Re: gothic_moth, codlin_moth failures on REL8_2_STABLE

Dne 11.03.10 17:37, Tom Lane napsal(a):
> Zdenek Kotala<Zdenek(dot)Kotala(at)Sun(dot)COM> writes:
>> "-xO4 -xalias_level=basic" generates problem.
>> "-xO3 -xalias_level=basic" works fine
>> "-xO5" works fine
>
>> As documentation say:
>
>> Cite from Sun studio compiler guide:
>> http://docs.sun.com/app/docs/doc/819-5265/bjapp?a=view
>
>> xalias_level=basic
>> ------------------
>> If you use the -xalias_level=basic option, the compiler assumes that
>> memory references that involve different C basic types do not alias each
>> other. The compiler also assumes that references to all other types can
>> alias each other as well as any C basic type. The compiler assumes that
>> references using char * can alias any other type.
>
>> For example, at the -xalias_level=basic level, the compiler assumes that
>> a pointer variable of type int * is not going to access a float object.
>> Therefore it is safe for the compiler to perform optimizations that
>> assume a pointer of type float * will not alias the same memory that is
>> referenced with a pointer of type int *.
>
> I think you need to turn that off. On gcc we use -fno-strict-aliasing
> which disables the type of compiler assumption that this is talking about.
> I'm not sure exactly how that might create the specific failure we are
> seeing here, but I can point you to lots and lots of places in the
> sources where such an assumption would break things.

OK. I first try to update compiler to latest version to see if it helps
and finally I will remove aliasing.

Thanks Zdenek