Don't inline callees with custom derivative before autodiff. (#3196)

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

1 files changed, 45 insertions, 0 deletions

diff --git a/tests/autodiff/inline.slang b/tests/autodiff/inline.slang
new file mode 100644
index 000000000..9b41b5f1f
--- /dev/null
+++ b/tests/autodiff/inline.slang
@@ -0,0 +1,45 @@
+//TEST(compute):COMPARE_COMPUTE_EX(filecheck-buffer=BUFFER):-slang -compute -shaderobj -output-using-type
+//TEST(compute, vulkan):COMPARE_COMPUTE_EX(filecheck-buffer=BUFFER):-vk -compute -shaderobj -output-using-type
+//TEST:SIMPLE(filecheck=CHECK):-stage compute -entry computeMain -target hlsl
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0 0 0 0], stride=4):out,name=outputBuffer
+RWStructuredBuffer<float> outputBuffer;
+
+typedef DifferentialPair<float> dpfloat;
+typedef float.Differential dfloat;
+
+// CHECK-NOT: void mySqr{{.*}}(
+
+// Test that calls to a ForceInline function stil get correct custom derivative.
+[BackwardDerivative(bwd_mySqr)]
+[ForceInline]
+void mySqr(float x, out float y)
+{
+    y = x * x;
+}
+
+void bwd_mySqr(inout DifferentialPair<float> dpx, in float.Differential dy)
+{
+    dpx = DifferentialPair<float>(dpx.p, 1001.0);
+}
+
+[Differentiable]
+void myF(float x, out float y)
+{
+    mySqr(x, y);
+}
+
+[numthreads(1, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    {
+        dpfloat dpa = dpfloat(2.0, 1.0);
+        __bwd_diff(myF)(dpa, 1.0);
+        // BUFFER: 1001.0
+        outputBuffer[0] = dpa.d;
+
+        float o;
+        myF(1.0, o);
+        outputBuffer[1] = o;
+    }
+}