[Wasm RyuJIT] Codegen for Const Vector Create and Basic Packed SIMD operations by adamperlin · Pull Request #129703 · dotnet/runtime

adamperlin · 2026-06-22T18:02:00Z

This PR implements support for Vector128.Create on Wasm with known constant args, as well as table-driven expansion and codegen for a large set of PackedSimd opcodes that operate on v128, (v128, v128) and (v128, v128, v128) type operands.

Notably absent from this PR: Vector128.Create with non-constants (requires additional lowering work), and SIMD compares (need special codegen for ulong since i64_u compare is not natively supported on Wasm).

Enable Wasm SIMD ISA for use in the JIT

…-basic-simd

…ector operands)

…simd, simd) param type operations (no integer operands or immediates supported yet)

dotnet-policy-service · 2026-06-22T18:03:16Z

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Copilot

Pull request overview

This PR extends CoreCLR’s Wasm (RyuJIT) pipeline to recognize Wasm SIMD instruction-set support and begin emitting v128 SIMD code, including constant Vector128.Create lowering to v128.const and table-driven codegen for many PackedSimd operations.

Changes:

Enable Wasm ISA flags (WasmBase, PackedSimd, Vector128) and wire up instruction-set support for Wasm32 (base, simd128).
Add GT_CNS_VEC emission via v128.const, plus v128 load/store selection for TYP_SIMD16.
Introduce initial importer/list/codegen plumbing for PackedSimd and Vector128.Create constants.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems	Enables `SupportsWasmIntrinsics` for CoreCLR Wasm builds.
src/coreclr/tools/Common/InstructionSetHelpers.cs	Adds Wasm32 baseline instruction sets (`base`, `simd128`).
src/coreclr/jit/lowerwasm.cpp	Starts allowing SIMD-category `GT_HWINTRINSIC` through lowering.
src/coreclr/jit/lower.cpp	Relaxes `TYP_SIMD12` assert for Wasm during lowering checks.
src/coreclr/jit/instr.cpp	Adds Wasm `v128_load`/`v128_store` mapping for `TYP_SIMD16`.
src/coreclr/jit/hwintrinsicwasm.cpp	Implements constant `Vector128.Create` import to `GT_CNS_VEC`.
src/coreclr/jit/hwintrinsiclistwasm.h	Adds `PackedSimd` intrinsic definitions and updates some `Vector128` entries.
src/coreclr/jit/hwintrinsiccodegenwasm.cpp	Adds initial table-driven Wasm HW intrinsic emission.
src/coreclr/jit/hwintrinsic.h	Adds a Wasm `HWIntrinsic` helper wrapper (but currently has a preprocessor issue).
src/coreclr/jit/hwintrinsic.cpp	Adds Wasm `PackedSimd` ISA range and simdSize validation for Wasm.
src/coreclr/jit/compiler.cpp	Forces Wasm baseline ISAs into JIT supported set, adds `Vector128`.
src/coreclr/jit/codegenwasm.cpp	Adds `GT_HWINTRINSIC` dispatch and `GT_CNS_VEC` emission (`v128.const`).
src/coreclr/jit/codegen.h	Declares Wasm vector-constant codegen helper.

Copilot

Pull request overview

Copilot reviewed 13 out of 13 changed files in this pull request and generated 7 comments.

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Copilot

Pull request overview

Copilot reviewed 13 out of 13 changed files in this pull request and generated 4 comments.

…case in SPMI (can happen if NYI_WASM_SIMD fires during import)

Copilot

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated 3 comments.

    <SupportsWasmIntrinsics Condition="'$(Platform)' == 'wasm' and '$(FeatureMono)' == 'true'">true</SupportsWasmIntrinsics>
+    <SupportsWasmIntrinsics Condition="'$(Platform)' == 'wasm' and '$(FeatureCoreCLR)' == 'true'">true</SupportsWasmIntrinsics>
    <SupportsWasmIntrinsics Condition="'$(SupportsWasmIntrinsics)' == ''">false</SupportsWasmIntrinsics>


+#define FIRST_NI_PackedSimd NI_PackedSimd_Abs
+HARDWARE_INTRINSIC(PackedSimd,    Abs,                                16,  1,   {INS_i8x16_abs, INS_invalid, INS_i16x8_abs, INS_invalid, INS_i32x4_abs, INS_invalid, INS_i64x2_abs, INS_invalid, INS_f32x4_abs, INS_f64x2_abs}, HW_Category_SIMD, HW_Flag_BaseTypeFromFirstArg)
+HARDWARE_INTRINSIC(PackedSimd,    Add,                                16,  2,   {INS_i8x16_add, INS_i8x16_add, INS_i16x8_add, INS_i16x8_add, INS_i32x4_add, INS_i32x4_add, INS_i64x2_add, INS_i64x2_add, INS_f32x4_add, INS_f64x2_add}, HW_Category_SIMD, HW_Flag_BaseTypeFromFirstArg|HW_Flag_Commutative)
+HARDWARE_INTRINSIC(PackedSimd,    AddPairwiseWidening,                16,  1,   {INS_i16x8_extadd_pairwise_s_i8x16, INS_i16x8_extadd_pairwise_u_i8x16, INS_i32x4_extadd_pairwise_s_i16x8, INS_i32x4_extadd_pairwise_u_i16x8, INS_invalid, INS_invalid, INS_invalid, INS_invalid, INS_invalid, INS_invalid}, HW_Category_SIMD, HW_Flag_BaseTypeFromFirstArg)
+HARDWARE_INTRINSIC(PackedSimd,    AddSaturate,                        16,  2,   {INS_i8x16_add_sat_s, INS_i8x16_add_sat_u, INS_i16x8_add_sat_s, INS_i16x8_add_sat_u, INS_invalid, INS_invalid, INS_invalid, INS_invalid, INS_invalid, INS_invalid}, HW_Category_SIMD, HW_Flag_BaseTypeFromFirstArg|HW_Flag_Commutative)


AndyAyersMS

I don't have anything to add over what copilot has pointed out.

I'll take another look when you've sorted through that; ping me.

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

…tor elements

Copilot

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated 4 comments.

Copilot

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated 1 comment.

+void CodeGen::genCodeForVectorConstant(GenTree* treeNode)
+{
+    assert(treeNode->IsCnsVec());
+    GenTreeVecCon* vecCon = treeNode->AsVecCon();
+
+    // There is only one type variant for v128.const, v128.const <byte[16]>
+    // and the bytes are reinterpreted according to whichever operation consumes the value.
+    GetEmitter()->emitIns_V128Imm(INS_v128_const, vecCon->gtSimd16Val.u8);
+    WasmProduceReg(treeNode);
+}


adamperlin added 8 commits June 17, 2026 15:05

Implement Wasm codegen for Vector128.Create with const operands

a1cd1f8

Enable Wasm SIMD ISA for use in the JIT

Merge branch 'main' of github.com:dotnet/runtime into adamperlin/wasm…

2921181

…-basic-simd

Fix categories and flags for some Vector128 Wasm hardware intrinsics

f4fd2fe

Checkpoint: PackedSimd.Add now compiles as an intrinsic (with const v…

48e0731

…ector operands)

Add a few more PackedSimd intrinsics

7bf550b

Add table-driven codegen entries for (simd), (simd, simd) and (simd, …

50f2359

…simd, simd) param type operations (no integer operands or immediates supported yet)

Add ifdefs and remove not fully implemented opcode

250aa59

Cleanup (for now) unused code

3766e1b

adamperlin requested a review from MichalStrehovsky as a code owner June 22, 2026 18:02

Copilot AI review requested due to automatic review settings June 22, 2026 18:02

github-actions Bot added the area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI label Jun 22, 2026

dotnet-policy-service Bot assigned adamperlin Jun 22, 2026

adamperlin requested review from AndyAyersMS and tannergooding June 22, 2026 18:04

Add #if FEATURE_SIMD

46ae244

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adamperlin added 2 commits June 22, 2026 11:50

jit-format

cb5a7e9

Fix ifdef condition syntax

c0f347d

Copilot AI review requested due to automatic review settings June 22, 2026 18:54

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Apply suggestions from code review

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Copilot AI review requested due to automatic review settings June 22, 2026 19:32

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Comment thread src/coreclr/jit/hwintrinsicwasm.cpp

Comment thread src/coreclr/jit/hwintrinsicwasm.cpp

Comment thread src/coreclr/jit/hwintrinsicwasm.cpp

Comment thread src/coreclr/jit/hwintrinsic.cpp Outdated

build-analysis Bot mentioned this pull request Jun 22, 2026

Intermittent build failure in AfterSourceBuild: "Could not write state file" #76488

Closed

Fix unconditional NYI_WASM_SIMD lower bailout, handle no disasm file …

628c47a

…case in SPMI (can happen if NYI_WASM_SIMD fires during import)

adamperlin commented Jun 23, 2026

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Comment thread src/coreclr/jit/instr.cpp

Comment thread src/coreclr/jit/hwintrinsicwasm.cpp

Remove TODO

4c056e3

Copilot AI review requested due to automatic review settings June 23, 2026 00:29

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AndyAyersMS reviewed Jun 23, 2026

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Potential fix for pull request finding

10ff35c

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Copilot AI review requested due to automatic review settings June 23, 2026 18:33

Copilot started reviewing on behalf of adamperlin June 23, 2026 18:33 View session

Copilot feedback: remove unconditional import NYI on non-constant vec…

6ecc662

…tor elements

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Comment thread src/coreclr/jit/hwintrinsiclistwasm.h Outdated

Comment thread src/coreclr/jit/hwintrinsiclistwasm.h Outdated

Comment thread src/coreclr/scripts/superpmi.py Outdated

Comment thread src/coreclr/jit/hwintrinsicwasm.cpp

adamperlin added 2 commits June 23, 2026 12:09

Format hwintrinsiclistwasm.h

292bcaf

More copilot feedback

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