From 551bbb5fbd61b53253de8f6ba3303bb4d29f8c86 Mon Sep 17 00:00:00 2001
From: Sai Praveen Bangaru <31557731+saipraveenb25@users.noreply.github.com>
Date: Tue, 11 Feb 2025 03:08:27 -0800
Subject: Add checking for differentiability of the primal substitute function.
 (#6277)

Co-authored-by: Yong He <yonghe@outlook.com>
Co-authored-by: Ellie Hermaszewska <ellieh@nvidia.com>
---
 tests/diagnostics/autodiff-primal-substitute.slang | 44 ++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 tests/diagnostics/autodiff-primal-substitute.slang

(limited to 'tests/diagnostics')

diff --git a/tests/diagnostics/autodiff-primal-substitute.slang b/tests/diagnostics/autodiff-primal-substitute.slang
new file mode 100644
index 000000000..178698719
--- /dev/null
+++ b/tests/diagnostics/autodiff-primal-substitute.slang
@@ -0,0 +1,44 @@
+//DIAGNOSTIC_TEST:SIMPLE(filecheck=CHECK): -target spirv -entry computeMain -stage compute
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name=outputBufferPrimal
+RWStructuredBuffer<float> outputBufferPrimal;
+
+//TEST_INPUT:ubuffer(data=[1 2 3 4], stride=4):name=gradBuffer
+RWStructuredBuffer<float> gradBuffer;
+
+struct BufferWithGrad
+{
+    RWStructuredBuffer<float> primal;
+    RWStructuredBuffer<float> grad;
+
+    [Differentiable]
+    void add(float value) { primal[0] = primal[0] + detach(value); }
+
+    // check for diagnostic:
+    // CHECK-DAG: ([[# @LINE+1]]): error 31158
+    [PrimalSubstituteOf(add)]
+    void add_subst(float value)
+    {
+    }
+
+    [BackwardDerivativeOf(add)]
+    void add_bwd(inout DifferentialPair<float> d)
+    {
+        d = diffPair(d.p, grad[0]);
+    }
+}
+
+[Differentiable]
+void diffCall(BufferWithGrad result)
+{
+    result.add(1.0f);
+}
+
+[shader("compute")]
+[numthreads(1, 1, 1)]
+void computeMain(uint3 dispatchThreadID: SV_DispatchThreadID)
+{
+    BufferWithGrad bg = {outputBufferPrimal, gradBuffer};
+    diffCall(bg); 
+    bwd_diff(diffCall)(bg);
+}
-- 
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