`ExprLoweringVisitorBase::getDefaultVal(Type*)` use `MakeVector/MatrixFromScalar` (#8512)

- Allows using `Vector/Matrix` type with yet unresolved dimensions
- Simpler implementation and in-line with default `Array`
- Added `test/bugs/gh-8512.slang`

2 files changed, 79 insertions, 0 deletions

diff --git a/tests/bugs/gh-8512-2.slang b/tests/bugs/gh-8512-2.slang
new file mode 100644
index 000000000..4c51af696
--- /dev/null
+++ b/tests/bugs/gh-8512-2.slang
@@ -0,0 +1,40 @@
+//TEST:INTERPRET(filecheck=ICHECK):
+
+__generic <Scalar : __BuiltinFloatingPointType, int Mode>
+struct Spectrum
+{
+	static const int Samples = Mode & 0xFF;
+	typealias VecT = vector<Scalar, Samples>;
+	VecT data;
+	
+	static const bool IsRGB = (Mode & 0x100) != 0;
+
+	__generic <Float : __BuiltinFloatingPointType>
+	__init(vector<Float, Samples> v)
+	{
+		this.data = VecT(v);
+	}
+
+	static This MakeFromRGB<Float : __BuiltinFloatingPointType>(vector<Float, 3> rgb)
+	{
+		if(IsRGB)
+		{
+			return (Spectrum<Scalar, 0x103>(rgb) as This).value;
+		}
+		else
+		{
+			return {};
+		}
+	}
+}
+
+static const int DefaultMode = 0x103;
+typealias Spec = Spectrum<float, DefaultMode>;
+
+void main()
+{
+	float3 color = {1, 2, 3};
+	let spec = Spec::MakeFromRGB(color);
+	// ICHECK: (1, 2, 3)
+	printf("(%.0f, %.0f, %.0f)", spec.data[0], spec.data[1], spec.data[2]);
+}
diff --git a/tests/bugs/gh-8512.slang b/tests/bugs/gh-8512.slang
new file mode 100644
index 000000000..e94d95719
--- /dev/null
+++ b/tests/bugs/gh-8512.slang
@@ -0,0 +1,39 @@
+//TEST:SIMPLE(filecheck=CHECK): -target spirv
+// CHECK: OpEntryPoint
+
+__generic <Scalar : __BuiltinFloatingPointType, int Mode>
+struct Spectrum
+{
+	static const int Samples = Mode & 0xFF;
+	typealias VecT = vector<Scalar, Samples>;
+	VecT data;
+	
+	static const bool IsRGB = (Mode & 0x100) != 0;
+
+	__generic <Float : __BuiltinFloatingPointType>
+	__init(vector<Float, Samples> v)
+	{
+		this.data = VecT(v);
+	}
+
+	static This MakeFromRGB<Float : __BuiltinFloatingPointType>(vector<Float, 3> rgb)
+	{
+		if(IsRGB)
+		{
+			return (Spectrum<Scalar, 0x103>(rgb) as This).value;
+		}
+		else
+		{
+			return {};
+		}
+	}
+}
+
+static const int DefaultMode = 0x103;
+typealias Spec = Spectrum<float, DefaultMode>;
+
+[shader("vertex")]
+Spec main(float3 vertex_color : COLOR0) : COLOR0
+{
+	return Spec::MakeFromRGB(vertex_color);
+}