Clean up type checking of higher order expressions. (#2519)

* Clean up type checking of higher order expressions.

* Replace `goto` with `break` to pacify clang.

* Fix.

* Fixes.

* Fix more tests.

* Fix lowerWitnessTable parameter error.

* Exclude attributes from ast printing.

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

2 files changed, 40 insertions, 0 deletions

diff --git a/tests/autodiff/high-order-diff-operator.slang b/tests/autodiff/high-order-diff-operator.slang
new file mode 100644
index 000000000..dca67e9f3
--- /dev/null
+++ b/tests/autodiff/high-order-diff-operator.slang
@@ -0,0 +1,35 @@
+//TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -shaderobj -output-using-type
+//TEST(compute, vulkan):COMPARE_COMPUTE_EX:-vk -compute -shaderobj -output-using-type
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name=outputBuffer
+RWStructuredBuffer<float> outputBuffer;
+
+[ForwardDifferentiable]
+float mySqr(float x)
+{
+    return x * x;
+}
+
+[ForwardDifferentiable]
+float f(float x)
+{
+    return mySqr(x * x);
+}
+
+[numthreads(1, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    // Given f(x) = x^4,
+    // f''(x) = 12 * x^2
+    // Expect f''(4) = 192
+    float.Differential t = 2;
+    outputBuffer[0] = __fwd_diff(__fwd_diff(f))(
+        DifferentialPair<DifferentialPair<float>>(
+            DifferentialPair<float>(4.0, 1.0), DifferentialPair<float>(1.0, 0.0))).d.d;
+            
+    // sin''(x) = cos'(x) = -sin(x).
+    // Expect sin''(Pi/2) = -1.
+    outputBuffer[1] = __fwd_diff(__fwd_diff(sin))(
+                          DifferentialPair<DifferentialPair<float>>(
+                              DifferentialPair<float>(float.getPi()/2, 1.0), DifferentialPair<float>(1.0, 0.0))).d.d; 
+}
diff --git a/tests/autodiff/high-order-diff-operator.slang.expected.txt b/tests/autodiff/high-order-diff-operator.slang.expected.txt
new file mode 100644
index 000000000..305a8e111
--- /dev/null
+++ b/tests/autodiff/high-order-diff-operator.slang.expected.txt
@@ -0,0 +1,5 @@
+type: float
+192.000000
+-1.000000
+0.000000
+0.000000