use static const unsigned Done instead of -1 int.

src/jit/assertionprop.cpp

@@ -169,7 +169,7 @@ void Compiler::optAddCopies()
         bool isDominatedByFirstBB = false;
 
         BlockSetOps::Iter iter(this, varDsc->lvRefBlks);
-        for (int blkNum = iter.NextElem(); blkNum != -1; blkNum = iter.NextElem())
+        for (int blkNum = iter.NextElem(); blkNum != BlockSetOps::Iter::Done; blkNum = iter.NextElem())
         {
             /* Find the block 'blkNum' */
             BasicBlock* block = fgFirstBB;
@@ -322,7 +322,7 @@ void Compiler::optAddCopies()
             /* We have already calculated paramImportantUseDom above. */
 
             BlockSetOps::Iter iter(this, paramImportantUseDom);
-            for (int blkNum = iter.NextElem(); blkNum != -1; blkNum = iter.NextElem())
+            for (int blkNum = iter.NextElem(); blkNum != BlockSetOps::Iter::Done; blkNum = iter.NextElem())
             {
                 /* Advance block to point to 'blkNum' */
                 /* This assumes that the iterator returns block number is increasing lexical order. */
@@ -2852,7 +2852,7 @@ GenTreePtr Compiler::optAssertionProp_LclVar(ASSERT_VALARG_TP assertions, const
     }
 
     BitVecOps::Iter iter(apTraits, assertions);
-    for (int i = iter.NextElem(); i != -1; i = iter.NextElem())
+    for (int i = iter.NextElem(); i != BitVecOps::Iter::Done; i = iter.NextElem())
     {
         AssertionIndex index = GetAssertionIndex(i);
         if (index > optAssertionCount)
@@ -2971,7 +2971,7 @@ AssertionIndex Compiler::optGlobalAssertionIsEqualOrNotEqual(ASSERT_VALARG_TP as
         return NO_ASSERTION_INDEX;
     }
     BitVecOps::Iter iter(apTraits, assertions);
-    for (int i = iter.NextElem(); i != -1; i = iter.NextElem())
+    for (int i = iter.NextElem(); i != BitVecOps::Iter::Done; i = iter.NextElem())
     {
         AssertionIndex index = GetAssertionIndex(i);
         if (index > optAssertionCount)
@@ -3531,7 +3531,7 @@ AssertionIndex Compiler::optAssertionIsNonNullInternal(GenTreePtr op, ASSERT_VAL
 
         // Check each assertion to find if we have a vn == or != null assertion.
         BitVecOps::Iter iter(apTraits, assertions);
-        for (int i = iter.NextElem(); i != -1; i = iter.NextElem())
+        for (int i = iter.NextElem(); i != BitVecOps::Iter::Done; i = iter.NextElem())
         {
             AssertionIndex index = GetAssertionIndex(i);
             if (index > optAssertionCount)
@@ -3704,7 +3704,7 @@ GenTreePtr Compiler::optAssertionProp_BndsChk(ASSERT_VALARG_TP assertions, const
 #endif // FEATURE_ENABLE_NO_RANGE_CHECKS
 
     BitVecOps::Iter iter(apTraits, assertions);
-    for (int i = iter.NextElem(); i != -1; i = iter.NextElem())
+    for (int i = iter.NextElem(); i != BitVecOps::Iter::Done; i = iter.NextElem())
     {
         AssertionIndex index = GetAssertionIndex(i);
         if (index > optAssertionCount)
@@ -3956,7 +3956,7 @@ void Compiler::optImpliedAssertions(AssertionIndex assertionIndex, ASSERT_TP& ac
 
         // Check each assertion in chkAssertions to see if it can be applied to curAssertion
         BitVecOps::Iter chkIter(apTraits, chkAssertions);
-        for (int i = chkIter.NextElem(); i != -1; i = chkIter.NextElem())
+        for (int i = chkIter.NextElem(); i != BitVecOps::Iter::Done; i = chkIter.NextElem())
         {
             AssertionIndex chkIndex = GetAssertionIndex(i);
             if (chkIndex > optAssertionCount)
@@ -4004,7 +4004,7 @@ void Compiler::optImpliedByTypeOfAssertions(ASSERT_TP& activeAssertions)
 
     // Check each assertion in activeAssertions to see if it can be applied to constAssertion
     BitVecOps::Iter chkIter(apTraits, activeAssertions);
-    for (int i = chkIter.NextElem(); i != -1; i = chkIter.NextElem())
+    for (int i = chkIter.NextElem(); i != BitVecOps::Iter::Done; i = chkIter.NextElem())
     {
         AssertionIndex chkIndex = GetAssertionIndex(i);
         if (chkIndex > optAssertionCount)
@@ -4100,7 +4100,7 @@ void Compiler::optImpliedByConstAssertion(AssertionDsc* constAssertion, ASSERT_T
 
     // Check each assertion in chkAssertions to see if it can be applied to constAssertion
     BitVecOps::Iter chkIter(apTraits, chkAssertions);
-    for (int i = chkIter.NextElem(); i != -1; i = chkIter.NextElem())
+    for (int i = chkIter.NextElem(); i != BitVecOps::Iter::Done; i = chkIter.NextElem())
     {
         AssertionIndex chkIndex = GetAssertionIndex(i);
         if (chkIndex > optAssertionCount)

src/jit/bitset.cpp

@@ -38,7 +38,7 @@ void BitSetSupport::RunTests(Env env)
 
     typename LclBitSetOps::Iter bsi(env, bs1);
     unsigned                    k = 0;
-    for (int bitNum = bsi.NextElem(); bitNum != -1; bitNum = bsi.NextElem())
+    for (int bitNum = bsi.NextElem(); bitNum != LclBitSetOps::Iter::Done; bitNum = bsi.NextElem())
     {
         assert(bitNum == bs1bits[k]);
         k++;
@@ -62,7 +62,7 @@ void BitSetSupport::RunTests(Env env)
     LclBitSetOps::AssignNoCopy(env, bsU12, LclBitSetOps::Union(env, bs1, bs2));
     k   = 0;
     bsi = typename LclBitSetOps::Iter(env, bsU12);
-    for (int bitNum = bsi.NextElem(); bitNum != -1; bitNum = bsi.NextElem())
+    for (int bitNum = bsi.NextElem(); bitNum != LclBitSetOps::Iter::Done; bitNum = bsi.NextElem())
     {
         assert(bitNum == unionBits[k]);
         k++;
@@ -71,7 +71,7 @@ void BitSetSupport::RunTests(Env env)
 
     k                                = 0;
     typename LclBitSetOps::Iter bsiL = typename LclBitSetOps::Iter(env, bsU12);
-    for (int bitNum = bsi.NextElem(); bitNum != -1; bitNum = bsi.NextElem())
+    for (int bitNum = bsi.NextElem(); bitNum != LclBitSetOps::Iter::Done; bitNum = bsi.NextElem())
     {
         assert(bitNum == unionBits[k]);
         k++;
@@ -83,7 +83,7 @@ void BitSetSupport::RunTests(Env env)
     LclBitSetOps::AssignNoCopy(env, bsI12, LclBitSetOps::Intersection(env, bs1, bs2));
     k   = 0;
     bsi = typename LclBitSetOps::Iter(env, bsI12);
-    for (int bitNum = bsi.NextElem(); bitNum != -1; bitNum = bsi.NextElem())
+    for (int bitNum = bsi.NextElem(); bitNum != LclBitSetOps::Iter::Done; bitNum = bsi.NextElem())
     {
         assert(bitNum == intersectionBits[k]);
         k++;

src/jit/bitset.h

@@ -147,8 +147,9 @@ FORCEINLINE unsigned BitSetSupport::CountBitsInIntegral<unsigned>(unsigned c)
 // In addition to implementing the method signatures here, an instantiation of BitSetOps must also export a
 // BitSetOps::Iter type, which supports the following operations:
 //      Iter(BitSetValueArgType):        a constructor
-//      int NextElem():  returns the next yielded member if the iteration is not complete,
-//                       or returns -1 if it is.
+//      unsigned NextElem():  returns the next yielded member if the iteration is not complete,
+//                       or returns Done if it is.
+//      static const unsigned Done = (unsigned)-1;
 //
 // Finally, it should export two further types:
 //
@@ -279,7 +280,8 @@ class BitSetOps
     class Iter {
       public:
         Iter(Env env, BitSetValueArgType bs) {}
-        int NextElem() { return -1; }
+        static const unsigned Done = (unsigned)-1;
+        unsigned NextElem() { return Done; }
     };
 
     typename ValArgType;
@@ -451,7 +453,9 @@ class BitSetOpsWithCounter
         {
         }
 
-        int NextElem()
+        static const unsigned Done = (unsigned)-1;
+
+        unsigned NextElem()
         {
             BitSetTraits::GetOpCounter(m_env)->RecordOp(BitSetSupport::BSOP_NextBit);
             return m_iter.NextElem();

src/jit/bitsetasshortlong.h

@@ -495,7 +495,9 @@ class BitSetOps</*BitSetType*/ BitSetShortLongRep,
             }
         }
 
-        int NextElem()
+        static const unsigned Done = (unsigned)-1;
+
+        unsigned NextElem()
         {
 #if BITSET_TRACK_OPCOUNTS
             BitSetStaticsImpl::RecordOp(BitSetStaticsImpl::BSOP_NextBit);

src/jit/bitsetasuint64.h

@@ -225,7 +225,9 @@ class BitSetOps</*BitSetType*/ UINT64,
         {
         }
 
-        int NextElem()
+        static const unsigned Done = (unsigned)-1;
+
+        unsigned NextElem()
         {
             // TODO-Throughtput: use BitScanForward64() intrinsic (see short/long implementation).
             if (m_bits)
@@ -242,7 +244,7 @@ class BitSetOps</*BitSetType*/ UINT64,
             }
             else
             {
-                return -1;
+                return Done;
             }
         }
     };

src/jit/bitsetasuint64inclass.h

@@ -471,7 +471,9 @@ class BitSetOps</*BitSetType*/ BitSetUint64<Env, BitSetTraits>,
         {
         }
 
-        int NextElem()
+        static const unsigned Done = (unsigned)-1;
+
+        unsigned NextElem()
         {
             static const unsigned UINT64_SIZE = 64;
 
@@ -500,7 +502,7 @@ class BitSetOps</*BitSetType*/ BitSetUint64<Env, BitSetTraits>,
                 }
                 else
                 {
-                    return -1;
+                    return Done;
                 }
             }
         }

src/jit/codegencommon.cpp

@@ -1100,7 +1100,8 @@ void Compiler::compChangeLife(VARSET_VALARG_TP newLife DEBUGARG(GenTreePtr tree)
     // This is because, in the RyuJIT backend case, they may occupy registers that
     // will be occupied by another var that is newly live.
     VarSetOps::Iter deadIter(this, deadSet);
-    for (int deadVarIndex = deadIter.NextElem(); deadVarIndex != -1; deadVarIndex = deadIter.NextElem())
+    for (int deadVarIndex = deadIter.NextElem(); deadVarIndex != VarSetOps::Iter::Done;
+         deadVarIndex     = deadIter.NextElem())
     {
         unsigned varNum = lvaTrackedToVarNum[deadVarIndex];
         varDsc          = lvaTable + varNum;
@@ -1135,7 +1136,8 @@ void Compiler::compChangeLife(VARSET_VALARG_TP newLife DEBUGARG(GenTreePtr tree)
     }
 
     VarSetOps::Iter bornIter(this, bornSet);
-    for (int bornVarIndex = bornIter.NextElem(); bornVarIndex != -1; bornVarIndex = bornIter.NextElem())
+    for (int bornVarIndex = bornIter.NextElem(); bornVarIndex != VarSetOps::Iter::Done;
+         bornVarIndex     = bornIter.NextElem())
     {
         unsigned varNum = lvaTrackedToVarNum[bornVarIndex];
         varDsc          = lvaTable + varNum;
@@ -1305,7 +1307,7 @@ regMaskTP CodeGenInterface::genLiveMask(VARSET_VALARG_TP liveSet)
     regMaskTP liveMask = 0;
 
     VarSetOps::Iter iter(compiler, liveSet);
-    for (int varIndex = iter.NextElem(); varIndex != -1; varIndex = iter.NextElem())
+    for (int varIndex = iter.NextElem(); varIndex != VarSetOps::Iter::Done; varIndex = iter.NextElem())
     {
 
         // If the variable is not enregistered, then it can't contribute to the liveMask

src/jit/codegenlegacy.cpp

@@ -53,7 +53,7 @@ void CodeGen::genDyingVars(VARSET_VALARG_TP beforeSet, VARSET_VALARG_TP afterSet
     /* iterate through the dead variables */
 
     VarSetOps::Iter iter(compiler, deadSet);
-    for (int varIndex = iter.NextElem(); varIndex != -1; varIndex = iter.NextElem())
+    for (int varIndex = iter.NextElem(); varIndex != VarSetOps::Iter::Done; varIndex = iter.NextElem())
     {
         varNum = compiler->lvaTrackedToVarNum[varIndex];
         varDsc = compiler->lvaTable + varNum;
@@ -5632,7 +5632,7 @@ void CodeGen::genCodeForQmark(GenTreePtr tree, regMaskTP destReg, regMaskTP best
             VARSET_TP regVarLiveNow(VarSetOps::Intersection(compiler, compiler->raRegVarsMask, rsLiveNow));
 
             VarSetOps::Iter iter(compiler, regVarLiveNow);
-            for (int varIndex = iter.NextElem(); varIndex != -1; varIndex = iter.NextElem())
+            for (int varIndex = iter.NextElem(); varIndex != VarSetOps::Iter::Done; varIndex = iter.NextElem())
             {
                 // Find the variable in compiler->lvaTable
                 unsigned   varNum = compiler->lvaTrackedToVarNum[varIndex];
@@ -12580,7 +12580,7 @@ void CodeGen::genCodeForBBlist()
         noway_assert((specialUseMask & regSet.rsMaskVars) == 0);
 
         VarSetOps::Iter iter(compiler, liveSet);
-        for (int varIndex = iter.NextElem(); varIndex != -1; varIndex = iter.NextElem())
+        for (int varIndex = iter.NextElem(); varIndex != VarSetOps::Iter::Done; varIndex = iter.NextElem())
         {
             varNum = compiler->lvaTrackedToVarNum[varIndex];
             varDsc = compiler->lvaTable + varNum;
@@ -15238,7 +15238,7 @@ unsigned CodeGen::genRegCountForLiveIntEnregVars(GenTreePtr tree)
     unsigned regCount = 0;
 
     VarSetOps::Iter iter(compiler, compiler->compCurLife);
-    for (int varIndex = iter.NextElem(); varIndex != -1; varIndex = iter.NextElem())
+    for (int varIndex = iter.NextElem(); varIndex != VarSetOps::Iter::Done; varIndex = iter.NextElem())
     {
         unsigned   lclNum = compiler->lvaTrackedToVarNum[varIndex];
         LclVarDsc* varDsc = &compiler->lvaTable[lclNum];

src/jit/codegenlinear.cpp

@@ -170,7 +170,7 @@ void CodeGen::genCodeForBBlist()
         VARSET_TP addedGCVars(VarSetOps::MakeEmpty(compiler));
 #endif
         VarSetOps::Iter iter(compiler, block->bbLiveIn);
-        for (int varIndex = iter.NextElem(); varIndex != -1; varIndex = iter.NextElem())
+        for (int varIndex = iter.NextElem(); varIndex != VarSetOps::Iter::Done; varIndex = iter.NextElem())
         {
             unsigned   varNum = compiler->lvaTrackedToVarNum[varIndex];
             LclVarDsc* varDsc = &(compiler->lvaTable[varNum]);
@@ -502,7 +502,7 @@ void CodeGen::genCodeForBBlist()
         VARSET_TP extraLiveVars(VarSetOps::Diff(compiler, block->bbLiveOut, compiler->compCurLife));
         VarSetOps::UnionD(compiler, extraLiveVars, VarSetOps::Diff(compiler, compiler->compCurLife, block->bbLiveOut));
         VarSetOps::Iter extraLiveVarIter(compiler, extraLiveVars);
-        for (int i = extraLiveVarIter.NextElem(); i != -1; i = extraLiveVarIter.NextElem())
+        for (int i = extraLiveVarIter.NextElem(); i != VarSetOps::Iter::Done; i = extraLiveVarIter.NextElem())
         {
             unsigned   varNum = compiler->lvaTrackedToVarNum[i];
             LclVarDsc* varDsc = compiler->lvaTable + varNum;

src/jit/compiler.cpp

@@ -8298,7 +8298,7 @@ void dumpConvertedVarSet(Compiler* comp, VARSET_VALARG_TP vars)
     memset(pVarNumSet, 0, varNumSetBytes); // empty the set
 
     VarSetOps::Iter iter(comp, vars);
-    for (int i = iter.NextElem(); i != -1; i = iter.NextElem())
+    for (int i = iter.NextElem(); i != VarSetOps::Iter::Done; i = iter.NextElem())
     {
         unsigned varNum = comp->lvaTrackedToVarNum[i];
         assert(varNum < comp->lvaCount);

src/jit/flowgraph.cpp

@@ -1936,7 +1936,7 @@ void Compiler::fgComputeEnterBlocksSet()
     {
         printf("Enter blocks: ");
         BlockSetOps::Iter iter(this, fgEnterBlks);
-        for (int bbNum = iter.NextElem(); bbNum != -1; bbNum = iter.NextElem())
+        for (int bbNum = iter.NextElem(); bbNum != BlockSetOps::Iter::Done; bbNum = iter.NextElem())
         {
             printf("BB%02u ", bbNum);
         }
@@ -2286,7 +2286,7 @@ BlockSet_ValRet_T Compiler::fgDomFindStartNodes()
     {
         printf("\nDominator computation start blocks (those blocks with no incoming edges):\n");
         BlockSetOps::Iter iter(this, startNodes);
-        for (int bbNum = iter.NextElem(); bbNum != -1; bbNum = iter.NextElem())
+        for (int bbNum = iter.NextElem(); bbNum != BlockSetOps::Iter::Done; bbNum = iter.NextElem())
         {
             printf("BB%02u ", bbNum);
         }
@@ -19597,7 +19597,7 @@ void Compiler::fgDispReach()
     {
         printf("BB%02u : ", block->bbNum);
         BlockSetOps::Iter iter(this, block->bbReach);
-        for (int bbNum = iter.NextElem(); bbNum != -1; bbNum = iter.NextElem())
+        for (int bbNum = iter.NextElem(); bbNum != BlockSetOps::Iter::Done; bbNum = iter.NextElem())
         {
             printf("BB%02u ", bbNum);
         }

src/jit/liveness.cpp

@@ -986,7 +986,7 @@ void Compiler::fgExtendDbgLifetimes()
         unsigned blockWeight = block->getBBWeight(this);
 
         VarSetOps::Iter iter(this, initVars);
-        for (int varIndex = iter.NextElem(); varIndex != -1; varIndex = iter.NextElem())
+        for (int varIndex = iter.NextElem(); varIndex != VarSetOps::Iter::Done; varIndex = iter.NextElem())
         {
             /* Create initialization tree */
 
@@ -1359,7 +1359,7 @@ bool Compiler::fgMarkIntf(VARSET_VALARG_TP varSet1, VARSET_VALARG_TP varSet2)
     VarSetOps::UnionD(this, fgMarkIntfUnionVS, varSet2);
 
     VarSetOps::Iter iter(this, fgMarkIntfUnionVS);
-    for (int refIndex = iter.NextElem(); refIndex != -1; refIndex = iter.NextElem())
+    for (int refIndex = iter.NextElem(); refIndex != VarSetOps::Iter::Done; refIndex = iter.NextElem())
     {
         // if varSet1 has this bit set then it interferes with varSet2
         if (VarSetOps::IsMember(this, varSet1, refIndex))
@@ -1412,7 +1412,7 @@ bool Compiler::fgMarkIntf(VARSET_VALARG_TP varSet)
     bool addedIntf = false; // This is set to true if we add any new interferences
 
     VarSetOps::Iter iter(this, varSet);
-    for (int refIndex = iter.NextElem(); refIndex != -1; refIndex = iter.NextElem())
+    for (int refIndex = iter.NextElem(); refIndex != VarSetOps::Iter::Done; refIndex = iter.NextElem())
     {
         // Calculate the set of new interference to add
         VARSET_TP newIntf(VarSetOps::Diff(this, varSet, lvaVarIntf[refIndex]));