[webkit-dev] jit, unordered compare

[Zoltan Herczeg]

Hi,

My stougle with USE_JSVALUE32_64 still continues on ARM. In
emit_op_jfalse, there is a comparison here (fpRegT0 contains 0.0):
 addJump(branchDouble(DoubleEqual, fpRegT0, fpRegT1), target + 2);

In x86, if either operand is NaN, the zero flag is set by definition
(ucomisd instruction). I have no idea why (NaN == anything is true?).
Unfortunately, ARM does not set the zero flag. What would be a portable
way to improve this instruction? (and emit_op_jtrue) Perhaps this affects
the possible thumb2 implementation with USE_JSVALUE32_64 as well.

Zoltan