--- thunderbird-60.6.1/js/src/jit/x86-shared/Assembler-x86-shared.cpp 2019-03-25 02:38:29.000000000 +0100 +++ thunderbird-60.6.1/js/src/jit/x86-shared/Assembler-x86-shared-patched.cpp 2019-05-15 13:28:23.230904975 +0200 @@ -340,12 +340,14 @@ avxPresent = (xcr0EAX & xcr0SSEBit) && (xcr0EAX & xcr0AVXBit); } + if (maxSSEVersion >= SSE2) { // CMOV instruction are supposed to be supported by all CPU which have SSE2 // enabled. While this might be true, this is not guaranteed by any // documentation, nor AMD, nor Intel. static const int CMOVBit = 1 << 15; MOZ_RELEASE_ASSERT(flagsEDX & CMOVBit, "CMOVcc instruction is not recognized by this CPU."); + } static const int POPCNTBit = 1 << 23; popcntPresent = (flagsECX & POPCNTBit);