tint: Add matrix identify and single-scalar ctors

Fixed: tint:1545 Change-Id: I86451223765f620861bf98861142e6d34c7e945b Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/90502 Reviewed-by: David Neto <dneto@google.com> Commit-Queue: Ben Clayton <bclayton@google.com>
2022-05-16 21:14:11 +00:00 · 2022-05-16 21:14:11 +00:00 · 3b5edf1435
parent 31b379409d
commit 3b5edf1435
95 changed files with 5468 additions and 4232 deletions
--- a/docs/tint/origin-trial-changes.md
+++ b/docs/tint/origin-trial-changes.md
@ -6,6 +6,7 @@

 * Produce warnings for when calling barriers, textureSample, and derivative
 builtins in non-uniform control flow [tint:880](crbug.com/tint/880)
+* Matrix identity constructors and constructors for a single scalar value are now supported [tint:1545](crbug.com/tint/1545)

 ## Changes for M102

--- a/src/tint/intrinsics.def
+++ b/src/tint/intrinsics.def
@ -605,6 +605,15 @@ ctor bool(bool) -> bool
 ctor vec2<T: scalar>(vec2<T>) -> vec2<T>
 ctor vec3<T: scalar>(vec3<T>) -> vec3<T>
 ctor vec4<T: scalar>(vec4<T>) -> vec4<T>
+ctor mat2x2<f32>(mat2x2<f32>) -> mat2x2<f32>
+ctor mat2x3<f32>(mat2x3<f32>) -> mat2x3<f32>
+ctor mat2x4<f32>(mat2x4<f32>) -> mat2x4<f32>
+ctor mat3x2<f32>(mat3x2<f32>) -> mat3x2<f32>
+ctor mat3x3<f32>(mat3x3<f32>) -> mat3x3<f32>
+ctor mat3x4<f32>(mat3x4<f32>) -> mat3x4<f32>
+ctor mat4x2<f32>(mat4x2<f32>) -> mat4x2<f32>
+ctor mat4x3<f32>(mat4x3<f32>) -> mat4x3<f32>
+ctor mat4x4<f32>(mat4x4<f32>) -> mat4x4<f32>

 // Vector constructors
 ctor vec2<T: scalar>(T) -> vec2<T>
@ -623,50 +632,59 @@ ctor vec4<T: scalar>(xyz: vec3<T>, w: T) -> vec4<T>
 ctor vec4<T: scalar>(x: T, zyw: vec3<T>) -> vec4<T>

 // Matrix constructors
-ctor mat2x2(f32, f32,
-            f32, f32) -> mat2x2<f32>
-ctor mat2x2(vec2<f32>, vec2<f32>) -> mat2x2<f32>
+ctor mat2x2<T: f32>(T) -> mat2x2<T>
+ctor mat2x2<T: f32>(T, T,
+                    T, T) -> mat2x2<T>
+ctor mat2x2<T: f32>(vec2<T>, vec2<T>) -> mat2x2<T>

-ctor mat2x3(f32, f32, f32,
-            f32, f32, f32) -> mat2x3<f32>
-ctor mat2x3(vec3<f32>, vec3<f32>) -> mat2x3<f32>
+ctor mat2x3<T: f32>(T) -> mat2x3<T>
+ctor mat2x3<T: f32>(T, T, T,
+                    T, T, T) -> mat2x3<T>
+ctor mat2x3<T: f32>(vec3<T>, vec3<T>) -> mat2x3<T>

-ctor mat2x4(f32, f32, f32, f32,
-            f32, f32, f32, f32) -> mat2x4<f32>
-ctor mat2x4(vec4<f32>, vec4<f32>) -> mat2x4<f32>
+ctor mat2x4<T: f32>(T) -> mat2x4<T>
+ctor mat2x4<T: f32>(T, T, T, T,
+                    T, T, T, T) -> mat2x4<T>
+ctor mat2x4<T: f32>(vec4<T>, vec4<T>) -> mat2x4<T>

-ctor mat3x2(f32, f32,
-            f32, f32,
-            f32, f32) -> mat3x2<f32>
-ctor mat3x2(vec2<f32>, vec2<f32>, vec2<f32>) -> mat3x2<f32>
+ctor mat3x2<T: f32>(T) -> mat3x2<T>
+ctor mat3x2<T: f32>(T, T,
+                    T, T,
+                    T, T) -> mat3x2<T>
+ctor mat3x2<T: f32>(vec2<T>, vec2<T>, vec2<T>) -> mat3x2<T>

-ctor mat3x3(f32, f32, f32,
-            f32, f32, f32,
-            f32, f32, f32) -> mat3x3<f32>
-ctor mat3x3(vec3<f32>, vec3<f32>, vec3<f32>) -> mat3x3<f32>
+ctor mat3x3<T: f32>(T) -> mat3x3<T>
+ctor mat3x3<T: f32>(T, T, T,
+                    T, T, T,
+                    T, T, T) -> mat3x3<T>
+ctor mat3x3<T: f32>(vec3<T>, vec3<T>, vec3<T>) -> mat3x3<T>

-ctor mat3x4(f32, f32, f32, f32,
-            f32, f32, f32, f32,
-            f32, f32, f32, f32) -> mat3x4<f32>
-ctor mat3x4(vec4<f32>, vec4<f32>, vec4<f32>) -> mat3x4<f32>
+ctor mat3x4<T: f32>(T) -> mat3x4<T>
+ctor mat3x4<T: f32>(T, T, T, T,
+                    T, T, T, T,
+                    T, T, T, T) -> mat3x4<T>
+ctor mat3x4<T: f32>(vec4<T>, vec4<T>, vec4<T>) -> mat3x4<T>

-ctor mat4x2(f32, f32,
-            f32, f32,
-            f32, f32,
-            f32, f32) -> mat4x2<f32>
-ctor mat4x2(vec2<f32>, vec2<f32>, vec2<f32>, vec2<f32>) -> mat4x2<f32>
+ctor mat4x2<T: f32>(T) -> mat4x2<T>
+ctor mat4x2<T: f32>(T, T,
+                    T, T,
+                    T, T,
+                    T, T) -> mat4x2<T>
+ctor mat4x2<T: f32>(vec2<T>, vec2<T>, vec2<T>, vec2<T>) -> mat4x2<T>

-ctor mat4x3(f32, f32, f32,
-            f32, f32, f32,
-            f32, f32, f32,
-            f32, f32, f32) -> mat4x3<f32>
-ctor mat4x3(vec3<f32>, vec3<f32>, vec3<f32>, vec3<f32>) -> mat4x3<f32>
+ctor mat4x3<T: f32>(T) -> mat4x3<T>
+ctor mat4x3<T: f32>(T, T, T,
+                    T, T, T,
+                    T, T, T,
+                    T, T, T) -> mat4x3<T>
+ctor mat4x3<T: f32>(vec3<T>, vec3<T>, vec3<T>, vec3<T>) -> mat4x3<T>

-ctor mat4x4(f32, f32, f32, f32,
-            f32, f32, f32, f32,
-            f32, f32, f32, f32,
-            f32, f32, f32, f32) -> mat4x4<f32>
-ctor mat4x4(vec4<f32>, vec4<f32>, vec4<f32>, vec4<f32>) -> mat4x4<f32>
+ctor mat4x4<T: f32>(T) -> mat4x4<T>
+ctor mat4x4<T: f32>(T, T, T, T,
+                    T, T, T, T,
+                    T, T, T, T,
+                    T, T, T, T) -> mat4x4<T>
+ctor mat4x4<T: f32>(vec4<T>, vec4<T>, vec4<T>, vec4<T>) -> mat4x4<T>

 ////////////////////////////////////////////////////////////////////////////////
 // Type conversions                                                           //
--- a/src/tint/resolver/intrinsic_table.inl
+++ b/src/tint/resolver/intrinsic_table.inl
--- a/src/tint/resolver/type_constructor_validation_test.cc
+++ b/src/tint/resolver/type_constructor_validation_test.cc
@ -235,15 +235,18 @@ constexpr Params ParamsFor(Kind kind) {
 }

 static constexpr Params valid_cases[] = {
-    // Direct init (non-conversions)
-    ParamsFor<bool, bool>(Kind::Construct),              //
-    ParamsFor<i32, i32>(Kind::Construct),                //
-    ParamsFor<u32, u32>(Kind::Construct),                //
-    ParamsFor<f32, f32>(Kind::Construct),                //
-    ParamsFor<vec3<bool>, vec3<bool>>(Kind::Construct),  //
-    ParamsFor<vec3<i32>, vec3<i32>>(Kind::Construct),    //
-    ParamsFor<vec3<u32>, vec3<u32>>(Kind::Construct),    //
-    ParamsFor<vec3<f32>, vec3<f32>>(Kind::Construct),    //
+    // Identity
+    ParamsFor<bool, bool>(Kind::Construct),                //
+    ParamsFor<i32, i32>(Kind::Construct),                  //
+    ParamsFor<u32, u32>(Kind::Construct),                  //
+    ParamsFor<f32, f32>(Kind::Construct),                  //
+    ParamsFor<vec3<bool>, vec3<bool>>(Kind::Construct),    //
+    ParamsFor<vec3<i32>, vec3<i32>>(Kind::Construct),      //
+    ParamsFor<vec3<u32>, vec3<u32>>(Kind::Construct),      //
+    ParamsFor<vec3<f32>, vec3<f32>>(Kind::Construct),      //
+    ParamsFor<mat3x3<f32>, mat3x3<f32>>(Kind::Construct),  //
+    ParamsFor<mat2x3<f32>, mat2x3<f32>>(Kind::Construct),  //
+    ParamsFor<mat3x2<f32>, mat3x2<f32>>(Kind::Construct),  //

    // Splat
    ParamsFor<vec3<bool>, bool>(Kind::Construct),  //
@ -251,6 +254,10 @@ static constexpr Params valid_cases[] = {
    ParamsFor<vec3<u32>, u32>(Kind::Construct),    //
    ParamsFor<vec3<f32>, f32>(Kind::Construct),    //

+    ParamsFor<mat3x3<f32>, f32>(Kind::Construct),  //
+    ParamsFor<mat2x3<f32>, f32>(Kind::Construct),  //
+    ParamsFor<mat3x2<f32>, f32>(Kind::Construct),  //
+
    // Conversion
    ParamsFor<bool, u32>(Kind::Conversion),  //
    ParamsFor<bool, i32>(Kind::Conversion),  //
@ -2016,9 +2023,8 @@ TEST_P(MatrixConstructorTest, Expr_ColumnConstructor_Error_TooFewArguments) {
    WrapInFunction(tc);

    EXPECT_FALSE(r()->Resolve());
-    EXPECT_THAT(r()->error(),
-                HasSubstr("12:34 error: no matching constructor for " + MatrixStr(param) + "(" +
-                          args_tys.str() + ")\n\n3 candidate constructors:"));
+    EXPECT_THAT(r()->error(), HasSubstr("12:34 error: no matching constructor for " +
+                                        MatrixStr(param) + "(" + args_tys.str() + ")"));
 }

 TEST_P(MatrixConstructorTest, Expr_ElementConstructor_Error_TooFewArguments) {
@ -2041,9 +2047,8 @@ TEST_P(MatrixConstructorTest, Expr_ElementConstructor_Error_TooFewArguments) {
    WrapInFunction(tc);

    EXPECT_FALSE(r()->Resolve());
-    EXPECT_THAT(r()->error(),
-                HasSubstr("12:34 error: no matching constructor for " + MatrixStr(param) + "(" +
-                          args_tys.str() + ")\n\n3 candidate constructors:"));
+    EXPECT_THAT(r()->error(), HasSubstr("12:34 error: no matching constructor for " +
+                                        MatrixStr(param) + "(" + args_tys.str() + ")"));
 }

 TEST_P(MatrixConstructorTest, Expr_ColumnConstructor_Error_TooManyArguments) {
@ -2067,9 +2072,8 @@ TEST_P(MatrixConstructorTest, Expr_ColumnConstructor_Error_TooManyArguments) {
    WrapInFunction(tc);

    EXPECT_FALSE(r()->Resolve());
-    EXPECT_THAT(r()->error(),
-                HasSubstr("12:34 error: no matching constructor for " + MatrixStr(param) + "(" +
-                          args_tys.str() + ")\n\n3 candidate constructors:"));
+    EXPECT_THAT(r()->error(), HasSubstr("12:34 error: no matching constructor for " +
+                                        MatrixStr(param) + "(" + args_tys.str() + ")"));
 }

 TEST_P(MatrixConstructorTest, Expr_ElementConstructor_Error_TooManyArguments) {
@ -2092,9 +2096,8 @@ TEST_P(MatrixConstructorTest, Expr_ElementConstructor_Error_TooManyArguments) {
    WrapInFunction(tc);

    EXPECT_FALSE(r()->Resolve());
-    EXPECT_THAT(r()->error(),
-                HasSubstr("12:34 error: no matching constructor for " + MatrixStr(param) + "(" +
-                          args_tys.str() + ")\n\n3 candidate constructors:"));
+    EXPECT_THAT(r()->error(), HasSubstr("12:34 error: no matching constructor for " +
+                                        MatrixStr(param) + "(" + args_tys.str() + ")"));
 }

 TEST_P(MatrixConstructorTest, Expr_ColumnConstructor_Error_InvalidArgumentType) {
@ -2118,9 +2121,8 @@ TEST_P(MatrixConstructorTest, Expr_ColumnConstructor_Error_InvalidArgumentType)
    WrapInFunction(tc);

    EXPECT_FALSE(r()->Resolve());
-    EXPECT_THAT(r()->error(),
-                HasSubstr("12:34 error: no matching constructor for " + MatrixStr(param) + "(" +
-                          args_tys.str() + ")\n\n3 candidate constructors:"));
+    EXPECT_THAT(r()->error(), HasSubstr("12:34 error: no matching constructor for " +
+                                        MatrixStr(param) + "(" + args_tys.str() + ")"));
 }

 TEST_P(MatrixConstructorTest, Expr_ElementConstructor_Error_InvalidArgumentType) {
@ -2143,9 +2145,8 @@ TEST_P(MatrixConstructorTest, Expr_ElementConstructor_Error_InvalidArgumentType)
    WrapInFunction(tc);

    EXPECT_FALSE(r()->Resolve());
-    EXPECT_THAT(r()->error(),
-                HasSubstr("12:34 error: no matching constructor for " + MatrixStr(param) + "(" +
-                          args_tys.str() + ")\n\n3 candidate constructors:"));
+    EXPECT_THAT(r()->error(), HasSubstr("12:34 error: no matching constructor for " +
+                                        MatrixStr(param) + "(" + args_tys.str() + ")"));
 }

 TEST_P(MatrixConstructorTest, Expr_ColumnConstructor_Error_TooFewRowsInVectorArgument) {
@ -2178,9 +2179,8 @@ TEST_P(MatrixConstructorTest, Expr_ColumnConstructor_Error_TooFewRowsInVectorArg
    WrapInFunction(tc);

    EXPECT_FALSE(r()->Resolve());
-    EXPECT_THAT(r()->error(),
-                HasSubstr("12:34 error: no matching constructor for " + MatrixStr(param) + "(" +
-                          args_tys.str() + ")\n\n3 candidate constructors:"));
+    EXPECT_THAT(r()->error(), HasSubstr("12:34 error: no matching constructor for " +
+                                        MatrixStr(param) + "(" + args_tys.str() + ")"));
 }

 TEST_P(MatrixConstructorTest, Expr_ColumnConstructor_Error_TooManyRowsInVectorArgument) {
@ -2212,9 +2212,8 @@ TEST_P(MatrixConstructorTest, Expr_ColumnConstructor_Error_TooManyRowsInVectorAr
    WrapInFunction(tc);

    EXPECT_FALSE(r()->Resolve());
-    EXPECT_THAT(r()->error(),
-                HasSubstr("12:34 error: no matching constructor for " + MatrixStr(param) + "(" +
-                          args_tys.str() + ")\n\n3 candidate constructors:"));
+    EXPECT_THAT(r()->error(), HasSubstr("12:34 error: no matching constructor for " +
+                                        MatrixStr(param) + "(" + args_tys.str() + ")"));
 }

 TEST_P(MatrixConstructorTest, Expr_Constructor_ZeroValue_Success) {
@ -2285,9 +2284,8 @@ TEST_P(MatrixConstructorTest, Expr_Constructor_ElementTypeAlias_Error) {
    WrapInFunction(tc);

    EXPECT_FALSE(r()->Resolve());
-    EXPECT_THAT(r()->error(),
-                HasSubstr("12:34 error: no matching constructor for " + MatrixStr(param) + "(" +
-                          args_tys.str() + ")\n\n3 candidate constructors:"));
+    EXPECT_THAT(r()->error(), HasSubstr("12:34 error: no matching constructor for " +
+                                        MatrixStr(param) + "(" + args_tys.str() + ")"));
 }

 TEST_P(MatrixConstructorTest, Expr_Constructor_ElementTypeAlias_Success) {
@ -2357,9 +2355,8 @@ TEST_P(MatrixConstructorTest, Expr_Constructor_ArgumentElementTypeAlias_Error) {
    WrapInFunction(tc);

    EXPECT_FALSE(r()->Resolve());
-    EXPECT_THAT(r()->error(),
-                HasSubstr("12:34 error: no matching constructor for " + MatrixStr(param) + "(" +
-                          args_tys.str() + ")\n\n3 candidate constructors:"));
+    EXPECT_THAT(r()->error(), HasSubstr("12:34 error: no matching constructor for " +
+                                        MatrixStr(param) + "(" + args_tys.str() + ")"));
 }

 TEST_P(MatrixConstructorTest, Expr_Constructor_ArgumentElementTypeAlias_Success) {
--- a/src/tint/transform/vectorize_scalar_matrix_constructors.cc
+++ b/src/tint/transform/vectorize_scalar_matrix_constructors.cc
@ -14,12 +14,14 @@

 #include "src/tint/transform/vectorize_scalar_matrix_constructors.h"

+#include <unordered_map>
 #include <utility>

 #include "src/tint/program_builder.h"
 #include "src/tint/sem/call.h"
 #include "src/tint/sem/expression.h"
 #include "src/tint/sem/type_constructor.h"
+#include "src/tint/utils/map.h"

 TINT_INSTANTIATE_TYPEINFO(tint::transform::VectorizeScalarMatrixConstructors);

@ -44,6 +46,8 @@ bool VectorizeScalarMatrixConstructors::ShouldRun(const Program* program, const
 }

 void VectorizeScalarMatrixConstructors::Run(CloneContext& ctx, const DataMap&, DataMap&) const {
+    std::unordered_map<const sem::Matrix*, Symbol> scalar_ctors;
+
    ctx.ReplaceAll([&](const ast::CallExpression* expr) -> const ast::CallExpression* {
        auto* call = ctx.src->Sem().Get(expr);
        auto* ty_ctor = call->Target()->As<sem::TypeConstructor>();
@ -64,21 +68,56 @@ void VectorizeScalarMatrixConstructors::Run(CloneContext& ctx, const DataMap&, D
            return nullptr;
        }

-        // Build a list of vector expressions for each column.
-        ast::ExpressionList columns;
-        for (uint32_t c = 0; c < mat_type->columns(); c++) {
-            // Build a list of scalar expressions for each value in the column.
-            ast::ExpressionList row_values;
-            for (uint32_t r = 0; r < mat_type->rows(); r++) {
-                row_values.push_back(ctx.Clone(args[c * mat_type->rows() + r]->Declaration()));
-            }
+        // Constructs a matrix using vector columns, with the elements constructed using the
+        // 'element(uint32_t c, uint32_t r)' callback.
+        auto build_mat = [&](auto&& element) {
+            ast::ExpressionList columns(mat_type->columns());
+            for (uint32_t c = 0; c < mat_type->columns(); c++) {
+                ast::ExpressionList row_values(mat_type->rows());
+                for (uint32_t r = 0; r < mat_type->rows(); r++) {
+                    row_values[r] = element(c, r);
+                }

-            // Construct the column vector.
-            auto* col =
-                ctx.dst->vec(CreateASTTypeFor(ctx, mat_type->type()), mat_type->rows(), row_values);
-            columns.push_back(col);
+                // Construct the column vector.
+                columns[c] = ctx.dst->vec(CreateASTTypeFor(ctx, mat_type->type()), mat_type->rows(),
+                                          row_values);
+            }
+            return ctx.dst->Construct(CreateASTTypeFor(ctx, mat_type), columns);
+        };
+
+        if (args.size() == 1) {
+            // Generate a helper function for constructing the matrix.
+            // This is done to ensure that the single argument value is only evaluated once, and
+            // with the correct expression evaluation order.
+            auto fn = utils::GetOrCreate(scalar_ctors, mat_type, [&] {
+                auto name =
+                    ctx.dst->Symbols().New("build_mat" + std::to_string(mat_type->columns()) + "x" +
+                                           std::to_string(mat_type->rows()));
+                ctx.dst->Func(name,
+                              {
+                                  // Single scalar parameter
+                                  ctx.dst->Param("value", CreateASTTypeFor(ctx, mat_type->type())),
+                              },
+                              CreateASTTypeFor(ctx, mat_type),
+                              {
+                                  ctx.dst->Return(build_mat([&](uint32_t, uint32_t) {  //
+                                      return ctx.dst->Expr("value");
+                                  })),
+                              });
+                return name;
+            });
+            return ctx.dst->Call(fn, ctx.Clone(args[0]->Declaration()));
        }
-        return ctx.dst->Construct(CreateASTTypeFor(ctx, mat_type), columns);
+
+        if (args.size() == mat_type->columns() * mat_type->rows()) {
+            return build_mat([&](uint32_t c, uint32_t r) {
+                return ctx.Clone(args[c * mat_type->rows() + r]->Declaration());
+            });
+        }
+
+        TINT_ICE(Transform, ctx.dst->Diagnostics())
+            << "matrix constructor has unexpected number of arguments";
+        return nullptr;
    });

    ctx.Clone();
--- a/src/tint/transform/vectorize_scalar_matrix_constructors_test.cc
+++ b/src/tint/transform/vectorize_scalar_matrix_constructors_test.cc
@ -31,7 +31,57 @@ TEST_F(VectorizeScalarMatrixConstructorsTest, ShouldRunEmptyModule) {
    EXPECT_FALSE(ShouldRun<VectorizeScalarMatrixConstructors>(src));
 }

-TEST_P(VectorizeScalarMatrixConstructorsTest, Basic) {
+TEST_P(VectorizeScalarMatrixConstructorsTest, SingleScalars) {
+    uint32_t cols = GetParam().first;
+    uint32_t rows = GetParam().second;
+    std::string matrix_no_type = "mat" + std::to_string(cols) + "x" + std::to_string(rows);
+    std::string matrix = matrix_no_type + "<f32>";
+    std::string vector = "vec" + std::to_string(rows) + "<f32>";
+    std::string values;
+    for (uint32_t c = 0; c < cols; c++) {
+        if (c > 0) {
+            values += ", ";
+        }
+        values += vector + "(";
+        for (uint32_t r = 0; r < rows; r++) {
+            if (r > 0) {
+                values += ", ";
+            }
+            values += "value";
+        }
+        values += ")";
+    }
+
+    std::string src = R"(
+@stage(fragment)
+fn main() {
+  let m = ${matrix}(42.0);
+}
+)";
+
+    std::string expect = R"(
+fn build_${matrix_no_type}(value : f32) -> ${matrix} {
+  return ${matrix}(${values});
+}
+
+@stage(fragment)
+fn main() {
+  let m = build_${matrix_no_type}(42.0);
+}
+)";
+    src = utils::ReplaceAll(src, "${matrix}", matrix);
+    expect = utils::ReplaceAll(expect, "${matrix}", matrix);
+    expect = utils::ReplaceAll(expect, "${matrix_no_type}", matrix_no_type);
+    expect = utils::ReplaceAll(expect, "${values}", values);
+
+    EXPECT_TRUE(ShouldRun<VectorizeScalarMatrixConstructors>(src));
+
+    auto got = Run<VectorizeScalarMatrixConstructors>(src);
+
+    EXPECT_EQ(expect, str(got));
+}
+
+TEST_P(VectorizeScalarMatrixConstructorsTest, MultipleScalars) {
    uint32_t cols = GetParam().first;
    uint32_t rows = GetParam().second;
    std::string mat_type = "mat" + std::to_string(cols) + "x" + std::to_string(rows) + "<f32>";
--- a/src/tint/writer/hlsl/generator_impl.cc
+++ b/src/tint/writer/hlsl/generator_impl.cc
@ -66,6 +66,7 @@
 #include "src/tint/transform/simplify_pointers.h"
 #include "src/tint/transform/unshadow.h"
 #include "src/tint/transform/unwind_discard_functions.h"
+#include "src/tint/transform/vectorize_scalar_matrix_constructors.h"
 #include "src/tint/transform/zero_init_workgroup_memory.h"
 #include "src/tint/utils/defer.h"
 #include "src/tint/utils/map.h"
@ -198,6 +199,7 @@ SanitizedResult Sanitize(const Program* in, const Options& options) {
    manager.Add<transform::ExpandCompoundAssignment>();
    manager.Add<transform::PromoteSideEffectsToDecl>();
    manager.Add<transform::UnwindDiscardFunctions>();
+    manager.Add<transform::VectorizeScalarMatrixConstructors>();
    manager.Add<transform::SimplifyPointers>();
    manager.Add<transform::RemovePhonies>();
    // ArrayLengthFromUniform must come after InlinePointerLets and Simplify, as
@ -1080,6 +1082,55 @@ bool GeneratorImpl::EmitTypeConstructor(std::ostream& out,
        return EmitZeroValue(out, type);
    }

+    if (auto* mat = call->Type()->As<sem::Matrix>()) {
+        if (ctor->Parameters().size() == 1) {
+            // Matrix constructor with single scalar.
+            auto fn = utils::GetOrCreate(matrix_scalar_ctors_, mat, [&]() -> std::string {
+                TextBuffer b;
+                TINT_DEFER(helpers_.Append(b));
+
+                auto name = UniqueIdentifier("build_mat" + std::to_string(mat->columns()) + "x" +
+                                             std::to_string(mat->rows()));
+                {
+                    auto l = line(&b);
+                    if (!EmitType(l, mat, ast::StorageClass::kNone, ast::Access::kUndefined, "")) {
+                        return "";
+                    }
+                    l << " " << name << "(";
+                    if (!EmitType(l, mat->type(), ast::StorageClass::kNone, ast::Access::kUndefined,
+                                  "")) {
+                        return "";
+                    }
+                    l << " value) {";
+                }
+                {
+                    ScopedIndent si(&b);
+                    auto l = line(&b);
+                    l << "return ";
+                    if (!EmitType(l, mat, ast::StorageClass::kNone, ast::Access::kUndefined, "")) {
+                        return "";
+                    }
+                    l << "(";
+                    for (uint32_t i = 0; i < mat->columns() * mat->rows(); i++) {
+                        l << ((i > 0) ? ", value" : "value");
+                    }
+                    l << ");";
+                }
+                line(&b) << "}";
+                return name;
+            });
+            if (fn.empty()) {
+                return false;
+            }
+            out << fn << "(";
+            if (!EmitExpression(out, call->Arguments()[0]->Declaration())) {
+                return false;
+            }
+            out << ")";
+            return true;
+        }
+    }
+
    bool brackets = type->IsAnyOf<sem::Array, sem::Struct>();

    // For single-value vector initializers, swizzle the scalar to the right
--- a/src/tint/writer/hlsl/generator_impl.h
+++ b/src/tint/writer/hlsl/generator_impl.h
@ -512,6 +512,7 @@ class GeneratorImpl : public TextGenerator {
    TextBuffer helpers_;  // Helper functions emitted at the top of the output
    std::function<bool()> emit_continuing_;
    std::unordered_map<DMAIntrinsic, std::string, DMAIntrinsic::Hasher> dma_intrinsics_;
+    std::unordered_map<const sem::Matrix*, std::string> matrix_scalar_ctors_;
    std::unordered_map<const sem::Builtin*, std::string> builtins_;
    std::unordered_map<const sem::Struct*, std::string> structure_builders_;
    std::unordered_map<const sem::Vector*, std::string> dynamic_vector_write_;
--- a/test/tint/expressions/index/let/let/literal/matrix.wgsl.expected.hlsl
+++ b/test/tint/expressions/index/let/let/literal/matrix.wgsl.expected.hlsl
@ -4,6 +4,6 @@ void unused_entry_point() {
 }

 float3 f() {
-  const float3x3 m = float3x3(1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f);
+  const float3x3 m = float3x3(float3(1.0f, 2.0f, 3.0f), float3(4.0f, 5.0f, 6.0f), float3(7.0f, 8.0f, 9.0f));
  return m[1];
 }
--- a/test/tint/expressions/index/let/let/param/matrix.wgsl.expected.hlsl
+++ b/test/tint/expressions/index/let/let/param/matrix.wgsl.expected.hlsl
@ -4,6 +4,6 @@ void unused_entry_point() {
 }

 float3 f(int x) {
-  const float3x3 m = float3x3(1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f);
+  const float3x3 m = float3x3(float3(1.0f, 2.0f, 3.0f), float3(4.0f, 5.0f, 6.0f), float3(7.0f, 8.0f, 9.0f));
  return m[x];
 }
--- a/test/tint/expressions/index/let/literal/matrix.wgsl.expected.hlsl
+++ b/test/tint/expressions/index/let/literal/matrix.wgsl.expected.hlsl
@ -4,6 +4,6 @@ void unused_entry_point() {
 }

 float3 f() {
-  const float3x3 m = float3x3(1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f);
+  const float3x3 m = float3x3(float3(1.0f, 2.0f, 3.0f), float3(4.0f, 5.0f, 6.0f), float3(7.0f, 8.0f, 9.0f));
  return m[1];
 }
--- a/test/tint/expressions/index/let/param/matrix.wgsl.expected.hlsl
+++ b/test/tint/expressions/index/let/param/matrix.wgsl.expected.hlsl
@ -4,6 +4,6 @@ void unused_entry_point() {
 }

 float3 f(int i) {
-  const float3x3 m = float3x3(1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f);
+  const float3x3 m = float3x3(float3(1.0f, 2.0f, 3.0f), float3(4.0f, 5.0f, 6.0f), float3(7.0f, 8.0f, 9.0f));
  return m[i];
 }
--- a/test/tint/expressions/index/let/var/literal/matrix.wgsl.expected.hlsl
+++ b/test/tint/expressions/index/let/var/literal/matrix.wgsl.expected.hlsl
@ -4,6 +4,6 @@ void unused_entry_point() {
 }

 float3 f() {
-  float3x3 m = float3x3(1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f);
+  float3x3 m = float3x3(float3(1.0f, 2.0f, 3.0f), float3(4.0f, 5.0f, 6.0f), float3(7.0f, 8.0f, 9.0f));
  return m[1];
 }
--- a/test/tint/expressions/index/var/let/literal/matrix.wgsl.expected.hlsl
+++ b/test/tint/expressions/index/var/let/literal/matrix.wgsl.expected.hlsl
@ -4,6 +4,6 @@ void unused_entry_point() {
 }

 float3 f() {
-  float3x3 m = float3x3(1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f);
+  float3x3 m = float3x3(float3(1.0f, 2.0f, 3.0f), float3(4.0f, 5.0f, 6.0f), float3(7.0f, 8.0f, 9.0f));
  return m[1];
 }
--- a/test/tint/expressions/index/var/let/param/matrix.wgsl.expected.hlsl
+++ b/test/tint/expressions/index/var/let/param/matrix.wgsl.expected.hlsl
@ -4,6 +4,6 @@ void unused_entry_point() {
 }

 float3 f(int x) {
-  float3x3 m = float3x3(1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f);
+  float3x3 m = float3x3(float3(1.0f, 2.0f, 3.0f), float3(4.0f, 5.0f, 6.0f), float3(7.0f, 8.0f, 9.0f));
  return m[x];
 }
--- a/test/tint/expressions/index/var/literal/matrix.wgsl.expected.hlsl
+++ b/test/tint/expressions/index/var/literal/matrix.wgsl.expected.hlsl
@ -4,6 +4,6 @@ void unused_entry_point() {
 }

 float3 f() {
-  float3x3 m = float3x3(1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f);
+  float3x3 m = float3x3(float3(1.0f, 2.0f, 3.0f), float3(4.0f, 5.0f, 6.0f), float3(7.0f, 8.0f, 9.0f));
  return m[1];
 }
--- a/test/tint/expressions/index/var/param/matrix.wgsl.expected.hlsl
+++ b/test/tint/expressions/index/var/param/matrix.wgsl.expected.hlsl
@ -4,6 +4,6 @@ void unused_entry_point() {
 }

 float3 f(int i) {
-  float3x3 m = float3x3(1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f);
+  float3x3 m = float3x3(float3(1.0f, 2.0f, 3.0f), float3(4.0f, 5.0f, 6.0f), float3(7.0f, 8.0f, 9.0f));
  return m[i];
 }
--- a/test/tint/expressions/splat/call/mat.wgsl
+++ b/test/tint/expressions/splat/call/mat.wgsl
@ -0,0 +1,13 @@
+fn get_f32() -> f32 { return 1.0; }
+
+fn f() {
+    var m2x2 : mat2x2<f32> = mat2x2<f32>(get_f32());
+    var m2x3 : mat2x3<f32> = mat2x3<f32>(get_f32());
+    var m2x4 : mat2x4<f32> = mat2x4<f32>(get_f32());
+    var m3x2 : mat3x2<f32> = mat3x2<f32>(get_f32());
+    var m3x3 : mat3x3<f32> = mat3x3<f32>(get_f32());
+    var m3x4 : mat3x4<f32> = mat3x4<f32>(get_f32());
+    var m4x2 : mat4x2<f32> = mat4x2<f32>(get_f32());
+    var m4x3 : mat4x3<f32> = mat4x3<f32>(get_f32());
+    var m4x4 : mat4x4<f32> = mat4x4<f32>(get_f32());
+}
--- a/test/tint/expressions/splat/call/mat.wgsl.expected.glsl
+++ b/test/tint/expressions/splat/call/mat.wgsl.expected.glsl
@ -0,0 +1,31 @@
+#version 310 es
+
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+void unused_entry_point() {
+  return;
+}
+float get_f32() {
+  return 1.0f;
+}
+
+void f() {
+  float tint_symbol = get_f32();
+  mat2 m2x2 = mat2(tint_symbol);
+  float tint_symbol_1 = get_f32();
+  mat2x3 m2x3 = mat2x3(tint_symbol_1);
+  float tint_symbol_2 = get_f32();
+  mat2x4 m2x4 = mat2x4(tint_symbol_2);
+  float tint_symbol_3 = get_f32();
+  mat3x2 m3x2 = mat3x2(tint_symbol_3);
+  float tint_symbol_4 = get_f32();
+  mat3 m3x3 = mat3(tint_symbol_4);
+  float tint_symbol_5 = get_f32();
+  mat3x4 m3x4 = mat3x4(tint_symbol_5);
+  float tint_symbol_6 = get_f32();
+  mat4x2 m4x2 = mat4x2(tint_symbol_6);
+  float tint_symbol_7 = get_f32();
+  mat4x3 m4x3 = mat4x3(tint_symbol_7);
+  float tint_symbol_8 = get_f32();
+  mat4 m4x4 = mat4(tint_symbol_8);
+}
+
--- a/test/tint/expressions/splat/call/mat.wgsl.expected.hlsl
+++ b/test/tint/expressions/splat/call/mat.wgsl.expected.hlsl
@ -0,0 +1,65 @@
+[numthreads(1, 1, 1)]
+void unused_entry_point() {
+  return;
+}
+
+float get_f32() {
+  return 1.0f;
+}
+
+float2x2 build_mat2x2(float value) {
+  return float2x2(float2(value, value), float2(value, value));
+}
+
+float2x3 build_mat2x3(float value) {
+  return float2x3(float3(value, value, value), float3(value, value, value));
+}
+
+float2x4 build_mat2x4(float value) {
+  return float2x4(float4(value, value, value, value), float4(value, value, value, value));
+}
+
+float3x2 build_mat3x2(float value) {
+  return float3x2(float2(value, value), float2(value, value), float2(value, value));
+}
+
+float3x3 build_mat3x3(float value) {
+  return float3x3(float3(value, value, value), float3(value, value, value), float3(value, value, value));
+}
+
+float3x4 build_mat3x4(float value) {
+  return float3x4(float4(value, value, value, value), float4(value, value, value, value), float4(value, value, value, value));
+}
+
+float4x2 build_mat4x2(float value) {
+  return float4x2(float2(value, value), float2(value, value), float2(value, value), float2(value, value));
+}
+
+float4x3 build_mat4x3(float value) {
+  return float4x3(float3(value, value, value), float3(value, value, value), float3(value, value, value), float3(value, value, value));
+}
+
+float4x4 build_mat4x4(float value) {
+  return float4x4(float4(value, value, value, value), float4(value, value, value, value), float4(value, value, value, value), float4(value, value, value, value));
+}
+
+void f() {
+  const float tint_symbol = get_f32();
+  float2x2 m2x2 = build_mat2x2(tint_symbol);
+  const float tint_symbol_1 = get_f32();
+  float2x3 m2x3 = build_mat2x3(tint_symbol_1);
+  const float tint_symbol_2 = get_f32();
+  float2x4 m2x4 = build_mat2x4(tint_symbol_2);
+  const float tint_symbol_3 = get_f32();
+  float3x2 m3x2 = build_mat3x2(tint_symbol_3);
+  const float tint_symbol_4 = get_f32();
+  float3x3 m3x3 = build_mat3x3(tint_symbol_4);
+  const float tint_symbol_5 = get_f32();
+  float3x4 m3x4 = build_mat3x4(tint_symbol_5);
+  const float tint_symbol_6 = get_f32();
+  float4x2 m4x2 = build_mat4x2(tint_symbol_6);
+  const float tint_symbol_7 = get_f32();
+  float4x3 m4x3 = build_mat4x3(tint_symbol_7);
+  const float tint_symbol_8 = get_f32();
+  float4x4 m4x4 = build_mat4x4(tint_symbol_8);
+}
--- a/test/tint/expressions/splat/call/mat.wgsl.expected.msl
+++ b/test/tint/expressions/splat/call/mat.wgsl.expected.msl
@ -0,0 +1,64 @@
+#include <metal_stdlib>
+
+using namespace metal;
+float get_f32() {
+  return 1.0f;
+}
+
+float2x2 build_mat2x2(float value) {
+  return float2x2(float2(value, value), float2(value, value));
+}
+
+float2x3 build_mat2x3(float value) {
+  return float2x3(float3(value, value, value), float3(value, value, value));
+}
+
+float2x4 build_mat2x4(float value) {
+  return float2x4(float4(value, value, value, value), float4(value, value, value, value));
+}
+
+float3x2 build_mat3x2(float value) {
+  return float3x2(float2(value, value), float2(value, value), float2(value, value));
+}
+
+float3x3 build_mat3x3(float value) {
+  return float3x3(float3(value, value, value), float3(value, value, value), float3(value, value, value));
+}
+
+float3x4 build_mat3x4(float value) {
+  return float3x4(float4(value, value, value, value), float4(value, value, value, value), float4(value, value, value, value));
+}
+
+float4x2 build_mat4x2(float value) {
+  return float4x2(float2(value, value), float2(value, value), float2(value, value), float2(value, value));
+}
+
+float4x3 build_mat4x3(float value) {
+  return float4x3(float3(value, value, value), float3(value, value, value), float3(value, value, value), float3(value, value, value));
+}
+
+float4x4 build_mat4x4(float value) {
+  return float4x4(float4(value, value, value, value), float4(value, value, value, value), float4(value, value, value, value), float4(value, value, value, value));
+}
+
+void f() {
+  float const tint_symbol = get_f32();
+  float2x2 m2x2 = build_mat2x2(tint_symbol);
+  float const tint_symbol_1 = get_f32();
+  float2x3 m2x3 = build_mat2x3(tint_symbol_1);
+  float const tint_symbol_2 = get_f32();
+  float2x4 m2x4 = build_mat2x4(tint_symbol_2);
+  float const tint_symbol_3 = get_f32();
+  float3x2 m3x2 = build_mat3x2(tint_symbol_3);
+  float const tint_symbol_4 = get_f32();
+  float3x3 m3x3 = build_mat3x3(tint_symbol_4);
+  float const tint_symbol_5 = get_f32();
+  float3x4 m3x4 = build_mat3x4(tint_symbol_5);
+  float const tint_symbol_6 = get_f32();
+  float4x2 m4x2 = build_mat4x2(tint_symbol_6);
+  float const tint_symbol_7 = get_f32();
+  float4x3 m4x3 = build_mat4x3(tint_symbol_7);
+  float const tint_symbol_8 = get_f32();
+  float4x4 m4x4 = build_mat4x4(tint_symbol_8);
+}
+
--- a/test/tint/expressions/splat/call/mat.wgsl.expected.spvasm
+++ b/test/tint/expressions/splat/call/mat.wgsl.expected.spvasm
@ -0,0 +1,194 @@
+; SPIR-V
+; Version: 1.3
+; Generator: Google Tint Compiler; 0
+; Bound: 123
+; Schema: 0
+               OpCapability Shader
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %unused_entry_point "unused_entry_point"
+               OpExecutionMode %unused_entry_point LocalSize 1 1 1
+               OpName %unused_entry_point "unused_entry_point"
+               OpName %get_f32 "get_f32"
+               OpName %build_mat2x2 "build_mat2x2"
+               OpName %value "value"
+               OpName %build_mat2x3 "build_mat2x3"
+               OpName %value_0 "value"
+               OpName %build_mat2x4 "build_mat2x4"
+               OpName %value_1 "value"
+               OpName %build_mat3x2 "build_mat3x2"
+               OpName %value_2 "value"
+               OpName %build_mat3x3 "build_mat3x3"
+               OpName %value_3 "value"
+               OpName %build_mat3x4 "build_mat3x4"
+               OpName %value_4 "value"
+               OpName %build_mat4x2 "build_mat4x2"
+               OpName %value_5 "value"
+               OpName %build_mat4x3 "build_mat4x3"
+               OpName %value_6 "value"
+               OpName %build_mat4x4 "build_mat4x4"
+               OpName %value_7 "value"
+               OpName %f "f"
+               OpName %m2x2 "m2x2"
+               OpName %m2x3 "m2x3"
+               OpName %m2x4 "m2x4"
+               OpName %m3x2 "m3x2"
+               OpName %m3x3 "m3x3"
+               OpName %m3x4 "m3x4"
+               OpName %m4x2 "m4x2"
+               OpName %m4x3 "m4x3"
+               OpName %m4x4 "m4x4"
+       %void = OpTypeVoid
+          %1 = OpTypeFunction %void
+      %float = OpTypeFloat 32
+          %5 = OpTypeFunction %float
+    %float_1 = OpConstant %float 1
+    %v2float = OpTypeVector %float 2
+%mat2v2float = OpTypeMatrix %v2float 2
+         %10 = OpTypeFunction %mat2v2float %float
+    %v3float = OpTypeVector %float 3
+%mat2v3float = OpTypeMatrix %v3float 2
+         %18 = OpTypeFunction %mat2v3float %float
+    %v4float = OpTypeVector %float 4
+%mat2v4float = OpTypeMatrix %v4float 2
+         %26 = OpTypeFunction %mat2v4float %float
+%mat3v2float = OpTypeMatrix %v2float 3
+         %34 = OpTypeFunction %mat3v2float %float
+%mat3v3float = OpTypeMatrix %v3float 3
+         %41 = OpTypeFunction %mat3v3float %float
+%mat3v4float = OpTypeMatrix %v4float 3
+         %48 = OpTypeFunction %mat3v4float %float
+%mat4v2float = OpTypeMatrix %v2float 4
+         %55 = OpTypeFunction %mat4v2float %float
+%mat4v3float = OpTypeMatrix %v3float 4
+         %62 = OpTypeFunction %mat4v3float %float
+%mat4v4float = OpTypeMatrix %v4float 4
+         %69 = OpTypeFunction %mat4v4float %float
+%_ptr_Function_mat2v2float = OpTypePointer Function %mat2v2float
+         %82 = OpConstantNull %mat2v2float
+%_ptr_Function_mat2v3float = OpTypePointer Function %mat2v3float
+         %87 = OpConstantNull %mat2v3float
+%_ptr_Function_mat2v4float = OpTypePointer Function %mat2v4float
+         %92 = OpConstantNull %mat2v4float
+%_ptr_Function_mat3v2float = OpTypePointer Function %mat3v2float
+         %97 = OpConstantNull %mat3v2float
+%_ptr_Function_mat3v3float = OpTypePointer Function %mat3v3float
+        %102 = OpConstantNull %mat3v3float
+%_ptr_Function_mat3v4float = OpTypePointer Function %mat3v4float
+        %107 = OpConstantNull %mat3v4float
+%_ptr_Function_mat4v2float = OpTypePointer Function %mat4v2float
+        %112 = OpConstantNull %mat4v2float
+%_ptr_Function_mat4v3float = OpTypePointer Function %mat4v3float
+        %117 = OpConstantNull %mat4v3float
+%_ptr_Function_mat4v4float = OpTypePointer Function %mat4v4float
+        %122 = OpConstantNull %mat4v4float
+%unused_entry_point = OpFunction %void None %1
+          %4 = OpLabel
+               OpReturn
+               OpFunctionEnd
+    %get_f32 = OpFunction %float None %5
+          %8 = OpLabel
+               OpReturnValue %float_1
+               OpFunctionEnd
+%build_mat2x2 = OpFunction %mat2v2float None %10
+      %value = OpFunctionParameter %float
+         %15 = OpLabel
+         %16 = OpCompositeConstruct %v2float %value %value
+         %17 = OpCompositeConstruct %mat2v2float %16 %16
+               OpReturnValue %17
+               OpFunctionEnd
+%build_mat2x3 = OpFunction %mat2v3float None %18
+    %value_0 = OpFunctionParameter %float
+         %23 = OpLabel
+         %24 = OpCompositeConstruct %v3float %value_0 %value_0 %value_0
+         %25 = OpCompositeConstruct %mat2v3float %24 %24
+               OpReturnValue %25
+               OpFunctionEnd
+%build_mat2x4 = OpFunction %mat2v4float None %26
+    %value_1 = OpFunctionParameter %float
+         %31 = OpLabel
+         %32 = OpCompositeConstruct %v4float %value_1 %value_1 %value_1 %value_1
+         %33 = OpCompositeConstruct %mat2v4float %32 %32
+               OpReturnValue %33
+               OpFunctionEnd
+%build_mat3x2 = OpFunction %mat3v2float None %34
+    %value_2 = OpFunctionParameter %float
+         %38 = OpLabel
+         %39 = OpCompositeConstruct %v2float %value_2 %value_2
+         %40 = OpCompositeConstruct %mat3v2float %39 %39 %39
+               OpReturnValue %40
+               OpFunctionEnd
+%build_mat3x3 = OpFunction %mat3v3float None %41
+    %value_3 = OpFunctionParameter %float
+         %45 = OpLabel
+         %46 = OpCompositeConstruct %v3float %value_3 %value_3 %value_3
+         %47 = OpCompositeConstruct %mat3v3float %46 %46 %46
+               OpReturnValue %47
+               OpFunctionEnd
+%build_mat3x4 = OpFunction %mat3v4float None %48
+    %value_4 = OpFunctionParameter %float
+         %52 = OpLabel
+         %53 = OpCompositeConstruct %v4float %value_4 %value_4 %value_4 %value_4
+         %54 = OpCompositeConstruct %mat3v4float %53 %53 %53
+               OpReturnValue %54
+               OpFunctionEnd
+%build_mat4x2 = OpFunction %mat4v2float None %55
+    %value_5 = OpFunctionParameter %float
+         %59 = OpLabel
+         %60 = OpCompositeConstruct %v2float %value_5 %value_5
+         %61 = OpCompositeConstruct %mat4v2float %60 %60 %60 %60
+               OpReturnValue %61
+               OpFunctionEnd
+%build_mat4x3 = OpFunction %mat4v3float None %62
+    %value_6 = OpFunctionParameter %float
+         %66 = OpLabel
+         %67 = OpCompositeConstruct %v3float %value_6 %value_6 %value_6
+         %68 = OpCompositeConstruct %mat4v3float %67 %67 %67 %67
+               OpReturnValue %68
+               OpFunctionEnd
+%build_mat4x4 = OpFunction %mat4v4float None %69
+    %value_7 = OpFunctionParameter %float
+         %73 = OpLabel
+         %74 = OpCompositeConstruct %v4float %value_7 %value_7 %value_7 %value_7
+         %75 = OpCompositeConstruct %mat4v4float %74 %74 %74 %74
+               OpReturnValue %75
+               OpFunctionEnd
+          %f = OpFunction %void None %1
+         %77 = OpLabel
+       %m2x2 = OpVariable %_ptr_Function_mat2v2float Function %82
+       %m2x3 = OpVariable %_ptr_Function_mat2v3float Function %87
+       %m2x4 = OpVariable %_ptr_Function_mat2v4float Function %92
+       %m3x2 = OpVariable %_ptr_Function_mat3v2float Function %97
+       %m3x3 = OpVariable %_ptr_Function_mat3v3float Function %102
+       %m3x4 = OpVariable %_ptr_Function_mat3v4float Function %107
+       %m4x2 = OpVariable %_ptr_Function_mat4v2float Function %112
+       %m4x3 = OpVariable %_ptr_Function_mat4v3float Function %117
+       %m4x4 = OpVariable %_ptr_Function_mat4v4float Function %122
+         %78 = OpFunctionCall %float %get_f32
+         %79 = OpFunctionCall %mat2v2float %build_mat2x2 %78
+               OpStore %m2x2 %79
+         %83 = OpFunctionCall %float %get_f32
+         %84 = OpFunctionCall %mat2v3float %build_mat2x3 %83
+               OpStore %m2x3 %84
+         %88 = OpFunctionCall %float %get_f32
+         %89 = OpFunctionCall %mat2v4float %build_mat2x4 %88
+               OpStore %m2x4 %89
+         %93 = OpFunctionCall %float %get_f32
+         %94 = OpFunctionCall %mat3v2float %build_mat3x2 %93
+               OpStore %m3x2 %94
+         %98 = OpFunctionCall %float %get_f32
+         %99 = OpFunctionCall %mat3v3float %build_mat3x3 %98
+               OpStore %m3x3 %99
+        %103 = OpFunctionCall %float %get_f32
+        %104 = OpFunctionCall %mat3v4float %build_mat3x4 %103
+               OpStore %m3x4 %104
+        %108 = OpFunctionCall %float %get_f32
+        %109 = OpFunctionCall %mat4v2float %build_mat4x2 %108
+               OpStore %m4x2 %109
+        %113 = OpFunctionCall %float %get_f32
+        %114 = OpFunctionCall %mat4v3float %build_mat4x3 %113
+               OpStore %m4x3 %114
+        %118 = OpFunctionCall %float %get_f32
+        %119 = OpFunctionCall %mat4v4float %build_mat4x4 %118
+               OpStore %m4x4 %119
+               OpReturn
+               OpFunctionEnd
--- a/test/tint/expressions/splat/call/mat.wgsl.expected.wgsl
+++ b/test/tint/expressions/splat/call/mat.wgsl.expected.wgsl
@ -0,0 +1,15 @@
+fn get_f32() -> f32 {
+  return 1.0;
+}
+
+fn f() {
+  var m2x2 : mat2x2<f32> = mat2x2<f32>(get_f32());
+  var m2x3 : mat2x3<f32> = mat2x3<f32>(get_f32());
+  var m2x4 : mat2x4<f32> = mat2x4<f32>(get_f32());
+  var m3x2 : mat3x2<f32> = mat3x2<f32>(get_f32());
+  var m3x3 : mat3x3<f32> = mat3x3<f32>(get_f32());
+  var m3x4 : mat3x4<f32> = mat3x4<f32>(get_f32());
+  var m4x2 : mat4x2<f32> = mat4x2<f32>(get_f32());
+  var m4x3 : mat4x3<f32> = mat4x3<f32>(get_f32());
+  var m4x4 : mat4x4<f32> = mat4x4<f32>(get_f32());
+}
--- a/test/tint/expressions/type_ctor/mat2x2/explicit/identity/f32.wgsl
+++ b/test/tint/expressions/type_ctor/mat2x2/explicit/identity/f32.wgsl
@ -0,0 +1 @@
+let m = mat2x2<f32>();
--- a/test/tint/expressions/type_ctor/mat2x2/explicit/identity/f32.wgsl.expected.glsl
+++ b/test/tint/expressions/type_ctor/mat2x2/explicit/identity/f32.wgsl.expected.glsl
@ -0,0 +1,7 @@
+#version 310 es
+
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+void unused_entry_point() {
+  return;
+}
+const mat2 m = mat2(0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat2x2/explicit/identity/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat2x2/explicit/identity/f32.wgsl.expected.hlsl
@ -0,0 +1,6 @@
+[numthreads(1, 1, 1)]
+void unused_entry_point() {
+  return;
+}
+
+static const float2x2 m = float2x2(0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat2x2/explicit/identity/f32.wgsl.expected.msl
+++ b/test/tint/expressions/type_ctor/mat2x2/explicit/identity/f32.wgsl.expected.msl
@ -0,0 +1,5 @@
+#include <metal_stdlib>
+
+using namespace metal;
+constant float2x2 m = float2x2();
+
--- a/test/tint/expressions/type_ctor/mat2x2/explicit/identity/f32.wgsl.expected.spvasm
+++ b/test/tint/expressions/type_ctor/mat2x2/explicit/identity/f32.wgsl.expected.spvasm
@ -0,0 +1,21 @@
+; SPIR-V
+; Version: 1.3
+; Generator: Google Tint Compiler; 0
+; Bound: 9
+; Schema: 0
+               OpCapability Shader
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %unused_entry_point "unused_entry_point"
+               OpExecutionMode %unused_entry_point LocalSize 1 1 1
+               OpName %m "m"
+               OpName %unused_entry_point "unused_entry_point"
+      %float = OpTypeFloat 32
+    %v2float = OpTypeVector %float 2
+%mat2v2float = OpTypeMatrix %v2float 2
+          %m = OpConstantNull %mat2v2float
+       %void = OpTypeVoid
+          %5 = OpTypeFunction %void
+%unused_entry_point = OpFunction %void None %5
+          %8 = OpLabel
+               OpReturn
+               OpFunctionEnd
--- a/test/tint/expressions/type_ctor/mat2x2/explicit/identity/f32.wgsl.expected.wgsl
+++ b/test/tint/expressions/type_ctor/mat2x2/explicit/identity/f32.wgsl.expected.wgsl
@ -0,0 +1 @@
+let m = mat2x2<f32>();
--- a/test/tint/expressions/type_ctor/mat2x2/explicit/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat2x2/explicit/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float2x2 m = float2x2(0.0f, 1.0f, 2.0f, 3.0f);
+static const float2x2 m = float2x2(float2(0.0f, 1.0f), float2(2.0f, 3.0f));
--- a/test/tint/expressions/type_ctor/mat2x2/inferred/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat2x2/inferred/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float2x2 m = float2x2(0.0f, 1.0f, 2.0f, 3.0f);
+static const float2x2 m = float2x2(float2(0.0f, 1.0f), float2(2.0f, 3.0f));
--- a/test/tint/expressions/type_ctor/mat2x3/explicit/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat2x3/explicit/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float2x3 m = float2x3(0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f);
+static const float2x3 m = float2x3(float3(0.0f, 1.0f, 2.0f), float3(3.0f, 4.0f, 5.0f));
--- a/test/tint/expressions/type_ctor/mat2x3/identity/f32.wgsl
+++ b/test/tint/expressions/type_ctor/mat2x3/identity/f32.wgsl
@ -0,0 +1 @@
+let m = mat2x3<f32>();
--- a/test/tint/expressions/type_ctor/mat2x3/identity/f32.wgsl.expected.glsl
+++ b/test/tint/expressions/type_ctor/mat2x3/identity/f32.wgsl.expected.glsl
@ -0,0 +1,7 @@
+#version 310 es
+
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+void unused_entry_point() {
+  return;
+}
+const mat2x3 m = mat2x3(0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat2x3/identity/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat2x3/identity/f32.wgsl.expected.hlsl
@ -0,0 +1,6 @@
+[numthreads(1, 1, 1)]
+void unused_entry_point() {
+  return;
+}
+
+static const float2x3 m = float2x3(0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat2x3/identity/f32.wgsl.expected.msl
+++ b/test/tint/expressions/type_ctor/mat2x3/identity/f32.wgsl.expected.msl
@ -0,0 +1,5 @@
+#include <metal_stdlib>
+
+using namespace metal;
+constant float2x3 m = float2x3();
+
--- a/test/tint/expressions/type_ctor/mat2x3/identity/f32.wgsl.expected.spvasm
+++ b/test/tint/expressions/type_ctor/mat2x3/identity/f32.wgsl.expected.spvasm
@ -0,0 +1,21 @@
+; SPIR-V
+; Version: 1.3
+; Generator: Google Tint Compiler; 0
+; Bound: 9
+; Schema: 0
+               OpCapability Shader
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %unused_entry_point "unused_entry_point"
+               OpExecutionMode %unused_entry_point LocalSize 1 1 1
+               OpName %m "m"
+               OpName %unused_entry_point "unused_entry_point"
+      %float = OpTypeFloat 32
+    %v3float = OpTypeVector %float 3
+%mat2v3float = OpTypeMatrix %v3float 2
+          %m = OpConstantNull %mat2v3float
+       %void = OpTypeVoid
+          %5 = OpTypeFunction %void
+%unused_entry_point = OpFunction %void None %5
+          %8 = OpLabel
+               OpReturn
+               OpFunctionEnd
--- a/test/tint/expressions/type_ctor/mat2x3/identity/f32.wgsl.expected.wgsl
+++ b/test/tint/expressions/type_ctor/mat2x3/identity/f32.wgsl.expected.wgsl
@ -0,0 +1 @@
+let m = mat2x3<f32>();
--- a/test/tint/expressions/type_ctor/mat2x3/inferred/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat2x3/inferred/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float2x3 m = float2x3(0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f);
+static const float2x3 m = float2x3(float3(0.0f, 1.0f, 2.0f), float3(3.0f, 4.0f, 5.0f));
--- a/test/tint/expressions/type_ctor/mat2x4/explicit/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat2x4/explicit/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float2x4 m = float2x4(0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f);
+static const float2x4 m = float2x4(float4(0.0f, 1.0f, 2.0f, 3.0f), float4(4.0f, 5.0f, 6.0f, 7.0f));
--- a/test/tint/expressions/type_ctor/mat2x4/identity/f32.wgsl
+++ b/test/tint/expressions/type_ctor/mat2x4/identity/f32.wgsl
@ -0,0 +1 @@
+let m = mat2x4<f32>();
--- a/test/tint/expressions/type_ctor/mat2x4/identity/f32.wgsl.expected.glsl
+++ b/test/tint/expressions/type_ctor/mat2x4/identity/f32.wgsl.expected.glsl
@ -0,0 +1,7 @@
+#version 310 es
+
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+void unused_entry_point() {
+  return;
+}
+const mat2x4 m = mat2x4(0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat2x4/identity/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat2x4/identity/f32.wgsl.expected.hlsl
@ -0,0 +1,6 @@
+[numthreads(1, 1, 1)]
+void unused_entry_point() {
+  return;
+}
+
+static const float2x4 m = float2x4(0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat2x4/identity/f32.wgsl.expected.msl
+++ b/test/tint/expressions/type_ctor/mat2x4/identity/f32.wgsl.expected.msl
@ -0,0 +1,5 @@
+#include <metal_stdlib>
+
+using namespace metal;
+constant float2x4 m = float2x4();
+
--- a/test/tint/expressions/type_ctor/mat2x4/identity/f32.wgsl.expected.spvasm
+++ b/test/tint/expressions/type_ctor/mat2x4/identity/f32.wgsl.expected.spvasm
@ -0,0 +1,21 @@
+; SPIR-V
+; Version: 1.3
+; Generator: Google Tint Compiler; 0
+; Bound: 9
+; Schema: 0
+               OpCapability Shader
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %unused_entry_point "unused_entry_point"
+               OpExecutionMode %unused_entry_point LocalSize 1 1 1
+               OpName %m "m"
+               OpName %unused_entry_point "unused_entry_point"
+      %float = OpTypeFloat 32
+    %v4float = OpTypeVector %float 4
+%mat2v4float = OpTypeMatrix %v4float 2
+          %m = OpConstantNull %mat2v4float
+       %void = OpTypeVoid
+          %5 = OpTypeFunction %void
+%unused_entry_point = OpFunction %void None %5
+          %8 = OpLabel
+               OpReturn
+               OpFunctionEnd
--- a/test/tint/expressions/type_ctor/mat2x4/identity/f32.wgsl.expected.wgsl
+++ b/test/tint/expressions/type_ctor/mat2x4/identity/f32.wgsl.expected.wgsl
@ -0,0 +1 @@
+let m = mat2x4<f32>();
--- a/test/tint/expressions/type_ctor/mat2x4/inferred/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat2x4/inferred/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float2x4 m = float2x4(0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f);
+static const float2x4 m = float2x4(float4(0.0f, 1.0f, 2.0f, 3.0f), float4(4.0f, 5.0f, 6.0f, 7.0f));
--- a/test/tint/expressions/type_ctor/mat3x2/explicit/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat3x2/explicit/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float3x2 m = float3x2(0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f);
+static const float3x2 m = float3x2(float2(0.0f, 1.0f), float2(2.0f, 3.0f), float2(4.0f, 5.0f));
--- a/test/tint/expressions/type_ctor/mat3x2/identity/f32.wgsl
+++ b/test/tint/expressions/type_ctor/mat3x2/identity/f32.wgsl
@ -0,0 +1 @@
+let m = mat3x2<f32>();
--- a/test/tint/expressions/type_ctor/mat3x2/identity/f32.wgsl.expected.glsl
+++ b/test/tint/expressions/type_ctor/mat3x2/identity/f32.wgsl.expected.glsl
@ -0,0 +1,7 @@
+#version 310 es
+
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+void unused_entry_point() {
+  return;
+}
+const mat3x2 m = mat3x2(0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat3x2/identity/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat3x2/identity/f32.wgsl.expected.hlsl
@ -0,0 +1,6 @@
+[numthreads(1, 1, 1)]
+void unused_entry_point() {
+  return;
+}
+
+static const float3x2 m = float3x2(0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat3x2/identity/f32.wgsl.expected.msl
+++ b/test/tint/expressions/type_ctor/mat3x2/identity/f32.wgsl.expected.msl
@ -0,0 +1,5 @@
+#include <metal_stdlib>
+
+using namespace metal;
+constant float3x2 m = float3x2();
+
--- a/test/tint/expressions/type_ctor/mat3x2/identity/f32.wgsl.expected.spvasm
+++ b/test/tint/expressions/type_ctor/mat3x2/identity/f32.wgsl.expected.spvasm
@ -0,0 +1,21 @@
+; SPIR-V
+; Version: 1.3
+; Generator: Google Tint Compiler; 0
+; Bound: 9
+; Schema: 0
+               OpCapability Shader
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %unused_entry_point "unused_entry_point"
+               OpExecutionMode %unused_entry_point LocalSize 1 1 1
+               OpName %m "m"
+               OpName %unused_entry_point "unused_entry_point"
+      %float = OpTypeFloat 32
+    %v2float = OpTypeVector %float 2
+%mat3v2float = OpTypeMatrix %v2float 3
+          %m = OpConstantNull %mat3v2float
+       %void = OpTypeVoid
+          %5 = OpTypeFunction %void
+%unused_entry_point = OpFunction %void None %5
+          %8 = OpLabel
+               OpReturn
+               OpFunctionEnd
--- a/test/tint/expressions/type_ctor/mat3x2/identity/f32.wgsl.expected.wgsl
+++ b/test/tint/expressions/type_ctor/mat3x2/identity/f32.wgsl.expected.wgsl
@ -0,0 +1 @@
+let m = mat3x2<f32>();
--- a/test/tint/expressions/type_ctor/mat3x2/inferred/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat3x2/inferred/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float3x2 m = float3x2(0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f);
+static const float3x2 m = float3x2(float2(0.0f, 1.0f), float2(2.0f, 3.0f), float2(4.0f, 5.0f));
--- a/test/tint/expressions/type_ctor/mat3x3/explicit/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat3x3/explicit/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float3x3 m = float3x3(0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f);
+static const float3x3 m = float3x3(float3(0.0f, 1.0f, 2.0f), float3(3.0f, 4.0f, 5.0f), float3(6.0f, 7.0f, 8.0f));
--- a/test/tint/expressions/type_ctor/mat3x3/identity/f32.wgsl
+++ b/test/tint/expressions/type_ctor/mat3x3/identity/f32.wgsl
@ -0,0 +1 @@
+let m = mat3x3<f32>();
--- a/test/tint/expressions/type_ctor/mat3x3/identity/f32.wgsl.expected.glsl
+++ b/test/tint/expressions/type_ctor/mat3x3/identity/f32.wgsl.expected.glsl
@ -0,0 +1,7 @@
+#version 310 es
+
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+void unused_entry_point() {
+  return;
+}
+const mat3 m = mat3(0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat3x3/identity/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat3x3/identity/f32.wgsl.expected.hlsl
@ -0,0 +1,6 @@
+[numthreads(1, 1, 1)]
+void unused_entry_point() {
+  return;
+}
+
+static const float3x3 m = float3x3(0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat3x3/identity/f32.wgsl.expected.msl
+++ b/test/tint/expressions/type_ctor/mat3x3/identity/f32.wgsl.expected.msl
@ -0,0 +1,5 @@
+#include <metal_stdlib>
+
+using namespace metal;
+constant float3x3 m = float3x3();
+
--- a/test/tint/expressions/type_ctor/mat3x3/identity/f32.wgsl.expected.spvasm
+++ b/test/tint/expressions/type_ctor/mat3x3/identity/f32.wgsl.expected.spvasm
@ -0,0 +1,21 @@
+; SPIR-V
+; Version: 1.3
+; Generator: Google Tint Compiler; 0
+; Bound: 9
+; Schema: 0
+               OpCapability Shader
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %unused_entry_point "unused_entry_point"
+               OpExecutionMode %unused_entry_point LocalSize 1 1 1
+               OpName %m "m"
+               OpName %unused_entry_point "unused_entry_point"
+      %float = OpTypeFloat 32
+    %v3float = OpTypeVector %float 3
+%mat3v3float = OpTypeMatrix %v3float 3
+          %m = OpConstantNull %mat3v3float
+       %void = OpTypeVoid
+          %5 = OpTypeFunction %void
+%unused_entry_point = OpFunction %void None %5
+          %8 = OpLabel
+               OpReturn
+               OpFunctionEnd
--- a/test/tint/expressions/type_ctor/mat3x3/identity/f32.wgsl.expected.wgsl
+++ b/test/tint/expressions/type_ctor/mat3x3/identity/f32.wgsl.expected.wgsl
@ -0,0 +1 @@
+let m = mat3x3<f32>();
--- a/test/tint/expressions/type_ctor/mat3x3/inferred/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat3x3/inferred/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float3x3 m = float3x3(0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f);
+static const float3x3 m = float3x3(float3(0.0f, 1.0f, 2.0f), float3(3.0f, 4.0f, 5.0f), float3(6.0f, 7.0f, 8.0f));
--- a/test/tint/expressions/type_ctor/mat3x4/explicit/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat3x4/explicit/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float3x4 m = float3x4(0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f, 10.0f, 11.0f);
+static const float3x4 m = float3x4(float4(0.0f, 1.0f, 2.0f, 3.0f), float4(4.0f, 5.0f, 6.0f, 7.0f), float4(8.0f, 9.0f, 10.0f, 11.0f));
--- a/test/tint/expressions/type_ctor/mat3x4/identity/f32.wgsl
+++ b/test/tint/expressions/type_ctor/mat3x4/identity/f32.wgsl
@ -0,0 +1 @@
+let m = mat3x4<f32>();
--- a/test/tint/expressions/type_ctor/mat3x4/identity/f32.wgsl.expected.glsl
+++ b/test/tint/expressions/type_ctor/mat3x4/identity/f32.wgsl.expected.glsl
@ -0,0 +1,7 @@
+#version 310 es
+
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+void unused_entry_point() {
+  return;
+}
+const mat3x4 m = mat3x4(0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat3x4/identity/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat3x4/identity/f32.wgsl.expected.hlsl
@ -0,0 +1,6 @@
+[numthreads(1, 1, 1)]
+void unused_entry_point() {
+  return;
+}
+
+static const float3x4 m = float3x4(0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat3x4/identity/f32.wgsl.expected.msl
+++ b/test/tint/expressions/type_ctor/mat3x4/identity/f32.wgsl.expected.msl
@ -0,0 +1,5 @@
+#include <metal_stdlib>
+
+using namespace metal;
+constant float3x4 m = float3x4();
+
--- a/test/tint/expressions/type_ctor/mat3x4/identity/f32.wgsl.expected.spvasm
+++ b/test/tint/expressions/type_ctor/mat3x4/identity/f32.wgsl.expected.spvasm
@ -0,0 +1,21 @@
+; SPIR-V
+; Version: 1.3
+; Generator: Google Tint Compiler; 0
+; Bound: 9
+; Schema: 0
+               OpCapability Shader
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %unused_entry_point "unused_entry_point"
+               OpExecutionMode %unused_entry_point LocalSize 1 1 1
+               OpName %m "m"
+               OpName %unused_entry_point "unused_entry_point"
+      %float = OpTypeFloat 32
+    %v4float = OpTypeVector %float 4
+%mat3v4float = OpTypeMatrix %v4float 3
+          %m = OpConstantNull %mat3v4float
+       %void = OpTypeVoid
+          %5 = OpTypeFunction %void
+%unused_entry_point = OpFunction %void None %5
+          %8 = OpLabel
+               OpReturn
+               OpFunctionEnd
--- a/test/tint/expressions/type_ctor/mat3x4/identity/f32.wgsl.expected.wgsl
+++ b/test/tint/expressions/type_ctor/mat3x4/identity/f32.wgsl.expected.wgsl
@ -0,0 +1 @@
+let m = mat3x4<f32>();
--- a/test/tint/expressions/type_ctor/mat3x4/inferred/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat3x4/inferred/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float3x4 m = float3x4(0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f, 10.0f, 11.0f);
+static const float3x4 m = float3x4(float4(0.0f, 1.0f, 2.0f, 3.0f), float4(4.0f, 5.0f, 6.0f, 7.0f), float4(8.0f, 9.0f, 10.0f, 11.0f));
--- a/test/tint/expressions/type_ctor/mat4x2/explicit/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat4x2/explicit/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float4x2 m = float4x2(0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f);
+static const float4x2 m = float4x2(float2(0.0f, 1.0f), float2(2.0f, 3.0f), float2(4.0f, 5.0f), float2(6.0f, 7.0f));
--- a/test/tint/expressions/type_ctor/mat4x2/identity/f32.wgsl
+++ b/test/tint/expressions/type_ctor/mat4x2/identity/f32.wgsl
@ -0,0 +1 @@
+let m = mat4x2<f32>();
--- a/test/tint/expressions/type_ctor/mat4x2/identity/f32.wgsl.expected.glsl
+++ b/test/tint/expressions/type_ctor/mat4x2/identity/f32.wgsl.expected.glsl
@ -0,0 +1,7 @@
+#version 310 es
+
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+void unused_entry_point() {
+  return;
+}
+const mat4x2 m = mat4x2(0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat4x2/identity/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat4x2/identity/f32.wgsl.expected.hlsl
@ -0,0 +1,6 @@
+[numthreads(1, 1, 1)]
+void unused_entry_point() {
+  return;
+}
+
+static const float4x2 m = float4x2(0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat4x2/identity/f32.wgsl.expected.msl
+++ b/test/tint/expressions/type_ctor/mat4x2/identity/f32.wgsl.expected.msl
@ -0,0 +1,5 @@
+#include <metal_stdlib>
+
+using namespace metal;
+constant float4x2 m = float4x2();
+
--- a/test/tint/expressions/type_ctor/mat4x2/identity/f32.wgsl.expected.spvasm
+++ b/test/tint/expressions/type_ctor/mat4x2/identity/f32.wgsl.expected.spvasm
@ -0,0 +1,21 @@
+; SPIR-V
+; Version: 1.3
+; Generator: Google Tint Compiler; 0
+; Bound: 9
+; Schema: 0
+               OpCapability Shader
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %unused_entry_point "unused_entry_point"
+               OpExecutionMode %unused_entry_point LocalSize 1 1 1
+               OpName %m "m"
+               OpName %unused_entry_point "unused_entry_point"
+      %float = OpTypeFloat 32
+    %v2float = OpTypeVector %float 2
+%mat4v2float = OpTypeMatrix %v2float 4
+          %m = OpConstantNull %mat4v2float
+       %void = OpTypeVoid
+          %5 = OpTypeFunction %void
+%unused_entry_point = OpFunction %void None %5
+          %8 = OpLabel
+               OpReturn
+               OpFunctionEnd
--- a/test/tint/expressions/type_ctor/mat4x2/identity/f32.wgsl.expected.wgsl
+++ b/test/tint/expressions/type_ctor/mat4x2/identity/f32.wgsl.expected.wgsl
@ -0,0 +1 @@
+let m = mat4x2<f32>();
--- a/test/tint/expressions/type_ctor/mat4x2/inferred/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat4x2/inferred/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float4x2 m = float4x2(0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f);
+static const float4x2 m = float4x2(float2(0.0f, 1.0f), float2(2.0f, 3.0f), float2(4.0f, 5.0f), float2(6.0f, 7.0f));
--- a/test/tint/expressions/type_ctor/mat4x3/explicit/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat4x3/explicit/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float4x3 m = float4x3(0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f, 10.0f, 11.0f);
+static const float4x3 m = float4x3(float3(0.0f, 1.0f, 2.0f), float3(3.0f, 4.0f, 5.0f), float3(6.0f, 7.0f, 8.0f), float3(9.0f, 10.0f, 11.0f));
--- a/test/tint/expressions/type_ctor/mat4x3/identity/f32.wgsl
+++ b/test/tint/expressions/type_ctor/mat4x3/identity/f32.wgsl
@ -0,0 +1 @@
+let m = mat4x3<f32>();
--- a/test/tint/expressions/type_ctor/mat4x3/identity/f32.wgsl.expected.glsl
+++ b/test/tint/expressions/type_ctor/mat4x3/identity/f32.wgsl.expected.glsl
@ -0,0 +1,7 @@
+#version 310 es
+
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+void unused_entry_point() {
+  return;
+}
+const mat4x3 m = mat4x3(0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat4x3/identity/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat4x3/identity/f32.wgsl.expected.hlsl
@ -0,0 +1,6 @@
+[numthreads(1, 1, 1)]
+void unused_entry_point() {
+  return;
+}
+
+static const float4x3 m = float4x3(0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat4x3/identity/f32.wgsl.expected.msl
+++ b/test/tint/expressions/type_ctor/mat4x3/identity/f32.wgsl.expected.msl
@ -0,0 +1,5 @@
+#include <metal_stdlib>
+
+using namespace metal;
+constant float4x3 m = float4x3();
+
--- a/test/tint/expressions/type_ctor/mat4x3/identity/f32.wgsl.expected.spvasm
+++ b/test/tint/expressions/type_ctor/mat4x3/identity/f32.wgsl.expected.spvasm
@ -0,0 +1,21 @@
+; SPIR-V
+; Version: 1.3
+; Generator: Google Tint Compiler; 0
+; Bound: 9
+; Schema: 0
+               OpCapability Shader
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %unused_entry_point "unused_entry_point"
+               OpExecutionMode %unused_entry_point LocalSize 1 1 1
+               OpName %m "m"
+               OpName %unused_entry_point "unused_entry_point"
+      %float = OpTypeFloat 32
+    %v3float = OpTypeVector %float 3
+%mat4v3float = OpTypeMatrix %v3float 4
+          %m = OpConstantNull %mat4v3float
+       %void = OpTypeVoid
+          %5 = OpTypeFunction %void
+%unused_entry_point = OpFunction %void None %5
+          %8 = OpLabel
+               OpReturn
+               OpFunctionEnd
--- a/test/tint/expressions/type_ctor/mat4x3/identity/f32.wgsl.expected.wgsl
+++ b/test/tint/expressions/type_ctor/mat4x3/identity/f32.wgsl.expected.wgsl
@ -0,0 +1 @@
+let m = mat4x3<f32>();
--- a/test/tint/expressions/type_ctor/mat4x3/inferred/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat4x3/inferred/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float4x3 m = float4x3(0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f, 10.0f, 11.0f);
+static const float4x3 m = float4x3(float3(0.0f, 1.0f, 2.0f), float3(3.0f, 4.0f, 5.0f), float3(6.0f, 7.0f, 8.0f), float3(9.0f, 10.0f, 11.0f));
--- a/test/tint/expressions/type_ctor/mat4x4/explicit/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat4x4/explicit/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float4x4 m = float4x4(0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f, 10.0f, 11.0f, 12.0f, 13.0f, 14.0f, 15.0f);
+static const float4x4 m = float4x4(float4(0.0f, 1.0f, 2.0f, 3.0f), float4(4.0f, 5.0f, 6.0f, 7.0f), float4(8.0f, 9.0f, 10.0f, 11.0f), float4(12.0f, 13.0f, 14.0f, 15.0f));
--- a/test/tint/expressions/type_ctor/mat4x4/identity/f32.wgsl
+++ b/test/tint/expressions/type_ctor/mat4x4/identity/f32.wgsl
@ -0,0 +1 @@
+let m = mat4x4<f32>();
--- a/test/tint/expressions/type_ctor/mat4x4/identity/f32.wgsl.expected.glsl
+++ b/test/tint/expressions/type_ctor/mat4x4/identity/f32.wgsl.expected.glsl
@ -0,0 +1,7 @@
+#version 310 es
+
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+void unused_entry_point() {
+  return;
+}
+const mat4 m = mat4(0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat4x4/identity/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat4x4/identity/f32.wgsl.expected.hlsl
@ -0,0 +1,6 @@
+[numthreads(1, 1, 1)]
+void unused_entry_point() {
+  return;
+}
+
+static const float4x4 m = float4x4(0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f);
--- a/test/tint/expressions/type_ctor/mat4x4/identity/f32.wgsl.expected.msl
+++ b/test/tint/expressions/type_ctor/mat4x4/identity/f32.wgsl.expected.msl
@ -0,0 +1,5 @@
+#include <metal_stdlib>
+
+using namespace metal;
+constant float4x4 m = float4x4();
+
--- a/test/tint/expressions/type_ctor/mat4x4/identity/f32.wgsl.expected.spvasm
+++ b/test/tint/expressions/type_ctor/mat4x4/identity/f32.wgsl.expected.spvasm
@ -0,0 +1,21 @@
+; SPIR-V
+; Version: 1.3
+; Generator: Google Tint Compiler; 0
+; Bound: 9
+; Schema: 0
+               OpCapability Shader
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %unused_entry_point "unused_entry_point"
+               OpExecutionMode %unused_entry_point LocalSize 1 1 1
+               OpName %m "m"
+               OpName %unused_entry_point "unused_entry_point"
+      %float = OpTypeFloat 32
+    %v4float = OpTypeVector %float 4
+%mat4v4float = OpTypeMatrix %v4float 4
+          %m = OpConstantNull %mat4v4float
+       %void = OpTypeVoid
+          %5 = OpTypeFunction %void
+%unused_entry_point = OpFunction %void None %5
+          %8 = OpLabel
+               OpReturn
+               OpFunctionEnd
--- a/test/tint/expressions/type_ctor/mat4x4/identity/f32.wgsl.expected.wgsl
+++ b/test/tint/expressions/type_ctor/mat4x4/identity/f32.wgsl.expected.wgsl
@ -0,0 +1 @@
+let m = mat4x4<f32>();
--- a/test/tint/expressions/type_ctor/mat4x4/inferred/scalars/f32.wgsl.expected.hlsl
+++ b/test/tint/expressions/type_ctor/mat4x4/inferred/scalars/f32.wgsl.expected.hlsl
@ -3,4 +3,4 @@ void unused_entry_point() {
  return;
 }

-static const float4x4 m = float4x4(0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f, 10.0f, 11.0f, 12.0f, 13.0f, 14.0f, 15.0f);
+static const float4x4 m = float4x4(float4(0.0f, 1.0f, 2.0f, 3.0f), float4(4.0f, 5.0f, 6.0f, 7.0f), float4(8.0f, 9.0f, 10.0f, 11.0f), float4(12.0f, 13.0f, 14.0f, 15.0f));