[llvm-branch-commits] [llvm] [SPIRV][SPIRVPrepareGlobals] Map AMD's dynamic LDS 0-element globals to arrays with UINT32_MAX elements (PR #166952)

[Juan Manuel Martinez Caamaño via llvm-branch-commits]

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@@ -43,6 +44,29 @@ bool tryExtendLLVMBitcodeMarker(GlobalVariable &Bitcode) {
   return true;
 }
 
+bool tryExtendDynamicLDSGlobal(GlobalVariable &GV) {
+  constexpr unsigned WorkgroupAS = 3;
+  const bool IsWorkgroupExternal =
+      GV.hasExternalLinkage() && GV.getAddressSpace() == WorkgroupAS;
+  if (!IsWorkgroupExternal)
+    return false;
+
+  const ArrayType *AT = dyn_cast<ArrayType>(GV.getValueType());
+  if (!AT || AT->getNumElements() != 0)
+    return false;
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jmmartinez wrote:

Sorry I'm not sure I understood the question.

This condition is matching globals that have an array type with 0 elements. If the global does not have an array type or if it is an array type with a size different from 0 this function returns false.

Maybe there is a mix from using `getValueType` vs `getType`. The first gives the type of the initializer of the global (the value stored in the global), the second returns the type of the global when used as a value in the llvm-ir (a pointer type).

https://github.com/llvm/llvm-project/pull/166952