Displaying 2 results from an estimated 2 matches for "armlowoverheadloops".
2020 Mar 12
2
Redundant copies
Hi all,
we have encountered a case of redundant copies still left in the final code
and we would like to, at least, mitigate it. The original motivating case
comes from a context where we have large vector registers. In that context,
copies are expensive and we would like to avoid them as much as possible.
This small testcase in C, similar to the original vector case, exposes the
issue but using
2020 Mar 16
2
Redundant copies
...?) to see if we are not missing something obvious.
>
> Regarding a post RA pass: you may want to have a look at the ARM
> hardware-loop pass. In order to make that beneficial, we have to do quite
> some dead code elimination post RA, both in inside loops and in preheaders,
> see e.g. ARMLowOverheadLoops::IterationCountDCE. This is using
> ReachingDefAnalysis (RDA), which has been extended by Sam and made more
> generic to support this, which was also going to be his eurollvm talk:
> http://llvm.org/devmtg/2020-04/talks.html#LightningTalk_26. End of
> advertisement. ;-) Basically what I...