1 files changed, 8 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/GlobalMerge.cpp b/llvm/lib/CodeGen/GlobalMerge.cpp
index 2ccf2de..3e9a12b 100644
--- a/llvm/lib/CodeGen/GlobalMerge.cpp
+++ b/llvm/lib/CodeGen/GlobalMerge.cpp
@@ -652,6 +652,14 @@ bool GlobalMerge::doInitialization(Module &M) {
     if (isMustKeepGlobalVariable(&GV))
       continue;
 
+    // Don't merge tagged globals, as each global should have its own unique
+    // memory tag at runtime. TODO(hctim): This can be relaxed: constant globals
+    // with compatible alignment and the same contents may be merged as long as
+    // the globals occupy the same number of tag granules (i.e. `size_a / 16 ==
+    // size_b / 16`).
+    if (GV.isTagged())
+      continue;
+
     Type *Ty = GV.getValueType();
     if (DL.getTypeAllocSize(Ty) < MaxOffset) {
       if (TM &&