Regression check for optimizing simplify instruction pass. | |

A pair (sub, neg) should not be transforemd to (sub) for | |

fp calculation because we can lose the sign of zero for | |

the following expression: | |

- ( A - B ) != B - A ; if B == A | |

Addition or subtraction with fp zero should not be eliminated | |

because: | |

-0.0 + 0.0 = 0.0 | |

-0.0 - -0.0 = 0.0 |