On 10/22/2015 02:10 PM, Jeff Law wrote:
As for when the shift occurs to bugfixing, it's usually in early/mid
November each year. That also happens the be the deadline for
development patches to have been posted for review, hence most folks are
busy trying to wrap up their development work.
I'
On 10/22/2015 01:38 AM, David Wohlferd wrote:
An updated Local Register Variables patch is attached with the changes
discussed. It also includes removing the extra space after '.' that
Segher has been giving me grief about and Jeff's request re Globals:
> Signaling that this stuff may change
On Thu, Oct 22, 2015 at 12:38:16AM -0700, David Wohlferd wrote:
> An updated Local Register Variables patch is attached with the changes
> discussed. It also includes removing the extra space after '.' that
> Segher has been giving me grief about and Jeff's request re Globals:
You must have und
Given this, I'm going to go ahead and re-work the local register
variables page (probably tomorrow) stating extended asm is the only
supported usage. Although I also think it's important to mention
Andrew's point. If someone sees it in code somewhere, at least the docs
will give them some idea
On 10/20/2015 10:35 PM, David Wohlferd wrote:
> Given the way the optimizers and register allocation work,
> I don't think we can make guarantees around [Andrew's] use
> of the feature. It happens to still work and may work
> forever, but I'm not going to set it in stone.
If the only usage
On 10/20/2015 01:40 PM, Segher Boessenkool wrote:
On Tue, Oct 20, 2015 at 12:01:26PM -0600, Jeff Law wrote:
On 10/20/2015 11:11 AM, Segher Boessenkool wrote:
On Tue, Oct 20, 2015 at 10:22:53AM -0600, Jeff Law wrote:
bz21182 has a testcase that's still helped by local register variables.
I tr
I'm trying to sum up what was discussed here. What I'm hearing is
(quoting Jeff):
> the technical reality is I can't see a use outside the extended asm.
Andrew has discussed some other uses, but as Jeff observed:
> Given the way the optimizers and register allocation work,
> I don't think we
On Tue, Oct 20, 2015 at 12:01:26PM -0600, Jeff Law wrote:
> On 10/20/2015 11:11 AM, Segher Boessenkool wrote:
> >On Tue, Oct 20, 2015 at 10:22:53AM -0600, Jeff Law wrote:
> >>bz21182 has a testcase that's still helped by local register variables.
> >
> >I tried it out, and it now is much worse *wit
On 10/20/2015 11:11 AM, Segher Boessenkool wrote:
On Tue, Oct 20, 2015 at 10:22:53AM -0600, Jeff Law wrote:
bz21182 has a testcase that's still helped by local register variables.
I tried it out, and it now is much worse *with* the reg vars than
without (and -O2 vs. -O3 makes no difference at
On Tue, Oct 20, 2015 at 10:22:53AM -0600, Jeff Law wrote:
> bz21182 has a testcase that's still helped by local register variables.
I tried it out, and it now is much worse *with* the reg vars than
without (and -O2 vs. -O3 makes no difference at all). It doesn't look
to have used the pre-determin
On 10/20/2015 10:39 AM, Andrew Haley wrote:
On 10/20/2015 05:22 PM, Jeff Law wrote:
On 10/20/2015 10:15 AM, Andrew Haley wrote:
But in that case, what do we guarantee.
We certainly don't guarantee that those objects will be in their
requested register at any point other than at the asm stateme
On 10/20/2015 05:22 PM, Jeff Law wrote:
> On 10/20/2015 10:15 AM, Andrew Haley wrote:
>>> But in that case, what do we guarantee.
>>>
>>> We certainly don't guarantee that those objects will be in their
>>> requested register at any point other than at the asm statements.
>>
>> OK, but this usage d
On 10/20/2015 10:15 AM, Andrew Haley wrote:
But in that case, what do we guarantee.
We certainly don't guarantee that those objects will be in their
requested register at any point other than at the asm statements.
OK, but this usage did work in the past: that it now doesn't is a
regression.
On 10/20/2015 05:12 PM, Jeff Law wrote:
> On 10/20/2015 10:05 AM, Andrew Haley wrote:
>> On 10/20/2015 05:00 PM, Jeff Law wrote:
>>> But the technical reality is I can't see a use outside the extended asm.
>>
>> I can. In the past (and probably still today) GCC did an awful job of
>> allocating re
On 10/20/2015 10:05 AM, Andrew Haley wrote:
On 10/20/2015 05:00 PM, Jeff Law wrote:
But the technical reality is I can't see a use outside the extended asm.
I can. In the past (and probably still today) GCC did an awful job of
allocating registers in a large function. This was visible in a
b
On 10/20/2015 05:00 PM, Jeff Law wrote:
> But the technical reality is I can't see a use outside the extended asm.
I can. In the past (and probably still today) GCC did an awful job of
allocating registers in a large function. This was visible in a
bytecode interpreter, where the programmer kno
On 10/20/2015 09:13 AM, Segher Boessenkool wrote:
On Mon, Oct 19, 2015 at 11:22:06PM -0600, Jeff Law wrote:
WRT your hope to limit this to only uses in extended asms. That'd be
nice, but that's never been an explicit limitation. I would strongly
hesitate to add that limitation at this point in
On Mon, Oct 19, 2015 at 11:22:06PM -0600, Jeff Law wrote:
> WRT your hope to limit this to only uses in extended asms. That'd be
> nice, but that's never been an explicit limitation. I would strongly
> hesitate to add that limitation at this point in time.
r88265 (from 2004) made explicit that
On 10/20/2015 03:29 AM, Segher Boessenkool wrote:
On Mon, Oct 19, 2015 at 11:25:27PM -0600, Jeff Law wrote:
+Defining a register variable does not reserve the register; it
+remains available for other uses in places where flow control determines
+the variable's value is not live. For this reaso
On Mon, Oct 19, 2015 at 11:25:27PM -0600, Jeff Law wrote:
> >>+Defining a register variable does not reserve the register; it
> >>+remains available for other uses in places where flow control determines
> >>+the variable's value is not live. For this reason, the following uses
> >
> >This is misl
On 10/19/2015 03:55 PM, Segher Boessenkool wrote:
On Mon, Oct 12, 2015 at 04:09:34PM -0700, David Wohlferd wrote:
I was hoping to modify the text to say that local register variables can
"only" be used to call Extended asm. This would greatly simplify this
section.
But it is not true: they ca
On 10/12/2015 05:09 PM, David Wohlferd wrote:
Patch 3/3 is the update for the Local Register Variables page (attached).
This patch starts with a question. Looking at bug
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64951 (register variable
with template function) is this a bug that will be fixe
On Mon, Oct 12, 2015 at 04:09:34PM -0700, David Wohlferd wrote:
> I was hoping to modify the text to say that local register variables can
> "only" be used to call Extended asm. This would greatly simplify this
> section.
But it is not true: they can be used anywhere any variable can be used.
O
Patch 3/3 is the update for the Local Register Variables page (attached).
This patch starts with a question. Looking at bug
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64951 (register variable
with template function) is this a bug that will be fixed? Or a
limitation that should be doc'ed? B
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