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Replace Create(ulong) with CreateScalar(uint) in PopCount#37912

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kunalspathak merged 2 commits intodotnet:masterfrom
kunalspathak:min-popcount
Jun 16, 2020
Merged

Replace Create(ulong) with CreateScalar(uint) in PopCount#37912
kunalspathak merged 2 commits intodotnet:masterfrom
kunalspathak:min-popcount

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@kunalspathak kunalspathak commented Jun 15, 2020

In PopCount(uint) implementation, we were creating Vector64<ulong> of input by casting uint to ulong because of #35976. However now that issue is fixed, revert to Vector.CreateScalar(uint) because that is more accurate readability wise and we generate equivalent optimal code.

Before:

G_M46009_IG02:
        2A0003E0          mov     w0, w0
        4E081C10          mov     v16.d[0], x0
        0E205A10          cnt     v16.8b, v16.8b
        0E31BA10          addv    b16, v16.8b
        0E013E00          umov    w0, v16.b[0]
                                                ;; bbWeight=1    PerfScore 5.50

After:

G_M46009_IG02:
        0F000410          movi    v16.2s, #0x00
        4E041C10          ins     v16.s[0], w0
        0E205A10          cnt     v16.8b, v16.8b
        0E31BA10          addv    b16, v16.8b
        0E013E00          umov    w0, v16.b[0]
                                                ;; bbWeight=1    PerfScore 5.50

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kunalspathak commented Jun 15, 2020

@tannergooding , @echesakovMSFT

@kunalspathak kunalspathak mentioned this pull request Jun 16, 2020
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@kunalspathak kunalspathak merged commit 132be64 into dotnet:master Jun 16, 2020
@kunalspathak kunalspathak deleted the min-popcount branch June 16, 2020 06:40
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@tannergooding tannergooding tannergooding approved these changes

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@echesakov echesakov echesakov approved these changes

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