Data flow validation pass for diagnosing derivative loss. (#2523)

1 files changed, 38 insertions, 0 deletions

diff --git a/tests/diagnostics/autodiff-data-flow.slang b/tests/diagnostics/autodiff-data-flow.slang
new file mode 100644
index 000000000..93c76c07e
--- /dev/null
+++ b/tests/diagnostics/autodiff-data-flow.slang
@@ -0,0 +1,38 @@
+//DIAGNOSTIC_TEST:SIMPLE:
+
+float nonDiff(float x)
+{
+    return x;
+}
+
+[ForwardDifferentiable]
+float f(float x)
+{
+    float val = 0;
+    if (x > 5)
+        val = x + 1;
+    else
+        val = nonDiff(x * 2.0f);
+    // Not all path propagates derivatives through.
+    return val;
+}
+
+// error: function does not return a differentiable value.
+[ForwardDifferentiable]
+void g(float x)
+{
+    float val = 0;
+    if (x > 5)
+        val = x + 1;
+    return;
+}
+
+
+[ForwardDifferentiable]
+float h(float x)
+{
+    float val = 0;
+    // no diagnostic by clarifying intention.
+    val = no_diff(nonDiff(x * 2.0f));
+    return val;
+}