Implement derivatives for HLSL intrinsics. (#2684)

* Implement derivatives for HLSL intrinsics.

* Vector intrinsics.

* Add all intrinsics.

---------

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

1 files changed, 36 insertions, 0 deletions

diff --git a/tests/autodiff-dstdlib/vector-length.slang b/tests/autodiff-dstdlib/vector-length.slang
new file mode 100644
index 000000000..c5064e54e
--- /dev/null
+++ b/tests/autodiff-dstdlib/vector-length.slang
@@ -0,0 +1,36 @@
+//TEST(compute, vulkan):COMPARE_COMPUTE_EX:-vk -compute -shaderobj -output-using-type
+//TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -shaderobj -output-using-type
+
+//TEST_INPUT:ubuffer(data=[0 0 0], stride=4):out,name=outputBuffer
+RWStructuredBuffer<float> outputBuffer;
+
+float lengthDiffX(float3 x)
+{
+    return (length(float3(x.x + 0.001, x.yz)) - length(float3(x.x - 0.001, x.yz))) / 0.002;
+}
+float lengthDiffY(float3 x)
+{
+    return (length(float3(x.x, x.y + 0.001, x.z)) - length(float3(x.x, x.y - 0.001, x.z))) / 0.002;
+}
+float lengthDiffZ(float3 x)
+{
+    return (length(float3(x.xy, x.z + 0.001)) - length(float3(x.xy, x.z - 0.001))) / 0.002;
+}
+
+[numthreads(1, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    {
+        let x = float3(12, 23, 31);
+        var dpx = diffPair(x);
+        __bwd_diff(length)(dpx, 1.0);
+        outputBuffer[0] = dpx.d[0];
+        outputBuffer[1] = dpx.d[1];
+        outputBuffer[2] = dpx.d[2];
+
+        // for reference:
+        //outputBuffer[3] = lengthDiffX(x);
+        //outputBuffer[4] = lengthDiffY(x);
+        //outputBuffer[5] = lengthDiffZ(x);
+    }
+}