target/3923: [Solaris 8 on Sparc IIe] -O2 option trashes variables

[rth@gcc.gnu.org]

Synopsis: [Solaris 8 on Sparc IIe] -O2 option trashes variables

State-Changed-From-To: open->closed
State-Changed-By: rth
State-Changed-When: Sat Mar 30 13:15:15 2002
State-Changed-Why:
        float fMantissa = input;
        fMantissa += 1.0F;
        fMantissa -= exponent;
        unsigned long &mantissa = * reinterpret_cast<unsigned long *> (&fMantissa);
    
    This is illegal.  An object may only be accessed through its
    proper type.  See section 6.5 paragraph 7 of the ISO C standard;
    there is a corresponding verbage in the C++ standard, but I
    forget the exact section number.
    
    Use a union instead:
    
       union {
          float f;
          unsigned long l;
       } u;
    
       u.f = input + 1.0f - exponent;
       u.l &= ...

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