Index: lib/Target/AMDGPU/SIMemoryLegalizer.cpp
===================================================================
--- lib/Target/AMDGPU/SIMemoryLegalizer.cpp
+++ lib/Target/AMDGPU/SIMemoryLegalizer.cpp
@@ -398,7 +398,8 @@
   if (MOI.isAtomic()) {
     if (MOI.getSSID() == SyncScope::System ||
         MOI.getSSID() == MMI->getAgentSSID()) {
-      if (MOI.getOrdering() == AtomicOrdering::Acquire ||
+      if (MOI.getOrdering() == AtomicOrdering::Monotonic ||
+          MOI.getOrdering() == AtomicOrdering::Acquire ||
           MOI.getOrdering() == AtomicOrdering::SequentiallyConsistent)
         Changed |= enableGLCBit(MI);
 
Index: test/CodeGen/AMDGPU/memory-legalizer-load.ll
===================================================================
--- test/CodeGen/AMDGPU/memory-legalizer-load.ll
+++ test/CodeGen/AMDGPU/memory-legalizer-load.ll
@@ -21,7 +21,7 @@
 
 ; GCN-LABEL: {{^}}system_monotonic
 ; GCN-NOT:   s_waitcnt vmcnt(0){{$}}
-; GCN:       flat_load_dword [[RET:v[0-9]+]], v[{{[0-9]+}}:{{[0-9]+}}]{{$}}
+; GCN:       flat_load_dword [[RET:v[0-9]+]], v[{{[0-9]+}}:{{[0-9]+}}] glc{{$}}
 ; GCN-NOT:   s_waitcnt vmcnt(0){{$}}
 ; GCN-NOT:   buffer_wbinvl1_vol
 ; GCN:       flat_store_dword v{{\[[0-9]+:[0-9]+\]}}, [[RET]]
@@ -133,7 +133,7 @@
 
 ; GCN-LABEL: {{^}}agent_monotonic
 ; GCN-NOT:   s_waitcnt vmcnt(0){{$}}
-; GCN:       flat_load_dword [[RET:v[0-9]+]], v[{{[0-9]+}}:{{[0-9]+}}]{{$}}
+; GCN:       flat_load_dword [[RET:v[0-9]+]], v[{{[0-9]+}}:{{[0-9]+}}] glc{{$}}
 ; GCN-NOT:   s_waitcnt vmcnt(0){{$}}
 ; GCN-NOT:   buffer_wbinvl1_vol
 ; GCN:       flat_store_dword v{{\[[0-9]+:[0-9]+\]}}, [[RET]]