WIP: Fixed inout struct and added testing for calls to non-differentiable functions (#2505)

* Added non-differentiable call test

* Extended testing for nondifferentiable calls

* Fixed subtle issue with extensions on generic types not applying the correct substitutions, leading to unspecialized generics at the emit stage

* More fixes. inout struct params now work fine

* Update inout-struct-parameters-jvp.slang

* Update slang-ir.cpp

* Fixed hoisting lookup_interface_method

* Fixed non-diff call return value

* Fixed issue with phi nodes

* Fixed problem with IRSpecialize preventing hoisitng of DifferentialPairType

* Fixed non-diff call test to conform to the new 'no_diff' system

4 files changed, 118 insertions, 0 deletions

diff --git a/tests/autodiff/inout-struct-parameters-jvp.slang b/tests/autodiff/inout-struct-parameters-jvp.slang
new file mode 100644
index 000000000..80ff57b7d
--- /dev/null
+++ b/tests/autodiff/inout-struct-parameters-jvp.slang
@@ -0,0 +1,41 @@
+//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;
+
+typedef DifferentialPair<float> dpfloat;
+
+struct A : IDifferentiable
+{
+    float p;
+    float3 q;
+}
+
+[ForwardDifferentiable]
+void g(A a, inout A aout)
+{
+    float t = a.p + a.q.y * a.q.x;
+    aout.p = aout.p + t;
+    aout.q = aout.q * t;
+}
+
+[numthreads(1, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    float p = 1.0;
+    float3 q = float3(1.0, 2.0, 3.0);
+
+    float dp = 1.0;
+    float3 dq = float3(1.0, 0.5, 0.25);
+
+    DifferentialPair<A> dpa = DifferentialPair<A>({p, q}, {dp, dq});
+
+    __fwd_diff(g)(DifferentialPair<A>( { p, q }, { dp, dq }), dpa);
+
+    outputBuffer[0] = dpa.p.p; // Expect: 4.0
+    outputBuffer[1] = dpa.d.q.x; // Expect: 6.5
+    outputBuffer[2] = dpa.d.q.y; // Expect: 8.5
+    outputBuffer[3] = dpa.d.q.z; // Expect: 11.25
+
+}
\ No newline at end of file
diff --git a/tests/autodiff/inout-struct-parameters-jvp.slang.expected.txt b/tests/autodiff/inout-struct-parameters-jvp.slang.expected.txt
new file mode 100644
index 000000000..4cc3c313d
--- /dev/null
+++ b/tests/autodiff/inout-struct-parameters-jvp.slang.expected.txt
@@ -0,0 +1,5 @@
+type: float
+4.000000
+6.500000
+8.500000
+11.25000
diff --git a/tests/autodiff/nondiff-call.slang b/tests/autodiff/nondiff-call.slang
new file mode 100644
index 000000000..d62de1b78
--- /dev/null
+++ b/tests/autodiff/nondiff-call.slang
@@ -0,0 +1,66 @@
+//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 0], stride=4):out,name=outputBuffer
+RWStructuredBuffer<float> outputBuffer;
+
+typedef DifferentialPair<float> dpfloat;
+typedef DifferentialPair<float3> dpfloat3;
+
+[ForwardDifferentiable]
+float f(float x)
+{
+    return x * x + x * x * x;
+}
+
+[ForwardDifferentiable]
+float f2(float x)
+{
+    return f(x);
+}
+
+float g(float x)
+{
+    return x * x + x * x * x;
+}
+
+[ForwardDifferentiable]
+float g2(float x)
+{
+    return no_diff(g(x));
+}
+
+struct A
+{
+    float o;
+
+    [ForwardDifferentiable]
+    float doSomethingDifferentiable(float b)
+    {
+        return o + b;
+    }
+
+    float doSomethingNotDifferentiable(float b)
+    {
+        return o * b;
+    }
+}
+
+[ForwardDifferentiable]
+float h2(A a, float k)
+{
+    float v = k * k;
+    return no_diff(a.doSomethingNotDifferentiable(k)) + v;
+}
+
+[numthreads(1, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+     {
+         outputBuffer[0] = f2(1.0); // Expect: 2.0
+         outputBuffer[1] = __fwd_diff(f2)(dpfloat(1.0, 1.0)).d; // Expect: 5.0
+         outputBuffer[2] = __fwd_diff(f2)(dpfloat(1.0, 1.0)).p; // Expect: 2.0
+         outputBuffer[3] = __fwd_diff(g2)(dpfloat(1.0, 1.0)).d; // Expect: 0.0
+         outputBuffer[4] = __fwd_diff(h2)({1.0}, DifferentialPair<float>(1.0, 2.0)).d; // Expect: 4.0
+    }
+}
diff --git a/tests/autodiff/nondiff-call.slang.expected.txt b/tests/autodiff/nondiff-call.slang.expected.txt
new file mode 100644
index 000000000..8f85913bc
--- /dev/null
+++ b/tests/autodiff/nondiff-call.slang.expected.txt
@@ -0,0 +1,6 @@
+type: float
+2.000000
+5.000000
+2.000000
+0.000000
+4.000000
\ No newline at end of file