On 09/10/2015 05:14 PM, Segher Boessenkool wrote:
This patch rewrites the shrink-wrapping algorithm, allowing non-linear
pieces of CFG to be duplicated for use without prologue instead of just
linear pieces.
An example would be good for this kind of patch, also in the comments.
- add_to_hard_reg_set (&hardregs, GET_MODE (dreg),
- REGNO (dreg));
+ add_to_hard_reg_set (&hardregs, GET_MODE (dreg), REGNO (dreg));
}
In general please try to avoid mixing formatting changes with functional
ones. No need to remove these ones from future versions of the patch though.
+ /* If there is more than one predecessor of PRO not dominated by PRO,
+ fail. We don't have to do this (can split the block), but do this
+ for now (the original code disallowed this, too).
Comments shouldn't reference previous versions. Also, a comment
describing the why rather than just what is being done would be more
helpful.
I'm wondering how your new algorithm prevents the prologue from being
placed inside a loop. Can you have a situation where this picks a
predecessor that is reachable but not dominated by PRO?
+ int num = (*entry_edge)->probability;
+ int den = REG_BR_PROB_BASE;
+
+
+ if (*entry_edge == orig_entry_edge)
+ goto out;
There are a couple of places where there are multiple blank lines. I
think we avoid that.
+ FOR_EACH_EDGE (e, ei, src->succs)
+ {
+ if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun))
{
- all_set = false;
- break;
}
Minor, but I'd prefer a continue rather than an empty { } block.
Other than that it looks pretty good.
Bernd
