1 files changed, 17 insertions, 4 deletions
diff --git a/lib/Analysis/GlobalsModRef.cpp b/lib/Analysis/GlobalsModRef.cpp
index 23109c67e5c3..daee93267f56 100644
--- a/lib/Analysis/GlobalsModRef.cpp
+++ b/lib/Analysis/GlobalsModRef.cpp
@@ -85,12 +85,17 @@ class GlobalsAAResult::FunctionInfo {
   /// The bit that flags that this function may read any global. This is
   /// chosen to mix together with ModRefInfo bits.
   /// FIXME: This assumes ModRefInfo lattice will remain 4 bits!
+  /// It overlaps with ModRefInfo::Must bit!
+  /// FunctionInfo.getModRefInfo() masks out everything except ModRef so
+  /// this remains correct, but the Must info is lost.
   enum { MayReadAnyGlobal = 4 };
 
   /// Checks to document the invariants of the bit packing here.
-  static_assert((MayReadAnyGlobal & static_cast<int>(ModRefInfo::ModRef)) == 0,
+  static_assert((MayReadAnyGlobal & static_cast<int>(ModRefInfo::MustModRef)) ==
+                    0,
                 "ModRef and the MayReadAnyGlobal flag bits overlap.");
-  static_assert(((MayReadAnyGlobal | static_cast<int>(ModRefInfo::ModRef)) >>
+  static_assert(((MayReadAnyGlobal |
+                  static_cast<int>(ModRefInfo::MustModRef)) >>
                  AlignedMapPointerTraits::NumLowBitsAvailable) == 0,
                 "Insufficient low bits to store our flag and ModRef info.");
 
@@ -125,14 +130,22 @@ public:
     return *this;
   }
 
+  /// This method clears MayReadAnyGlobal bit added by GlobalsAAResult to return
+  /// the corresponding ModRefInfo. It must align in functionality with
+  /// clearMust().
+  ModRefInfo globalClearMayReadAnyGlobal(int I) const {
+    return ModRefInfo((I & static_cast<int>(ModRefInfo::ModRef)) |
+                      static_cast<int>(ModRefInfo::NoModRef));
+  }
+
   /// Returns the \c ModRefInfo info for this function.
   ModRefInfo getModRefInfo() const {
-    return ModRefInfo(Info.getInt() & static_cast<int>(ModRefInfo::ModRef));
+    return globalClearMayReadAnyGlobal(Info.getInt());
   }
 
   /// Adds new \c ModRefInfo for this function to its state.
   void addModRefInfo(ModRefInfo NewMRI) {
-    Info.setInt(Info.getInt() | static_cast<int>(NewMRI));
+    Info.setInt(Info.getInt() | static_cast<int>(setMust(NewMRI)));
   }
 
   /// Returns whether this function may read any global variable, and we don't