[PATCH] D20178: Fix PR26055 - LiveDebugValues is very slow

[Daniel Berlin via llvm-commits]

Yeah, i honestly don't know.
It's a need way to avoid constructing a real hash, my next question would
be "is it actually demonstrably slower to compute a hash for real"?

Also, since the stuff is constant anyway, can't you just compute it at init
time anyway?
It's not like you have to compute it repeatedly.



On Wed, May 25, 2016 at 1:15 PM, Adrian Prantl <aprantl at apple.com> wrote:

> aprantl added inline comments.
>
> ================
> Comment at: lib/CodeGen/LiveDebugValues.cpp:103
> @@ +102,3 @@
> +      } RegisterLoc;
> +      uint64_t Hash;
> +    } Loc;
> ----------------
> dberlin wrote:
> > Errr, do you really never use the hash and the registerloc at the same
> time?
> >
> The hash is meant to be a convenient alternative view of the the two
> uint32_t as a single uint64_t. Now that I think of it, I wonder whether
> that is guaranteed on all imaginable architectures.
>
>
> http://reviews.llvm.org/D20178
>
>
>
>
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