Index: vm/jitrino/src/codegenerator/ia32/Ia32InstCodeSelector.cpp =================================================================== --- vm/jitrino/src/codegenerator/ia32/Ia32InstCodeSelector.cpp (revision 557558) +++ vm/jitrino/src/codegenerator/ia32/Ia32InstCodeSelector.cpp (working copy) @@ -1624,7 +1624,8 @@ appendInsts(irManager.newRuntimeHelperCallInst( CompilationInterface::Helper_IsValidElemType, lengthof(args), args, flag)); - bzero(CompareZeroOp::Ref, flag); + // the helper returns boolean value + bzero(CompareZeroOp::I4, flag); codeSelector.genTrueEdge(currentBasicBlock, throwBasicBlock, 0); return getTauUnsafe();