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* [Bug target/43862] GCC doesn't use 16-bit armv5te multiplies when possible
[not found] <bug-43862-4@http.gcc.gnu.org/bugzilla/>
@ 2011-08-23 10:08 ` ams at gcc dot gnu.org
0 siblings, 0 replies; 3+ messages in thread
From: ams at gcc dot gnu.org @ 2011-08-23 10:08 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43862
Andrew Stubbs <ams at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ams at gcc dot gnu.org
--- Comment #3 from Andrew Stubbs <ams at gcc dot gnu.org> 2011-08-23 09:57:38 UTC ---
I've just committed some patches to address use of the widening multiplies,
both in the RTL optimizers and the tree-ssa optimizers.
David, please check again and see if this works for you now. If you find some
missed opportunities that might be useful.
My patches should address smulxy and smlalxy. It may also indirectly improve
use of smulwy and smlawy but that job will have to be finished with combine, so
YMMV.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug target/43862] GCC doesn't use 16-bit armv5te multiplies when possible
2010-04-23 3:03 [Bug target/43862] New: " lessen42+gcc at gmail dot com
2010-04-23 3:03 ` [Bug target/43862] " lessen42+gcc at gmail dot com
@ 2010-04-28 10:06 ` ramana at gcc dot gnu dot org
1 sibling, 0 replies; 3+ messages in thread
From: ramana at gcc dot gnu dot org @ 2010-04-28 10:06 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from ramana at gcc dot gnu dot org 2010-04-28 10:06 -------
* I don't see why smulbb, smultb, smulbt, smultt shouldn't be generated for
their respective cases. So, yes that's correct.
* smulwy is not supported in the backend, so that's a feature enhancement
* smlawy is again not supported in the backend and anyone implementing this
should note that overflow in the accumulate step is a part of the saturated Q
bit. Also it isn't correct to be generating smlawy in the cases mentioned
there.
* smlaxy is something that could be generated in a few of the occasions but the
PCS defeats us in these circumstances because we assume that the values passed
in are appropriately zero /sign extended.
--
ramana at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Keywords| |missed-optimization
Known to fail| |4.5.0
Last reconfirmed|0000-00-00 00:00:00 |2010-04-28 10:06:44
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43862
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug target/43862] GCC doesn't use 16-bit armv5te multiplies when possible
2010-04-23 3:03 [Bug target/43862] New: " lessen42+gcc at gmail dot com
@ 2010-04-23 3:03 ` lessen42+gcc at gmail dot com
2010-04-28 10:06 ` ramana at gcc dot gnu dot org
1 sibling, 0 replies; 3+ messages in thread
From: lessen42+gcc at gmail dot com @ 2010-04-23 3:03 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from lessen42+gcc at gmail dot com 2010-04-23 03:03 -------
Created an attachment (id=20467)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20467&action=view)
smul/smla in C
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43862
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2011-08-23 9:58 UTC | newest]
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[not found] <bug-43862-4@http.gcc.gnu.org/bugzilla/>
2011-08-23 10:08 ` [Bug target/43862] GCC doesn't use 16-bit armv5te multiplies when possible ams at gcc dot gnu.org
2010-04-23 3:03 [Bug target/43862] New: " lessen42+gcc at gmail dot com
2010-04-23 3:03 ` [Bug target/43862] " lessen42+gcc at gmail dot com
2010-04-28 10:06 ` ramana at gcc dot gnu dot org
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