[PATCH] Replace custom getNumPreds/etc with PredIteratorCache that does the same thing

Daniel Berlin dberlin at dberlin.org
Thu Apr 30 12:38:03 PDT 2015


FWIW, while I did not speed test *this* change, In timings elsewhere,
i've found that PredIteratorCache is often slower than the pred
iterator for counting preds
(because it copies the pred list), and only faster in really
degenerate cases for walking preds.

So i'm not going to submit this.


On Thu, Apr 30, 2015 at 12:01 PM, Quentin Colombet <qcolombet at apple.com> wrote:
> Hi Daniel,
>
> Don’t know either if that makes sense, but LGTM ;).
>
> Cheers,
> -Quentin
>
>
> ================
> Comment at: lib/Transforms/Utils/PromoteMemoryToRegister.cpp:269
> @@ -267,3 +268,3 @@
>
> -  /// Lazily compute the number of predecessors a block has.
> -  DenseMap<const BasicBlock *, unsigned> BBNumPreds;
> +  /// Cache of predecessor info
> +  PredIteratorCache PredCache;
> ----------------
> Period at the end of the comment ;).
>
> http://reviews.llvm.org/D9167
>
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