From 579870b714e76cc92300cef1fdf091993bb55954 Mon Sep 17 00:00:00 2001
From: Yong He <yonghe@outlook.com>
Date: Mon, 27 Mar 2023 19:51:21 -0700
Subject: Apply IR simplifcation immediately after specialization to avoid
 duplicates. (#2739)

* Apply IR simplifcation immediately after specialization to avoid duplicates.

* Update source/slang/slang-ir-specialize.cpp

Co-authored-by: Ellie Hermaszewska <github@sub.monoid.al>

---------

Co-authored-by: Yong He <yhe@nvidia.com>
Co-authored-by: Ellie Hermaszewska <github@sub.monoid.al>
---
 source/slang/slang-ir-specialize.cpp              | 10 ++++++++
 tests/bugs/generic-groupshared.slang              | 29 +++++++++++++++++++++++
 tests/bugs/generic-groupshared.slang.expected.txt |  4 ++++
 3 files changed, 43 insertions(+)
 create mode 100644 tests/bugs/generic-groupshared.slang
 create mode 100644 tests/bugs/generic-groupshared.slang.expected.txt

diff --git a/source/slang/slang-ir-specialize.cpp b/source/slang/slang-ir-specialize.cpp
index 05c28d131..d2e042363 100644
--- a/source/slang/slang-ir-specialize.cpp
+++ b/source/slang/slang-ir-specialize.cpp
@@ -2439,6 +2439,16 @@ IRInst* specializeGenericImpl(
                 // value.
                 cloneInstDecorationsAndChildren(
                     &env, module, specializeInst, specializedVal);
+
+                // Perform IR simplifications to fold constants in this specialized value if it is a function, so 
+                // further specializations from the specialized function will have as simple specialization 
+                // arguments as possible to avoid creating specializations that eventually simplified into 
+                // the same thing.
+                if (auto func = as<IRFunc>(specializedVal))
+                {
+                    simplifyFunc(func);
+                }
+
                 return specializedVal;
             }
 
diff --git a/tests/bugs/generic-groupshared.slang b/tests/bugs/generic-groupshared.slang
new file mode 100644
index 000000000..c5ed8cf40
--- /dev/null
+++ b/tests/bugs/generic-groupshared.slang
@@ -0,0 +1,29 @@
+//TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -shaderobj
+//TEST(compute,vulkan):COMPARE_COMPUTE_EX:-vk -slang -compute -shaderobj
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name outputBuffer
+RWStructuredBuffer<int> outputBuffer;
+
+[ForceInline]
+Ref<uint> table<let n: int>(int index)
+{
+    static groupshared uint array[n];
+    return array[index];
+}
+
+struct S<let n : int>
+{
+    static const int M = n * 2;
+    int doSomething()
+    {
+        table<M>(0) = M;
+        return table<M>(0);
+    }
+}
+
+[numthreads(1, 1, 1)]
+void computeMain(int3 dispatchThreadID: SV_DispatchThreadID)
+{
+    S<2> s;
+    outputBuffer[0] = s.doSomething();
+}
\ No newline at end of file
diff --git a/tests/bugs/generic-groupshared.slang.expected.txt b/tests/bugs/generic-groupshared.slang.expected.txt
new file mode 100644
index 000000000..a358987a6
--- /dev/null
+++ b/tests/bugs/generic-groupshared.slang.expected.txt
@@ -0,0 +1,4 @@
+4
+0
+0
+0
-- 
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