Add more diagnostics around use of custom derivatives. (#3291)

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

1 files changed, 51 insertions, 0 deletions

diff --git a/tests/diagnostics/custom-derivative-generic.slang b/tests/diagnostics/custom-derivative-generic.slang
new file mode 100644
index 000000000..5f2cd9951
--- /dev/null
+++ b/tests/diagnostics/custom-derivative-generic.slang
@@ -0,0 +1,51 @@
+//DIAGNOSTIC_TEST:SIMPLE(filecheck=CHECK):
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0 0], stride=4):out,name=outputBuffer
+RWStructuredBuffer<float> outputBuffer;
+
+typedef DifferentialPair<float> dpfloat;
+
+interface IFoo
+{
+    static float bar1(float x);
+
+    // CHECK-DAG: {{.*}}(13): error 31152
+    [PrimalSubstitute(bar1)]
+    static float bar(float x);
+
+    static DifferentialPair<float> dd(DifferentialPair<float> x);
+}
+
+__generic<let N:int>
+float f(float x)
+{
+    return N*x*x;
+}
+
+// CHECK-DAG: {{.*}}(26): error 31153
+[ForwardDerivative(IFoo.dd)]
+float bbb(float x);
+
+// CHECK-DAG: {{.*}}(30): error 31152
+[ForwardDerivativeOf(IFoo.bar)]
+DifferentialPair<float> dd1(DifferentialPair<float> x)
+{
+    return x;
+}
+
+// CHECK-DAG: {{.*}}(37): error 31151
+[BackwardDerivative(f)]
+DifferentialPair<float> df<let N:int>(inout DifferentialPair<float> x, float dOut)
+{
+    var primal = x.p * x.p;
+    var diff = 2 * x.p * x.d * N;
+    return DifferentialPair<float>(primal, diff);
+}
+[numthreads(1, 1, 1)]
+void computeMain(uint3 dispatchThreadID: SV_DispatchThreadID)
+{
+    {
+        dpfloat dpa = dpfloat(3.0, 1.0);
+        outputBuffer[1] = __fwd_diff(f<3>)(dpa).d; // Expect: 6.0
+    }
+}