[llvm] [AMDGPU][LowerModuleLDS] Refactor partially lowered module detection (PR #85793)

[Jon Chesterfield via llvm-commits]

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@@ -469,6 +454,31 @@ class AMDGPULowerModuleLDS {
       }
     }
 
+    // Verify that we fall into one of 2 cases:
+    //    - All variables are absolute: this is a re-run of the pass
+    //      so we don't have anything to do.
+    //    - No variables are absolute.
+    std::optional<bool> HasAbsoluteGVs;
+    for (auto Map : {direct_map_kernel, indirect_map_kernel}) {
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JonChesterfield wrote:

Is this a copy? Might need a & to avoid that

https://github.com/llvm/llvm-project/pull/85793