[clang] [Matrix] Add a row\col major toggle in the clang driver (PR #167628)
Farzon Lotfi via cfe-commits
cfe-commits at lists.llvm.org
Wed Nov 26 10:44:30 PST 2025
https://github.com/farzonl updated https://github.com/llvm/llvm-project/pull/167628
>From aff57766dd1d9a02cb32b0a5603a1fb028f4bb0a Mon Sep 17 00:00:00 2001
From: Farzon Lotfi <farzonlotfi at microsoft.com>
Date: Tue, 11 Nov 2025 22:13:57 -0500
Subject: [PATCH 1/9] [Matrix] Add a row\col major toggle in the clang driver
fixes #167621
- define the new options in `Options.td` limit the naming to row-major or
column-major.
- In `ToolChains/Clang.cpp` limit the opt usage to only when
`-fenable-matrix` is used.
- make sure we set the flags llvm needs for the lower-matrix-intrinsics
pass.
---
clang/include/clang/Options/Options.td | 5 +++
clang/lib/Driver/ToolChains/Clang.cpp | 11 +++++++
clang/test/Driver/fmatrix-default-layout.c | 38 ++++++++++++++++++++++
3 files changed, 54 insertions(+)
create mode 100644 clang/test/Driver/fmatrix-default-layout.c
diff --git a/clang/include/clang/Options/Options.td b/clang/include/clang/Options/Options.td
index a8fc1c4326cc5..86ce67f6ff237 100644
--- a/clang/include/clang/Options/Options.td
+++ b/clang/include/clang/Options/Options.td
@@ -4664,6 +4664,11 @@ def fenable_matrix : Flag<["-"], "fenable-matrix">, Group<f_Group>,
HelpText<"Enable matrix data type and related builtin functions">,
MarshallingInfoFlag<LangOpts<"MatrixTypes">, hlsl.KeyPath>;
+def fmatrix_default_layout_EQ : Joined<["-"], "fmatrix-default-layout=">,
+ HelpText<"Set default matrix layout (row-major or column-major)">,
+ Values<"row-major,column-major">,
+ Group<f_Group>;
+
defm raw_string_literals : BoolFOption<"raw-string-literals",
LangOpts<"RawStringLiterals">, Default<std#".hasRawStringLiterals()">,
PosFlag<SetTrue, [], [], "Enable">,
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index c5d40c9825fab..a3aabbc35b043 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -5692,6 +5692,17 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
CmdArgs.push_back("-fenable-matrix");
CmdArgs.push_back("-mllvm");
CmdArgs.push_back("-enable-matrix");
+ // Only handle default layout if matrix is enabled
+ if (const Arg *A =
+ Args.getLastArg(options::OPT_fmatrix_default_layout_EQ)) {
+ StringRef Val = A->getValue();
+ if (Val == "row-major" || Val == "column-major") {
+ CmdArgs.push_back("-mllvm");
+ CmdArgs.push_back(Args.MakeArgString("-matrix-default-layout=" + Val));
+ } else {
+ D.Diag(diag::err_drv_invalid_value) << A->getAsString(Args) << Val;
+ }
+ }
}
CodeGenOptions::FramePointerKind FPKeepKind =
diff --git a/clang/test/Driver/fmatrix-default-layout.c b/clang/test/Driver/fmatrix-default-layout.c
new file mode 100644
index 0000000000000..c89396f4452f6
--- /dev/null
+++ b/clang/test/Driver/fmatrix-default-layout.c
@@ -0,0 +1,38 @@
+// RUN: %clang --target=x86_64-linux-gnu -fenable-matrix -fmatrix-default-layout=column-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-COL-MAJOR
+// CHECK-COL-MAJOR: -fenable-matrix
+// CHECK-COL-MAJOR: -mllvm
+// CHECK-COL-MAJOR: -enable-matrix
+// CHECK-COL-MAJOR: -mllvm
+// CHECK-COL-MAJOR: -matrix-default-layout=column-major
+
+// RUN: %clang --target=x86_64-linux-gnu -fenable-matrix -fmatrix-default-layout=row-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ROW-MAJOR
+// CHECK-ROW-MAJOR: -fenable-matrix
+// CHECK-ROW-MAJOR: -mllvm
+// CHECK-ROW-MAJOR: -enable-matrix
+// CHECK-ROW-MAJOR: -mllvm
+// CHECK-ROW-MAJOR: -matrix-default-layout=row-major
+
+// RUN: not %clang --target=x86_64-linux-gnu -fenable-matrix -fmatrix-default-layout=error-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ERROR-MAJOR
+// CHECK-ERROR-MAJOR: error: invalid value 'error-major' in '-fmatrix-default-layout=error-major'
+
+// RUN: %clang --target=x86_64-linux-gnu -fmatrix-default-layout=column-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-COL-MAJOR-DISABLED
+// CHECK-COL-MAJOR-DISABLED-NOT: -fenable-matrix
+// CHECK-COL-MAJOR-DISABLED-NOT: -mllvm
+// CHECK-COL-MAJOR-DISABLED-NOT: -enable-matrix
+// CHECK-COL-MAJOR-DISABLED-NOT: -mllvm
+// CHECK-COL-MAJOR-DISABLED-NOT: -matrix-default-layout=column-major
+
+// RUN: %clang --target=x86_64-linux-gnu -fmatrix-default-layout=row-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ROW-MAJOR-DISABLED
+// CHECK-ROW-MAJOR-DISABLED-NOT: -fenable-matrix
+// CHECK-ROW-MAJOR-DISABLED-NOT: -mllvm
+// CHECK-ROW-MAJOR-DISABLED-NOT: -enable-matrix
+// CHECK-ROW-MAJOR-DISABLED-NOT: -mllvm
+// CHECK-ROW-MAJOR-DISABLED-NOT: -matrix-default-layout=row-major
+
+// RUN: %clang --target=x86_64-linux-gnu -fenable-matrix %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-MATRIX-ENABLED
+// CHECK-MATRIX-ENABLED: -fenable-matrix
+// CHECK-MATRIX-ENABLED: -mllvm
+// CHECK-MATRIX-ENABLED: -enable-matrix
+// CHECK-MATRIX-ENABLED-NOT: -mllvm
+// CHECK-MATRIX-ENABLED-NOT: -matrix-default-layout=row-major
+// CHECK-MATRIX-ENABLED-NOT: -matrix-default-layout=column-major
>From a025783bb34f443e80423d1846f4f841b6f7b759 Mon Sep 17 00:00:00 2001
From: Farzon Lotfi <farzonlotfi at microsoft.com>
Date: Wed, 12 Nov 2025 18:51:44 -0500
Subject: [PATCH 2/9] add new documentation to address pr concerns
---
clang/docs/LanguageExtensions.rst | 5 +++++
clang/docs/MatrixTypes.rst | 5 +++++
clang/docs/ReleaseNotes.rst | 1 +
3 files changed, 11 insertions(+)
diff --git a/clang/docs/LanguageExtensions.rst b/clang/docs/LanguageExtensions.rst
index a3db3e5d356b3..88abc270fccf6 100644
--- a/clang/docs/LanguageExtensions.rst
+++ b/clang/docs/LanguageExtensions.rst
@@ -1073,6 +1073,11 @@ The matrix type extension supports explicit casts. Implicit type conversion betw
i = static_cast<matrix_5_5<int>>(d);
}
+The matrix type extension will support column and row major layouts. The flag
+to change this behavior is `-fmatrix-default-layout` used like so
+`-fmatrix-default-layout=column-major` for column major and like so
+`-fmatrix-default-layout=row-major` for row major.
+
Half-Precision Floating Point
=============================
diff --git a/clang/docs/MatrixTypes.rst b/clang/docs/MatrixTypes.rst
index b3a2c8cf53670..6c5392149a814 100644
--- a/clang/docs/MatrixTypes.rst
+++ b/clang/docs/MatrixTypes.rst
@@ -287,6 +287,11 @@ part of the draft specification.
The elements of a value of a matrix type are laid out in column-major order
without padding.
+To change the default order to row major use the `-fmatrix-default-layout` flag.
+This flag supports two flag argument values either `column-major` or `row-major`
+used like so `-fmatrix-default-layout=column-major`.` This flag controls the
+memory layout of matrix types.
+
We propose to provide a Clang option to override this behavior and allow
contraction of those operations (e.g. *-ffp-contract=matrix*).
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 51f07256c5d9f..e03de8198b244 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -327,6 +327,7 @@ New Compiler Flags
- New option ``-fsanitize-debug-trap-reasons=`` added to control emitting trap reasons into the debug info when compiling with trapping UBSan (e.g. ``-fsanitize-trap=undefined``).
- New options for enabling allocation token instrumentation: ``-fsanitize=alloc-token``, ``-falloc-token-max=``, ``-fsanitize-alloc-token-fast-abi``, ``-fsanitize-alloc-token-extended``.
- The ``-resource-dir`` option is now displayed in the list of options shown by ``--help``.
+- New option ``-fmatrix-default-layout`` added to control the memory layout of Clang matrix types. (e.g. ``-fmatrix-default-layout=column-major`` or ``-fmatrix-default-layout=row-major``).
Lanai Support
^^^^^^^^^^^^^^
>From c3e1f76a30dfb9e6ef80a00c364865d2b78b334a Mon Sep 17 00:00:00 2001
From: Farzon Lotfi <farzonlotfi at microsoft.com>
Date: Fri, 14 Nov 2025 14:57:54 -0500
Subject: [PATCH 3/9] Address pr comments, drop the -mllvm flags make this just
about memory layout. So this change actually does something move the lang opt
changes into this pr
---
clang/docs/LanguageExtensions.rst | 6 +--
clang/docs/MatrixTypes.rst | 5 +--
clang/docs/ReleaseNotes.rst | 2 +-
clang/include/clang/Basic/LangOptions.def | 1 +
clang/include/clang/Basic/LangOptions.h | 7 ++++
clang/include/clang/Options/Options.td | 5 ++-
clang/lib/Driver/ToolChains/Clang.cpp | 6 +--
clang/lib/Frontend/CompilerInvocation.cpp | 19 ++++++++++
clang/test/Driver/fmatrix-default-layout.c | 38 -------------------
clang/test/Driver/fmatrix-memory-layout.c | 35 +++++++++++++++++
.../Frontend/CompilerInvocationTest.cpp | 36 ++++++++++++++++++
11 files changed, 109 insertions(+), 51 deletions(-)
delete mode 100644 clang/test/Driver/fmatrix-default-layout.c
create mode 100644 clang/test/Driver/fmatrix-memory-layout.c
diff --git a/clang/docs/LanguageExtensions.rst b/clang/docs/LanguageExtensions.rst
index 88abc270fccf6..cc5ae719080f0 100644
--- a/clang/docs/LanguageExtensions.rst
+++ b/clang/docs/LanguageExtensions.rst
@@ -1074,9 +1074,9 @@ The matrix type extension supports explicit casts. Implicit type conversion betw
}
The matrix type extension will support column and row major layouts. The flag
-to change this behavior is `-fmatrix-default-layout` used like so
-`-fmatrix-default-layout=column-major` for column major and like so
-`-fmatrix-default-layout=row-major` for row major.
+to change this behavior is `-fmatrix-memory-layout` used like so
+`-fmatrix-memory-layout=column-major` for column major and like so
+`-fmatrix-memory-layout=row-major` for row major.
Half-Precision Floating Point
=============================
diff --git a/clang/docs/MatrixTypes.rst b/clang/docs/MatrixTypes.rst
index 6c5392149a814..bc36857800aa4 100644
--- a/clang/docs/MatrixTypes.rst
+++ b/clang/docs/MatrixTypes.rst
@@ -287,10 +287,9 @@ part of the draft specification.
The elements of a value of a matrix type are laid out in column-major order
without padding.
-To change the default order to row major use the `-fmatrix-default-layout` flag.
+To change memory layout to row major use the `-fmatrix-default-layout` flag.
This flag supports two flag argument values either `column-major` or `row-major`
-used like so `-fmatrix-default-layout=column-major`.` This flag controls the
-memory layout of matrix types.
+used like so `-fmatrix-default-layout=column-major`.`
We propose to provide a Clang option to override this behavior and allow
contraction of those operations (e.g. *-ffp-contract=matrix*).
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index e03de8198b244..bd045d7169c01 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -327,7 +327,7 @@ New Compiler Flags
- New option ``-fsanitize-debug-trap-reasons=`` added to control emitting trap reasons into the debug info when compiling with trapping UBSan (e.g. ``-fsanitize-trap=undefined``).
- New options for enabling allocation token instrumentation: ``-fsanitize=alloc-token``, ``-falloc-token-max=``, ``-fsanitize-alloc-token-fast-abi``, ``-fsanitize-alloc-token-extended``.
- The ``-resource-dir`` option is now displayed in the list of options shown by ``--help``.
-- New option ``-fmatrix-default-layout`` added to control the memory layout of Clang matrix types. (e.g. ``-fmatrix-default-layout=column-major`` or ``-fmatrix-default-layout=row-major``).
+- New option ``-fmatrix-memory-layout`` added to control the memory layout of Clang matrix types. (e.g. ``-fmatrix-memory-layout=column-major`` or ``-fmatrix-memory-layout=row-major``).
Lanai Support
^^^^^^^^^^^^^^
diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
index 40fc66ea12e34..bc2226942f7e4 100644
--- a/clang/include/clang/Basic/LangOptions.def
+++ b/clang/include/clang/Basic/LangOptions.def
@@ -434,6 +434,7 @@ ENUM_LANGOPT(RegisterStaticDestructors, RegisterStaticDestructorsKind, 2,
LANGOPT(RegCall4, 1, 0, NotCompatible, "Set __regcall4 as a default calling convention to respect __regcall ABI v.4")
LANGOPT(MatrixTypes, 1, 0, NotCompatible, "Enable or disable the builtin matrix type")
+ENUM_LANGOPT(DefaultMatrixMemoryLayout, MatrixMemoryLayout, 1, MatrixColMajor, NotCompatible, "Defines the default memory Layout for matrices")
VALUE_LANGOPT(MaxMatrixDimension, 32, (1 << 20) - 1, NotCompatible, "maximum allowed matrix dimension")
LANGOPT(CXXAssumptions, 1, 1, NotCompatible, "Enable or disable codegen and compile-time checks for C++23's [[assume]] attribute")
diff --git a/clang/include/clang/Basic/LangOptions.h b/clang/include/clang/Basic/LangOptions.h
index 3f042f8ddb5a1..dd1260ed88f9c 100644
--- a/clang/include/clang/Basic/LangOptions.h
+++ b/clang/include/clang/Basic/LangOptions.h
@@ -251,6 +251,13 @@ class LangOptionsBase {
FEM_UnsetOnCommandLine = 3
};
+ enum MatrixMemoryLayout : unsigned {
+ // Use column-major layout for matrices
+ MatrixColMajor = 0,
+ // Use row-major layout for matrices
+ MatrixRowMajor = 1,
+ };
+
enum ExcessPrecisionKind { FPP_Standard, FPP_Fast, FPP_None };
enum class LaxVectorConversionKind {
diff --git a/clang/include/clang/Options/Options.td b/clang/include/clang/Options/Options.td
index 86ce67f6ff237..08150550ba2a5 100644
--- a/clang/include/clang/Options/Options.td
+++ b/clang/include/clang/Options/Options.td
@@ -4664,8 +4664,9 @@ def fenable_matrix : Flag<["-"], "fenable-matrix">, Group<f_Group>,
HelpText<"Enable matrix data type and related builtin functions">,
MarshallingInfoFlag<LangOpts<"MatrixTypes">, hlsl.KeyPath>;
-def fmatrix_default_layout_EQ : Joined<["-"], "fmatrix-default-layout=">,
- HelpText<"Set default matrix layout (row-major or column-major)">,
+def fmatrix_memory_layout_EQ : Joined<["-"], "fmatrix-memory-layout=">,
+ Visibility<[ClangOption, CC1Option]>,
+ HelpText<"Sets the matrix memory layout (row-major or column-major)">,
Values<"row-major,column-major">,
Group<f_Group>;
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index a3aabbc35b043..c579b4ce72ec9 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -5693,12 +5693,10 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
CmdArgs.push_back("-mllvm");
CmdArgs.push_back("-enable-matrix");
// Only handle default layout if matrix is enabled
- if (const Arg *A =
- Args.getLastArg(options::OPT_fmatrix_default_layout_EQ)) {
+ if (const Arg *A = Args.getLastArg(options::OPT_fmatrix_memory_layout_EQ)) {
StringRef Val = A->getValue();
if (Val == "row-major" || Val == "column-major") {
- CmdArgs.push_back("-mllvm");
- CmdArgs.push_back(Args.MakeArgString("-matrix-default-layout=" + Val));
+ CmdArgs.push_back(Args.MakeArgString("-fmatrix-memory-layout=" + Val));
} else {
D.Diag(diag::err_drv_invalid_value) << A->getAsString(Args) << Val;
}
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index c7c29a91721c0..efd27e89309ab 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -3973,6 +3973,13 @@ void CompilerInvocationBase::GenerateLangArgs(const LangOptions &Opts,
}
GenerateArg(Consumer, OPT_falloc_token_mode_EQ, S);
}
+ // Enable options for Matrices
+ if (Opts.MatrixTypes) {
+ if (Opts.DefaultMatrixMemoryLayout == LangOptions::MatrixColMajor)
+ GenerateArg(Consumer, OPT_fmatrix_memory_layout_EQ, "column-major");
+ if (Opts.DefaultMatrixMemoryLayout == LangOptions::MatrixRowMajor)
+ GenerateArg(Consumer, OPT_fmatrix_memory_layout_EQ, "row-major");
+ }
}
bool CompilerInvocation::ParseLangArgs(LangOptions &Opts, ArgList &Args,
@@ -4567,6 +4574,18 @@ bool CompilerInvocation::ParseLangArgs(LangOptions &Opts, ArgList &Args,
Diags.Report(diag::err_drv_invalid_value) << Arg->getAsString(Args) << S;
}
+ if (Opts.MatrixTypes) {
+ if (const Arg *A = Args.getLastArg(OPT_fmatrix_memory_layout_EQ)) {
+ StringRef Val = A->getValue();
+ if (Val == "row-major")
+ Opts.setDefaultMatrixMemoryLayout(
+ LangOptions::MatrixMemoryLayout::MatrixRowMajor);
+ else
+ Opts.setDefaultMatrixMemoryLayout(
+ LangOptions::MatrixMemoryLayout::MatrixColMajor);
+ }
+ }
+
// Validate options for HLSL
if (Opts.HLSL) {
// TODO: Revisit restricting SPIR-V to logical once we've figured out how to
diff --git a/clang/test/Driver/fmatrix-default-layout.c b/clang/test/Driver/fmatrix-default-layout.c
deleted file mode 100644
index c89396f4452f6..0000000000000
--- a/clang/test/Driver/fmatrix-default-layout.c
+++ /dev/null
@@ -1,38 +0,0 @@
-// RUN: %clang --target=x86_64-linux-gnu -fenable-matrix -fmatrix-default-layout=column-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-COL-MAJOR
-// CHECK-COL-MAJOR: -fenable-matrix
-// CHECK-COL-MAJOR: -mllvm
-// CHECK-COL-MAJOR: -enable-matrix
-// CHECK-COL-MAJOR: -mllvm
-// CHECK-COL-MAJOR: -matrix-default-layout=column-major
-
-// RUN: %clang --target=x86_64-linux-gnu -fenable-matrix -fmatrix-default-layout=row-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ROW-MAJOR
-// CHECK-ROW-MAJOR: -fenable-matrix
-// CHECK-ROW-MAJOR: -mllvm
-// CHECK-ROW-MAJOR: -enable-matrix
-// CHECK-ROW-MAJOR: -mllvm
-// CHECK-ROW-MAJOR: -matrix-default-layout=row-major
-
-// RUN: not %clang --target=x86_64-linux-gnu -fenable-matrix -fmatrix-default-layout=error-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ERROR-MAJOR
-// CHECK-ERROR-MAJOR: error: invalid value 'error-major' in '-fmatrix-default-layout=error-major'
-
-// RUN: %clang --target=x86_64-linux-gnu -fmatrix-default-layout=column-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-COL-MAJOR-DISABLED
-// CHECK-COL-MAJOR-DISABLED-NOT: -fenable-matrix
-// CHECK-COL-MAJOR-DISABLED-NOT: -mllvm
-// CHECK-COL-MAJOR-DISABLED-NOT: -enable-matrix
-// CHECK-COL-MAJOR-DISABLED-NOT: -mllvm
-// CHECK-COL-MAJOR-DISABLED-NOT: -matrix-default-layout=column-major
-
-// RUN: %clang --target=x86_64-linux-gnu -fmatrix-default-layout=row-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ROW-MAJOR-DISABLED
-// CHECK-ROW-MAJOR-DISABLED-NOT: -fenable-matrix
-// CHECK-ROW-MAJOR-DISABLED-NOT: -mllvm
-// CHECK-ROW-MAJOR-DISABLED-NOT: -enable-matrix
-// CHECK-ROW-MAJOR-DISABLED-NOT: -mllvm
-// CHECK-ROW-MAJOR-DISABLED-NOT: -matrix-default-layout=row-major
-
-// RUN: %clang --target=x86_64-linux-gnu -fenable-matrix %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-MATRIX-ENABLED
-// CHECK-MATRIX-ENABLED: -fenable-matrix
-// CHECK-MATRIX-ENABLED: -mllvm
-// CHECK-MATRIX-ENABLED: -enable-matrix
-// CHECK-MATRIX-ENABLED-NOT: -mllvm
-// CHECK-MATRIX-ENABLED-NOT: -matrix-default-layout=row-major
-// CHECK-MATRIX-ENABLED-NOT: -matrix-default-layout=column-major
diff --git a/clang/test/Driver/fmatrix-memory-layout.c b/clang/test/Driver/fmatrix-memory-layout.c
new file mode 100644
index 0000000000000..b6ed6ac9d9061
--- /dev/null
+++ b/clang/test/Driver/fmatrix-memory-layout.c
@@ -0,0 +1,35 @@
+// RUN: %clang --target=x86_64-linux-gnu -fenable-matrix -fmatrix-memory-layout=column-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-COL-MAJOR
+// CHECK-COL-MAJOR: -fenable-matrix
+// CHECK-COL-MAJOR: -mllvm
+// CHECK-COL-MAJOR: -enable-matrix
+// CHECK-COL-MAJOR: -fmatrix-memory-layout=column-major
+
+// RUN: %clang --target=x86_64-linux-gnu -fenable-matrix -fmatrix-memory-layout=row-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ROW-MAJOR
+// CHECK-ROW-MAJOR: -fenable-matrix
+// CHECK-ROW-MAJOR: -mllvm
+// CHECK-ROW-MAJOR: -enable-matrix
+// CHECK-ROW-MAJOR: -fmatrix-memory-layout=row-major
+
+// RUN: not %clang --target=x86_64-linux-gnu -fenable-matrix -fmatrix-memory-layout=error-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ERROR-MAJOR
+// CHECK-ERROR-MAJOR: error: invalid value 'error-major' in '-fmatrix-memory-layout=error-major'
+
+// RUN: %clang --target=x86_64-linux-gnu -fmatrix-memory-layout=column-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-COL-MAJOR-DISABLED
+// CHECK-COL-MAJOR-DISABLED: clang: warning: argument unused during compilation: '-fmatrix-memory-layout=column-major'
+// CHECK-COL-MAJOR-DISABLED-NOT: -fenable-matrix
+// CHECK-COL-MAJOR-DISABLED-NOT: -mllvm
+// CHECK-COL-MAJOR-DISABLED-NOT: -enable-matrix
+// CHECK-COL-MAJOR-DISABLED-NOT: -fmatrix-memory-layout=column-major
+
+// RUN: %clang --target=x86_64-linux-gnu -fmatrix-memory-layout=row-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ROW-MAJOR-DISABLED
+// CHECK-ROW-MAJOR-DISABLED: clang: warning: argument unused during compilation: '-fmatrix-memory-layout=row-major'
+// CHECK-ROW-MAJOR-DISABLED-NOT: -fenable-matrix
+// CHECK-ROW-MAJOR-DISABLED-NOT: -mllvm
+// CHECK-ROW-MAJOR-DISABLED-NOT: -enable-matrix
+// CHECK-ROW-MAJOR-DISABLED-NOT: -fmatrix-memory-layout=row-major
+
+// RUN: %clang --target=x86_64-linux-gnu -fenable-matrix %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-MATRIX-ENABLED
+// CHECK-MATRIX-ENABLED: -fenable-matrix
+// CHECK-MATRIX-ENABLED: -mllvm
+// CHECK-MATRIX-ENABLED: -enable-matrix
+// CHECK-MATRIX-ENABLED-NOT: -fmatrix-memory-layout=row-major
+// CHECK-MATRIX-ENABLED-NOT: -fmatrix-memory-layout=column-major
diff --git a/clang/unittests/Frontend/CompilerInvocationTest.cpp b/clang/unittests/Frontend/CompilerInvocationTest.cpp
index 1332422688fe6..f03e1db6644be 100644
--- a/clang/unittests/Frontend/CompilerInvocationTest.cpp
+++ b/clang/unittests/Frontend/CompilerInvocationTest.cpp
@@ -738,6 +738,18 @@ TEST_F(CommandLineTest, ConditionalParsingIfHLSLFlagPresent) {
CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
ASSERT_EQ(Invocation.getLangOpts().MaxMatrixDimension, 4u);
+ ASSERT_EQ(Invocation.getLangOpts().getDefaultMatrixMemoryLayout(),
+ LangOptions::MatrixColMajor);
+
+ Invocation.generateCC1CommandLine(GeneratedArgs, *this);
+}
+
+TEST_F(CommandLineTest, ConditionalParsingHLSLRowMajor) {
+ const char *Args[] = {"-xhlsl", "-fmatrix-memory-layout=row-major"};
+
+ CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
+ ASSERT_EQ(Invocation.getLangOpts().getDefaultMatrixMemoryLayout(),
+ LangOptions::MatrixRowMajor);
Invocation.generateCC1CommandLine(GeneratedArgs, *this);
}
@@ -748,6 +760,30 @@ TEST_F(CommandLineTest, ConditionalParsingIfHLSLFlagNotPresent) {
CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
ASSERT_EQ(Invocation.getLangOpts().MaxMatrixDimension, 1048575u);
+ ASSERT_EQ(Invocation.getLangOpts().getDefaultMatrixMemoryLayout(),
+ LangOptions::MatrixColMajor);
+
+ Invocation.generateCC1CommandLine(GeneratedArgs, *this);
+}
+
+TEST_F(CommandLineTest, ConditionalParsingClangRowMajor) {
+ const char *Args[] = {"-fenable-matrix", "-fmatrix-memory-layout=row-major"};
+
+ CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
+
+ ASSERT_EQ(Invocation.getLangOpts().getDefaultMatrixMemoryLayout(),
+ LangOptions::MatrixRowMajor);
+
+ Invocation.generateCC1CommandLine(GeneratedArgs, *this);
+}
+
+TEST_F(CommandLineTest, ConditionalParsingIgnoreRowMajorIfMatrixNotEnabled) {
+ const char *Args[] = {"-fmatrix-memory-layout=row-major"};
+
+ CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
+
+ ASSERT_EQ(Invocation.getLangOpts().getDefaultMatrixMemoryLayout(),
+ LangOptions::MatrixColMajor);
Invocation.generateCC1CommandLine(GeneratedArgs, *this);
}
>From c918e06ee722fbf309884a33bbf9d2de2beea0f6 Mon Sep 17 00:00:00 2001
From: Farzon Lotfi <farzonl at gmail.com>
Date: Mon, 17 Nov 2025 12:07:14 -0500
Subject: [PATCH 4/9] Update comments in CompilerInvocation.cpp
---
clang/lib/Frontend/CompilerInvocation.cpp | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index efd27e89309ab..cafbf08f071e7 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -3973,7 +3973,7 @@ void CompilerInvocationBase::GenerateLangArgs(const LangOptions &Opts,
}
GenerateArg(Consumer, OPT_falloc_token_mode_EQ, S);
}
- // Enable options for Matrices
+ // Generate args for Matrices
if (Opts.MatrixTypes) {
if (Opts.DefaultMatrixMemoryLayout == LangOptions::MatrixColMajor)
GenerateArg(Consumer, OPT_fmatrix_memory_layout_EQ, "column-major");
@@ -4574,6 +4574,7 @@ bool CompilerInvocation::ParseLangArgs(LangOptions &Opts, ArgList &Args,
Diags.Report(diag::err_drv_invalid_value) << Arg->getAsString(Args) << S;
}
+ // Enable options for Matrices
if (Opts.MatrixTypes) {
if (const Arg *A = Args.getLastArg(OPT_fmatrix_memory_layout_EQ)) {
StringRef Val = A->getValue();
>From 94487a1530fc13cfb6e42d5ad8caedf36222ada2 Mon Sep 17 00:00:00 2001
From: Farzon Lotfi <farzonl at gmail.com>
Date: Fri, 21 Nov 2025 09:20:47 -0500
Subject: [PATCH 5/9] Apply suggestions from code review
Improve documentation and comments.
Co-authored-by: Florian Hahn <flo at fhahn.com>
---
clang/docs/LanguageExtensions.rst | 6 ++----
clang/lib/Frontend/CompilerInvocation.cpp | 4 ++--
2 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/clang/docs/LanguageExtensions.rst b/clang/docs/LanguageExtensions.rst
index cc5ae719080f0..824fb84a9e53b 100644
--- a/clang/docs/LanguageExtensions.rst
+++ b/clang/docs/LanguageExtensions.rst
@@ -1073,10 +1073,8 @@ The matrix type extension supports explicit casts. Implicit type conversion betw
i = static_cast<matrix_5_5<int>>(d);
}
-The matrix type extension will support column and row major layouts. The flag
-to change this behavior is `-fmatrix-memory-layout` used like so
-`-fmatrix-memory-layout=column-major` for column major and like so
-`-fmatrix-memory-layout=row-major` for row major.
+The matrix type extension supports column and row major memory layouts, but not all builtins are supported with row-major layout.
+The layout defaults to column major and can be specified using `-fmatrix-memory-layout`. To enable column major layout, use `-fmatrix-memory-layout=column-major`, and for row major layout use `-fmatrix-memory-layout=row-major`
Half-Precision Floating Point
=============================
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index cafbf08f071e7..9d71734065d9c 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -3973,7 +3973,7 @@ void CompilerInvocationBase::GenerateLangArgs(const LangOptions &Opts,
}
GenerateArg(Consumer, OPT_falloc_token_mode_EQ, S);
}
- // Generate args for Matrices
+ // Generate args for matrix types.
if (Opts.MatrixTypes) {
if (Opts.DefaultMatrixMemoryLayout == LangOptions::MatrixColMajor)
GenerateArg(Consumer, OPT_fmatrix_memory_layout_EQ, "column-major");
@@ -4574,7 +4574,7 @@ bool CompilerInvocation::ParseLangArgs(LangOptions &Opts, ArgList &Args,
Diags.Report(diag::err_drv_invalid_value) << Arg->getAsString(Args) << S;
}
- // Enable options for Matrices
+ // Enable options for matrix types.
if (Opts.MatrixTypes) {
if (const Arg *A = Args.getLastArg(OPT_fmatrix_memory_layout_EQ)) {
StringRef Val = A->getValue();
>From 61b2bfe3c771ddd44139a221d4a93bd003da3bd7 Mon Sep 17 00:00:00 2001
From: Farzon Lotfi <farzon at farzon.org>
Date: Fri, 21 Nov 2025 09:48:21 -0500
Subject: [PATCH 6/9] conform rst files to 80 column limit
---
clang/docs/LanguageExtensions.rst | 7 +++++--
clang/docs/MatrixTypes.rst | 4 ++--
2 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/clang/docs/LanguageExtensions.rst b/clang/docs/LanguageExtensions.rst
index 824fb84a9e53b..9c6aca662bb80 100644
--- a/clang/docs/LanguageExtensions.rst
+++ b/clang/docs/LanguageExtensions.rst
@@ -1073,8 +1073,11 @@ The matrix type extension supports explicit casts. Implicit type conversion betw
i = static_cast<matrix_5_5<int>>(d);
}
-The matrix type extension supports column and row major memory layouts, but not all builtins are supported with row-major layout.
-The layout defaults to column major and can be specified using `-fmatrix-memory-layout`. To enable column major layout, use `-fmatrix-memory-layout=column-major`, and for row major layout use `-fmatrix-memory-layout=row-major`
+The matrix type extension supports column and row major memory layouts, but not
+all builtins are supported with row-major layout. The layout defaults to column
+major and can be specified using `-fmatrix-memory-layout`. To enable column
+major layout, use `-fmatrix-memory-layout=column-major`, and for row major
+layout use `-fmatrix-memory-layout=row-major`
Half-Precision Floating Point
=============================
diff --git a/clang/docs/MatrixTypes.rst b/clang/docs/MatrixTypes.rst
index bc36857800aa4..1caf4bde28117 100644
--- a/clang/docs/MatrixTypes.rst
+++ b/clang/docs/MatrixTypes.rst
@@ -288,8 +288,8 @@ The elements of a value of a matrix type are laid out in column-major order
without padding.
To change memory layout to row major use the `-fmatrix-default-layout` flag.
-This flag supports two flag argument values either `column-major` or `row-major`
-used like so `-fmatrix-default-layout=column-major`.`
+This flag supports two flag argument values either `column-major` or
+`row-major` used like so `-fmatrix-default-layout=column-major`.`
We propose to provide a Clang option to override this behavior and allow
contraction of those operations (e.g. *-ffp-contract=matrix*).
>From 966a3d7bd2320b819ee9af3786f050cd86ce24ec Mon Sep 17 00:00:00 2001
From: Farzon Lotfi <farzonlotfi at microsoft.com>
Date: Wed, 26 Nov 2025 09:55:17 -0500
Subject: [PATCH 7/9] Fix typo in docs after flag name changed in driver.
---
clang/docs/MatrixTypes.rst | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/clang/docs/MatrixTypes.rst b/clang/docs/MatrixTypes.rst
index 1caf4bde28117..8701baa2d0f1c 100644
--- a/clang/docs/MatrixTypes.rst
+++ b/clang/docs/MatrixTypes.rst
@@ -287,9 +287,9 @@ part of the draft specification.
The elements of a value of a matrix type are laid out in column-major order
without padding.
-To change memory layout to row major use the `-fmatrix-default-layout` flag.
+To change memory layout to row major use the `-fmatrix-memory-layout` flag.
This flag supports two flag argument values either `column-major` or
-`row-major` used like so `-fmatrix-default-layout=column-major`.`
+`row-major` used like so `-fmatrix-memory-layout=column-major`.`
We propose to provide a Clang option to override this behavior and allow
contraction of those operations (e.g. *-ffp-contract=matrix*).
>From 1ecfa5a8036f7e588ab5c544dfd08ad4459d0cba Mon Sep 17 00:00:00 2001
From: Farzon Lotfi <farzonlotfi at microsoft.com>
Date: Wed, 26 Nov 2025 13:35:49 -0500
Subject: [PATCH 8/9] add back the -mllvm flags. Force the opt flags and clang
flags to match. Force clang builtins to error if the wrong major order is
selected
---
.../clang/Basic/DiagnosticDriverKinds.td | 3 +++
.../include/clang/Basic/DiagnosticSemaKinds.td | 2 ++
clang/lib/Driver/ToolChains/Clang.cpp | 3 +++
clang/lib/Frontend/CompilerInvocation.cpp | 10 ++++++++--
clang/lib/Sema/SemaChecking.cpp | 17 +++++++++++++++++
clang/test/Driver/fmatrix-memory-layout.c | 14 ++++++++++++++
.../Sema/matrix-col-major-builtin-disable.c | 13 +++++++++++++
7 files changed, 60 insertions(+), 2 deletions(-)
create mode 100644 clang/test/Sema/matrix-col-major-builtin-disable.c
diff --git a/clang/include/clang/Basic/DiagnosticDriverKinds.td b/clang/include/clang/Basic/DiagnosticDriverKinds.td
index f262db55a0d92..3ba05ffd10807 100644
--- a/clang/include/clang/Basic/DiagnosticDriverKinds.td
+++ b/clang/include/clang/Basic/DiagnosticDriverKinds.td
@@ -792,6 +792,9 @@ def err_cc1_round_trip_mismatch : Error<
def err_cc1_unbounded_vscale_min : Error<
"minimum vscale must be an unsigned integer greater than 0">;
+def err_conflicting_matrix_layout_flags: Error<
+ "-fmatrix-memory-layout=%0 conflicts with -mllvm -matrix-default-layout=%1">;
+
def err_drv_using_omit_rtti_component_without_no_rtti : Error<
"-fexperimental-omit-vtable-rtti call only be used with -fno-rtti">;
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 53aa86a7dabde..cf06e31403039 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -13006,6 +13006,8 @@ def err_builtin_trivially_relocate_invalid_arg_type: Error <
def err_builtin_matrix_disabled: Error<
"matrix types extension is disabled. Pass -fenable-matrix to enable it">;
+def err_builtin_matrix_major_order_disabled: Error<
+ "matrix %select{row|column}0 major %select{load|store}1 is disabled. Pass -fmatrix-memory-layout=%select{row|column}0-major to enable it">;
def err_matrix_index_not_integer: Error<
"matrix %select{row|column}0 index is not an integer">;
def err_matrix_index_outside_range: Error<
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index c579b4ce72ec9..c03a92c623f8c 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -5697,6 +5697,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
StringRef Val = A->getValue();
if (Val == "row-major" || Val == "column-major") {
CmdArgs.push_back(Args.MakeArgString("-fmatrix-memory-layout=" + Val));
+ CmdArgs.push_back("-mllvm");
+ CmdArgs.push_back(Args.MakeArgString("-matrix-default-layout=" + Val));
+
} else {
D.Diag(diag::err_drv_invalid_value) << A->getAsString(Args) << Val;
}
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 9d71734065d9c..27b23a4958af3 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -4577,13 +4577,19 @@ bool CompilerInvocation::ParseLangArgs(LangOptions &Opts, ArgList &Args,
// Enable options for matrix types.
if (Opts.MatrixTypes) {
if (const Arg *A = Args.getLastArg(OPT_fmatrix_memory_layout_EQ)) {
- StringRef Val = A->getValue();
- if (Val == "row-major")
+ StringRef ClangValue = A->getValue();
+ if (ClangValue == "row-major")
Opts.setDefaultMatrixMemoryLayout(
LangOptions::MatrixMemoryLayout::MatrixRowMajor);
else
Opts.setDefaultMatrixMemoryLayout(
LangOptions::MatrixMemoryLayout::MatrixColMajor);
+
+ for (Arg *A : Args.filtered(options::OPT_mllvm)) {
+ StringRef OptValue = A->getValue();
+ if (OptValue.consume_front("-matrix-default-layout=") && ClangValue != OptValue)
+ Diags.Report(diag::err_conflicting_matrix_layout_flags) << ClangValue << OptValue;
+ }
}
}
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index f4e58de91286b..851ceed5ce3fc 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -16342,6 +16342,12 @@ ExprResult Sema::BuiltinMatrixColumnMajorLoad(CallExpr *TheCall,
return ExprError();
}
+ if(getLangOpts().getDefaultMatrixMemoryLayout() != LangOptions::MatrixColMajor) {
+ Diag(TheCall->getBeginLoc(), diag::err_builtin_matrix_major_order_disabled)
+ << /*column*/1 << /*load*/ 0;
+ return ExprError();
+ }
+
if (checkArgCount(TheCall, 4))
return ExprError();
@@ -16454,6 +16460,17 @@ ExprResult Sema::BuiltinMatrixColumnMajorLoad(CallExpr *TheCall,
ExprResult Sema::BuiltinMatrixColumnMajorStore(CallExpr *TheCall,
ExprResult CallResult) {
+ if (!getLangOpts().MatrixTypes) {
+ Diag(TheCall->getBeginLoc(), diag::err_builtin_matrix_disabled);
+ return ExprError();
+ }
+
+ if(getLangOpts().getDefaultMatrixMemoryLayout() != LangOptions::MatrixColMajor) {
+ Diag(TheCall->getBeginLoc(), diag::err_builtin_matrix_major_order_disabled)
+ << /*column*/1 << /*store*/ 1;
+ return ExprError();
+ }
+
if (checkArgCount(TheCall, 3))
return ExprError();
diff --git a/clang/test/Driver/fmatrix-memory-layout.c b/clang/test/Driver/fmatrix-memory-layout.c
index b6ed6ac9d9061..f05cd8f26c004 100644
--- a/clang/test/Driver/fmatrix-memory-layout.c
+++ b/clang/test/Driver/fmatrix-memory-layout.c
@@ -3,12 +3,16 @@
// CHECK-COL-MAJOR: -mllvm
// CHECK-COL-MAJOR: -enable-matrix
// CHECK-COL-MAJOR: -fmatrix-memory-layout=column-major
+// CHECK-COL-MAJOR: -mllvm
+// CHECK-COL-MAJOR: -matrix-default-layout=column-major
// RUN: %clang --target=x86_64-linux-gnu -fenable-matrix -fmatrix-memory-layout=row-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ROW-MAJOR
// CHECK-ROW-MAJOR: -fenable-matrix
// CHECK-ROW-MAJOR: -mllvm
// CHECK-ROW-MAJOR: -enable-matrix
// CHECK-ROW-MAJOR: -fmatrix-memory-layout=row-major
+// CHECK-ROW-MAJOR: -mllvm
+// CHECK-ROW-MAJOR: -matrix-default-layout=row-major
// RUN: not %clang --target=x86_64-linux-gnu -fenable-matrix -fmatrix-memory-layout=error-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ERROR-MAJOR
// CHECK-ERROR-MAJOR: error: invalid value 'error-major' in '-fmatrix-memory-layout=error-major'
@@ -19,6 +23,8 @@
// CHECK-COL-MAJOR-DISABLED-NOT: -mllvm
// CHECK-COL-MAJOR-DISABLED-NOT: -enable-matrix
// CHECK-COL-MAJOR-DISABLED-NOT: -fmatrix-memory-layout=column-major
+// CHECK-COL-MAJOR-DISABLED-NOT: -mllvm
+// CHECK-COL-MAJOR-DISABLED-NOT: -matrix-default-layout=column-major
// RUN: %clang --target=x86_64-linux-gnu -fmatrix-memory-layout=row-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ROW-MAJOR-DISABLED
// CHECK-ROW-MAJOR-DISABLED: clang: warning: argument unused during compilation: '-fmatrix-memory-layout=row-major'
@@ -26,6 +32,8 @@
// CHECK-ROW-MAJOR-DISABLED-NOT: -mllvm
// CHECK-ROW-MAJOR-DISABLED-NOT: -enable-matrix
// CHECK-ROW-MAJOR-DISABLED-NOT: -fmatrix-memory-layout=row-major
+// CHECK-ROW-MAJOR-DISABLED-NOT: -mllvm
+// CHECK-ROW-MAJOR-DISABLED-NOT: -matrix-default-layout=row-major
// RUN: %clang --target=x86_64-linux-gnu -fenable-matrix %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-MATRIX-ENABLED
// CHECK-MATRIX-ENABLED: -fenable-matrix
@@ -33,3 +41,9 @@
// CHECK-MATRIX-ENABLED: -enable-matrix
// CHECK-MATRIX-ENABLED-NOT: -fmatrix-memory-layout=row-major
// CHECK-MATRIX-ENABLED-NOT: -fmatrix-memory-layout=column-major
+// CHECK-MATRIX-ENABLED-NOT: -mllvm
+// CHECK-MATRIX-ENABLED-NOT: -matrix-default-layout=row-major
+// CHECK-MATRIX-ENABLED-NOT: -matrix-default-layout=column-major
+
+// RUN: not %clang --target=x86_64-linux-gnu -fenable-matrix -fmatrix-memory-layout=column-major -mllvm -matrix-default-layout=row-major %s -fsyntax-only 2>&1 | FileCheck %s --check-prefix=CHECK-MISMATCH-MAJOR
+// CHECK-MISMATCH-MAJOR: error: -fmatrix-memory-layout=column-major conflicts with -mllvm -matrix-default-layout=row-major
diff --git a/clang/test/Sema/matrix-col-major-builtin-disable.c b/clang/test/Sema/matrix-col-major-builtin-disable.c
new file mode 100644
index 0000000000000..0be010b30c286
--- /dev/null
+++ b/clang/test/Sema/matrix-col-major-builtin-disable.c
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 %s -fenable-matrix -fmatrix-memory-layout=row-major -pedantic -verify -triple=x86_64-apple-darwin9
+
+typedef float sx5x10_t __attribute__((matrix_type(5, 10)));
+
+void column_major_load(float *p1) {
+ sx5x10_t a1 = __builtin_matrix_column_major_load(p1, 5, 11, 5);
+ // expected-error at -1 {{matrix column major load is disabled. Pass -fmatrix-memory-layout=column-major to enable it}}
+}
+
+void column_major_store(sx5x10_t *m1, float *p1) {
+ __builtin_matrix_column_major_store(*m1, p1, 1);
+ // expected-error at -1 {{matrix column major store is disabled. Pass -fmatrix-memory-layout=column-major to enable it}}
+}
\ No newline at end of file
>From 6fd2afed6a28819558ae262cf8578074be18c2ef Mon Sep 17 00:00:00 2001
From: Farzon Lotfi <farzonlotfi at microsoft.com>
Date: Wed, 26 Nov 2025 13:44:11 -0500
Subject: [PATCH 9/9] fix formatting
---
clang/lib/Driver/ToolChains/Clang.cpp | 2 +-
clang/lib/Frontend/CompilerInvocation.cpp | 8 +++++---
clang/lib/Sema/SemaChecking.cpp | 18 ++++++++++--------
3 files changed, 16 insertions(+), 12 deletions(-)
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index c03a92c623f8c..5e4cb434f3485 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -5699,7 +5699,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
CmdArgs.push_back(Args.MakeArgString("-fmatrix-memory-layout=" + Val));
CmdArgs.push_back("-mllvm");
CmdArgs.push_back(Args.MakeArgString("-matrix-default-layout=" + Val));
-
+
} else {
D.Diag(diag::err_drv_invalid_value) << A->getAsString(Args) << Val;
}
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 27b23a4958af3..0ce60c21c565f 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -4584,11 +4584,13 @@ bool CompilerInvocation::ParseLangArgs(LangOptions &Opts, ArgList &Args,
else
Opts.setDefaultMatrixMemoryLayout(
LangOptions::MatrixMemoryLayout::MatrixColMajor);
-
+
for (Arg *A : Args.filtered(options::OPT_mllvm)) {
StringRef OptValue = A->getValue();
- if (OptValue.consume_front("-matrix-default-layout=") && ClangValue != OptValue)
- Diags.Report(diag::err_conflicting_matrix_layout_flags) << ClangValue << OptValue;
+ if (OptValue.consume_front("-matrix-default-layout=") &&
+ ClangValue != OptValue)
+ Diags.Report(diag::err_conflicting_matrix_layout_flags)
+ << ClangValue << OptValue;
}
}
}
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 851ceed5ce3fc..39fc262735d51 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -16342,9 +16342,10 @@ ExprResult Sema::BuiltinMatrixColumnMajorLoad(CallExpr *TheCall,
return ExprError();
}
- if(getLangOpts().getDefaultMatrixMemoryLayout() != LangOptions::MatrixColMajor) {
- Diag(TheCall->getBeginLoc(), diag::err_builtin_matrix_major_order_disabled)
- << /*column*/1 << /*load*/ 0;
+ if (getLangOpts().getDefaultMatrixMemoryLayout() !=
+ LangOptions::MatrixColMajor) {
+ Diag(TheCall->getBeginLoc(), diag::err_builtin_matrix_major_order_disabled)
+ << /*column*/ 1 << /*load*/ 0;
return ExprError();
}
@@ -16464,13 +16465,14 @@ ExprResult Sema::BuiltinMatrixColumnMajorStore(CallExpr *TheCall,
Diag(TheCall->getBeginLoc(), diag::err_builtin_matrix_disabled);
return ExprError();
}
-
- if(getLangOpts().getDefaultMatrixMemoryLayout() != LangOptions::MatrixColMajor) {
- Diag(TheCall->getBeginLoc(), diag::err_builtin_matrix_major_order_disabled)
- << /*column*/1 << /*store*/ 1;
+
+ if (getLangOpts().getDefaultMatrixMemoryLayout() !=
+ LangOptions::MatrixColMajor) {
+ Diag(TheCall->getBeginLoc(), diag::err_builtin_matrix_major_order_disabled)
+ << /*column*/ 1 << /*store*/ 1;
return ExprError();
}
-
+
if (checkArgCount(TheCall, 3))
return ExprError();
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