[v2] regrename: Skip renaming if instruction is noop move.
Commit Message
Skip renaming if instruction is noop move, and it will
been removed for performance.
gcc/
* regrename.c (find_rename_reg): Return satisfied regno
if instruction is noop move.
---
gcc/regrename.c | 5 +++++
1 file changed, 5 insertions(+)
Comments
On 12/2/2021 9:26 PM, Jojo R wrote:
> Skip renaming if instruction is noop move, and it will
> been removed for performance.
>
> gcc/
> * regrename.c (find_rename_reg): Return satisfied regno
> if instruction is noop move.
OK
jeff
Hi,
Thank you for your review & help.
I could not fetch the merged patch from gcc master of git.
Is there any problem for this ?
Thanks.
— Jojo
在 2021年12月3日 +0800 PM10:57,Jeff Law <jeffreyalaw@gmail.com>,写道:
>
>
> On 12/2/2021 9:26 PM, Jojo R wrote:
> > Skip renaming if instruction is noop move, and it will
> > been removed for performance.
> >
> > gcc/
> > * regrename.c (find_rename_reg): Return satisfied regno
> > if instruction is noop move.
> OK
> jeff
On 12/13/2021 6:40 PM, Jojo R wrote:
> Hi,
>
> Thank you for your review & help.
>
> I could not fetch the merged patch from gcc master of git.
>
> Is there any problem for this ?
I assumed you'd commit the change. I thought you had commit
privileges. I'll go ahead and push it momentarily.
Thanks for following up.
Jeff
@@ -394,6 +394,11 @@ find_rename_reg (du_head_p this_head, enum reg_class super_class,
this_head, *unavailable))
return this_head->tied_chain->regno;
+ /* If this insn is a noop move, then do not rename in this chain as doing so
+ would inhibit removal of the noop move. */
+ if (noop_move_p (this_head->first->insn))
+ return best_new_reg;
+
/* If PREFERRED_CLASS is not NO_REGS, we iterate in the first pass
over registers that belong to PREFERRED_CLASS and try to find the
best register within the class. If that failed, we iterate in