diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -11949,9 +11949,15 @@
               .getValueAsString() != "true")
         return AtomicExpansionKind::CmpXChg;
 
-      if (Subtarget->hasGFX90AInsts())
+      if (Subtarget->hasGFX90AInsts()) {
+        auto SSID = RMW->getSyncScopeID();
+        if (SSID == SyncScope::System ||
+            SSID == RMW->getContext().getOrInsertSyncScopeID("one-as"))
+          return AtomicExpansionKind::CmpXChg;
+
         return (Ty->isFloatTy() && AS == AMDGPUAS::FLAT_ADDRESS) ?
           AtomicExpansionKind::CmpXChg : AtomicExpansionKind::None;
+      }
 
       if (!Subtarget->hasGFX90AInsts() && AS != AMDGPUAS::GLOBAL_ADDRESS)
         return AtomicExpansionKind::CmpXChg;
diff --git a/llvm/test/CodeGen/AMDGPU/fp64-atomics-gfx90a.ll b/llvm/test/CodeGen/AMDGPU/fp64-atomics-gfx90a.ll
--- a/llvm/test/CodeGen/AMDGPU/fp64-atomics-gfx90a.ll
+++ b/llvm/test/CodeGen/AMDGPU/fp64-atomics-gfx90a.ll
@@ -415,19 +415,80 @@
 ; GFX90A-LABEL: global_atomic_fadd_f64_noret_pat:
 ; GFX90A:       ; %bb.0: ; %main_body
 ; GFX90A-NEXT:    s_load_dwordx2 s[0:1], s[0:1], 0x24
+; GFX90A-NEXT:    s_mov_b64 s[2:3], 0
+; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX90A-NEXT:    s_load_dwordx2 s[4:5], s[0:1], 0x0
+; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX90A-NEXT:    v_pk_mov_b32 v[2:3], s[4:5], s[4:5] op_sel:[0,1]
+; GFX90A-NEXT:  BB24_1: ; %atomicrmw.start
+; GFX90A-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX90A-NEXT:    v_mov_b32_e32 v4, 0
+; GFX90A-NEXT:    v_add_f64 v[0:1], v[2:3], 4.0
+; GFX90A-NEXT:    buffer_wbl2
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    global_atomic_cmpswap_x2 v[0:1], v4, v[0:3], s[0:1] glc scc
+; GFX90A-NEXT:    s_waitcnt vmcnt(0)
+; GFX90A-NEXT:    buffer_invl2
+; GFX90A-NEXT:    s_waitcnt vmcnt(0)
+; GFX90A-NEXT:    buffer_wbinvl1_vol
+; GFX90A-NEXT:    v_cmp_eq_u64_e32 vcc, v[0:1], v[2:3]
+; GFX90A-NEXT:    s_or_b64 s[2:3], vcc, s[2:3]
+; GFX90A-NEXT:    v_pk_mov_b32 v[2:3], v[0:1], v[0:1] op_sel:[0,1]
+; GFX90A-NEXT:    s_andn2_b64 exec, exec, s[2:3]
+; GFX90A-NEXT:    s_cbranch_execnz BB24_1
+; GFX90A-NEXT:  ; %bb.2: ; %atomicrmw.end
+; GFX90A-NEXT:    s_endpgm
+main_body:
+  %ret = atomicrmw fadd double addrspace(1)* %ptr, double 4.0 seq_cst
+  ret void
+}
+
+define amdgpu_kernel void @global_atomic_fadd_f64_noret_pat_agent(double addrspace(1)* %ptr) #1 {
+; GFX90A-LABEL: global_atomic_fadd_f64_noret_pat_agent:
+; GFX90A:       ; %bb.0: ; %main_body
+; GFX90A-NEXT:    s_load_dwordx2 s[0:1], s[0:1], 0x24
 ; GFX90A-NEXT:    v_mov_b32_e32 v0, 0
 ; GFX90A-NEXT:    v_mov_b32_e32 v2, 0
 ; GFX90A-NEXT:    v_mov_b32_e32 v1, 0x40100000
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    global_atomic_add_f64 v2, v[0:1], s[0:1]
+; GFX90A-NEXT:    s_waitcnt vmcnt(0)
+; GFX90A-NEXT:    buffer_wbinvl1_vol
+; GFX90A-NEXT:    s_endpgm
+main_body:
+  %ret = atomicrmw fadd double addrspace(1)* %ptr, double 4.0 syncscope("agent") seq_cst
+  ret void
+}
+
+define amdgpu_kernel void @global_atomic_fadd_f64_noret_pat_system(double addrspace(1)* %ptr) #1 {
+; GFX90A-LABEL: global_atomic_fadd_f64_noret_pat_system:
+; GFX90A:       ; %bb.0: ; %main_body
+; GFX90A-NEXT:    s_load_dwordx2 s[0:1], s[0:1], 0x24
+; GFX90A-NEXT:    s_mov_b64 s[2:3], 0
+; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX90A-NEXT:    s_load_dwordx2 s[4:5], s[0:1], 0x0
+; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX90A-NEXT:    v_pk_mov_b32 v[2:3], s[4:5], s[4:5] op_sel:[0,1]
+; GFX90A-NEXT:  BB26_1: ; %atomicrmw.start
+; GFX90A-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX90A-NEXT:    v_mov_b32_e32 v4, 0
+; GFX90A-NEXT:    v_add_f64 v[0:1], v[2:3], 4.0
 ; GFX90A-NEXT:    buffer_wbl2
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
-; GFX90A-NEXT:    global_atomic_add_f64 v2, v[0:1], s[0:1] scc
+; GFX90A-NEXT:    global_atomic_cmpswap_x2 v[0:1], v4, v[0:3], s[0:1] glc scc
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0)
 ; GFX90A-NEXT:    buffer_invl2
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0)
 ; GFX90A-NEXT:    buffer_wbinvl1_vol
+; GFX90A-NEXT:    v_cmp_eq_u64_e32 vcc, v[0:1], v[2:3]
+; GFX90A-NEXT:    s_or_b64 s[2:3], vcc, s[2:3]
+; GFX90A-NEXT:    v_pk_mov_b32 v[2:3], v[0:1], v[0:1] op_sel:[0,1]
+; GFX90A-NEXT:    s_andn2_b64 exec, exec, s[2:3]
+; GFX90A-NEXT:    s_cbranch_execnz BB26_1
+; GFX90A-NEXT:  ; %bb.2: ; %atomicrmw.end
 ; GFX90A-NEXT:    s_endpgm
 main_body:
-  %ret = atomicrmw fadd double addrspace(1)* %ptr, double 4.0 seq_cst
+  %ret = atomicrmw fadd double addrspace(1)* %ptr, double 4.0 syncscope("one-as") seq_cst
   ret void
 }
 
@@ -440,7 +501,7 @@
 ; GFX90A-NEXT:    s_load_dwordx2 s[4:5], s[0:1], 0x0
 ; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
 ; GFX90A-NEXT:    v_pk_mov_b32 v[2:3], s[4:5], s[4:5] op_sel:[0,1]
-; GFX90A-NEXT:  BB25_1: ; %atomicrmw.start
+; GFX90A-NEXT:  BB27_1: ; %atomicrmw.start
 ; GFX90A-NEXT:    ; =>This Inner Loop Header: Depth=1
 ; GFX90A-NEXT:    v_mov_b32_e32 v4, 0
 ; GFX90A-NEXT:    v_add_f64 v[0:1], v[2:3], 4.0
@@ -455,11 +516,11 @@
 ; GFX90A-NEXT:    s_or_b64 s[2:3], vcc, s[2:3]
 ; GFX90A-NEXT:    v_pk_mov_b32 v[2:3], v[0:1], v[0:1] op_sel:[0,1]
 ; GFX90A-NEXT:    s_andn2_b64 exec, exec, s[2:3]
-; GFX90A-NEXT:    s_cbranch_execnz BB25_1
+; GFX90A-NEXT:    s_cbranch_execnz BB27_1
 ; GFX90A-NEXT:  ; %bb.2: ; %atomicrmw.end
 ; GFX90A-NEXT:    s_endpgm
 main_body:
-  %ret = atomicrmw fadd double addrspace(1)* %ptr, double 4.0 seq_cst
+  %ret = atomicrmw fadd double addrspace(1)* %ptr, double 4.0 syncscope("agent") seq_cst
   ret void
 }
 
@@ -479,18 +540,79 @@
 ; GFX90A-LABEL: global_atomic_fadd_f64_rtn_pat:
 ; GFX90A:       ; %bb.0: ; %main_body
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    global_load_dwordx2 v[2:3], v[0:1], off
+; GFX90A-NEXT:    s_mov_b64 s[4:5], 0
+; GFX90A-NEXT:  BB29_1: ; %atomicrmw.start
+; GFX90A-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX90A-NEXT:    s_waitcnt vmcnt(0)
+; GFX90A-NEXT:    v_pk_mov_b32 v[4:5], v[2:3], v[2:3] op_sel:[0,1]
+; GFX90A-NEXT:    v_add_f64 v[2:3], v[4:5], 4.0
+; GFX90A-NEXT:    buffer_wbl2
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    global_atomic_cmpswap_x2 v[2:3], v[0:1], v[2:5], off glc scc
+; GFX90A-NEXT:    s_waitcnt vmcnt(0)
+; GFX90A-NEXT:    buffer_invl2
+; GFX90A-NEXT:    s_waitcnt vmcnt(0)
+; GFX90A-NEXT:    buffer_wbinvl1_vol
+; GFX90A-NEXT:    v_cmp_eq_u64_e32 vcc, v[2:3], v[4:5]
+; GFX90A-NEXT:    s_or_b64 s[4:5], vcc, s[4:5]
+; GFX90A-NEXT:    s_andn2_b64 exec, exec, s[4:5]
+; GFX90A-NEXT:    s_cbranch_execnz BB29_1
+; GFX90A-NEXT:  ; %bb.2: ; %atomicrmw.end
+; GFX90A-NEXT:    s_or_b64 exec, exec, s[4:5]
+; GFX90A-NEXT:    v_mov_b32_e32 v0, v2
+; GFX90A-NEXT:    v_mov_b32_e32 v1, v3
+; GFX90A-NEXT:    s_setpc_b64 s[30:31]
+main_body:
+  %ret = atomicrmw fadd double addrspace(1)* %ptr, double 4.0 seq_cst
+  ret double %ret
+}
+
+define double @global_atomic_fadd_f64_rtn_pat_agent(double addrspace(1)* %ptr, double %data) #1 {
+; GFX90A-LABEL: global_atomic_fadd_f64_rtn_pat_agent:
+; GFX90A:       ; %bb.0: ; %main_body
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
 ; GFX90A-NEXT:    v_mov_b32_e32 v2, 0
 ; GFX90A-NEXT:    v_mov_b32_e32 v3, 0x40100000
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    global_atomic_add_f64 v[0:1], v[0:1], v[2:3], off glc
+; GFX90A-NEXT:    s_waitcnt vmcnt(0)
+; GFX90A-NEXT:    buffer_wbinvl1_vol
+; GFX90A-NEXT:    s_setpc_b64 s[30:31]
+main_body:
+  %ret = atomicrmw fadd double addrspace(1)* %ptr, double 4.0 syncscope("agent") seq_cst
+  ret double %ret
+}
+
+define double @global_atomic_fadd_f64_rtn_pat_system(double addrspace(1)* %ptr, double %data) #1 {
+; GFX90A-LABEL: global_atomic_fadd_f64_rtn_pat_system:
+; GFX90A:       ; %bb.0: ; %main_body
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    global_load_dwordx2 v[2:3], v[0:1], off
+; GFX90A-NEXT:    s_mov_b64 s[4:5], 0
+; GFX90A-NEXT:  BB31_1: ; %atomicrmw.start
+; GFX90A-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX90A-NEXT:    s_waitcnt vmcnt(0)
+; GFX90A-NEXT:    v_pk_mov_b32 v[4:5], v[2:3], v[2:3] op_sel:[0,1]
+; GFX90A-NEXT:    v_add_f64 v[2:3], v[4:5], 4.0
 ; GFX90A-NEXT:    buffer_wbl2
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
-; GFX90A-NEXT:    global_atomic_add_f64 v[0:1], v[0:1], v[2:3], off glc scc
+; GFX90A-NEXT:    global_atomic_cmpswap_x2 v[2:3], v[0:1], v[2:5], off glc scc
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0)
 ; GFX90A-NEXT:    buffer_invl2
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0)
 ; GFX90A-NEXT:    buffer_wbinvl1_vol
+; GFX90A-NEXT:    v_cmp_eq_u64_e32 vcc, v[2:3], v[4:5]
+; GFX90A-NEXT:    s_or_b64 s[4:5], vcc, s[4:5]
+; GFX90A-NEXT:    s_andn2_b64 exec, exec, s[4:5]
+; GFX90A-NEXT:    s_cbranch_execnz BB31_1
+; GFX90A-NEXT:  ; %bb.2: ; %atomicrmw.end
+; GFX90A-NEXT:    s_or_b64 exec, exec, s[4:5]
+; GFX90A-NEXT:    v_mov_b32_e32 v0, v2
+; GFX90A-NEXT:    v_mov_b32_e32 v1, v3
 ; GFX90A-NEXT:    s_setpc_b64 s[30:31]
 main_body:
-  %ret = atomicrmw fadd double addrspace(1)* %ptr, double 4.0 seq_cst
+  %ret = atomicrmw fadd double addrspace(1)* %ptr, double 4.0 syncscope("one-as") seq_cst
   ret double %ret
 }
 
@@ -522,20 +644,81 @@
 ; GFX90A-LABEL: flat_atomic_fadd_f64_noret_pat:
 ; GFX90A:       ; %bb.0: ; %main_body
 ; GFX90A-NEXT:    s_load_dwordx2 s[0:1], s[0:1], 0x24
+; GFX90A-NEXT:    s_mov_b64 s[2:3], 0
+; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX90A-NEXT:    v_pk_mov_b32 v[0:1], s[0:1], s[0:1] op_sel:[0,1]
+; GFX90A-NEXT:    flat_load_dwordx2 v[2:3], v[0:1]
+; GFX90A-NEXT:  BB34_1: ; %atomicrmw.start
+; GFX90A-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    v_add_f64 v[0:1], v[2:3], 4.0
+; GFX90A-NEXT:    v_pk_mov_b32 v[4:5], s[0:1], s[0:1] op_sel:[0,1]
+; GFX90A-NEXT:    buffer_wbl2
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    flat_atomic_cmpswap_x2 v[0:1], v[4:5], v[0:3] glc scc
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    buffer_invl2
+; GFX90A-NEXT:    s_waitcnt vmcnt(0)
+; GFX90A-NEXT:    buffer_wbinvl1_vol
+; GFX90A-NEXT:    v_cmp_eq_u64_e32 vcc, v[0:1], v[2:3]
+; GFX90A-NEXT:    s_or_b64 s[2:3], vcc, s[2:3]
+; GFX90A-NEXT:    v_pk_mov_b32 v[2:3], v[0:1], v[0:1] op_sel:[0,1]
+; GFX90A-NEXT:    s_andn2_b64 exec, exec, s[2:3]
+; GFX90A-NEXT:    s_cbranch_execnz BB34_1
+; GFX90A-NEXT:  ; %bb.2: ; %atomicrmw.end
+; GFX90A-NEXT:    s_endpgm
+main_body:
+  %ret = atomicrmw fadd double* %ptr, double 4.0 seq_cst
+  ret void
+}
+
+define amdgpu_kernel void @flat_atomic_fadd_f64_noret_pat_agent(double* %ptr) #1 {
+; GFX90A-LABEL: flat_atomic_fadd_f64_noret_pat_agent:
+; GFX90A:       ; %bb.0: ; %main_body
+; GFX90A-NEXT:    s_load_dwordx2 s[0:1], s[0:1], 0x24
 ; GFX90A-NEXT:    v_mov_b32_e32 v2, 0
 ; GFX90A-NEXT:    v_mov_b32_e32 v3, 0x40100000
 ; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
 ; GFX90A-NEXT:    v_pk_mov_b32 v[0:1], s[0:1], s[0:1] op_sel:[0,1]
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    flat_atomic_add_f64 v[0:1], v[2:3]
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    buffer_wbinvl1_vol
+; GFX90A-NEXT:    s_endpgm
+main_body:
+  %ret = atomicrmw fadd double* %ptr, double 4.0 syncscope("agent") seq_cst
+  ret void
+}
+
+define amdgpu_kernel void @flat_atomic_fadd_f64_noret_pat_system(double* %ptr) #1 {
+; GFX90A-LABEL: flat_atomic_fadd_f64_noret_pat_system:
+; GFX90A:       ; %bb.0: ; %main_body
+; GFX90A-NEXT:    s_load_dwordx2 s[0:1], s[0:1], 0x24
+; GFX90A-NEXT:    s_mov_b64 s[2:3], 0
+; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX90A-NEXT:    v_pk_mov_b32 v[0:1], s[0:1], s[0:1] op_sel:[0,1]
+; GFX90A-NEXT:    flat_load_dwordx2 v[2:3], v[0:1]
+; GFX90A-NEXT:  BB36_1: ; %atomicrmw.start
+; GFX90A-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    v_add_f64 v[0:1], v[2:3], 4.0
+; GFX90A-NEXT:    v_pk_mov_b32 v[4:5], s[0:1], s[0:1] op_sel:[0,1]
 ; GFX90A-NEXT:    buffer_wbl2
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
-; GFX90A-NEXT:    flat_atomic_add_f64 v[0:1], v[2:3] scc
+; GFX90A-NEXT:    flat_atomic_cmpswap_x2 v[0:1], v[4:5], v[0:3] glc scc
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
 ; GFX90A-NEXT:    buffer_invl2
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0)
 ; GFX90A-NEXT:    buffer_wbinvl1_vol
+; GFX90A-NEXT:    v_cmp_eq_u64_e32 vcc, v[0:1], v[2:3]
+; GFX90A-NEXT:    s_or_b64 s[2:3], vcc, s[2:3]
+; GFX90A-NEXT:    v_pk_mov_b32 v[2:3], v[0:1], v[0:1] op_sel:[0,1]
+; GFX90A-NEXT:    s_andn2_b64 exec, exec, s[2:3]
+; GFX90A-NEXT:    s_cbranch_execnz BB36_1
+; GFX90A-NEXT:  ; %bb.2: ; %atomicrmw.end
 ; GFX90A-NEXT:    s_endpgm
 main_body:
-  %ret = atomicrmw fadd double* %ptr, double 4.0 seq_cst
+  %ret = atomicrmw fadd double* %ptr, double 4.0 syncscope("one-as") seq_cst
   ret void
 }
 
@@ -543,18 +726,80 @@
 ; GFX90A-LABEL: flat_atomic_fadd_f64_rtn_pat:
 ; GFX90A:       ; %bb.0: ; %main_body
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    flat_load_dwordx2 v[2:3], v[0:1]
+; GFX90A-NEXT:    s_mov_b64 s[4:5], 0
+; GFX90A-NEXT:  BB37_1: ; %atomicrmw.start
+; GFX90A-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    v_pk_mov_b32 v[4:5], v[2:3], v[2:3] op_sel:[0,1]
+; GFX90A-NEXT:    v_add_f64 v[2:3], v[4:5], 4.0
+; GFX90A-NEXT:    buffer_wbl2
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    flat_atomic_cmpswap_x2 v[2:3], v[0:1], v[2:5] glc scc
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    buffer_invl2
+; GFX90A-NEXT:    s_waitcnt vmcnt(0)
+; GFX90A-NEXT:    buffer_wbinvl1_vol
+; GFX90A-NEXT:    v_cmp_eq_u64_e32 vcc, v[2:3], v[4:5]
+; GFX90A-NEXT:    s_or_b64 s[4:5], vcc, s[4:5]
+; GFX90A-NEXT:    s_andn2_b64 exec, exec, s[4:5]
+; GFX90A-NEXT:    s_cbranch_execnz BB37_1
+; GFX90A-NEXT:  ; %bb.2: ; %atomicrmw.end
+; GFX90A-NEXT:    s_or_b64 exec, exec, s[4:5]
+; GFX90A-NEXT:    v_mov_b32_e32 v0, v2
+; GFX90A-NEXT:    v_mov_b32_e32 v1, v3
+; GFX90A-NEXT:    s_setpc_b64 s[30:31]
+main_body:
+  %ret = atomicrmw fadd double* %ptr, double 4.0 seq_cst
+  ret double %ret
+}
+
+define double @flat_atomic_fadd_f64_rtn_pat_agent(double* %ptr) #1 {
+; GFX90A-LABEL: flat_atomic_fadd_f64_rtn_pat_agent:
+; GFX90A:       ; %bb.0: ; %main_body
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
 ; GFX90A-NEXT:    v_mov_b32_e32 v2, 0
 ; GFX90A-NEXT:    v_mov_b32_e32 v3, 0x40100000
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    flat_atomic_add_f64 v[0:1], v[0:1], v[2:3] glc
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    buffer_wbinvl1_vol
+; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX90A-NEXT:    s_setpc_b64 s[30:31]
+main_body:
+  %ret = atomicrmw fadd double* %ptr, double 4.0 syncscope("agent") seq_cst
+  ret double %ret
+}
+
+define double @flat_atomic_fadd_f64_rtn_pat_system(double* %ptr) #1 {
+; GFX90A-LABEL: flat_atomic_fadd_f64_rtn_pat_system:
+; GFX90A:       ; %bb.0: ; %main_body
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    flat_load_dwordx2 v[2:3], v[0:1]
+; GFX90A-NEXT:    s_mov_b64 s[4:5], 0
+; GFX90A-NEXT:  BB39_1: ; %atomicrmw.start
+; GFX90A-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    v_pk_mov_b32 v[4:5], v[2:3], v[2:3] op_sel:[0,1]
+; GFX90A-NEXT:    v_add_f64 v[2:3], v[4:5], 4.0
 ; GFX90A-NEXT:    buffer_wbl2
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
-; GFX90A-NEXT:    flat_atomic_add_f64 v[0:1], v[0:1], v[2:3] glc scc
+; GFX90A-NEXT:    flat_atomic_cmpswap_x2 v[2:3], v[0:1], v[2:5] glc scc
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
 ; GFX90A-NEXT:    buffer_invl2
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0)
 ; GFX90A-NEXT:    buffer_wbinvl1_vol
+; GFX90A-NEXT:    v_cmp_eq_u64_e32 vcc, v[2:3], v[4:5]
+; GFX90A-NEXT:    s_or_b64 s[4:5], vcc, s[4:5]
+; GFX90A-NEXT:    s_andn2_b64 exec, exec, s[4:5]
+; GFX90A-NEXT:    s_cbranch_execnz BB39_1
+; GFX90A-NEXT:  ; %bb.2: ; %atomicrmw.end
+; GFX90A-NEXT:    s_or_b64 exec, exec, s[4:5]
+; GFX90A-NEXT:    v_mov_b32_e32 v0, v2
+; GFX90A-NEXT:    v_mov_b32_e32 v1, v3
 ; GFX90A-NEXT:    s_setpc_b64 s[30:31]
 main_body:
-  %ret = atomicrmw fadd double* %ptr, double 4.0 seq_cst
+  %ret = atomicrmw fadd double* %ptr, double 4.0 syncscope("one-as") seq_cst
   ret double %ret
 }
 
@@ -696,7 +941,7 @@
 ; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
 ; GFX90A-NEXT:    v_mov_b32_e32 v0, s0
 ; GFX90A-NEXT:    ds_read_b64 v[0:1], v0
-; GFX90A-NEXT:  BB41_1: ; %atomicrmw.start
+; GFX90A-NEXT:  BB49_1: ; %atomicrmw.start
 ; GFX90A-NEXT:    ; =>This Inner Loop Header: Depth=1
 ; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
 ; GFX90A-NEXT:    v_add_f64 v[2:3], v[0:1], 4.0
@@ -708,7 +953,7 @@
 ; GFX90A-NEXT:    s_or_b64 s[2:3], vcc, s[2:3]
 ; GFX90A-NEXT:    v_pk_mov_b32 v[0:1], v[2:3], v[2:3] op_sel:[0,1]
 ; GFX90A-NEXT:    s_andn2_b64 exec, exec, s[2:3]
-; GFX90A-NEXT:    s_cbranch_execnz BB41_1
+; GFX90A-NEXT:    s_cbranch_execnz BB49_1
 ; GFX90A-NEXT:  ; %bb.2: ; %atomicrmw.end
 ; GFX90A-NEXT:    s_endpgm
 main_body:
diff --git a/llvm/test/CodeGen/AMDGPU/global-atomics-fp.ll b/llvm/test/CodeGen/AMDGPU/global-atomics-fp.ll
--- a/llvm/test/CodeGen/AMDGPU/global-atomics-fp.ll
+++ b/llvm/test/CodeGen/AMDGPU/global-atomics-fp.ll
@@ -59,15 +59,29 @@
 ; GFX90A-LABEL: global_atomic_fadd_ret_f32:
 ; GFX90A:       ; %bb.0:
 ; GFX90A-NEXT:    s_load_dwordx2 s[0:1], s[0:1], 0x24
-; GFX90A-NEXT:    v_mov_b32_e32 v0, 0
-; GFX90A-NEXT:    v_mov_b32_e32 v1, 4.0
+; GFX90A-NEXT:    s_mov_b64 s[2:3], 0
+; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX90A-NEXT:    s_load_dword s4, s[0:1], 0x0
+; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX90A-NEXT:    v_mov_b32_e32 v0, s4
+; GFX90A-NEXT:  BB0_1: ; %atomicrmw.start
+; GFX90A-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX90A-NEXT:    v_mov_b32_e32 v1, v0
+; GFX90A-NEXT:    v_mov_b32_e32 v2, 0
+; GFX90A-NEXT:    v_add_f32_e32 v0, 4.0, v1
 ; GFX90A-NEXT:    buffer_wbl2
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
-; GFX90A-NEXT:    global_atomic_add_f32 v0, v0, v1, s[0:1] glc scc
+; GFX90A-NEXT:    global_atomic_cmpswap v0, v2, v[0:1], s[0:1] glc scc
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0)
 ; GFX90A-NEXT:    buffer_invl2
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0)
 ; GFX90A-NEXT:    buffer_wbinvl1_vol
+; GFX90A-NEXT:    v_cmp_eq_u32_e32 vcc, v0, v1
+; GFX90A-NEXT:    s_or_b64 s[2:3], vcc, s[2:3]
+; GFX90A-NEXT:    s_andn2_b64 exec, exec, s[2:3]
+; GFX90A-NEXT:    s_cbranch_execnz BB0_1
+; GFX90A-NEXT:  ; %bb.2: ; %atomicrmw.end
+; GFX90A-NEXT:    s_or_b64 exec, exec, s[2:3]
 ; GFX90A-NEXT:    global_store_dword v[0:1], v0, off
 ; GFX90A-NEXT:    s_endpgm
   %result = atomicrmw fadd float addrspace(1)* %ptr, float 4.0 seq_cst
@@ -156,7 +170,7 @@
 ; GFX90A-NEXT:    s_or_b64 exec, exec, s[2:3]
 ; GFX90A-NEXT:    global_store_dword v[0:1], v0, off
 ; GFX90A-NEXT:    s_endpgm
-  %result = atomicrmw fadd float addrspace(1)* %ptr, float 4.0 seq_cst
+  %result = atomicrmw fadd float addrspace(1)* %ptr, float 4.0 syncscope("agent") seq_cst
   store float %result, float addrspace(1)* undef
   ret void
 }
@@ -202,15 +216,12 @@
 ; GFX90A-NEXT:    s_load_dwordx2 s[0:1], s[0:1], 0x24
 ; GFX90A-NEXT:    v_mov_b32_e32 v0, 0
 ; GFX90A-NEXT:    v_mov_b32_e32 v1, 4.0
-; GFX90A-NEXT:    buffer_wbl2
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
-; GFX90A-NEXT:    global_atomic_add_f32 v0, v1, s[0:1] scc
-; GFX90A-NEXT:    s_waitcnt vmcnt(0)
-; GFX90A-NEXT:    buffer_invl2
+; GFX90A-NEXT:    global_atomic_add_f32 v0, v1, s[0:1]
 ; GFX90A-NEXT:    s_waitcnt vmcnt(0)
 ; GFX90A-NEXT:    buffer_wbinvl1_vol
 ; GFX90A-NEXT:    s_endpgm
-  %result = atomicrmw fadd float addrspace(1)* %ptr, float 4.0 seq_cst
+  %result = atomicrmw fadd float addrspace(1)* %ptr, float 4.0 syncscope("agent") seq_cst
   ret void
 }
 
@@ -289,7 +300,162 @@
 ; GFX90A-NEXT:    s_cbranch_execnz BB3_1
 ; GFX90A-NEXT:  ; %bb.2: ; %atomicrmw.end
 ; GFX90A-NEXT:    s_endpgm
-  %result = atomicrmw fadd float addrspace(1)* %ptr, float 4.0 seq_cst
+  %result = atomicrmw fadd float addrspace(1)* %ptr, float 4.0 syncscope("agent") seq_cst
+  ret void
+}
+
+define amdgpu_kernel void @global_atomic_fadd_ret_f32_agent(float addrspace(1)* %ptr) #0 {
+; GFX900-LABEL: global_atomic_fadd_ret_f32_agent:
+; GFX900:       ; %bb.0:
+; GFX900-NEXT:    s_load_dwordx2 s[0:1], s[0:1], 0x24
+; GFX900-NEXT:    s_mov_b64 s[2:3], 0
+; GFX900-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX900-NEXT:    s_load_dword s4, s[0:1], 0x0
+; GFX900-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX900-NEXT:    v_mov_b32_e32 v0, s4
+; GFX900-NEXT:  BB4_1: ; %atomicrmw.start
+; GFX900-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX900-NEXT:    v_mov_b32_e32 v1, v0
+; GFX900-NEXT:    v_mov_b32_e32 v2, 0
+; GFX900-NEXT:    v_add_f32_e32 v0, 4.0, v1
+; GFX900-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX900-NEXT:    global_atomic_cmpswap v0, v2, v[0:1], s[0:1] glc
+; GFX900-NEXT:    s_waitcnt vmcnt(0)
+; GFX900-NEXT:    buffer_wbinvl1_vol
+; GFX900-NEXT:    v_cmp_eq_u32_e32 vcc, v0, v1
+; GFX900-NEXT:    s_or_b64 s[2:3], vcc, s[2:3]
+; GFX900-NEXT:    s_andn2_b64 exec, exec, s[2:3]
+; GFX900-NEXT:    s_cbranch_execnz BB4_1
+; GFX900-NEXT:  ; %bb.2: ; %atomicrmw.end
+; GFX900-NEXT:    s_or_b64 exec, exec, s[2:3]
+; GFX900-NEXT:    global_store_dword v[0:1], v0, off
+; GFX900-NEXT:    s_endpgm
+;
+; GFX908-LABEL: global_atomic_fadd_ret_f32_agent:
+; GFX908:       ; %bb.0:
+; GFX908-NEXT:    s_load_dwordx2 s[0:1], s[0:1], 0x24
+; GFX908-NEXT:    s_mov_b64 s[2:3], 0
+; GFX908-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX908-NEXT:    s_load_dword s4, s[0:1], 0x0
+; GFX908-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX908-NEXT:    v_mov_b32_e32 v0, s4
+; GFX908-NEXT:  BB4_1: ; %atomicrmw.start
+; GFX908-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX908-NEXT:    v_mov_b32_e32 v1, v0
+; GFX908-NEXT:    v_mov_b32_e32 v2, 0
+; GFX908-NEXT:    v_add_f32_e32 v0, 4.0, v1
+; GFX908-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX908-NEXT:    global_atomic_cmpswap v0, v2, v[0:1], s[0:1] glc
+; GFX908-NEXT:    s_waitcnt vmcnt(0)
+; GFX908-NEXT:    buffer_wbinvl1_vol
+; GFX908-NEXT:    v_cmp_eq_u32_e32 vcc, v0, v1
+; GFX908-NEXT:    s_or_b64 s[2:3], vcc, s[2:3]
+; GFX908-NEXT:    s_andn2_b64 exec, exec, s[2:3]
+; GFX908-NEXT:    s_cbranch_execnz BB4_1
+; GFX908-NEXT:  ; %bb.2: ; %atomicrmw.end
+; GFX908-NEXT:    s_or_b64 exec, exec, s[2:3]
+; GFX908-NEXT:    global_store_dword v[0:1], v0, off
+; GFX908-NEXT:    s_endpgm
+;
+; GFX90A-LABEL: global_atomic_fadd_ret_f32_agent:
+; GFX90A:       ; %bb.0:
+; GFX90A-NEXT:    s_load_dwordx2 s[0:1], s[0:1], 0x24
+; GFX90A-NEXT:    v_mov_b32_e32 v0, 0
+; GFX90A-NEXT:    v_mov_b32_e32 v1, 4.0
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    global_atomic_add_f32 v0, v0, v1, s[0:1] glc
+; GFX90A-NEXT:    s_waitcnt vmcnt(0)
+; GFX90A-NEXT:    buffer_wbinvl1_vol
+; GFX90A-NEXT:    global_store_dword v[0:1], v0, off
+; GFX90A-NEXT:    s_endpgm
+  %result = atomicrmw fadd float addrspace(1)* %ptr, float 4.0 syncscope("agent") seq_cst
+  store float %result, float addrspace(1)* undef
+  ret void
+}
+
+define amdgpu_kernel void @global_atomic_fadd_ret_f32_system(float addrspace(1)* %ptr) #0 {
+; GFX900-LABEL: global_atomic_fadd_ret_f32_system:
+; GFX900:       ; %bb.0:
+; GFX900-NEXT:    s_load_dwordx2 s[0:1], s[0:1], 0x24
+; GFX900-NEXT:    s_mov_b64 s[2:3], 0
+; GFX900-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX900-NEXT:    s_load_dword s4, s[0:1], 0x0
+; GFX900-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX900-NEXT:    v_mov_b32_e32 v0, s4
+; GFX900-NEXT:  BB5_1: ; %atomicrmw.start
+; GFX900-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX900-NEXT:    v_mov_b32_e32 v1, v0
+; GFX900-NEXT:    v_mov_b32_e32 v2, 0
+; GFX900-NEXT:    v_add_f32_e32 v0, 4.0, v1
+; GFX900-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX900-NEXT:    global_atomic_cmpswap v0, v2, v[0:1], s[0:1] glc
+; GFX900-NEXT:    s_waitcnt vmcnt(0)
+; GFX900-NEXT:    buffer_wbinvl1_vol
+; GFX900-NEXT:    v_cmp_eq_u32_e32 vcc, v0, v1
+; GFX900-NEXT:    s_or_b64 s[2:3], vcc, s[2:3]
+; GFX900-NEXT:    s_andn2_b64 exec, exec, s[2:3]
+; GFX900-NEXT:    s_cbranch_execnz BB5_1
+; GFX900-NEXT:  ; %bb.2: ; %atomicrmw.end
+; GFX900-NEXT:    s_or_b64 exec, exec, s[2:3]
+; GFX900-NEXT:    global_store_dword v[0:1], v0, off
+; GFX900-NEXT:    s_endpgm
+;
+; GFX908-LABEL: global_atomic_fadd_ret_f32_system:
+; GFX908:       ; %bb.0:
+; GFX908-NEXT:    s_load_dwordx2 s[0:1], s[0:1], 0x24
+; GFX908-NEXT:    s_mov_b64 s[2:3], 0
+; GFX908-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX908-NEXT:    s_load_dword s4, s[0:1], 0x0
+; GFX908-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX908-NEXT:    v_mov_b32_e32 v0, s4
+; GFX908-NEXT:  BB5_1: ; %atomicrmw.start
+; GFX908-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX908-NEXT:    v_mov_b32_e32 v1, v0
+; GFX908-NEXT:    v_mov_b32_e32 v2, 0
+; GFX908-NEXT:    v_add_f32_e32 v0, 4.0, v1
+; GFX908-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX908-NEXT:    global_atomic_cmpswap v0, v2, v[0:1], s[0:1] glc
+; GFX908-NEXT:    s_waitcnt vmcnt(0)
+; GFX908-NEXT:    buffer_wbinvl1_vol
+; GFX908-NEXT:    v_cmp_eq_u32_e32 vcc, v0, v1
+; GFX908-NEXT:    s_or_b64 s[2:3], vcc, s[2:3]
+; GFX908-NEXT:    s_andn2_b64 exec, exec, s[2:3]
+; GFX908-NEXT:    s_cbranch_execnz BB5_1
+; GFX908-NEXT:  ; %bb.2: ; %atomicrmw.end
+; GFX908-NEXT:    s_or_b64 exec, exec, s[2:3]
+; GFX908-NEXT:    global_store_dword v[0:1], v0, off
+; GFX908-NEXT:    s_endpgm
+;
+; GFX90A-LABEL: global_atomic_fadd_ret_f32_system:
+; GFX90A:       ; %bb.0:
+; GFX90A-NEXT:    s_load_dwordx2 s[0:1], s[0:1], 0x24
+; GFX90A-NEXT:    s_mov_b64 s[2:3], 0
+; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX90A-NEXT:    s_load_dword s4, s[0:1], 0x0
+; GFX90A-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX90A-NEXT:    v_mov_b32_e32 v0, s4
+; GFX90A-NEXT:  BB5_1: ; %atomicrmw.start
+; GFX90A-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX90A-NEXT:    v_mov_b32_e32 v1, v0
+; GFX90A-NEXT:    v_mov_b32_e32 v2, 0
+; GFX90A-NEXT:    v_add_f32_e32 v0, 4.0, v1
+; GFX90A-NEXT:    buffer_wbl2
+; GFX90A-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX90A-NEXT:    global_atomic_cmpswap v0, v2, v[0:1], s[0:1] glc scc
+; GFX90A-NEXT:    s_waitcnt vmcnt(0)
+; GFX90A-NEXT:    buffer_invl2
+; GFX90A-NEXT:    s_waitcnt vmcnt(0)
+; GFX90A-NEXT:    buffer_wbinvl1_vol
+; GFX90A-NEXT:    v_cmp_eq_u32_e32 vcc, v0, v1
+; GFX90A-NEXT:    s_or_b64 s[2:3], vcc, s[2:3]
+; GFX90A-NEXT:    s_andn2_b64 exec, exec, s[2:3]
+; GFX90A-NEXT:    s_cbranch_execnz BB5_1
+; GFX90A-NEXT:  ; %bb.2: ; %atomicrmw.end
+; GFX90A-NEXT:    s_or_b64 exec, exec, s[2:3]
+; GFX90A-NEXT:    global_store_dword v[0:1], v0, off
+; GFX90A-NEXT:    s_endpgm
+  %result = atomicrmw fadd float addrspace(1)* %ptr, float 4.0 syncscope("one-as") seq_cst
+  store float %result, float addrspace(1)* undef
   ret void
 }
 
@@ -302,7 +468,7 @@
 ; GCN-NEXT:    s_load_dword s4, s[0:1], 0x0
 ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
 ; GCN-NEXT:    v_mov_b32_e32 v0, s4
-; GCN-NEXT:  BB4_1: ; %atomicrmw.start
+; GCN-NEXT:  BB6_1: ; %atomicrmw.start
 ; GCN-NEXT:    ; =>This Inner Loop Header: Depth=1
 ; GCN-NEXT:    v_mov_b32_e32 v1, v0
 ; GCN-NEXT:    v_mov_b32_e32 v2, 0
@@ -314,12 +480,12 @@
 ; GCN-NEXT:    v_cmp_eq_u32_e32 vcc, v0, v1
 ; GCN-NEXT:    s_or_b64 s[2:3], vcc, s[2:3]
 ; GCN-NEXT:    s_andn2_b64 exec, exec, s[2:3]
-; GCN-NEXT:    s_cbranch_execnz BB4_1
+; GCN-NEXT:    s_cbranch_execnz BB6_1
 ; GCN-NEXT:  ; %bb.2: ; %atomicrmw.end
 ; GCN-NEXT:    s_or_b64 exec, exec, s[2:3]
 ; GCN-NEXT:    global_store_dword v[0:1], v0, off
 ; GCN-NEXT:    s_endpgm
-  %result = atomicrmw fadd float addrspace(1)* %ptr, float 4.0 seq_cst
+  %result = atomicrmw fadd float addrspace(1)* %ptr, float 4.0 syncscope("agent") seq_cst
   store float %result, float addrspace(1)* undef
   ret void
 }
@@ -335,7 +501,7 @@
 ; GCN-NEXT:    s_waitcnt vmcnt(0)
 ; GCN-NEXT:    buffer_wbinvl1_vol
 ; GCN-NEXT:    s_endpgm
-  %result = atomicrmw fadd float addrspace(1)* %ptr, float 4.0 seq_cst
+  %result = atomicrmw fadd float addrspace(1)* %ptr, float 4.0 syncscope("agent") seq_cst
   ret void
 }