Probably due to bugs in interpreter. There are likely multiple issues that will need to be split into several bugs. See Tiger Skipped file for an up to date list. Currently, it's: fast/js/sputnik/Conformance/07_Lexical_Conventions/7.8_Literals/7.8.5_Regular_Expression_Literals/S7.8.5_A1.4_T2.html fast/js/sputnik/Conformance/07_Lexical_Conventions/7.8_Literals/7.8.5_Regular_Expression_Literals/S7.8.5_A2.4_T2.html fast/js/sputnik/Conformance/11_Expressions/11.5_Multiplicative_Operators/11.5.3_Applying_the_percent_Operator/S11.5.3_A4_T2.html fast/js/sputnik/Conformance/15_Native_Objects/15.3_Function/15.3.4/15.3.4.3_Function.prototype.apply/S15.3.4.3_A6_T1.html fast/js/sputnik/Conformance/15_Native_Objects/15.3_Function/15.3.4/15.3.4.3_Function.prototype.apply/S15.3.4.3_A6_T4.html fast/js/sputnik/Conformance/15_Native_Objects/15.3_Function/15.3.5/S15.3.5.3_A2_T6.html fast/js/sputnik/Conformance/15_Native_Objects/15.10_RegExp/15.10.2/15.10.2.12_CharacterClassEscape/S15.10.2.12_A1_T1.html fast/js/sputnik/Conformance/15_Native_Objects/15.10_RegExp/15.10.2/15.10.2.12_CharacterClassEscape/S15.10.2.12_A1_T2.html fast/js/sputnik/Conformance/15_Native_Objects/15.10_RegExp/15.10.2/15.10.2.12_CharacterClassEscape/S15.10.2.12_A2_T1.html fast/js/sputnik/Conformance/15_Native_Objects/15.10_RegExp/15.10.2/15.10.2.12_CharacterClassEscape/S15.10.2.12_A2_T2.html
<rdar://problem/7928474>
See also: Bug 44242 Bug 44243 Bug 44244 Bug 44245 Bug 44247 Bug 44248
From testing on desktop interpreter builds, I'm no longer seeing functional differences to the JIT. This is likely predominantly due to replacing PCRE with YARR, along with other recent bug fixes.