Patched support for multi-return and fallthrough if-else with break stmts (#2617)

3 files changed, 60 insertions, 5 deletions

diff --git a/tests/autodiff/reverse-multi-return.slang b/tests/autodiff/reverse-multi-return.slang
new file mode 100644
index 000000000..ee8bb9a4c
--- /dev/null
+++ b/tests/autodiff/reverse-multi-return.slang
@@ -0,0 +1,50 @@
+//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 0], stride=4):out,name=outputBuffer
+RWStructuredBuffer<float> outputBuffer;
+
+typedef DifferentialPair<float> dpfloat;
+typedef float.Differential dfloat;
+
+[BackwardDifferentiable]
+float test_multi_return(float y)
+{
+    if (y > 0.6)
+    {
+        if (y > 0.8)
+        {
+            return y * 10.0f;
+        }
+        else
+        {
+            return y * 4.0f;
+        }
+    }
+    return y * 6.0f;
+}
+
+[numthreads(1, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    {
+        dpfloat dpa = dpfloat(1.0, 0.0);
+
+        __bwd_diff(test_multi_return)(dpa, 1.0f);
+        outputBuffer[0] = dpa.d; // Expect: 10.0
+    }
+
+    {
+        dpfloat dpa = dpfloat(0.4, 0.0);
+        
+        __bwd_diff(test_multi_return)(dpa, 1.0f);
+        outputBuffer[1] = dpa.d; // Expect: 6.0
+    }
+
+    {
+        dpfloat dpa = dpfloat(0.7, 0.0);
+        
+        __bwd_diff(test_multi_return)(dpa, 1.0f);
+        outputBuffer[2] = dpa.d; // Expect: 4.0
+    }
+}
diff --git a/tests/autodiff/reverse-multi-return.slang.expected.txt b/tests/autodiff/reverse-multi-return.slang.expected.txt
new file mode 100644
index 000000000..115191b13
--- /dev/null
+++ b/tests/autodiff/reverse-multi-return.slang.expected.txt
@@ -0,0 +1,7 @@
+type: float
+10.000000
+6.000000
+4.000000
+0.000000
+0.000000
+0.000000
diff --git a/tests/autodiff/reverse-single-iter-loop.slang b/tests/autodiff/reverse-single-iter-loop.slang
index 47232147a..20c26e000 100644
--- a/tests/autodiff/reverse-single-iter-loop.slang
+++ b/tests/autodiff/reverse-single-iter-loop.slang
@@ -49,11 +49,9 @@ float test_nested_if_else_single_iter_loop(float y)
                 break;
             }
         }
-        else
-        {
-            x = y * 6.0f;
-            break;
-        }
+
+        x = y * 6.0f;
+        break;
     }
 
     return x;