samuel at ibrium.se
Sat Nov 30 04:49:42 EST 2002
On Fri, Nov 29, 2002 at 05:21:50PM +0100, Gabriel Paubert wrote:
> On Fri, 29 Nov 2002, Samuel Rydh wrote:
> How is "addr" declared ? This may be an aliasing problem. Does adding
> -fno-strict-aliasing to the options help ? Or changing the "=m" to "+m" as
> an incorrect, but less penalizing than a memory clobber, bandaid. Or
> declaring addr as pointer to volatile ?
Turning of aliasing did indeed solve the problem. As did changing
unsigned long to int.
> > Adding "memory" to the clobber list seems to be the only way to make
> > gcc do the right thing :-(.
> A "memory" clobber is such an optimization killer that it is not
> acceptable in this situation (actually I consider a memory clober hardly
> ever acceptable).
Agreed. A "memory" clobber is definitely suboptimal.
> I see that your example involves local variables, does
> it also happen in the non-automatic case ?
It happens in the non-automatic case too. I'll try the
latest gcc version later.
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