From 0b5190226b3061597f0fd88ca6b1f304f2c6af38 Mon Sep 17 00:00:00 2001
From: ArielG-NV <159081215+ArielG-NV@users.noreply.github.com>
Date: Fri, 28 Jun 2024 09:44:33 -0400
Subject: fix `WorkgroupSize()` compiler failiure (#4505)

in some cases was not destroying the hoisted to global `WorkgroupSize()` function

removed capability requirement on `gl_WorkGroupSize` since no longer appies (kIROp of `WorkgroupSize` is implemented for all targets)

change when destroying inst
---
 source/slang/glsl.meta.slang                       |  2 +-
 .../slang/slang-ir-translate-glsl-global-var.cpp   |  3 +++
 tests/bugs/gh-4504.slang                           | 23 ++++++++++++++++++++++
 3 files changed, 27 insertions(+), 1 deletion(-)
 create mode 100644 tests/bugs/gh-4504.slang

diff --git a/source/slang/glsl.meta.slang b/source/slang/glsl.meta.slang
index 85d39493b..cf314fcdc 100644
--- a/source/slang/glsl.meta.slang
+++ b/source/slang/glsl.meta.slang
@@ -126,7 +126,7 @@ public property uint3 gl_NumWorkGroups {
 public property uint3 gl_WorkGroupSize
 {
     [__unsafeForceInlineEarly]
-    [require(glsl_spirv, GLSL_430_SPIRV_1_0_compute)]
+    [require(compute)]
     get
     {
         return WorkgroupSize();
diff --git a/source/slang/slang-ir-translate-glsl-global-var.cpp b/source/slang/slang-ir-translate-glsl-global-var.cpp
index 42e70ac78..8cb7fa8e9 100644
--- a/source/slang/slang-ir-translate-glsl-global-var.cpp
+++ b/source/slang/slang-ir-translate-glsl-global-var.cpp
@@ -262,7 +262,10 @@ namespace Slang
             // We need to introduce a global variable and assign value to it in each entry point.
 
             if (!workgroupSizeInst->hasUses())
+            {
+                workgroupSizeInst->removeAndDeallocate();
                 return;
+            }
             builder.setInsertBefore(workgroupSizeInst);
             auto globalVar = builder.createGlobalVar(workgroupSizeInst->getFullType());
 
diff --git a/tests/bugs/gh-4504.slang b/tests/bugs/gh-4504.slang
new file mode 100644
index 000000000..d6fc28e0c
--- /dev/null
+++ b/tests/bugs/gh-4504.slang
@@ -0,0 +1,23 @@
+//TEST(compute):COMPARE_COMPUTE(filecheck-buffer=CHECK):-slang -dx12 -compute -shaderobj
+//TEST(compute, vulkan):COMPARE_COMPUTE(filecheck-buffer=CHECK):-vk -compute -shaderobj
+//TEST(compute, vulkan):COMPARE_COMPUTE(filecheck-buffer=CHECK):-vk -glsl -compute -shaderobj
+//TEST(compute, vulkan):COMPARE_COMPUTE(filecheck-buffer=CHECK):-mtl -compute -shaderobj
+
+//TEST_INPUT:ubuffer(data=[0], stride=4):out,name=outputBuffer
+RWStructuredBuffer<uint> outputBuffer;
+
+// note: `WorkgroupSize()` resolves into a compile time constant,
+// it is possible `size.x == 5` and others will resolve into `true`
+// at compile time. A compute test is required.
+[shader("compute")]
+[numthreads(5, 2, 1)]
+void computeMain(uint3 threadId: SV_DispatchThreadID)
+{
+    // CHECK: 1
+    int3 size = WorkgroupSize();
+    outputBuffer[0] = true
+        && size.x == 5
+        && size.y == 2
+        && size.z == 1
+        ;
+}
\ No newline at end of file
-- 
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