diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 476c68a6c0a..f34884391a7 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -494,6 +494,14 @@ bool BitcodeReader::ParseAttributeBlock() {
       Attrs.clear();
       break;
     }
+    case bitc::PARAMATTR_CODE_ENTRY: { // ENTRY: [attrgrp0, attrgrp1, ...]
+      for (unsigned i = 0, e = Record.size(); i != e; ++i)
+        Attrs.push_back(MAttributeGroups[Record[i]]);
+
+      MAttributes.push_back(AttributeSet::get(Context, Attrs));
+      Attrs.clear();
+      break;
+    }
     }
   }
 }
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index 84f67ad05c2..1b73f23e8f6 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -209,30 +209,6 @@ static void WriteAttributeGroupTable(const ValueEnumerator &VE,
   Stream.ExitBlock();
 }
 
-/// \brief This returns an integer containing an encoding of all the LLVM
-/// attributes found in the given attribute bitset.  Any change to this encoding
-/// is a breaking change to bitcode compatibility.
-/// N.B. This should be used only by the bitcode writer!
-static uint64_t encodeLLVMAttributesForBitcode(AttributeSet Attrs,
-                                               unsigned Index) {
-  // FIXME: Remove in 4.0!
-
-  // FIXME: It doesn't make sense to store the alignment information as an
-  // expanded out value, we should store it as a log2 value.  However, we can't
-  // just change that here without breaking bitcode compatibility.  If this ever
-  // becomes a problem in practice, we should introduce new tag numbers in the
-  // bitcode file and have those tags use a more efficiently encoded alignment
-  // field.
-
-  // Store the alignment in the bitcode as a 16-bit raw value instead of a 5-bit
-  // log2 encoded value. Shift the bits above the alignment up by 11 bits.
-  uint64_t EncodedAttrs = Attrs.Raw(Index) & 0xffff;
-  if (Attrs.hasAttribute(Index, Attribute::Alignment))
-    EncodedAttrs |= Attrs.getParamAlignment(Index) << 16;
-  EncodedAttrs |= (Attrs.Raw(Index) & (0xfffffULL << 21)) << 11;
-  return EncodedAttrs;
-}
-
 static void WriteAttributeTable(const ValueEnumerator &VE,
                                 BitstreamWriter &Stream) {
   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
@@ -240,19 +216,13 @@ static void WriteAttributeTable(const ValueEnumerator &VE,
 
   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 
-  // FIXME: Remove this! It no longer works with the current attributes classes.
-
   SmallVector<uint64_t, 64> Record;
   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
     const AttributeSet &A = Attrs[i];
-    for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
-      unsigned Index = A.getSlotIndex(i);
-      Record.push_back(Index);
-      Record.push_back(encodeLLVMAttributesForBitcode(A.getSlotAttributes(i),
-                                                      Index));
-    }
+    for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
+      Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
 
-    Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY_OLD, Record);
+    Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
     Record.clear();
   }