From 6bca0ec355aae2955c7de1cd16c2dc0dfe46f19c Mon Sep 17 00:00:00 2001
From: Sai Praveen Bangaru <31557731+saipraveenb25@users.noreply.github.com>
Date: Tue, 21 Feb 2023 11:37:15 -0500
Subject: Added support for simple while loops (#2667)

* Added support for simple while loops

* Fix support for while loops by changing logic to grab the loop update block
---
 tests/autodiff/reverse-while-loop.slang | 47 +++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 tests/autodiff/reverse-while-loop.slang

(limited to 'tests/autodiff/reverse-while-loop.slang')

diff --git a/tests/autodiff/reverse-while-loop.slang b/tests/autodiff/reverse-while-loop.slang
new file mode 100644
index 000000000..c8d2c542a
--- /dev/null
+++ b/tests/autodiff/reverse-while-loop.slang
@@ -0,0 +1,47 @@
+//TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -shaderobj -output-using-type
+//TEST(compute, vulkan):COMPARE_COMPUTE_EX:-vk -compute -shaderobj -output-using-type
+//TEST(compute):COMPARE_COMPUTE_EX:-cpu -compute -output-using-type -shaderobj
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0 0], stride=4):out,name=outputBuffer
+RWStructuredBuffer<float> outputBuffer;
+
+typedef DifferentialPair<float> dpfloat;
+typedef float.Differential dfloat;
+
+[BackwardDifferentiable]
+float test_simple_while(float y)
+{
+    float t = y;
+
+    bool keepGoing = true;
+    int i = 2;
+
+    [MaxIters(3)]
+    while (keepGoing)
+    {
+        i++;
+        t = t * t;
+
+        keepGoing = (i < 5);
+    }
+
+    return t;
+}
+
+[numthreads(1, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    {
+        dpfloat dpa = dpfloat(1.0, 0.0);
+
+        __bwd_diff(test_simple_while)(dpa, 1.0f);
+        outputBuffer[0] = dpa.d; // Expect: 8.0
+    }
+
+    {
+        dpfloat dpa = dpfloat(0.4, 0.0);
+
+        __bwd_diff(test_simple_while)(dpa, 1.0f);
+        outputBuffer[1] = dpa.d; // Expect: 0.0131072
+    }
+}
-- 
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