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

1 files changed, 23 insertions, 0 deletions

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