Re: [PATCH] sel-sched: forbid differing modes in substitution (PR 50205)

[Vladimir Makarov <vmakarov at redhat dot com>]

On 09/07/2011 05:38 AM, Alexander Monakov wrote:
> Hello,
>
> The patch repairs a problem when we attempt to substitute an insn like
> (... (cmp (mem (reg:DI ax)) (reg:SI ax))) (note different modes) through
> (set (reg:DI ax) (reg:DI dx)), which leaves the (reg:SI ax) part of the
> comparison intact, causing an ICE later on when we notice that the dependency
> on ax is still present.  As this is quite rare, we can simply forbid
> substitution in such circumstances, much like substitution of multiple hard
> reg references is forbidden now.
>
> En passant, the patch simplifes the code a little, as we never try to
> substitute anything but registers.
>
> Bootstrapped and regtested on x86_64-linux with sel-sched enabled at -O2, OK?
> (I'll add the testcase from Bugzilla when committing)
Ok.  Thanks for the patch.
> 2011-09-07  Alexander Monakov<amonakov@ispras.ru>
>
> 	PR rtl-optimization/50205
> 	* sel-sched.c (count_occurrences_1): Simplify on the assumption that
> 	p->x is a register.  Forbid substitution when the same register is
> 	found in a different mode.
> 	(count_occurrences_equiv): Assert that 'what' is a register.