Fold static readonly struct X = <zero> to a jit-time const, e.g. Guid.Empty #77354

EgorBo · 2022-10-23T14:01:57Z

This PR does two things:

Imports all static readonly <struct> = 0 as ASG(struct, 0) - it's mostly for Guid.Empty (and e.g. decimal.Zero)
Adds AggressiveInlining to Guid.EqualsCore

Overall jit-diff (-f -cctors) is negative (-28473 bytes) so no significant size regressions due to AggressiveInlining.

Benchmark:

[Benchmark]
[ArgumentsSource(nameof(TestData1))]
public bool GuidIsEmpty(Guid g) => g == Guid.Empty; // test effect from AggressiveInling + .Empty folding

[Benchmark]
[ArgumentsSource(nameof(TestData2))]
public bool GuidsEqual(Guid g1, Guid g2) => g1 == g2; // test effect from AggressiveInling 

// Test data:

public static IEnumerable<Guid> TestData1()
{
    yield return Guid.Empty;
    yield return new Guid("503AA73D-DA86-4A7D-A369-192A1766DFA2");
}

public static IEnumerable<object[]> TestData2()
{
    yield return new object[]
    {
        new Guid("503AA73D-DA86-4A7D-A369-192A1766DFA2"), 
        Guid.Empty
    };
    yield return new object[]
    { 
        new Guid("503AA73D-DA86-4A7D-A369-192A1766DFA2"), 
        new Guid("503AA73D-DA86-4A7D-A369-192A1766DFA2")
    };
}

Method	Toolchain	Mean
GuidIsEmpty	\Core_Root\corerun.exe	0.3040 ns
GuidIsEmpty	\Core_Root_base\corerun.exe	1.0961 ns

GuidIsEmpty	\Core_Root\corerun.exe	0.3286 ns
GuidIsEmpty	\Core_Root_base\corerun.exe	1.0916 ns

GuidsEqual	\Core_Root\corerun.exe	0.4003 ns
GuidsEqual	\Core_Root_base\corerun.exe	0.9250 ns

GuidsEqual	\Core_Root\corerun.exe	0.4378 ns
GuidsEqual	\Core_Root_base\corerun.exe	0.9272 ns

Codegen diff

static bool IsEmpty(Guid g) => g == Guid.Empty;

Was:

; Assembly listing for method Program:IsEmpty(System.Guid):bool
G_M000_IG01:                ;; offset=0000H
       4883EC48             sub      rsp, 72
       C5F877               vzeroupper 
G_M000_IG02:                ;; offset=0007H
       C5F91001             vmovupd  xmm0, xmmword ptr [rcx]
       C5F911442438         vmovupd  xmmword ptr [rsp+38H], xmm0
       48B9980280E1FA010000 mov      rcx, 0x1FAE1800298 ;; boxed static Guid.Empty
       488B09               mov      rcx, gword ptr [rcx]
       C5F9104108           vmovupd  xmm0, xmmword ptr [rcx+08H]
       C5F911442428         vmovupd  xmmword ptr [rsp+28H], xmm0
       488D4C2438           lea      rcx, [rsp+38H]
       488D542428           lea      rdx, [rsp+28H]
       FF15AFB50E00         call     [System.Guid:EqualsCore(byref,byref):bool]
       90                   nop      
G_M000_IG03:                ;; offset=003AH
       4883C448             add      rsp, 72
       C3                   ret      
; Total bytes of code 63

Now:

; Assembly listing for method Program:IsEmpty(System.Guid):bool
G_M8154_IG01:              ;; offset=0000H
       4883EC28             sub      rsp, 40
       C5F877               vzeroupper 
G_M8154_IG02:              ;; offset=0007H
       C5F91001             vmovupd  xmm0, xmmword ptr [rcx]
       C5F911442418         vmovupd  xmmword ptr [rsp+18H], xmm0
       C5F857C0             vxorps   xmm0, xmm0, xmm0
       C5F911442408         vmovupd  xmmword ptr [rsp+08H], xmm0  ;; TODO: remove this spill
       C5FA6F442418         vmovdqu  xmm0, xmmword ptr [rsp+18H]
       C5F974442408         vpcmpeqb xmm0, xmm0, xmmword ptr [rsp+08H]
       C5F9D7C0             vpmovmskb eax, xmm0
       3DFFFF0000           cmp      eax, 0xFFFF
       0F94C0               sete     al
       0FB6C0               movzx    rax, al
G_M8154_IG03:              ;; offset=0036H
       4883C428             add      rsp, 40
       C3                   ret      
; Total bytes of code 59

ghost · 2022-10-23T14:02:06Z

Tagging subscribers to this area: @JulieLeeMSFT, @jakobbotsch
See info in area-owners.md if you want to be subscribed.

Issue Details

This PR does two things:

Imports all static readonly <struct> = 0 as ASG(struct, 0) - it's mostly for Guid.Empty
Adds AggressiveInlining to Guid.EqualsCore

Overall jit-diff (-f -cctors) is negative (-28473 bytes) so no significant size regressions due to AggressiveInlining.

Benchmark:

[Benchmark]
[ArgumentsSource(nameof(TestData1))]
public bool GuidIsEmpty(Guid g) => g == Guid.Empty;

[Benchmark]
[ArgumentsSource(nameof(TestData2))]
public bool GuidsEqual(Guid g1, Guid g2) => g1 == g2;

// Test data:

public static IEnumerable<Guid> TestData1()
{
    yield return Guid.Empty;
    yield return new Guid("503AA73D-DA86-4A7D-A369-192A1766DFA2");
}

public static IEnumerable<object[]> TestData2()
{
    yield return new object[]
    {
        new Guid("503AA73D-DA86-4A7D-A369-192A1766DFA2"), 
        Guid.Empty
    };
    yield return new object[]
    { 
        new Guid("503AA73D-DA86-4A7D-A369-192A1766DFA2"), 
        new Guid("503AA73D-DA86-4A7D-A369-192A1766DFA2")
    };
}

Method	Toolchain	Mean
GuidIsEmpty	\Core_Root\corerun.exe	0.3040 ns
GuidIsEmpty	\Core_Root_base\corerun.exe	1.0961 ns

GuidIsEmpty	\Core_Root\corerun.exe	0.3286 ns
GuidIsEmpty	\Core_Root_base\corerun.exe	1.0916 ns

GuidsEqual	\Core_Root\corerun.exe	0.4003 ns
GuidsEqual	\Core_Root_base\corerun.exe	0.9250 ns

GuidsEqual	\Core_Root\corerun.exe	0.4378 ns
GuidsEqual	\Core_Root_base\corerun.exe	0.9272 ns

Codegen diff

static bool IsEmpty(Guid g) => g == Guid.Empty;

Was:

; Assembly listing for method Program:IsEmpty(System.Guid):bool
G_M000_IG01:                ;; offset=0000H
       4883EC48             sub      rsp, 72
       C5F877               vzeroupper 
G_M000_IG02:                ;; offset=0007H
       C5F91001             vmovupd  xmm0, xmmword ptr [rcx]
       C5F911442438         vmovupd  xmmword ptr [rsp+38H], xmm0
       48B9980280E1FA010000 mov      rcx, 0x1FAE1800298
       488B09               mov      rcx, gword ptr [rcx]
       C5F9104108           vmovupd  xmm0, xmmword ptr [rcx+08H]
       C5F911442428         vmovupd  xmmword ptr [rsp+28H], xmm0
       488D4C2438           lea      rcx, [rsp+38H]
       488D542428           lea      rdx, [rsp+28H]
       FF15AFB50E00         call     [System.Guid:EqualsCore(byref,byref):bool]
       90                   nop      
G_M000_IG03:                ;; offset=003AH
       4883C448             add      rsp, 72
       C3                   ret      
; Total bytes of code 63

Now:

; Assembly listing for method Program:IsEmpty(System.Guid):bool
G_M8154_IG01:              ;; offset=0000H
       4883EC28             sub      rsp, 40
       C5F877               vzeroupper 
G_M8154_IG02:              ;; offset=0007H
       C5F91001             vmovupd  xmm0, xmmword ptr [rcx]
       C5F911442418         vmovupd  xmmword ptr [rsp+18H], xmm0
       C5F857C0             vxorps   xmm0, xmm0, xmm0
       C5F911442408         vmovupd  xmmword ptr [rsp+08H], xmm0  ;; TODO: remove this spill
       C5FA6F442418         vmovdqu  xmm0, xmmword ptr [rsp+18H]
       C5F974442408         vpcmpeqb xmm0, xmm0, xmmword ptr [rsp+08H]
       C5F9D7C0             vpmovmskb eax, xmm0
       3DFFFF0000           cmp      eax, 0xFFFF
       0F94C0               sete     al
       0FB6C0               movzx    rax, al
G_M8154_IG03:              ;; offset=0036H
       4883C428             add      rsp, 40
       C3                   ret      
; Total bytes of code 59

Author:	EgorBo
Assignees:	-
Labels:	`area-CodeGen-coreclr`
Milestone:	-

EgorBo · 2022-10-23T14:28:26Z

static decimal Test() => decimal.Zero;

Codegen diff:

; Assembly listing for method Program:Test():System.Decimal
       C5F877               vzeroupper 
-      48B86000C07FC0020000 mov      rax, 0x2C07FC00060
-      488B00               mov      rax, gword ptr [rax]
-      C5F9104008           vmovupd  xmm0, xmmword ptr [rax+08H]
+      C5F857C0             vxorps   xmm0, xmm0
       C5F91101             vmovupd  xmmword ptr [rcx], xmm0
       488BC1               mov      rax, rcx
       C3                   ret      
; Total bytes of code 29

src/coreclr/jit/importer.cpp

EgorBo · 2022-10-23T22:59:46Z

it's ready for review: @dotnet/jit-contrib @AndyAyersMS @SingleAccretion PTAL

src/coreclr/jit/importer.cpp

EgorBo · 2022-10-25T14:51:28Z

@jakobbotsch @AndyAyersMS PTAL

Import large empty structs as ASG(struct, 0)

96b00b2

dotnet-issue-labeler bot added the area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI label Oct 23, 2022

ghost assigned EgorBo Oct 23, 2022

EgorBo added 2 commits October 23, 2022 16:42

Update importer.cpp

524723c

Update importer.cpp

2b95c2e

SingleAccretion reviewed Oct 23, 2022

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SingleAccretion reviewed Oct 23, 2022

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src/coreclr/jit/importer.cpp Outdated Show resolved Hide resolved

Simplify logic

99085f7

EgorBo changed the title ~~Optimize comparisons against Guid.Empty~~ Fold static readonly struct X = <zero> to a jit-time const, e.g. Guid.Empty Oct 23, 2022

Fix asserts

c4a7a08

SingleAccretion reviewed Oct 23, 2022

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src/coreclr/jit/importer.cpp Outdated Show resolved Hide resolved

Fix simd case

fbe201d

runfoapp bot mentioned this pull request Oct 24, 2022

Infra improvements for Helix #68176

Closed

AndyAyersMS approved these changes Oct 25, 2022

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EgorBo merged commit 609ef46 into dotnet:main Oct 25, 2022

This was referenced Nov 1, 2022

[Perf] Alpine/x64: 24 Regressions on 10/25/2022 7:09:53 PM dotnet/perf-autofiling-issues#9390

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[Perf] Linux/x64: 32 Regressions on 10/25/2022 7:09:53 PM dotnet/perf-autofiling-issues#9302

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lewing mentioned this pull request Nov 3, 2022

[Perf] Linux/x64: 4 Improvements on 10/25/2022 7:09:53 PM dotnet/perf-autofiling-issues#9366

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kunalspathak mentioned this pull request Nov 18, 2022

Test failure System.Numerics.Tests.ComplexTests.Reciprocal(real: 0, imaginary: -1) #78298

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Fold static readonly struct X = <zero> to a jit-time const, e.g. Guid.Empty #77354

Fold static readonly struct X = <zero> to a jit-time const, e.g. Guid.Empty #77354

EgorBo commented Oct 23, 2022 •

edited

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ghost commented Oct 23, 2022

Codegen diff

EgorBo commented Oct 23, 2022 •

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EgorBo commented Oct 23, 2022

EgorBo commented Oct 25, 2022

Fold static readonly struct X = <zero> to a jit-time const, e.g. Guid.Empty #77354

Fold static readonly struct X = <zero> to a jit-time const, e.g. Guid.Empty #77354

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