Specialize generic/existential calls within generic functions. (#2294)

* Expose internals of dce and use it to implement call graph walk.

* Specialize calls in generic functions.

* Fix clang error.

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

2 files changed, 67 insertions, 0 deletions

diff --git a/tests/compute/dynamic-dispatch-19.slang b/tests/compute/dynamic-dispatch-19.slang
new file mode 100644
index 000000000..573cade82
--- /dev/null
+++ b/tests/compute/dynamic-dispatch-19.slang
@@ -0,0 +1,65 @@
+// Test use of unrelated generics in a dynamically dispatched generic function can be specialized.
+
+//TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -dx12 -profile sm_6_0 -use-dxil -output-using-type
+//TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -dx11 -profile sm_5_0 -output-using-type
+//TEST(compute, vulkan):COMPARE_COMPUTE_EX:-vk -compute  -output-using-type
+
+interface IValueGetter
+{
+    float get();
+}
+
+struct MyWrapper<T:IValueGetter>
+{
+    T getter;
+    float getVal()
+    {
+        return getter.get();
+    }
+}
+
+interface IFoo
+{
+    int getIntVal(int x);
+}
+
+[anyValueSize(16)]
+interface IInterface
+{
+    float callGetter<T:IFoo>(T foo);
+}
+
+struct Impl : IInterface
+{
+    int data;
+    struct GetterImpl : IValueGetter { float val; float get(){return val;} }
+    float callGetter<T:IFoo>(T foo)
+    {
+        // We should be able to specialize `wrapper` even if it is
+        // used in this dynamically dispatched method.
+        MyWrapper<GetterImpl> wrapper;
+        wrapper.getter.val = 2.0f;
+        return wrapper.getVal() * foo.getIntVal(1);
+    }
+};
+
+struct IdentityFoo : IFoo { int getIntVal(int x) { return x; } }
+
+float test()
+{
+    IInterface obj = createDynamicObject<IInterface, uint4>(3, uint4(1,2,3,4));
+    IdentityFoo foo;
+    // Call via dynamic dispatch
+    return obj.callGetter(foo);
+}
+
+//TEST_INPUT:ubuffer(data=[0], stride=4):out,name=gOutputBuffer
+RWStructuredBuffer<float> gOutputBuffer;
+
+//TEST_INPUT: type_conformance Impl:IInterface = 3
+
+[numthreads(1, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    gOutputBuffer[0] = test();
+}
diff --git a/tests/compute/dynamic-dispatch-19.slang.expected.txt b/tests/compute/dynamic-dispatch-19.slang.expected.txt
new file mode 100644
index 000000000..395c7d3be
--- /dev/null
+++ b/tests/compute/dynamic-dispatch-19.slang.expected.txt
@@ -0,0 +1,2 @@
+type: float
+2.0