Fix `sessionDesc.defaultMatrixLayoutMode` being ineffective. (#3753)

* Fix `sessionDesc.defaultMatrixLayoutMode` being ineffective.

* Fix matrix layout in buffer pointer.

* Attempt to fix.

* Fix buffer element type lowering for buffer pointers.

* Add comment.

* Fix test.

* Fix member lookup in `Ref<T>`.

* Fix validation error.

* Enhance test.

1 files changed, 34 insertions, 0 deletions

diff --git a/tests/spirv/buffer-pointer-matrix-layout.slang b/tests/spirv/buffer-pointer-matrix-layout.slang
new file mode 100644
index 000000000..2ccde7b71
--- /dev/null
+++ b/tests/spirv/buffer-pointer-matrix-layout.slang
@@ -0,0 +1,34 @@
+//TEST:SIMPLE(filecheck=CHECK): -target spirv -emit-spirv-directly -stage compute -entry main -matrix-layout-column-major
+
+// CHECK: OpLoad %_MatrixStorage_float3x4_ColMajornatural {{.*}} Aligned 4
+// CHECK: OpLoad %_MatrixStorage_float3x4_ColMajornatural {{.*}} Aligned 4
+
+struct Push
+{
+    float3x4* ptr;
+};
+
+[[vk::push_constant]] Push push;
+[shader("compute")]
+[numthreads(1, 1, 1)]
+void main(uint3 dtid : SV_DispatchThreadID)
+{    
+    // This matrix is in memry column major. Slang respects this here and load it properly!
+    float3x4 correctly_read_matrix = *push.ptr;
+    printf("(%f,%f,%f,%f)\n(%f,%f,%f,%f)\n",
+        correctly_read_matrix[0][0], correctly_read_matrix[0][1], correctly_read_matrix[0][2], correctly_read_matrix[0][3],
+        correctly_read_matrix[1][0], correctly_read_matrix[1][1], correctly_read_matrix[1][2], correctly_read_matrix[1][3]
+    );
+    printf("(%f,%f,%f,%f)\n\n",
+        correctly_read_matrix[2][0], correctly_read_matrix[2][1], correctly_read_matrix[2][2], correctly_read_matrix[2][3]
+    );
+    // With this syntax however, Slang ignores the column major setting and loads it as it it was row major!
+    float3x4 broken_matrix = push.ptr[0];
+    printf("(%f,%f,%f,%f)\n(%f,%f,%f,%f)\n",
+        broken_matrix[0][0], broken_matrix[0][1], broken_matrix[0][2], broken_matrix[0][3],
+        broken_matrix[1][0], broken_matrix[1][1], broken_matrix[1][2], broken_matrix[1][3]
+    );
+    printf("(%f,%f,%f,%f)\n\n",
+        broken_matrix[2][0], broken_matrix[2][1], broken_matrix[2][2], broken_matrix[2][3]
+    );
+}
\ No newline at end of file