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    SubjectRe: pre egcs-1.1 testing and Linux 2.1.x
    On Mon, 24 Aug 1998, Philip Blundell wrote:

    >Precisely, and my objection to Andrea's patch was that it just disabled more
    >optimisations, again to hide the bug.

    Hmm, Philip you _could_ be right.

    >Andrea wrote:
    >
    >>What I think is that the optimization code I commented out is buggy and
    >>the bug is triggered by the regparm attribute.
    >
    >I think it's more subtle than that. The bug is not in the optimisations per
    >se, it's in the register allocator and just happens to be provoked more often
    >by higher optimisation (particularly when regparm is in use, because that
    >increases register pressure significantly near function calls).

    Are you sure? Did you tried it in practice? I thought that was the RTL
    code generated by the optimization function (not arch dependent) that was
    buggy:

    GOOD RTL -> buggy optimization function -> BAD RTL

    The RTL is arch indipendent.

    As you say it could be also that:

    GOOD RTL -> not buggy optimization function -> GOOD RTL 2

    and that:

    GOOD RTL -> buggy asm generator -> GOOD ASM

    GOOD RTL 2 -> buggy asm generator -> BAD ASM

    It should be trivial to understand this for a gcc hacker (it' s not for me
    ;-).

    Andrea[s] Arcangeli


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