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Investigate emitting movq for the CreateScalarUnsafe helper intrinsics that take a long/ulong on x86 #11626

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#112728
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Investigate emitting movq for the CreateScalarUnsafe helper intrinsics that take a long/ulong on x86#11626
#112728
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arch-x86area-CodeGen-coreclrCLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMIin-prThere is an active PR which will close this issue when it is merged
Milestone
Future

Description

@tannergooding
tannergooding
opened on Dec 6, 2018

For the CreateScalarUnsafe helper intrinsics that take a long/ulong, it may be beneficial to emit the movq xmm, [mem] instruction on x86, rather than falling back to emulating the behavior in software.

Given that the input is a regular long/ulong, but on x86 the instruction requires the second operand come from memory, this may require some additional work to make happen or we may find it not worthwhile to do at all.

category:cq
theme:hardware-intrinsics
skill-level:beginner
cost:small

Activity

  1. tannergooding commented on Dec 6, 2018

    @tannergooding
    tannergooding
    on Dec 6, 2018
    MemberAuthor

    CC. @CarolEidt, @fiigii

    As per https://github.com/dotnet/coreclr/pull/21351/files/ff31bc6a186a15cd9395928c546e82de077f7246#r239645439

  2. CarolEidt commented on Dec 6, 2018

    @CarolEidt
    CarolEidt
    on Dec 6, 2018
    Contributor

    @tannergooding - thanks for capturing this.

  3. msftgits
    transferred this issue fromdotnet/coreclron Jan 31, 2020
  4. msftgits
    added this to the Future milestone on Jan 31, 2020

  5. anthonycanino commented on Sep 12, 2022

    @anthonycanino
    anthonycanino
    on Sep 12, 2022
    Contributor

    @tannergooding I think this is no longer applicable.

    On SharpLab

    using System;

using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.X86;

public class C {
    public Vector128<long> Foo(long u1) {
        return Vector128.CreateScalarUnsafe(u1);
    }
}

    gives

    C.Foo(Int64)
    L0000: vzeroupper
    L0003: vmovq xmm0, r8
    L0008: vmovupd [rdx], xmm0
    L000c: mov rax, rdx
    L000f: ret

  6. saucecontrol commented on Sep 12, 2022

    @saucecontrol
    saucecontrol
    on Sep 12, 2022
    Member

    mov rax, rdx

    that's x64 code.

    here's x86

    C.Foo(Int64)
    L0000: push dword ptr [esp+8]
    L0004: push dword ptr [esp+8]
    L0008: mov ecx, edx
    L000a: call System.Runtime.Intrinsics.Vector128.CreateScalarUnsafe(Int64)
    L000f: ret 8

  7. anthonycanino commented on Sep 12, 2022

    @anthonycanino
    anthonycanino
    on Sep 12, 2022
    Contributor

    Got it --- thanks for that. My mistake.

  8. dotnet-policy-service
    added
    in-prThere is an active PR which will close this issue when it is merged
    on Feb 28, 2025
  9. BruceForstall
    closed this as completedin #112728on Mar 20, 2025
  10. github-actions
    locked and limited conversation to collaborators on Apr 19, 2025
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