This is mostly the same as ValueToInt32.

Comment on attachment 556767 [details] [diff] [review] actual patch Review of attachment 556767 [details] [diff] [review]: ----------------------------------------------------------------- ::: js/src/ion/LIR-Common.h @@ +534,5 @@ > > +// Convert a double to a truncated int32. > +// Input: floating-point register > +// Output: 32-bit integer > +// Bailout: edge cases of DoubleToECMAInt32 js_DoubleToECMAInt32 ::: js/src/ion/Lowering.cpp @@ +448,5 @@ > + > + case MIRType_Double: > + { > + LTruncateDToInt32 *lir = new LTruncateDToInt32(useRegister(opd)); > + return define(lir, truncate) && assignSnapshot(lir); Unrelated to this patch, but it would be very useful for instructions with known bail-out points to assert that they have snapshots assigned. ::: js/src/ion/shared/CodeGenerator-x86-shared.cpp @@ +634,5 @@ > +void > +CodeGeneratorX86Shared::emitTruncateDouble(const FloatRegister &src, const Register &dest, Label *fail) > +{ > + masm.cvttsd2si(src, dest); > + masm.cmpl(dest, Imm32(0x80000000)); #define CVTTSD2SI_INDEFINITE_INTEGER 0x80000000