Re: RFH: _inter_-procedure optimizations"CALL_REALLY_USED_REGISTERS"

[Daniel Berlin <dberlin at dberlin dot org>]

On Tue, 2005-08-09 at 23:06 +0200, Björn Haase wrote:
> Steven Bosscher wrote:
> > In
> > any case, you should assume that it is a much bigger job than just
> > modifying the call expander.
> 
> Ok, I had a closer look at what is happening in present state gcc and I 
> understand that it is indeed a much more complex task than I first thought. 
> One Issue would be also, that it probably would be worth considering which 
> other kind of information (except register clobbering information) on a 
> static leaf function would be worth to be shared with the caller:
> 
> memory usage of the called function / memory clobbers, information on whether 
> it's a pure function ?

Uh, we produce memory ref/clober info at the tree-ssa level, just not at
the RTL level.

However,  RTL level uses the callgraph info about pure/const functions,
which is already extracted through interprocedural analysis (see
ipa-pure-const.c)