Re: AUTOMATON_STATE_ALTS not used, yet takes 60KB of insn-attrtab.c

[Vladimir Makarov <vmakarov at redhat dot com>]

Zack Weinberg wrote:
> 
> As far as I can tell, the code in insn-attrtab.c controlled by #if
> AUTOMATON_STATE_ALTS is used nowhere.  To be more precise, I can find
> no circumstance under which that macro is defined with value 1, in CVS
> mainline.
> 
> Having a facility which is not currently used is no big deal.
> However, the process of generating this unused code creates the
> derived attribute function insn_alts() as a side effect.  This
> function is not used either, but it is *not* wrapped in #if -- and
> it takes up 64129 bytes of space in insn-attrtab.o.
> 
> I am tempted to take a chainsaw to all the AUTOMATON_STATE_ALTS code.
> However, I can be persuaded to just figure out a way to put
> insn_alts() under #if too.  Do you plan to have AUTOMATON_STATE_ALTS
> be used for anything - even on just one platform - in GCC 3.4?

Originally, it was used for Itanium scheduler heuristics.  Now ia64 port
has a general (not heuristic) solution for this.  Generally speaking,
this code could be used for improving scheduling for some processors.

Code of insn_alts is smaller than code for insn_state_alts.  Therefore I
did not wrap it up.
I'll wrap up insn_alts code too (using new macro AUTOMATON_ALTS) because
now it is not used.

Thank you for pointing me this up.

Vlad