Re: [lno] Bootstrap failure on Alpha due to miscompilation

[Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>]

Hello,

> lno fails to bootstrap on Alpha for several days now; it segfaults
> while compiling libgcc in the second stage, so apparently it
> miscompiles itself.
> 
> The only test suite failure that does not already occur on mainline
> Alpha or on lno ia64 (according to gcc-testresults) is
> gcc.c-torture/execute/961017-1.c. There, lno compiles at -O and above
> 
>   unsigned char z = 0;
>   do ;  while (--z > 0);
> 
> to a loop over the whole 64 bit space:
> 
>         clr $1
>         [...]
> $L2:    lda $1,1($1)
>         bne $1,$L2
> 
> I'm not sure, however, whether it is this problem that causes the
> bootstrap failure (people don't often rely on unsigned wrapping
> semantics in loops...).

I will have a look at this testsuite failure; however I do not have an
access to the Alpha machine just now, so I won't be of much help with
the bootstrap problem.

Zdenek