diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 0c91e1ba06..48a9c2e745 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -114,6 +114,11 @@ namespace ts {
             getIdentifierCount: () => sum(host.getSourceFiles(), "identifierCount"),
             getSymbolCount: () => sum(host.getSourceFiles(), "symbolCount") + symbolCount,
             getTypeCount: () => typeCount,
+            getRelationCacheSizes: () => ({
+                assignable: assignableRelation.size,
+                identity: identityRelation.size,
+                subtype: subtypeRelation.size,
+            }),
             isUndefinedSymbol: symbol => symbol === undefinedSymbol,
             isArgumentsSymbol: symbol => symbol === argumentsSymbol,
             isUnknownSymbol: symbol => symbol === unknownSymbol,
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 74bb8e1b1c..4f50aa3ab1 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -927,6 +927,7 @@ namespace ts {
             getIdentifierCount: () => getDiagnosticsProducingTypeChecker().getIdentifierCount(),
             getSymbolCount: () => getDiagnosticsProducingTypeChecker().getSymbolCount(),
             getTypeCount: () => getDiagnosticsProducingTypeChecker().getTypeCount(),
+            getRelationCacheSizes: () => getDiagnosticsProducingTypeChecker().getRelationCacheSizes(),
             getFileProcessingDiagnostics: () => fileProcessingDiagnostics,
             getResolvedTypeReferenceDirectives: () => resolvedTypeReferenceDirectives,
             isSourceFileFromExternalLibrary,
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 6fba5f149c..1e50c59fc9 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2961,6 +2961,7 @@ namespace ts {
         /* @internal */ getIdentifierCount(): number;
         /* @internal */ getSymbolCount(): number;
         /* @internal */ getTypeCount(): number;
+        /* @internal */ getRelationCacheSizes(): { assignable: number, identity: number, subtype: number };
 
         /* @internal */ getFileProcessingDiagnostics(): DiagnosticCollection;
         /* @internal */ getResolvedTypeReferenceDirectives(): Map<ResolvedTypeReferenceDirective | undefined>;
@@ -3246,6 +3247,7 @@ namespace ts {
         /* @internal */ getIdentifierCount(): number;
         /* @internal */ getSymbolCount(): number;
         /* @internal */ getTypeCount(): number;
+        /* @internal */ getRelationCacheSizes(): { assignable: number, identity: number, subtype: number };
 
         /* @internal */ isArrayType(type: Type): boolean;
         /* @internal */ isTupleType(type: Type): boolean;
diff --git a/src/tsc/tsc.ts b/src/tsc/tsc.ts
index 984ebe21cf..500480463b 100644
--- a/src/tsc/tsc.ts
+++ b/src/tsc/tsc.ts
@@ -340,6 +340,10 @@ namespace ts {
             const checkTime = performance.getDuration("Check");
             const emitTime = performance.getDuration("Emit");
             if (compilerOptions.extendedDiagnostics) {
+                const caches = program.getRelationCacheSizes();
+                reportCountStatistic("Assignability cache size", caches.assignable);
+                reportCountStatistic("Identity cache size", caches.identity);
+                reportCountStatistic("Subtype cache size", caches.subtype);
                 performance.forEachMeasure((name, duration) => reportTimeStatistic(`${name} time`, duration));
             }
             else {