1 files changed, 25 insertions, 15 deletions

diff --git a/llvm/lib/Target/AMDGPU/AMDGPULowerModuleLDSPass.cpp b/llvm/lib/Target/AMDGPU/AMDGPULowerModuleLDSPass.cpp
index b85cb26fdc95..595f09664c55 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPULowerModuleLDSPass.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPULowerModuleLDSPass.cpp
@@ -340,26 +340,11 @@ public:
 
     // Get uses from the current function, excluding uses by called functions
     // Two output variables to avoid walking the globals list twice
-    std::optional<bool> HasAbsoluteGVs;
     for (auto &GV : M.globals()) {
       if (!AMDGPU::isLDSVariableToLower(GV)) {
         continue;
       }
 
-      // Check if the module is consistent: either all GVs are absolute (happens
-      // when we run the pass more than once), or none are.
-      const bool IsAbsolute = GV.isAbsoluteSymbolRef();
-      if (HasAbsoluteGVs.has_value()) {
-        if (*HasAbsoluteGVs != IsAbsolute) {
-          report_fatal_error(
-              "Module cannot mix absolute and non-absolute LDS GVs");
-        }
-      } else
-        HasAbsoluteGVs = IsAbsolute;
-
-      if (IsAbsolute)
-        continue;
-
       for (User *V : GV.users()) {
         if (auto *I = dyn_cast<Instruction>(V)) {
           Function *F = I->getFunction();
@@ -469,6 +454,31 @@ public:
       }
     }
 
+    // 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}) {
+      for (auto &[Fn, GVs] : Map) {
+        for (auto *GV : GVs) {
+          bool IsAbsolute = GV->isAbsoluteSymbolRef();
+          if (HasAbsoluteGVs.has_value()) {
+            if (*HasAbsoluteGVs != IsAbsolute) {
+              report_fatal_error(
+                  "Module cannot mix absolute and non-absolute LDS GVs");
+            }
+          } else
+            HasAbsoluteGVs = IsAbsolute;
+        }
+      }
+    }
+
+    // If we only had absolute GVs, we have nothing to do, return an empty
+    // result.
+    if (HasAbsoluteGVs && *HasAbsoluteGVs)
+      return {FunctionVariableMap(), FunctionVariableMap()};
+
     return {std::move(direct_map_kernel), std::move(indirect_map_kernel)};
   }