), etc...
-    gtSetStmtInfo(stmt);
-
-    // Re-thread the nodes if necessary
-    if (fgStmtListThreaded)
-    {
-        fgSetStmtSeq(stmt);
-    }
-
 #ifdef DEBUG
     if (verbose)
     {

src/coreclr/jit/rangecheck.cpp

@@ -24,6 +24,7 @@ RangeCheck::RangeCheck(Compiler* pCompiler)
     , m_pCompiler(pCompiler)
     , m_alloc(pCompiler->getAllocator(CMK_RangeCheck))
     , m_nVisitBudget(MAX_VISIT_BUDGET)
+    , m_updateStmt(false)
 {
 }
 
@@ -255,6 +256,7 @@ void RangeCheck::OptimizeRangeCheck(BasicBlock* block, Statement* stmt, GenTree*
         {
             JITDUMP("Removing range check\n");
             m_pCompiler->optRemoveRangeCheck(bndsChk, comma, stmt);
+            m_updateStmt = true;
             return;
         }
     }
@@ -296,8 +298,8 @@ void RangeCheck::OptimizeRangeCheck(BasicBlock* block, Statement* stmt, GenTree*
     {
         JITDUMP("[RangeCheck::OptimizeRangeCheck] Between bounds\n");
         m_pCompiler->optRemoveRangeCheck(bndsChk, comma, stmt);
+        m_updateStmt = true;
     }
-    return;
 }
 
 void RangeCheck::Widen(BasicBlock* block, GenTree* tree, Range* pRange)
@@ -1545,14 +1547,23 @@ void RangeCheck::OptimizeRangeChecks()
     {
         for (Statement* const stmt : block->Statements())
         {
+            m_updateStmt = false;
+
             for (GenTree* const tree : stmt->TreeList())
             {
-                if (IsOverBudget())
+                if (IsOverBudget() && !m_updateStmt)
                 {
                     return;
                 }
+
                 OptimizeRangeCheck(block, stmt, tree);
             }
+
+            if (m_updateStmt)
+            {
+                m_pCompiler->gtSetStmtInfo(stmt);
+                m_pCompiler->fgSetStmtSeq(stmt);
+            }
         }
     }
 }

src/coreclr/jit/rangecheck.h

@@ -650,4 +650,7 @@ class RangeCheck
     // The number of nodes for which range is computed throughout the current method.
     // When this limit is zero, we have exhausted all the budget to walk the ud-chain.
     int m_nVisitBudget;
+
+    // Set to "true" whenever we remove a check and need to re-thread the statement.
+    bool m_updateStmt;
 };