[AMDGPU] Enhance s_waitcnt insertion before barrier for gfx12 (#90595)

Code to determine if a waitcnt is required before a barrier instruction only considered S_BARRIER. gfx12 adds barrier_signal/wait so need to enhance the existing code to look for a barrier start (which is just an S_BARRIER for earlier architectures).
llvm · May 9, 2024 · 58e44d3 · 58e44d3
1 parent d1d7131
commit 58e44d3
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diff --git a/llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp b/llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp
@@ -1832,7 +1832,7 @@ bool SIInsertWaitcnts::generateWaitcntInstBefore(MachineInstr &MI,
   // not, we need to ensure the subtarget is capable of backing off barrier
   // instructions in case there are any outstanding memory operations that may
   // cause an exception. Otherwise, insert an explicit S_WAITCNT 0 here.
-  if (MI.getOpcode() == AMDGPU::S_BARRIER &&
+  if (TII->isBarrierStart(MI.getOpcode()) &&
       !ST->hasAutoWaitcntBeforeBarrier() && !ST->supportsBackOffBarrier()) {
     Wait = Wait.combined(
         AMDGPU::Waitcnt::allZero(ST->hasExtendedWaitCounts(), ST->hasVscnt()));

diff --git a/llvm/lib/Target/AMDGPU/SIInstrInfo.h b/llvm/lib/Target/AMDGPU/SIInstrInfo.h
@@ -908,6 +908,17 @@ class SIInstrInfo final : public AMDGPUGenInstrInfo {
     return MI.getDesc().TSFlags & SIInstrFlags::IsNeverUniform;
   }
 
+  // Check to see if opcode is for a barrier start. Pre gfx12 this is just the
+  // S_BARRIER, but after support for S_BARRIER_SIGNAL* / S_BARRIER_WAIT we want
+  // to check for the barrier start (S_BARRIER_SIGNAL*)
+  bool isBarrierStart(unsigned Opcode) const {
+    return Opcode == AMDGPU::S_BARRIER ||
+           Opcode == AMDGPU::S_BARRIER_SIGNAL_M0 ||
+           Opcode == AMDGPU::S_BARRIER_SIGNAL_ISFIRST_M0 ||
+           Opcode == AMDGPU::S_BARRIER_SIGNAL_IMM ||
+           Opcode == AMDGPU::S_BARRIER_SIGNAL_ISFIRST_IMM;
+  }
+
   static bool doesNotReadTiedSource(const MachineInstr &MI) {
     return MI.getDesc().TSFlags & SIInstrFlags::TiedSourceNotRead;
   }

diff --git a/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.s.barrier.ll b/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.s.barrier.ll
@@ -96,6 +96,7 @@ define amdgpu_kernel void @test_barrier(ptr addrspace(1) %out, i32 %size) #0 {
 ; VARIANT4-NEXT:    s_wait_kmcnt 0x0
 ; VARIANT4-NEXT:    v_xad_u32 v1, v0, -1, s2
 ; VARIANT4-NEXT:    global_store_b32 v3, v0, s[0:1]
+; VARIANT4-NEXT:    s_wait_storecnt 0x0
 ; VARIANT4-NEXT:    s_barrier_signal -1
 ; VARIANT4-NEXT:    s_barrier_wait -1
 ; VARIANT4-NEXT:    v_ashrrev_i32_e32 v2, 31, v1
@@ -142,6 +143,7 @@ define amdgpu_kernel void @test_barrier(ptr addrspace(1) %out, i32 %size) #0 {
 ; VARIANT6-NEXT:    v_dual_mov_b32 v4, s1 :: v_dual_mov_b32 v3, s0
 ; VARIANT6-NEXT:    v_sub_nc_u32_e32 v1, s2, v0
 ; VARIANT6-NEXT:    global_store_b32 v5, v0, s[0:1]
+; VARIANT6-NEXT:    s_wait_storecnt 0x0
 ; VARIANT6-NEXT:    s_barrier_signal -1
 ; VARIANT6-NEXT:    s_barrier_wait -1
 ; VARIANT6-NEXT:    v_ashrrev_i32_e32 v2, 31, v1

diff --git a/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.s.barrier.wait.ll b/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.s.barrier.wait.ll
@@ -12,6 +12,7 @@ define amdgpu_kernel void @test1_s_barrier_signal(ptr addrspace(1) %out) #0 {
 ; GCN-NEXT:    v_sub_nc_u32_e32 v0, v1, v0
 ; GCN-NEXT:    s_wait_kmcnt 0x0
 ; GCN-NEXT:    global_store_b32 v3, v2, s[0:1]
+; GCN-NEXT:    s_wait_storecnt 0x0
 ; GCN-NEXT:    s_barrier_signal -1
 ; GCN-NEXT:    s_barrier_wait -1
 ; GCN-NEXT:    global_store_b32 v3, v0, s[0:1]
@@ -28,6 +29,7 @@ define amdgpu_kernel void @test1_s_barrier_signal(ptr addrspace(1) %out) #0 {
 ; GLOBAL-ISEL-NEXT:    v_sub_nc_u32_e32 v0, v1, v0
 ; GLOBAL-ISEL-NEXT:    s_wait_kmcnt 0x0
 ; GLOBAL-ISEL-NEXT:    global_store_b32 v3, v2, s[0:1]
+; GLOBAL-ISEL-NEXT:    s_wait_storecnt 0x0
 ; GLOBAL-ISEL-NEXT:    s_barrier_signal -1
 ; GLOBAL-ISEL-NEXT:    s_barrier_wait -1
 ; GLOBAL-ISEL-NEXT:    global_store_b32 v3, v0, s[0:1]
@@ -56,6 +58,7 @@ define amdgpu_kernel void @test2_s_barrier_signal(ptr addrspace(1) %out) #0 {
 ; GCN-NEXT:    v_sub_nc_u32_e32 v0, v1, v0
 ; GCN-NEXT:    s_wait_kmcnt 0x0
 ; GCN-NEXT:    global_store_b32 v3, v2, s[0:1]
+; GCN-NEXT:    s_wait_storecnt 0x0
 ; GCN-NEXT:    s_barrier_signal 1
 ; GCN-NEXT:    s_barrier_wait 1
 ; GCN-NEXT:    global_store_b32 v3, v0, s[0:1]
@@ -72,6 +75,7 @@ define amdgpu_kernel void @test2_s_barrier_signal(ptr addrspace(1) %out) #0 {
 ; GLOBAL-ISEL-NEXT:    v_sub_nc_u32_e32 v0, v1, v0
 ; GLOBAL-ISEL-NEXT:    s_wait_kmcnt 0x0
 ; GLOBAL-ISEL-NEXT:    global_store_b32 v3, v2, s[0:1]
+; GLOBAL-ISEL-NEXT:    s_wait_storecnt 0x0
 ; GLOBAL-ISEL-NEXT:    s_barrier_signal 1
 ; GLOBAL-ISEL-NEXT:    s_barrier_wait 1
 ; GLOBAL-ISEL-NEXT:    global_store_b32 v3, v0, s[0:1]
@@ -100,6 +104,7 @@ define amdgpu_kernel void @test3_s_barrier_signal(ptr addrspace(1) %out) #0 {
 ; GCN-NEXT:    v_sub_nc_u32_e32 v0, v1, v0
 ; GCN-NEXT:    s_wait_kmcnt 0x0
 ; GCN-NEXT:    global_store_b32 v3, v2, s[0:1]
+; GCN-NEXT:    s_wait_storecnt 0x0
 ; GCN-NEXT:    s_barrier_signal 0
 ; GCN-NEXT:    s_barrier_wait 0
 ; GCN-NEXT:    global_store_b32 v3, v0, s[0:1]
@@ -116,6 +121,7 @@ define amdgpu_kernel void @test3_s_barrier_signal(ptr addrspace(1) %out) #0 {
 ; GLOBAL-ISEL-NEXT:    v_sub_nc_u32_e32 v0, v1, v0
 ; GLOBAL-ISEL-NEXT:    s_wait_kmcnt 0x0
 ; GLOBAL-ISEL-NEXT:    global_store_b32 v3, v2, s[0:1]
+; GLOBAL-ISEL-NEXT:    s_wait_storecnt 0x0
 ; GLOBAL-ISEL-NEXT:    s_barrier_signal 0
 ; GLOBAL-ISEL-NEXT:    s_barrier_wait 0
 ; GLOBAL-ISEL-NEXT:    global_store_b32 v3, v0, s[0:1]
@@ -146,6 +152,7 @@ define amdgpu_kernel void @test1_s_barrier_signal_var(ptr addrspace(1) %out) #0
 ; GCN-NEXT:    v_sub_nc_u32_e32 v0, v2, v0
 ; GCN-NEXT:    s_wait_kmcnt 0x0
 ; GCN-NEXT:    global_store_b32 v3, v1, s[0:1]
+; GCN-NEXT:    s_wait_storecnt 0x0
 ; GCN-NEXT:    s_barrier_signal m0
 ; GCN-NEXT:    s_barrier_wait 1
 ; GCN-NEXT:    global_store_b32 v3, v0, s[0:1]
@@ -163,6 +170,7 @@ define amdgpu_kernel void @test1_s_barrier_signal_var(ptr addrspace(1) %out) #0
 ; GLOBAL-ISEL-NEXT:    v_sub_nc_u32_e32 v0, v1, v0
 ; GLOBAL-ISEL-NEXT:    s_wait_kmcnt 0x0
 ; GLOBAL-ISEL-NEXT:    global_store_b32 v3, v2, s[0:1]
+; GLOBAL-ISEL-NEXT:    s_wait_storecnt 0x0
 ; GLOBAL-ISEL-NEXT:    s_barrier_signal m0
 ; GLOBAL-ISEL-NEXT:    s_barrier_wait 1
 ; GLOBAL-ISEL-NEXT:    global_store_b32 v3, v0, s[0:1]
@@ -192,6 +200,7 @@ define void @test2_s_barrier_signal_var(i32 %arg) {
 ; GCN-NEXT:    v_readfirstlane_b32 s0, v0
 ; GCN-NEXT:    s_delay_alu instid0(VALU_DEP_1)
 ; GCN-NEXT:    s_mov_b32 m0, s0
+; GCN-NEXT:    s_wait_storecnt 0x0
 ; GCN-NEXT:    s_barrier_signal m0
 ; GCN-NEXT:    s_setpc_b64 s[30:31]
 ;
@@ -203,6 +212,7 @@ define void @test2_s_barrier_signal_var(i32 %arg) {
 ; GLOBAL-ISEL-NEXT:    s_wait_bvhcnt 0x0
 ; GLOBAL-ISEL-NEXT:    s_wait_kmcnt 0x0
 ; GLOBAL-ISEL-NEXT:    v_readfirstlane_b32 m0, v0
+; GLOBAL-ISEL-NEXT:    s_wait_storecnt 0x0
 ; GLOBAL-ISEL-NEXT:    s_barrier_signal m0
 ; GLOBAL-ISEL-NEXT:    s_setpc_b64 s[30:31]
   call void @llvm.amdgcn.s.barrier.signal.var(i32 %arg)
@@ -216,6 +226,7 @@ define amdgpu_kernel void @test1_s_barrier_signal_isfirst(ptr addrspace(1) %a, p
 ; GCN-NEXT:    v_dual_mov_b32 v1, 0 :: v_dual_lshlrev_b32 v0, 2, v0
 ; GCN-NEXT:    s_wait_kmcnt 0x0
 ; GCN-NEXT:    global_store_b32 v0, v1, s[6:7]
+; GCN-NEXT:    s_wait_storecnt 0x0
 ; GCN-NEXT:    s_barrier_signal_isfirst -1
 ; GCN-NEXT:    s_cselect_b32 s3, s3, s5
 ; GCN-NEXT:    s_cselect_b32 s2, s2, s4
@@ -235,6 +246,7 @@ define amdgpu_kernel void @test1_s_barrier_signal_isfirst(ptr addrspace(1) %a, p
 ; GLOBAL-ISEL-NEXT:    v_dual_mov_b32 v1, 0 :: v_dual_lshlrev_b32 v0, 2, v0
 ; GLOBAL-ISEL-NEXT:    s_wait_kmcnt 0x0
 ; GLOBAL-ISEL-NEXT:    global_store_b32 v0, v1, s[6:7]
+; GLOBAL-ISEL-NEXT:    s_wait_storecnt 0x0
 ; GLOBAL-ISEL-NEXT:    s_barrier_signal_isfirst -1
 ; GLOBAL-ISEL-NEXT:    s_cselect_b32 s8, 1, 0
 ; GLOBAL-ISEL-NEXT:    s_delay_alu instid0(SALU_CYCLE_1) | instskip(NEXT) | instid1(SALU_CYCLE_1)
@@ -270,6 +282,7 @@ define amdgpu_kernel void @test2_s_barrier_signal_isfirst(ptr addrspace(1) %a, p
 ; GCN-NEXT:    v_dual_mov_b32 v1, 0 :: v_dual_lshlrev_b32 v0, 2, v0
 ; GCN-NEXT:    s_wait_kmcnt 0x0
 ; GCN-NEXT:    global_store_b32 v0, v1, s[6:7]
+; GCN-NEXT:    s_wait_storecnt 0x0
 ; GCN-NEXT:    s_barrier_signal_isfirst 1
 ; GCN-NEXT:    s_cselect_b32 s3, s3, s5
 ; GCN-NEXT:    s_cselect_b32 s2, s2, s4
@@ -289,6 +302,7 @@ define amdgpu_kernel void @test2_s_barrier_signal_isfirst(ptr addrspace(1) %a, p
 ; GLOBAL-ISEL-NEXT:    v_dual_mov_b32 v1, 0 :: v_dual_lshlrev_b32 v0, 2, v0
 ; GLOBAL-ISEL-NEXT:    s_wait_kmcnt 0x0
 ; GLOBAL-ISEL-NEXT:    global_store_b32 v0, v1, s[6:7]
+; GLOBAL-ISEL-NEXT:    s_wait_storecnt 0x0
 ; GLOBAL-ISEL-NEXT:    s_barrier_signal_isfirst 1
 ; GLOBAL-ISEL-NEXT:    s_cselect_b32 s8, 1, 0
 ; GLOBAL-ISEL-NEXT:    s_delay_alu instid0(SALU_CYCLE_1) | instskip(NEXT) | instid1(SALU_CYCLE_1)
@@ -324,6 +338,7 @@ define amdgpu_kernel void @test3_s_barrier_signal_isfirst(ptr addrspace(1) %a, p
 ; GCN-NEXT:    v_dual_mov_b32 v1, 0 :: v_dual_lshlrev_b32 v0, 2, v0
 ; GCN-NEXT:    s_wait_kmcnt 0x0
 ; GCN-NEXT:    global_store_b32 v0, v1, s[6:7]
+; GCN-NEXT:    s_wait_storecnt 0x0
 ; GCN-NEXT:    s_barrier_signal_isfirst 1
 ; GCN-NEXT:    s_cselect_b32 s3, s3, s5
 ; GCN-NEXT:    s_cselect_b32 s2, s2, s4
@@ -343,6 +358,7 @@ define amdgpu_kernel void @test3_s_barrier_signal_isfirst(ptr addrspace(1) %a, p
 ; GLOBAL-ISEL-NEXT:    v_dual_mov_b32 v1, 0 :: v_dual_lshlrev_b32 v0, 2, v0
 ; GLOBAL-ISEL-NEXT:    s_wait_kmcnt 0x0
 ; GLOBAL-ISEL-NEXT:    global_store_b32 v0, v1, s[6:7]
+; GLOBAL-ISEL-NEXT:    s_wait_storecnt 0x0
 ; GLOBAL-ISEL-NEXT:    s_barrier_signal_isfirst 1
 ; GLOBAL-ISEL-NEXT:    s_cselect_b32 s8, 1, 0
 ; GLOBAL-ISEL-NEXT:    s_delay_alu instid0(SALU_CYCLE_1) | instskip(NEXT) | instid1(SALU_CYCLE_1)
@@ -379,6 +395,7 @@ define amdgpu_kernel void @test1_s_barrier_signal_isfirst_var(ptr addrspace(1) %
 ; GCN-NEXT:    s_mov_b32 m0, 1
 ; GCN-NEXT:    s_wait_kmcnt 0x0
 ; GCN-NEXT:    global_store_b32 v0, v1, s[6:7]
+; GCN-NEXT:    s_wait_storecnt 0x0
 ; GCN-NEXT:    s_barrier_signal_isfirst m0
 ; GCN-NEXT:    s_cselect_b32 s3, s3, s5
 ; GCN-NEXT:    s_cselect_b32 s2, s2, s4
@@ -399,6 +416,7 @@ define amdgpu_kernel void @test1_s_barrier_signal_isfirst_var(ptr addrspace(1) %
 ; GLOBAL-ISEL-NEXT:    s_mov_b32 m0, 1
 ; GLOBAL-ISEL-NEXT:    s_wait_kmcnt 0x0
 ; GLOBAL-ISEL-NEXT:    global_store_b32 v0, v1, s[6:7]
+; GLOBAL-ISEL-NEXT:    s_wait_storecnt 0x0
 ; GLOBAL-ISEL-NEXT:    s_barrier_signal_isfirst m0
 ; GLOBAL-ISEL-NEXT:    s_cselect_b32 s8, 1, 0
 ; GLOBAL-ISEL-NEXT:    s_delay_alu instid0(SALU_CYCLE_1) | instskip(NEXT) | instid1(SALU_CYCLE_1)
@@ -444,6 +462,7 @@ define void @test2_s_barrier_signal_isfirst_var(ptr addrspace(1) %a, ptr addrspa
 ; GCN-NEXT:    v_add_co_u32 v7, vcc_lo, v7, v9
 ; GCN-NEXT:    v_add_co_ci_u32_e32 v8, vcc_lo, 0, v8, vcc_lo
 ; GCN-NEXT:    global_store_b32 v[7:8], v10, off
+; GCN-NEXT:    s_wait_storecnt 0x0
 ; GCN-NEXT:    s_barrier_signal_isfirst m0
 ; GCN-NEXT:    s_cselect_b32 vcc_lo, -1, 0
 ; GCN-NEXT:    v_dual_cndmask_b32 v2, v4, v2 :: v_dual_cndmask_b32 v3, v5, v3
@@ -470,6 +489,7 @@ define void @test2_s_barrier_signal_isfirst_var(ptr addrspace(1) %a, ptr addrspa
 ; GLOBAL-ISEL-NEXT:    v_add_co_ci_u32_e32 v8, vcc_lo, 0, v8, vcc_lo
 ; GLOBAL-ISEL-NEXT:    v_mov_b32_e32 v9, 0
 ; GLOBAL-ISEL-NEXT:    global_store_b32 v[7:8], v9, off
+; GLOBAL-ISEL-NEXT:    s_wait_storecnt 0x0
 ; GLOBAL-ISEL-NEXT:    s_barrier_signal_isfirst m0
 ; GLOBAL-ISEL-NEXT:    s_cselect_b32 s0, 1, 0
 ; GLOBAL-ISEL-NEXT:    s_delay_alu instid0(SALU_CYCLE_1) | instskip(NEXT) | instid1(SALU_CYCLE_1)
@@ -1339,6 +1359,7 @@ define amdgpu_kernel void @test_barrier_convert(ptr addrspace(1) %out) #0 {
 ; GCN-NEXT:    v_sub_nc_u32_e32 v0, v1, v0
 ; GCN-NEXT:    s_wait_kmcnt 0x0
 ; GCN-NEXT:    global_store_b32 v3, v2, s[0:1]
+; GCN-NEXT:    s_wait_storecnt 0x0
 ; GCN-NEXT:    s_barrier_signal -1
 ; GCN-NEXT:    s_barrier_wait -1
 ; GCN-NEXT:    global_store_b32 v3, v0, s[0:1]
@@ -1355,6 +1376,7 @@ define amdgpu_kernel void @test_barrier_convert(ptr addrspace(1) %out) #0 {
 ; GLOBAL-ISEL-NEXT:    v_sub_nc_u32_e32 v0, v1, v0
 ; GLOBAL-ISEL-NEXT:    s_wait_kmcnt 0x0
 ; GLOBAL-ISEL-NEXT:    global_store_b32 v3, v2, s[0:1]
+; GLOBAL-ISEL-NEXT:    s_wait_storecnt 0x0
 ; GLOBAL-ISEL-NEXT:    s_barrier_signal -1
 ; GLOBAL-ISEL-NEXT:    s_barrier_wait -1
 ; GLOBAL-ISEL-NEXT:    global_store_b32 v3, v0, s[0:1]