Add a missed CommonLinkage check.

llvm-svn: 51503
diff --git a/llvm/lib/Target/PowerPC/PPCSubtarget.cpp b/llvm/lib/Target/PowerPC/PPCSubtarget.cpp
index 6cf6ca6..14983fc 100644
--- a/llvm/lib/Target/PowerPC/PPCSubtarget.cpp
+++ b/llvm/lib/Target/PowerPC/PPCSubtarget.cpp
@@ -143,5 +143,6 @@
     return false;
   
   return GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
+         GV->hasCommonLinkage() ||
          (GV->isDeclaration() && !GV->hasNotBeenReadFromBitcode());
 }