Fix existential specialization of mutable buffer loads. (#1671)

* Fix existential specialization of mutable buffer loads.

* fix

Co-authored-by: Yong He <yhe@nvidia.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/tests/bugs/rwstructuredbuffer-existential-in-struct.slang b/tests/bugs/rwstructuredbuffer-existential-in-struct.slang
new file mode 100644
index 000000000..c763dd3c1
--- /dev/null
+++ b/tests/bugs/rwstructuredbuffer-existential-in-struct.slang
@@ -0,0 +1,32 @@
+//TEST(compute):COMPARE_COMPUTE:-dx11 -shaderobj
+
+[anyValueSize(8)]
+interface IMaterial
+{
+    float eval();
+}
+
+struct MaterialImpl : IMaterial
+{
+    float eval() { return 0.0f; }
+};
+
+struct Parameters
+{
+    uint ordinary;
+
+//TEST_INPUT: entryPointExistentialType MaterialImpl
+//TEST_INPUT:ubuffer(data=[0 0 0 0 0 0], stride=4):name=params.materials
+    RWStructuredBuffer<IMaterial> materials;
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name=params.result
+    RWStructuredBuffer<float> result;
+};
+
+[numthreads(4, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID, uniform Parameters params, uniform int id)
+{
+    uint tid = dispatchThreadID.x;
+    float rs = params.materials[0].eval();
+    params.result[tid] = rs;
+}