Compact regsiter allocation

[Ian Lance Taylor]

Jamie Prescott <jpresss@yahoo.com> writes:

> The target reorg is great, but it had two problems for me. One is that it was issued after the
> prologue/epilogue,

Oh yeah, you probably do want to introduce a pass before
prologue/epilogue generation but after register allocation.  There isn't
any mechanism for that at present, although it's easy to do in your own
sources--just add something to init_optimization_passes in passes.c.

> This seems to be working fine, but my biggest doubt is that way I dig into the single instructions to
> find REG RTXs to remap.
> I looked around and I ended up with the code below, partially stolen from print_rtx().
> Is there a public/non-hackish API to enum all the RTXs contained inside an instruction?

Use for_each_rtx to walk through an RTX.  There are lots of handy
functions like that in rtlanal.c.

Ian