[PATCH] D99629: [GlobalOpt] Don't replace alias with aliasee if aliasee is interposable

[Arthur Eubanks via Phabricator via llvm-commits]

aeubanks updated this revision to Diff 334312.
aeubanks added a comment.

update


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D99629/new/

https://reviews.llvm.org/D99629

Files:
  llvm/lib/Transforms/IPO/GlobalOpt.cpp
  llvm/test/Transforms/GlobalOpt/alias-resolve.ll


Index: llvm/test/Transforms/GlobalOpt/alias-resolve.ll
===================================================================
--- llvm/test/Transforms/GlobalOpt/alias-resolve.ll
+++ llvm/test/Transforms/GlobalOpt/alias-resolve.ll
@@ -33,7 +33,10 @@
 ; CHECK: call void @bar2()
 
          call void @weak1()
-; CHECK: call void @weak1()
+; CHECK: call void @bar2()
+
+         call void @bar6()
+; CHECK: call void @bar6()
          ret void
 }
 
@@ -44,3 +47,9 @@
   ret void
 }
 ;CHECK: define void @foo3
+
+define weak void @bar5() {
+  ret void
+}
+
+ at bar6 = alias void(), void ()* @bar5
Index: llvm/lib/Transforms/IPO/GlobalOpt.cpp
===================================================================
--- llvm/lib/Transforms/IPO/GlobalOpt.cpp
+++ llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -2932,16 +2932,14 @@
       continue;
     }
 
-    // If the alias can change at link time, nothing can be done - bail out.
-    if (J->isInterposable())
-      continue;
-
     Constant *Aliasee = J->getAliasee();
     GlobalValue *Target = dyn_cast<GlobalValue>(Aliasee->stripPointerCasts());
     // We can't trivially replace the alias with the aliasee if the aliasee is
-    // non-trivial in some way.
+    // non-trivial in some way. We also can't replace the alias with the aliasee
+    // if the aliasee is interposable because aliases point to the local
+    // definition.
     // TODO: Try to handle non-zero GEPs of local aliasees.
-    if (!Target)
+    if (!Target || Target->isInterposable())
       continue;
     Target->removeDeadConstantUsers();
 


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