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Minor cleanups for System.Runtime.Numerics #53984

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merged 10 commits into from
Aug 2, 2021
Merged

Minor cleanups for System.Runtime.Numerics #53984

merged 10 commits into from
Aug 2, 2021

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huoyaoyuan
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Mainly utilizing [^1] and BitOperations.

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ghost commented Jun 10, 2021

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Mainly utilizing [^1] and BitOperations.

Author: huoyaoyuan
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area-System.Numerics
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@MartyIX
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MartyIX commented Jun 10, 2021

@huoyaoyuan Just out of curiosity: I understand what ^1 does but I'm not sure how it works under the hood. Is it transpiled to byteCount - 1 by Roslyn or is it supported by some IL instruction?

Sorry for off topic question. I hope you guys won't mind too much.

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huoyaoyuan commented Jun 10, 2021 •
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Yes. Roslyn will compose it. See sharplab

Roslyn will first find an indexer accepts System.Index. If not found, then it will find an integer indexer and a recognizable length property (it finds for Length and Count).

tannergooding
tannergooding reviewed Jun 10, 2021
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src/libraries/System.Runtime.Numerics/src/System/Numerics/BigInteger.cs
@@ -263,7 +263,7 @@ public BigInteger(ReadOnlySpan<byte> value, bool isUnsigned = false, bool isBigE
bool isNegative;
if (byteCount > 0)
{
byte mostSignificantByte = isBigEndian ? value[0] : value[byteCount - 1];
byte mostSignificantByte = isBigEndian ? value[0] : value[^1];
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Does this impact codegen at all? I could imagine this being equivalent to value.Length - 1, which might result in a secondary read from memory.

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Given the size of this method, I think 1 length load should be OK

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Probably and for consistency, I'd just like to know if it is impactful at all, so we can more readily pin-point any changes in the perf issue triage.

tannergooding
tannergooding approved these changes Jun 10, 2021
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CC. @pgovind can you review as well?

huoyaoyuan and others added 2 commits June 10, 2021 23:56
@huoyaoyuan @tannergooding
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3022198 
Co-authored-by: Tanner Gooding <tagoo@outlook.com>
@huoyaoyuan
Convert body-less for to while
b450c7a
pgovind
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LGTM!

@tannergooding tannergooding added the api-approved API was approved in API review, it can be implemented label Jun 10, 2021
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tannergooding commented Jun 10, 2021 •
edited by dotnet-api-review bot
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Thanks for the cleanup here!

@tannergooding tannergooding removed the api-approved API was approved in API review, it can be implemented label Jun 11, 2021
@karelz karelz mentioned this pull request Jun 24, 2021
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@terrajobst terrajobst added the community-contribution Indicates that the PR has been added by a community member label Jul 19, 2021
@jeffhandley
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As far as I can tell, this is ready to merge if the last leg turns green after re-running.

@pgovind I've assigned to you for follow-up before the RC1 snap, and I've restarted the leg.

@pgovind pgovind merged commit 65439de into dotnet:main Aug 2, 2021
@huoyaoyuan huoyaoyuan deleted the numerics-cleanup branch August 3, 2021 09:27
sakno added a commit to sakno/runtime that referenced this pull request Aug 5, 2021
@sakno
Manual merge with dotnet#53984 PR
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@stephentoub stephentoub mentioned this pull request Aug 12, 2021
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tannergooding added a commit to tannergooding/runtime that referenced this pull request Aug 12, 2021
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Revert "Minor cleanups for System.Runtime.Numerics (dotnet#53984)"
f4d4224 
This reverts commit 65439de.
tannergooding added a commit that referenced this pull request Aug 12, 2021
@tannergooding
Revert "Minor cleanups for System.Runtime.Numerics (#53984)" (#57297)
fcf276c 
This reverts commit 65439de.
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@tannergooding tannergooding tannergooding approved these changes

@pgovind pgovind pgovind approved these changes

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@huoyaoyuan @MartyIX @tannergooding @jeffhandley @stephentoub @pgovind @terrajobst