[llvm-dev] RFC: DenseMap grow() slowness

[Xinliang David Li via llvm-dev]

On Tue, Mar 15, 2016 at 3:54 PM, <escha at apple.com> wrote:

>
> > On Mar 15, 2016, at 3:52 PM, Xinliang David Li <xinliangli at gmail.com>
> wrote:
> >
> > In earlyCSE case, the size of DenseMap can be determined ahead of time
>
> Only an upper bound; the actual max size is the number of CSE-able
> instructions “live” in scope at any one time (I think), so at least in
> theory it could be a gross overestimate.
>

Perhaps some heuristics can be applied to reduce the estimated size
assuming there are some correlation on average, I guess.

David


>
> —escha
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