Index: clang/docs/ClangCommandLineReference.rst
===================================================================
--- clang/docs/ClangCommandLineReference.rst
+++ clang/docs/ClangCommandLineReference.rst
@@ -2997,6 +2997,10 @@
 
 Specify XNACK mode (AMDGPU only)
 
+.. option:: -munsafe-fp-atomics, -mno-unsafe-fp-atomics
+
+Enable unsafe floating point atomic instructions. Bypasses denormal mode checks and allows to use atomics on a potentially unsupported memory types. (AMDGPU only)
+
 ARM
 ---
 .. option:: -faapcs-bitfield-load
Index: llvm/lib/Target/AMDGPU/SIISelLowering.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -12055,7 +12055,10 @@
 
     if ((AS == AMDGPUAS::GLOBAL_ADDRESS || AS == AMDGPUAS::FLAT_ADDRESS) &&
          Subtarget->hasAtomicFaddInsts()) {
-      if (!fpModeMatchesGlobalFPAtomicMode(RMW) ||
+      // The amdgpu-unsafe-fp-atomics attribute allows to bypass denormal mode
+      // checks and allows to use atomics on a potentially unsupported memory
+      // types.
+      if (!fpModeMatchesGlobalFPAtomicMode(RMW) &&
           RMW->getFunction()->getFnAttribute("amdgpu-unsafe-fp-atomics")
               .getValueAsString() != "true")
         return AtomicExpansionKind::CmpXChg;
Index: llvm/test/CodeGen/AMDGPU/fp64-atomics-gfx90a.ll
===================================================================
--- llvm/test/CodeGen/AMDGPU/fp64-atomics-gfx90a.ll
+++ llvm/test/CodeGen/AMDGPU/fp64-atomics-gfx90a.ll
@@ -490,25 +490,13 @@
 ; GFX90A-LABEL: global_atomic_fadd_f64_noret_pat_flush:
 ; 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:  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
+; 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_cmpswap_x2 v[0:1], v4, v[0:3], s[0:1] glc
+; 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:    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 BB27_1
-; GFX90A-NEXT:  ; %bb.2: ; %atomicrmw.end
 ; GFX90A-NEXT:    s_endpgm
 main_body:
   %ret = atomicrmw fadd double addrspace(1)* %ptr, double 4.0 syncscope("agent") seq_cst
Index: llvm/test/CodeGen/AMDGPU/global-atomics-fp.ll
===================================================================
--- llvm/test/CodeGen/AMDGPU/global-atomics-fp.ll
+++ llvm/test/CodeGen/AMDGPU/global-atomics-fp.ll
@@ -171,26 +171,12 @@
 ; GFX90A-LABEL: global_atomic_fadd_ret_f32_ieee:
 ; 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:  BB1_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:    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_cmpswap v0, v2, v[0:1], s[0:1] glc
+; 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:    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 BB1_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
 ;
@@ -330,49 +316,23 @@
 ; GFX908-LABEL: global_atomic_fadd_noret_f32_ieee:
 ; 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 v1, s4
-; GFX908-NEXT:  BB3_1: ; %atomicrmw.start
-; GFX908-NEXT:    ; =>This Inner Loop Header: Depth=1
-; GFX908-NEXT:    v_mov_b32_e32 v2, 0
-; GFX908-NEXT:    v_add_f32_e32 v0, 4.0, v1
+; GFX908-NEXT:    v_mov_b32_e32 v0, 0
+; GFX908-NEXT:    v_mov_b32_e32 v1, 4.0
 ; GFX908-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
-; GFX908-NEXT:    global_atomic_cmpswap v0, v2, v[0:1], s[0:1] glc
+; GFX908-NEXT:    global_atomic_add_f32 v0, v1, s[0:1]
 ; 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:    v_mov_b32_e32 v1, v0
-; GFX908-NEXT:    s_andn2_b64 exec, exec, s[2:3]
-; GFX908-NEXT:    s_cbranch_execnz BB3_1
-; GFX908-NEXT:  ; %bb.2: ; %atomicrmw.end
 ; GFX908-NEXT:    s_endpgm
 ;
 ; GFX90A-LABEL: global_atomic_fadd_noret_f32_ieee:
 ; 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 v1, s4
-; GFX90A-NEXT:  BB3_1: ; %atomicrmw.start
-; GFX90A-NEXT:    ; =>This Inner Loop Header: Depth=1
-; GFX90A-NEXT:    v_mov_b32_e32 v2, 0
-; GFX90A-NEXT:    v_add_f32_e32 v0, 4.0, v1
+; 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_cmpswap v0, v2, v[0:1], s[0:1] glc
+; GFX90A-NEXT:    global_atomic_add_f32 v0, v1, s[0:1]
 ; 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:    v_mov_b32_e32 v1, v0
-; GFX90A-NEXT:    s_andn2_b64 exec, exec, s[2:3]
-; GFX90A-NEXT:    s_cbranch_execnz BB3_1
-; GFX90A-NEXT:  ; %bb.2: ; %atomicrmw.end
 ; GFX90A-NEXT:    s_endpgm
 ;
 ; GFX10-LABEL: global_atomic_fadd_noret_f32_ieee: