[RFA:] Fix g77.f-torture/compile/970915-0.f, -Os verify_local_live_at_start MMIX

[Hans-Peter Nilsson]

Thanks for the review; I consistently forget to say that.

On Tue, 16 Apr 2002, Richard Henderson wrote:
> That is,
>
> 	update_life_info (NULL, UPDATE_LIFE_GLOBAL,
> 			  PROP_SCAN_DEAD_CODE
> 			  | PROP_KILL_DEAD_CODE
> 			  | PROP_ALLOW_CFG_CHANGES);
>
> immediately followed by
>
> 	update_life_info (NULL, UPDATE_LIFE_LOCAL, 0);
>
> must *never* fail the verify_local_live_at_start test.

IIRC that's not what we had in this case; the latter local call
removed dead code too.

In the case at hand, there was a dead store (of an uninitialized
pseudo).  The only insn that used that pseudo was the dead store
that wasn't removed due to capping.  So G_L_A_S was correct at
that time.  On a later *local* revisit, the other dead stores
were gone, so the remaining dead store fit the list and was
discovered.  Removing it also caused the pseudo to be removed
from G_L_A_S.

This in rapidly vanishing recollection.  I'll revisit the second
inconsistency-causing update_life_info call to see what comes
out.

brgds, H-P