Index: llvm/trunk/include/llvm/IR/Intrinsics.td
===================================================================
--- llvm/trunk/include/llvm/IR/Intrinsics.td
+++ llvm/trunk/include/llvm/IR/Intrinsics.td
@@ -38,6 +38,17 @@
 // 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 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: llvm/trunk/include/llvm/IR/IntrinsicsAMDGPU.td
===================================================================
--- llvm/trunk/include/llvm/IR/IntrinsicsAMDGPU.td
+++ llvm/trunk/include/llvm/IR/IntrinsicsAMDGPU.td
@@ -243,7 +243,7 @@
    llvm_i32_ty,       // offset(SGPR/VGPR/imm)
    llvm_i1_ty,        // glc(imm)
    llvm_i1_ty],       // slc(imm)
-  []>;
+  [IntrWriteMem]>;
 def int_amdgcn_buffer_store_format : AMDGPUBufferStore;
 def int_amdgcn_buffer_store : AMDGPUBufferStore;
 
Index: llvm/trunk/lib/Target/AMDGPU/SIInstructions.td
===================================================================
--- llvm/trunk/lib/Target/AMDGPU/SIInstructions.td
+++ llvm/trunk/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
 >;
@@ -996,11 +991,6 @@
   mubuf<0x1a>, "buffer_store_short", VGPR_32, i32, truncstorei16_global
 >;
 
-// Without mayLoad and hasSideEffects, TableGen complains about the pattern
-// matching llvm.amdgcn.buffer.store. Eventually, we'll want a WriteOnly
-// property to express the effects of this intrinsic more precisely, see
-// http://reviews.llvm.org/D18291
-let mayLoad = 1, hasSideEffects = 1 in {
 defm BUFFER_STORE_DWORD : MUBUF_Store_Helper <
   mubuf<0x1c>, "buffer_store_dword", VGPR_32, i32, global_store
 >;
@@ -1012,7 +1002,6 @@
 defm BUFFER_STORE_DWORDX4 : MUBUF_Store_Helper <
   mubuf<0x1e, 0x1f>, "buffer_store_dwordx4", VReg_128, v4i32, global_store
 >;
-}
 
 defm BUFFER_ATOMIC_SWAP : MUBUF_Atomic <
   mubuf<0x30, 0x40>, "buffer_atomic_swap", VGPR_32, i32, atomic_swap_global
Index: llvm/trunk/test/CodeGen/AMDGPU/captured-frame-index.ll
===================================================================
--- llvm/trunk/test/CodeGen/AMDGPU/captured-frame-index.ll
+++ llvm/trunk/test/CodeGen/AMDGPU/captured-frame-index.ll
@@ -16,11 +16,11 @@
 
 ; Offset is applied
 ; GCN-LABEL: {{^}}stored_fi_to_lds_2_small_objects:
-; GCN: v_mov_b32_e32 [[ZERO:v[0-9]+]], 0{{$}}
-; GCN: buffer_store_dword v{{[0-9]+}}, [[ZERO]], s{{\[[0-9]+:[0-9]+\]}}, s{{[0-9]+}} offen{{$}}
-; GCN: buffer_store_dword v{{[0-9]+}}, [[ZERO]], s{{\[[0-9]+:[0-9]+\]}}, s{{[0-9]+}} offen offset:4{{$}}
+; GCN-DAG: v_mov_b32_e32 [[ZERO:v[0-9]+]], 0{{$}}
+; GCN-DAG: buffer_store_dword v{{[0-9]+}}, [[ZERO]], s{{\[[0-9]+:[0-9]+\]}}, s{{[0-9]+}} offen{{$}}
+; GCN-DAG: buffer_store_dword v{{[0-9]+}}, [[ZERO]], s{{\[[0-9]+:[0-9]+\]}}, s{{[0-9]+}} offen offset:4{{$}}
 
-; GCN: s_load_dword [[LDSPTR:s[0-9]+]]
+; GCN-DAG: s_load_dword [[LDSPTR:s[0-9]+]]
 
 ; GCN-DAG: v_mov_b32_e32 [[VLDSPTR:v[0-9]+]], [[LDSPTR]]
 ; GCN: ds_write_b32  [[VLDSPTR]], [[ZERO]]
Index: llvm/trunk/test/CodeGen/AMDGPU/si-triv-disjoint-mem-access.ll
===================================================================
--- llvm/trunk/test/CodeGen/AMDGPU/si-triv-disjoint-mem-access.ll
+++ llvm/trunk/test/CodeGen/AMDGPU/si-triv-disjoint-mem-access.ll
@@ -11,8 +11,8 @@
 
 ; FUNC-LABEL: @reorder_local_load_global_store_local_load
 ; CI: ds_read_b32 {{v[0-9]+}}, {{v[0-9]+}} offset:4
-; CI-NEXT: buffer_store_dword
 ; CI-NEXT: ds_read_b32 {{v[0-9]+}}, {{v[0-9]+}} offset:8
+; CI: buffer_store_dword
 define void @reorder_local_load_global_store_local_load(i32 addrspace(1)* %out, i32 addrspace(1)* %gptr) #0 {
   %ptr0 = load i32 addrspace(3)*, i32 addrspace(3)* addrspace(3)* @stored_lds_ptr, align 4
 
@@ -71,9 +71,9 @@
 }
 
 ; FUNC-LABEL: @reorder_constant_load_global_store_constant_load
+; CI: buffer_store_dword
 ; CI: v_readfirstlane_b32 s[[PTR_LO:[0-9]+]], v{{[0-9]+}}
 ; CI: v_readfirstlane_b32 s[[PTR_HI:[0-9]+]], v{{[0-9]+}}
-; CI-DAG: buffer_store_dword
 ; CI-DAG: s_load_dword s{{[0-9]+}}, s{{\[}}[[PTR_LO]]:[[PTR_HI]]{{\]}}, 0x1
 ; CI-DAG: s_load_dword s{{[0-9]+}}, s{{\[}}[[PTR_LO]]:[[PTR_HI]]{{\]}}, 0x2
 ; CI: buffer_store_dword
@@ -184,11 +184,11 @@
 }
 
 ; FUNC-LABEL: @reorder_global_offsets
-; CI: buffer_store_dword {{v[0-9]+}}, {{s\[[0-9]+:[0-9]+\]}}, 0 offset:12
 ; CI: buffer_load_dword {{v[0-9]+}}, {{s\[[0-9]+:[0-9]+\]}}, 0 offset:400
 ; CI: buffer_load_dword {{v[0-9]+}}, {{s\[[0-9]+:[0-9]+\]}}, 0 offset:404
-; CI: buffer_store_dword {{v[0-9]+}}, {{s\[[0-9]+:[0-9]+\]}}, 0 offset:400
+; CI: buffer_store_dword {{v[0-9]+}}, {{s\[[0-9]+:[0-9]+\]}}, 0 offset:12
 ; CI: buffer_load_dword {{v[0-9]+}}, {{s\[[0-9]+:[0-9]+\]}}, 0 offset:12
+; CI: buffer_store_dword {{v[0-9]+}}, {{s\[[0-9]+:[0-9]+\]}}, 0 offset:400
 ; CI: buffer_store_dword {{v[0-9]+}}, {{s\[[0-9]+:[0-9]+\]}}, 0 offset:404
 ; CI: buffer_store_dword
 ; CI: s_endpgm
Index: llvm/trunk/utils/TableGen/CodeGenDAGPatterns.cpp
===================================================================
--- llvm/trunk/utils/TableGen/CodeGenDAGPatterns.cpp
+++ llvm/trunk/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: llvm/trunk/utils/TableGen/CodeGenIntrinsics.h
===================================================================
--- llvm/trunk/utils/TableGen/CodeGenIntrinsics.h
+++ llvm/trunk/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,
+    };
+
+    /// 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,
     };
-    ModRefKind ModRef;
+    ModRefBehavior ModRef;
 
     /// This is set to true if the intrinsic is overloaded by its argument
     /// types.
Index: llvm/trunk/utils/TableGen/CodeGenTarget.cpp
===================================================================
--- llvm/trunk/utils/TableGen/CodeGenTarget.cpp
+++ llvm/trunk/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: llvm/trunk/utils/TableGen/IntrinsicEmitter.cpp
===================================================================
--- llvm/trunk/utils/TableGen/IntrinsicEmitter.cpp
+++ llvm/trunk/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;
       }