Guarded devirtualization: multiple type checks

src/coreclr/jit/gentree.cpp

@@ -2164,12 +2164,12 @@ GenTree* Compiler::getArrayLengthFromAllocation(GenTree* tree DEBUGARG(BasicBloc
 }
 
 //-------------------------------------------------------------------------
-// SetSingleInlineCadidateInfo: set a single inline candidate info in the current call.
+// SetSingleInlineCandidateInfo: set a single inline candidate info in the current call.
 //
 // Arguments:
 //     candidateInfo - inline candidate info
 //
-void GenTreeCall::SetSingleInlineCadidateInfo(InlineCandidateInfo* candidateInfo)
+void GenTreeCall::SetSingleInlineCandidateInfo(InlineCandidateInfo* candidateInfo)
 {
     if (candidateInfo != nullptr)
     {
@@ -2199,7 +2199,7 @@ InlineCandidateInfo* GenTreeCall::GetGDVCandidateInfo(uint8_t index)
 
 //-------------------------------------------------------------------------
 // AddGDVCandidateInfo: Record a guarded devirtualization (GDV) candidate info
-//     for this call. For now, we only support one GDV candidate per call.
+//     for this call. A call can't have more than MAX_GDV_TYPE_CHECKS number of candidates
 //
 // Arguments:
 //     comp          - Compiler instance
@@ -9352,8 +9352,8 @@ GenTreeCall* Compiler::gtCloneExprCallHelper(GenTreeCall* tree,
     {
         copy->gtCallMethHnd         = tree->gtCallMethHnd;
         copy->gtInlineCandidateInfo = tree->gtInlineCandidateInfo;
+        copy->gtInlineInfoCount     = tree->gtInlineInfoCount;
     }
-    copy->gtInlineInfoCount = tree->gtInlineInfoCount;
 
     copy->gtCallType   = tree->gtCallType;
     copy->gtReturnType = tree->gtReturnType;

src/coreclr/jit/gentree.h

@@ -5423,22 +5423,29 @@ struct GenTreeCall final : public GenTree
 
     InlineCandidateInfo* GetSingleInlineCandidateInfo()
     {
-        if (gtInlineInfoCount > 1)
+        // gtInlineInfoCount can be 0 (not an inline candidate) or 1
+        if (gtInlineInfoCount == 0)
         {
-            assert(!"Call has multiple inline candidates - use GetGDVCandidateInfo instead");
+            assert(!IsInlineCandidate());
+            assert(gtInlineCandidateInfo == nullptr);
+            return nullptr;
+        }
+        else if (gtInlineInfoCount > 1)
+        {
+            assert(!"Call has multiple inline candidates");
         }
         return gtInlineCandidateInfo;
     }
 
-    void SetSingleInlineCadidateInfo(InlineCandidateInfo* candidateInfo);
+    void SetSingleInlineCandidateInfo(InlineCandidateInfo* candidateInfo);
 
     InlineCandidateInfo* GetGDVCandidateInfo(uint8_t index);
 
     void AddGDVCandidateInfo(Compiler* comp, InlineCandidateInfo* candidateInfo);
 
     void ClearInlineInfo()
     {
-        SetSingleInlineCadidateInfo(nullptr);
+        SetSingleInlineCandidateInfo(nullptr);
     }
 
     uint8_t GetInlineCandidatesCount()

src/coreclr/jit/importercalls.cpp

@@ -5903,12 +5903,9 @@ void Compiler::considerGuardedDevirtualization(GenTreeCall*            call,
         }
         else
         {
-            assert(numExactClasses <= maxTypeChecks);
+            assert((numExactClasses > 0) && (numExactClasses <= maxTypeChecks));
             JITDUMP("We have exactly %d classes implementing %s:\n", numExactClasses, eeGetClassName(baseClass));
 
-            // NOTE: The case where we have only a single implementation is handled naturally
-            // through gtGetClassHandle without help of GDV.
-            //
             int skipped = 0;
             for (int exactClsIdx = 0; exactClsIdx < numExactClasses; exactClsIdx++)
             {
@@ -6523,7 +6520,7 @@ bool Compiler::impMarkInlineCandidateHelper(GenTreeCall*           call,
     else
     {
         assert(candidateIndex == 0);
-        call->SetSingleInlineCadidateInfo(inlineCandidateInfo);
+        call->SetSingleInlineCandidateInfo(inlineCandidateInfo);
     }
 
     // Let the strategy know there's another candidate.

src/coreclr/jit/indirectcalltransformer.cpp

@@ -588,14 +588,8 @@ class IndirectCallTransformer
                 compiler->fgAddRefPred(checkBlock, prevCheckBlock);
 
                 // Weight for the new secondary check is the difference between the previous check and the thenBlock.
-                weight_t newWeight = prevCheckBlock->bbWeight - thenBlock->bbWeight;
-                if (newWeight < 0)
-                {
-                    // There could be a small error leading to e.g. -0.00001 instead of 0.0 here
-                    // Mostly because of inheritWeightPercentage for thenBlock;
-                    newWeight = 0;
-                }
-                checkBlock->setBBProfileWeight(newWeight);
+                checkBlock->inheritWeightPercentage(prevCheckBlock,
+                                                    100 - origCall->GetGDVCandidateInfo(checkIdx)->likelihood);
             }
 
             // Find last arg with a side effect. All args with any effect
@@ -932,7 +926,7 @@ class IndirectCallTransformer
                 inlineInfo->clsHandle            = compiler->info.compCompHnd->getMethodClass(methodHnd);
                 inlineInfo->exactContextHnd      = context;
                 inlineInfo->preexistingSpillTemp = returnTemp;
-                call->SetSingleInlineCadidateInfo(inlineInfo);
+                call->SetSingleInlineCandidateInfo(inlineInfo);
 
                 // If there was a ret expr for this call, we need to create a new one
                 // and append it just after the call.
@@ -990,15 +984,17 @@ class IndirectCallTransformer
             compiler->fgAddRefPred(remainderBlock, elseBlock);
             compiler->fgAddRefPred(elseBlock, checkBlock);
 
-            weight_t newWeight = checkBlock->bbWeight - thenBlock->bbWeight;
-            if (newWeight < 0)
+            // Calculate the likelihood of the else block as a remainder of the sum
+            // of all the other likelihoods.
+            unsigned elseLikelihood = 100;
+            for (uint8_t i = 0; i < origCall->GetInlineCandidatesCount(); i++)
             {
-                // There could be a small error leading to e.g. -0.00001 instead of 0.0 here
-                // Mostly because of inheritWeightPercentage for thenBlock;
-                newWeight = 0;
+                elseLikelihood -= origCall->GetGDVCandidateInfo(i)->likelihood;
             }
+            // Make sure it didn't overflow
+            assert(elseLikelihood <= 100);
 
-            elseBlock->setBBProfileWeight(newWeight);
+            elseBlock->inheritWeightPercentage(currBlock, elseLikelihood);
 
             GenTreeCall* call    = origCall;
             Statement*   newStmt = compiler->gtNewStmt(call, stmt->GetDebugInfo());