Fix pr14893.

When simplifycfg moves an instruction, it must drop metadata it doesn't know
is still valid with the preconditions changes. In particular, it must drop
the range and tbaa metadata.

The patch implements this with an utility function to drop all metadata not
in a white list.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200322 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 16 insertions, 0 deletions

diff --git a/include/llvm/IR/Instruction.h b/include/llvm/IR/Instruction.h
index 5721d8f2f3..0a245483ff 100644
--- a/include/llvm/IR/Instruction.h
+++ b/include/llvm/IR/Instruction.h
@@ -15,6 +15,7 @@
 #ifndef LLVM_IR_INSTRUCTION_H
 #define LLVM_IR_INSTRUCTION_H
 
+#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/ilist_node.h"
 #include "llvm/IR/User.h"
 #include "llvm/Support/DebugLoc.h"
@@ -171,6 +172,21 @@ public:
   void setMetadata(unsigned KindID, MDNode *Node);
   void setMetadata(StringRef Kind, MDNode *Node);
 
+  /// \brief Drop unknown metadata.
+  /// Passes are required to drop metadata they don't understand. This is a
+  /// convenience method for passes to do so.
+  void dropUnknownMetadata(ArrayRef<unsigned> KnownIDs);
+  void dropUnknownMetadata() {
+    return dropUnknownMetadata(ArrayRef<unsigned>());
+  }
+  void dropUnknownMetadata(unsigned ID1) {
+    return dropUnknownMetadata(makeArrayRef(ID1));
+  }
+  void dropUnknownMetadata(unsigned ID1, unsigned ID2) {
+    unsigned IDs[] = {ID1, ID2};
+    return dropUnknownMetadata(IDs);
+  }
+
   /// setDebugLoc - Set the debug location information for this instruction.
   void setDebugLoc(const DebugLoc &Loc) { DbgLoc = Loc; }