[llvm] [AMDGPU][LowerModuleLDS] Handle non-dynlds zero sized type (PR #84742)

[Pierre van Houtryve via llvm-commits]

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@@ -1398,8 +1398,8 @@ class AMDGPULowerModuleLDS {
           LDSVarsToTransform.begin(), LDSVarsToTransform.end()));
 
       for (GlobalVariable *GV : Sorted) {
-        OptimizedStructLayoutField F(GV,
-                                     DL.getTypeAllocSize(GV->getValueType()),
+        unsigned Size = DL.getTypeAllocSize(GV->getValueType());
+        OptimizedStructLayoutField F(GV, Size ? Size : 1,
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Pierre-vh wrote:

It's really an edge case, it can happen if the compiler allows something like `static unsigned arr[0]` (zero-sized externals become dynlds I think)
I can try to not add it and refactor the code as needed to make it work, I just thought it wasn't really worth it for such an edge case.

https://github.com/llvm/llvm-project/pull/84742