Re: [PATCH, 1/2] shrink wrap a function with a single loop: copy propagation

[Jeff Law <law at redhat dot com>]

On 05/09/14 01:30, Zhenqiang Chen wrote:
> > So why restrict this to just cases where we have to propagate into a COMPARE
> > at the end of a block?   So in your example, assume the first block looks
> > like
>
> prepare_shrink_wrap will move_insn_for_shrink_wrap in BB_INSNS_REVERSE
> order. Current prepare_shrink_wrap should handle the case since there
> is no data flow dependence.
OK.

> > My first thought here was that we must have some code which does 90% of what
> > you need.  Did you look at any of the existing RTL optimization
> > infrastructure to see if there was code you could extend to handle this?
>
> Most the codes are from function copyprop_hardreg_forward_1 in
> "cprop_hardreg" pass. Previously I had a patch to reuse it:
> http://gcc.gnu.org/ml/gcc-patches/2013-06/msg00305.html. What do you
> think about the old patch?
Utilizing routines from the hard register copy propagation pass seems 
wise.  I'll take a look at the updated patch.

jeff