[PATCH] D12345: [Reassociate]: Add intermediate subtract instructions created while negating to be redone later for more reassociate opportunities

[Daniel Berlin via llvm-commits]

SGTM then.


On Fri, Nov 13, 2015 at 11:04 PM, Owen Anderson <resistor at mac.com> wrote:

>
> On Nov 13, 2015, at 9:59 AM, Owen Anderson via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
>
> I'm not opposed, I'd like to see compile time numbers first since it
> transforms reassociate into an iterative algorithm.
>
>
> I’ll see what I can get you on that.
>
>
> I measured the compile time impact on “opt -O3” on a single-bitcode-file
> for all of opt itself.
>
> — Reassociate accounts for about 0.5% of total time.
> — I had a hard time getting stable numbers, but assuming the worst case
> Reassociate regresses about 2%.
>
> I would consider this firmly below the noise floor.
>
> —Owen
>
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