[SM6.10] Add LinAng Matrix attributes and two new attributed matrix types by hekota · Pull Request #8125 · microsoft/DirectXShaderCompiler

hekota · 2026-02-02T01:25:11Z

Adds new type attribute __LinAlg_Matrix_Attributes that can be attached to __builtin_LinAlg_Matrix built-in matrix handle type to specify the matrix component type, dimensions, use and scope. Includes enabling C11++ -style attributes on types in DXC.

Adds two new AST types that are used to capture the information from the attribute:

AttributedLinAlgMatrixType type is used when the attribute specifies concrete matrix parameters
DependentAttributedLinAlgMatrixType is for cases where the type attributes arguments are dependent on template instantiation

The AttributedLinAlgMatrixType is linked to LinAlgMatrix type alias used in gen_intrin_main.txt for built-in function APIs.

This change also adds the outline of the LinAlg Matrix template class to dx/linalg.h, including the enumeration types used as arguments to the new attribute and as template parameters of Matrix.

Note that the ComponentType enum in dx/linalg.h is defined using values matching the existing internal ComponentType enum that was added in SM 6.9 for cooperative vectors. This is different from the current LinAlg spec. The issue to update the spec is microsoft/hlsl-specs#779.

Fixes #8122

Adds a built-in type `__builtin_LinAlg_Matrix` that will be used in LinAlg Matrix implementation.

…iler into matrix-builtin-handle-type

Fixes microsoft#8122

tools/clang/include/clang/AST/DataRecursiveASTVisitor.h

tools/clang/include/clang/AST/RecursiveASTVisitor.h

tools/clang/include/clang/AST/Type.h

tools/clang/lib/AST/ASTDumper.cpp

tools/clang/lib/Parse/ParseDeclCXX.cpp

tools/clang/lib/Serialization/ASTWriter.cpp

tools/clang/test/SemaHLSL/hlsl/linalg/linalg-matrix-error.hlsl

tex3d · 2026-02-03T00:42:12Z

tools/clang/test/SemaHLSL/hlsl/linalg/linalg-matrix-error.hlsl

+    __builtin_LinAlg_Matrix [[__LinAlg_Matrix_Attributes(ComponentType::I32, 4, 5, MatrixUse::B, MatrixScope::ThreadGroup)]] mat8;
+
+    // expected-error@+1 {{cannot initialize a variable of type '__builtin_LinAlg_Matrix' with an lvalue of type '__builtin_LinAlg_Matrix [[__LinAlg_Matrix_Attributes(ComponentType::I32, 4, 5, MatrixUse::B, MatrixScope::ThreadGroup)]]'}}
+    __builtin_LinAlg_Matrix naked_mat = mat8;


Should it be illegal to declare this type without attributes? Is that the reason for TMP?

We could make it illegal by intercepting every place where a type can be used and adding a special check and error if it is the __builtin_LinAlgMatrix without attributes. Or we can do nothing because the naked typed cannot be used for anything anyway. The __builtin prefix means users should not be using these directly.

tools/clang/lib/Sema/SemaHLSL.cpp

tex3d · 2026-02-03T00:54:09Z

tools/clang/lib/Sema/SemaHLSL.cpp

+
+  // Check that the value is a valid range.
+  int64_t Value = APVal.getLimitedValue();
+  if (Value < 0) {


Should we enforce any maximum?

The spec has maximums for the K dimension but no specified maximum the M or N dimensions:

| Matrix Scope | Scalar element dimensions | | ------------ | ------------------------- | | Thread | [4,128] | | Wave | [4,128] | | ThreadGroup | [1,1024] |

The "scalar element" refers to the dimensions being 4x that number if the data type is an 8-bit type represented in packed data types.

…://github.com/microsoft/DirectXShaderCompiler into linalg-matrix-attributes-and-types

V-FEXrt

LGTM but I did a very rush job on the review. Wanted to mark my general approval before being out the next couple days

github-actions · 2026-02-03T02:31:44Z

✅ With the latest revision this PR passed the C/C++ code formatter.

llvm-beanz

There's a lot of boilerplate here, but it all looks pretty reasonable to me.

llvm-beanz · 2026-02-05T00:20:59Z

tools/clang/lib/Headers/hlsl/dx/linalg.h

+#ifdef __hlsl_dx_compiler
+#define SIZE_TYPE int
+#else
+#define SIZE_TYPE uint
+#endif


I don't expect that this header will be portable to clang, so for the purposes of DXC we can simplify this to just:

Suggested change

#ifdef __hlsl_dx_compiler

#define SIZE_TYPE int

#else

#define SIZE_TYPE uint

#endif

#define SIZE_TYPE int

We should probably file an issue to decide what to do about size types generally in HLSL. I don't love that DXC decided size types were signed 32-bit integers, but we may want Clang to match that for at least some language modes (cc @tex3d & @bogner for visibility about Clang and language spec issues).

llvm-beanz · 2026-02-05T00:30:28Z

tools/clang/lib/Sema/SemaHLSL.cpp

+
+  // Check that the value is a valid range.
+  int64_t Value = APVal.getLimitedValue();
+  if (Value < 0) {


The spec has maximums for the K dimension but no specified maximum the M or N dimensions:

| Matrix Scope | Scalar element dimensions | | ------------ | ------------------------- | | Thread | [4,128] | | Wave | [4,128] | | ThreadGroup | [1,1024] |

The "scalar element" refers to the dimensions being 4x that number if the data type is an 8-bit type represented in packed data types.

tools/clang/lib/Sema/SemaHLSL.cpp

…ectly in error reporting

…iler into linalg-matrix-attributes-and-types

pow2clk

I just implemented almost this exact change, so I had many thoughts. Nothing is really blocking, but some things you may want to consider

tools/clang/lib/AST/TypePrinter.cpp

tools/clang/include/clang/Basic/DiagnosticSemaKinds.td

tools/clang/lib/Sema/SemaHLSL.cpp

include/dxc/dxcapi.internal.h

tools/clang/include/clang/AST/DataRecursiveASTVisitor.h

tools/clang/include/clang/AST/Type.h

tools/clang/include/clang/Serialization/ASTBitCodes.h

tools/clang/lib/AST/ASTDumper.cpp

tools/clang/lib/AST/TypePrinter.cpp

tools/clang/include/clang/Basic/Attr.td

V-FEXrt · 2026-02-06T23:54:01Z

tools/clang/lib/Headers/hlsl/dx/linalg.h


 #endif // SM 6.9 check and HV version check
+
+#if ((__SHADER_TARGET_MAJOR > 6) ||                                            \


Personally I'd like this to not be in the same file as the coopvec header code. Imo that's going to cause a lot of confusion.

Maybe we rename the old file to coopvec.h and note it as a breaking change in the next release? If that doesn't work we should create a new file for the new code

V-FEXrt · 2026-02-06T23:55:22Z

tools/clang/lib/Headers/hlsl/dx/linalg.h

+template <ComponentEnum ComponentTy, SIZE_TYPE M, SIZE_TYPE N,
+          MatrixUseEnum Use, MatrixScopeEnum Scope>
+class Matrix {
+  int TestField;


Suggested change

int TestField;

V-FEXrt · 2026-02-07T00:08:34Z

utils/hct/hctdb.py

            Node\w* | RWNode\w* | EmptyNode\w* |
            AnyNodeOutput\w* | NodeOutputRecord\w* | GroupShared\w* |
-            VkBufferPointer
+            VkBufferPointer |  LinAlgMatrix


Suggested change

VkBufferPointer | LinAlgMatrix

VkBufferPointer | LinAlgMatrix

hekota and others added 9 commits January 22, 2026 12:54

[SM6.10] Add built-in type for LinAlg Matrix handle

5390e54

Adds a built-in type `__builtin_LinAlg_Matrix` that will be used in LinAlg Matrix implementation.

Fallback to default debug infor handling

be693b2

Fix type name string

ed855c6

chore: autopublish 2026-01-29T18:27:59Z

9b6f7a7

Merge branch 'main' of https://github.com/microsoft/DirectXShaderComp…

deaac93

…iler into matrix-builtin-handle-type

Move tests back under linalg/builtins

716c63a

Update __buitin_LinAlg_Matrix codegen

8e956a8

Merge branch 'main' of https://github.com/microsoft/DirectXShaderComp…

2e32605

…iler into matrix-builtin-handle-type

Add LinAng Matrix attributes and two new attributed matrix types

3065524

Fixes microsoft#8122

github-project-automation bot added this to HLSL Roadmap Feb 2, 2026

github-project-automation bot moved this to New in HLSL Roadmap Feb 2, 2026

hekota marked this pull request as ready for review February 2, 2026 18:14

hekota requested a review from llvm-beanz February 2, 2026 18:15

hekota changed the title ~~Add LinAng Matrix attributes and two new attributed matrix types~~ [SM6.10] Add LinAng Matrix attributes and two new attributed matrix types Feb 2, 2026

hekota linked an issue Feb 2, 2026 that may be closed by this pull request

Implement attributed matrix handle in the AST #8122

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tex3d reviewed Feb 2, 2026

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hekota mentioned this pull request Feb 3, 2026

[SM6.10] Add built-in type for LinAlg Matrix handle #8090

Merged

Code review feedback

e9a6bb6

tex3d reviewed Feb 3, 2026

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hekota added 2 commits February 2, 2026 17:09

Rename the type to __builtin_LinAlgMatrix

eea0b2b

Merge branch 'user/hekota/pr8090-matrix-builtin-handle-type' of https…

94a389f

…://github.com/microsoft/DirectXShaderCompiler into linalg-matrix-attributes-and-types

V-FEXrt reviewed Feb 3, 2026

View reviewed changes

Rename attributes to __LinAlgMatrix_Attributes

c0f4761

hekota and others added 5 commits February 2, 2026 19:04

code review feedback - add missing attributes, remove stale comments

cd120b0

Do not break spirv C++11-style attributes

7f61a48

Few more changes (alignment and type visiting)

f63ceb0

one more rename

57a71b0

chore: autopublish 2026-02-04T18:29:11Z

afe3f11

llvm-beanz reviewed Feb 5, 2026

View reviewed changes

hekota added 2 commits February 4, 2026 17:05

code review feedback - simplify SIZE_TYPE definition, use numbers dir…

d4b899d

…ectly in error reporting

Merge branch 'main' of https://github.com/microsoft/DirectXShaderComp…

9bce569

…iler into linalg-matrix-attributes-and-types

hekota changed the base branch from user/hekota/pr8090-matrix-builtin-handle-type to main February 5, 2026 01:09

pow2clk reviewed Feb 5, 2026

View reviewed changes

hekota added 3 commits February 5, 2026 10:06

fix build break

ec83c2d

fix bad merge (or accidentally removed code?)

d4ad293

code review feedback

0f73d5d

V-FEXrt approved these changes Feb 7, 2026

View reviewed changes


		#endif // SM 6.9 check and HV version check

		#if ((__SHADER_TARGET_MAJOR > 6) \|\| \

	VkBufferPointer \| LinAlgMatrix
	VkBufferPointer \| LinAlgMatrix

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