neat bug in alias analysis

[Mark Mitchell]

>>>>> "Andi" == Andi Kleen <ak@muc.de> writes:

    >>  I already tried in an earlier email.  The point is that the
    >> types we are looking at here are the types of the memory being
    >> referenced, not the types that we are using to reference it.
    >> An `int **' cannot point at the same thing as a `const int **'
    >> as `int *' and `const int *' are not compatible types.  So,
    >> `const int*' and `int *' should be in different alias sets.

    Andi> So what was wrong with the example Mike provided, which was
    Andi> basically:

    Andi> inline int do_with_p(const int *p) { return *p + 1; }

    Andi> int func(void) { int t = 1; return do_with_p(&t); }

    Andi> After the inlining *p and t are the same in the same
    Andi> function and need to be in the same alias class.

Yup.  Apparently, I don't write very well.

Look, the *memory* referenced here is `*p' and `t'.  One is an `int';
one is a `const int'.  These have the same alias set.

However, there's no reason that `const int *' and `int *' should have
the same alias set.

--
Mark Mitchell                   mark@codesourcery.com
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