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

2 files changed, 4 insertions, 1 deletions

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());