Update enforceKnownAlignment after the isWeakForLinker semantic change

Previously we would refrain from attempting to increase the linkage of
available_externally globals because they were considered weak for the
linker. Now they are treated more like a declaration instead of a weak
definition.

This was causing SSE alignment faults in Chromuim, when some code
assumed it could increase the alignment of a dllimported global that it
didn't control.  http://crbug.com/509256

llvm-svn: 242091

1 files changed, 4 insertions, 7 deletions

diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 56085579b61..50ca6234d0b 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -900,13 +900,10 @@ static unsigned enforceKnownAlignment(Value *V, unsigned Align,
 
   if (auto *GO = dyn_cast<GlobalObject>(V)) {
     // If there is a large requested alignment and we can, bump up the alignment
-    // of the global.
-    if (GO->isDeclaration())
-      return Align;
-    // If the memory we set aside for the global may not be the memory used by
-    // the final program then it is impossible for us to reliably enforce the
-    // preferred alignment.
-    if (GO->isWeakForLinker())
+    // of the global.  If the memory we set aside for the global may not be the
+    // memory used by the final program then it is impossible for us to reliably
+    // enforce the preferred alignment.
+    if (!GO->isStrongDefinitionForLinker())
       return Align;
 
     if (GO->getAlignment() >= PrefAlign)