Index: include/llvm/IR/Intrinsics.td
===================================================================
--- include/llvm/IR/Intrinsics.td
+++ include/llvm/IR/Intrinsics.td
@@ -38,6 +38,18 @@
 // deleted if dead.
 def IntrReadMem : IntrinsicProperty;
 
+// IntrWriteMem - This intrinsic writes to unspecified memory, but does not
+// read from memory, and has no other side effects. This means dead stores
+// before calls to this intrinsics may be removed.
+def IntrWriteMem : IntrinsicProperty;
+
+// IntrWriteArgMem - This intrinsic writes only to memory that one of its
+// arguments points to, but may access an unspecified amount. The writes may
+// be volatile, but the intrinsic does not read from memory and has no other
+// side effects. This means that dead stores before calls to this intrinsics
+// may be removed.
+def IntrWriteArgMem : IntrinsicProperty;
+
 // IntrReadWriteArgMem - This intrinsic reads and writes only from memory that
 // one of its arguments points to, but may access an unspecified amount.  The
 // reads and writes may be volatile, but except for this it has no other side
Index: include/llvm/IR/IntrinsicsAMDGPU.td
===================================================================
--- include/llvm/IR/IntrinsicsAMDGPU.td
+++ include/llvm/IR/IntrinsicsAMDGPU.td
@@ -230,7 +230,7 @@
    llvm_i32_ty,       // offset(SGPR/VGPR/imm)
    llvm_i1_ty,        // glc(imm)
    llvm_i1_ty],       // slc(imm)
-  []>;
+  [IntrWriteMem]>;
 
 class AMDGPUBufferAtomic : Intrinsic <
   [llvm_i32_ty],
Index: lib/Target/AMDGPU/SIInstructions.td
===================================================================
--- lib/Target/AMDGPU/SIInstructions.td
+++ lib/Target/AMDGPU/SIInstructions.td
@@ -949,23 +949,18 @@
 defm BUFFER_LOAD_FORMAT_XYZW : MUBUF_Load_Helper <
   mubuf<0x03>, "buffer_load_format_xyzw", VReg_128
 >;
-// Without mayLoad and hasSideEffects, TableGen complains about the pattern
-// matching llvm.amdgcn.buffer.store.format. Eventually, we'll need a way
-// to express the effects of the intrinsic more precisely.
-let mayLoad = 1, hasSideEffects = 1 in {
-  defm BUFFER_STORE_FORMAT_X : MUBUF_Store_Helper <
-    mubuf<0x04>, "buffer_store_format_x", VGPR_32
-  >;
-  defm BUFFER_STORE_FORMAT_XY : MUBUF_Store_Helper <
-    mubuf<0x05>, "buffer_store_format_xy", VReg_64
-  >;
-  defm BUFFER_STORE_FORMAT_XYZ : MUBUF_Store_Helper <
-    mubuf<0x06>, "buffer_store_format_xyz", VReg_96
-  >;
-  defm BUFFER_STORE_FORMAT_XYZW : MUBUF_Store_Helper <
-    mubuf<0x07>, "buffer_store_format_xyzw", VReg_128
-  >;
-}
+defm BUFFER_STORE_FORMAT_X : MUBUF_Store_Helper <
+  mubuf<0x04>, "buffer_store_format_x", VGPR_32
+>;
+defm BUFFER_STORE_FORMAT_XY : MUBUF_Store_Helper <
+  mubuf<0x05>, "buffer_store_format_xy", VReg_64
+>;
+defm BUFFER_STORE_FORMAT_XYZ : MUBUF_Store_Helper <
+  mubuf<0x06>, "buffer_store_format_xyz", VReg_96
+>;
+defm BUFFER_STORE_FORMAT_XYZW : MUBUF_Store_Helper <
+  mubuf<0x07>, "buffer_store_format_xyzw", VReg_128
+>;
 defm BUFFER_LOAD_UBYTE : MUBUF_Load_Helper <
   mubuf<0x08, 0x10>, "buffer_load_ubyte", VGPR_32, i32, az_extloadi8_global
 >;
Index: utils/TableGen/CodeGenDAGPatterns.cpp
===================================================================
--- utils/TableGen/CodeGenDAGPatterns.cpp
+++ utils/TableGen/CodeGenDAGPatterns.cpp
@@ -2816,14 +2816,14 @@
 
     if (const CodeGenIntrinsic *IntInfo = N->getIntrinsicInfo(CDP)) {
       // If this is an intrinsic, analyze it.
-      if (IntInfo->ModRef >= CodeGenIntrinsic::ReadArgMem)
+      if (IntInfo->ModRef & CodeGenIntrinsic::MR_Ref)
         mayLoad = true;// These may load memory.
 
-      if (IntInfo->ModRef >= CodeGenIntrinsic::ReadWriteArgMem)
+      if (IntInfo->ModRef & CodeGenIntrinsic::MR_Mod)
         mayStore = true;// Intrinsics that can write to memory are 'mayStore'.
 
       if (IntInfo->ModRef >= CodeGenIntrinsic::ReadWriteMem)
-        // WriteMem intrinsics can have other strange effects.
+        // ReadWriteMem intrinsics can have other strange effects.
         hasSideEffects = true;
     }
   }
Index: utils/TableGen/CodeGenIntrinsics.h
===================================================================
--- utils/TableGen/CodeGenIntrinsics.h
+++ utils/TableGen/CodeGenIntrinsics.h
@@ -59,11 +59,36 @@
 
     IntrinsicSignature IS;
 
-    // Memory mod/ref behavior of this intrinsic.
-    enum ModRefKind {
-      NoMem, ReadArgMem, ReadMem, ReadWriteArgMem, ReadWriteMem
+    /// Bit flags describing the type (ref/mod) and location of memory
+    /// accesses that may be performed by the intrinsics. Analogous to
+    /// \c FunctionModRefBehaviour.
+    enum ModRefBits {
+      /// The intrinsic may access memory anywhere, i.e. it is not restricted
+      /// to access through pointer arguments.
+      MR_Anywhere = 1,
+
+      /// The intrinsic may read memory.
+      MR_Ref = 2,
+
+      /// The intrinsic may write memory.
+      MR_Mod = 4,
+
+      /// The intrinsic may both read and write memory.
+      MR_ModRef = MR_Ref | MR_Mod,
     };
-    ModRefKind ModRef;
+
+    /// Memory mod/ref behavior of this intrinsic, corresponding to
+    /// intrinsic properties (IntrReadMem, IntrReadArgMem, etc.).
+    enum ModRefBehavior {
+      NoMem = 0,
+      ReadArgMem = MR_Ref,
+      ReadMem = MR_Ref | MR_Anywhere,
+      WriteArgMem = MR_Mod,
+      WriteMem = MR_Mod | MR_Anywhere,
+      ReadWriteArgMem = MR_ModRef,
+      ReadWriteMem = MR_ModRef | MR_Anywhere,
+    };
+    ModRefBehavior ModRef;
 
     /// This is set to true if the intrinsic is overloaded by its argument
     /// types.
Index: utils/TableGen/CodeGenTarget.cpp
===================================================================
--- utils/TableGen/CodeGenTarget.cpp
+++ utils/TableGen/CodeGenTarget.cpp
@@ -577,6 +577,10 @@
       ModRef = ReadArgMem;
     else if (Property->getName() == "IntrReadMem")
       ModRef = ReadMem;
+    else if (Property->getName() == "IntrWriteMem")
+      ModRef = WriteMem;
+    else if (Property->getName() == "IntrWriteArgMem")
+      ModRef = WriteArgMem;
     else if (Property->getName() == "IntrReadWriteArgMem")
       ModRef = ReadWriteArgMem;
     else if (Property->getName() == "Commutative")
Index: utils/TableGen/IntrinsicEmitter.cpp
===================================================================
--- utils/TableGen/IntrinsicEmitter.cpp
+++ utils/TableGen/IntrinsicEmitter.cpp
@@ -462,8 +462,8 @@
       return R->isConvergent;
 
     // Try to order by readonly/readnone attribute.
-    CodeGenIntrinsic::ModRefKind LK = L->ModRef;
-    CodeGenIntrinsic::ModRefKind RK = R->ModRef;
+    CodeGenIntrinsic::ModRefBehavior LK = L->ModRef;
+    CodeGenIntrinsic::ModRefBehavior RK = R->ModRef;
     if (LK != RK) return (LK > RK);
 
     // Order by argument attributes.
@@ -616,11 +616,13 @@
           OS << ",";
         OS << "Attribute::ReadOnly";
         break;
+      case CodeGenIntrinsic::WriteArgMem:
       case CodeGenIntrinsic::ReadWriteArgMem:
         if (addComma)
           OS << ",";
         OS << "Attribute::ArgMemOnly";
         break;
+      case CodeGenIntrinsic::WriteMem:
       case CodeGenIntrinsic::ReadWriteMem:
         break;
       }