[AMDGPU] Apply pre-emit s_cbranch_vcc optimation to more patterns

[critson]

Summary

Depends on D83637 for test correctness, but not operation.
Add handling of s_andn2 and mask of 0.
This eliminates code from uniform control flows.

[rampitec]

llvm/lib/Target/AMDGPU/SIPreEmitPeephole.cpp

129

Technically here MaskValue can be anything, not just -1 or 0.

134

.. and here you squash it. I think it needs a check.

llvm/test/CodeGen/AMDGPU/infinite-loop.ll

161

Looks like s_mov_b64 vcc, 0?

llvm/test/CodeGen/AMDGPU/sgpr-control-flow.ll

14

Do you mind to pre-commit white space changes?

[critson]

llvm/lib/Target/AMDGPU/SIPreEmitPeephole.cpp

129

Line 102 ensures MaskValue is 0 or -1.
I can add an assertion here as well.

llvm/test/CodeGen/AMDGPU/infinite-loop.ll

161

Yes, hence how this becomes an unconditional branch.
Are you suggesting that we add a peephole to clean up "s_and_b* vcc, exec, 0" -> "s_mov_b* vcc, 0" in this case ?

llvm/test/CodeGen/AMDGPU/sgpr-control-flow.ll

14

Will do.

[critson]

Rebase on top of test pre-commit.
Add assertions relating to MaskValue.

[arsenm]

llvm/lib/Target/AMDGPU/SIPreEmitPeephole.cpp

131

llvm_unreachable

llvm/test/CodeGen/AMDGPU/insert-skip-from-vcc.mir

343–344

Negative checks make me nervous. Can you generate these?

[critson]

llvm/test/CodeGen/AMDGPU/insert-skip-from-vcc.mir

343–344

We could switch the entire test to being generate, but generated MIR tests don't use CHECK-NEXT, so these would still fall through the cracks.

[critson]

Change assertion to llvm_unreachable.

[rampitec]

LGTM with a nit.

llvm/lib/Target/AMDGPU/SIPreEmitPeephole.cpp

129

OK, see it. Thanks.

135

It is MaskValue = ~MaskValue; right? I think it is just more clear with negation.

llvm/test/CodeGen/AMDGPU/infinite-loop.ll

161

Yes, but not in this change.

llvm/lib/Target/AMDGPU/SIPreEmitPeephole.cpp

INITIALIZE_PASS(SIPreEmitPeephole, DEBUG_TYPE,
                 "SI peephole optimizations", false, false)
 
 char SIPreEmitPeephole::ID = 0;
 
 char &llvm::SIPreEmitPeepholeID = SIPreEmitPeephole::ID;
 
 bool SIPreEmitPeephole::optimizeVccBranch(MachineInstr &MI) const {
   // Match:
-  // sreg = -1
-  // vcc = S_AND_B64 exec, sreg
+  // sreg = -1 or 0
+  // vcc = S_AND_B64 exec, sreg or S_ANDN2_B64 exec, sreg
   // S_CBRANCH_VCC[N]Z
   // =>
   // S_CBRANCH_EXEC[N]Z
   // We end up with this pattern sometimes after basic block placement.
-  // It happens while combining a block which assigns -1 to a saved mask and
-  // another block which consumes that saved mask and then a branch.
+  // It happens while combining a block which assigns -1 or 0 to a saved mask
+  // and another block which consumes that saved mask and then a branch.
   bool Changed = false;
   MachineBasicBlock &MBB = *MI.getParent();
   const GCNSubtarget &ST = MBB.getParent()->getSubtarget<GCNSubtarget>();
   const bool IsWave32 = ST.isWave32();
   const unsigned CondReg = TRI->getVCC();
   const unsigned ExecReg = IsWave32 ? AMDGPU::EXEC_LO : AMDGPU::EXEC;
   const unsigned And = IsWave32 ? AMDGPU::S_AND_B32 : AMDGPU::S_AND_B64;
+  const unsigned AndN2 = IsWave32 ? AMDGPU::S_ANDN2_B32 : AMDGPU::S_ANDN2_B64;
 
   MachineBasicBlock::reverse_iterator A = MI.getReverseIterator(),
                                       E = MBB.rend();
   bool ReadsCond = false;
   unsigned Threshold = 5;
   for (++A; A != E; ++A) {
     if (!--Threshold)
       return false;
     if (A->modifiesRegister(ExecReg, TRI))
       return false;
     if (A->modifiesRegister(CondReg, TRI)) {
-      if (!A->definesRegister(CondReg, TRI) || A->getOpcode() != And)
+      if (!A->definesRegister(CondReg, TRI) ||
+          (A->getOpcode() != And && A->getOpcode() != AndN2))
         return false;
       break;
     }
     ReadsCond |= A->readsRegister(CondReg, TRI);
   }
   if (A == E)
     return false;
 
   MachineOperand &Op1 = A->getOperand(1);
   MachineOperand &Op2 = A->getOperand(2);
   if (Op1.getReg() != ExecReg && Op2.isReg() && Op2.getReg() == ExecReg) {
     TII->commuteInstruction(*A);
     Changed = true;
   }
   if (Op1.getReg() != ExecReg)
     return Changed;
-  if (Op2.isImm() && Op2.getImm() != -1)
+  if (Op2.isImm() && !(Op2.getImm() == -1 || Op2.getImm() == 0))
     return Changed;
 
+  int64_t MaskValue;
   Register SReg;
   if (Op2.isReg()) {
     SReg = Op2.getReg();
     auto M = std::next(A);
     bool ReadsSreg = false;
     for (; M != E; ++M) {
       if (M->definesRegister(SReg, TRI))
         break;
       if (M->modifiesRegister(SReg, TRI))
         return Changed;
       ReadsSreg |= M->readsRegister(SReg, TRI);
     }
     if (M == E || !M->isMoveImmediate() || !M->getOperand(1).isImm() ||
-        M->getOperand(1).getImm() != -1)
+        (M->getOperand(1).getImm() != -1 && M->getOperand(1).getImm() != 0))
       return Changed;
-    // First if sreg is only used in and instruction fold the immediate
-    // into that and.
+    MaskValue = M->getOperand(1).getImm();
+    // First if sreg is only used in the AND instruction fold the immediate
+    // into into the AND.
     if (!ReadsSreg && Op2.isKill()) {
-      A->getOperand(2).ChangeToImmediate(-1);
+      A->getOperand(2).ChangeToImmediate(MaskValue);
       M->eraseFromParent();
     }
+  } else if (Op2.isImm()) {
+    MaskValue = Op2.getImm();
   }
 
+  // Invert mask for s_andn2
+  if (A->getOpcode() == AndN2)
+    MaskValue = MaskValue == 0 ? -1 : 0;
+
   if (!ReadsCond && A->registerDefIsDead(AMDGPU::SCC) &&
       MI.killsRegister(CondReg, TRI))
     A->eraseFromParent();
 
   bool IsVCCZ = MI.getOpcode() == AMDGPU::S_CBRANCH_VCCZ;
   if (SReg == ExecReg) {
+    // EXEC is updated directly
     if (IsVCCZ) {
       MI.eraseFromParent();
       return true;
     }
     MI.setDesc(TII->get(AMDGPU::S_BRANCH));
+  } else if (IsVCCZ && MaskValue == 0) {
+    // Will always branch
+    // Remove all succesors shadowed by new unconditional branch
+    MachineBasicBlock *Parent = MI.getParent();
+    SmallVector<MachineInstr *, 4> ToRemove;
+    bool Found = false;
+    for (MachineInstr &Term : Parent->terminators()) {
+      if (Found) {
+        if (Term.isBranch())
+          ToRemove.push_back(&Term);
       } else {
+        Found = Term.isIdenticalTo(MI);
+      }
+    }
+    assert(Found && "conditional branch is not terminator");
+    for (auto BranchMI : ToRemove) {
+      MachineOperand &Dst = BranchMI->getOperand(0);
+      assert(Dst.isMBB() && "destination is not basic block");
+      Parent->removeSuccessor(Dst.getMBB());
+      BranchMI->eraseFromParent();
+    }
+
+    if (MachineBasicBlock *Succ = Parent->getFallThrough()) {
+      Parent->removeSuccessor(Succ);
+    }
+
+    // Rewrite to unconditional branch
+    MI.setDesc(TII->get(AMDGPU::S_BRANCH));
+  } else if (!IsVCCZ && MaskValue == 0) {
+    // Will never branch
+    MachineOperand &Dst = MI.getOperand(0);
+    assert(Dst.isMBB() && "destination is not basic block");
+    MI.getParent()->removeSuccessor(Dst.getMBB());
+    MI.eraseFromParent();
+    return true;
+  } else if (MaskValue == -1) {
+    // Depends only on EXEC
     MI.setDesc(
         TII->get(IsVCCZ ? AMDGPU::S_CBRANCH_EXECZ : AMDGPU::S_CBRANCH_EXECNZ));
   }
 
   MI.RemoveOperand(MI.findRegisterUseOperandIdx(CondReg, false /*Kill*/, TRI));
   MI.addImplicitDefUseOperands(*MBB.getParent());
 
   return true;

llvm/test/CodeGen/AMDGPU/branch-relaxation.ll

 ; GCN-LABEL: {{^}}long_branch_hang:
 ; GCN: s_cmp_lt_i32 s{{[0-9]+}}, 6
 ; GCN: s_cbranch_scc{{[0-1]}} [[LONG_BR_0:BB[0-9]+_[0-9]+]]
 ; GCN-NEXT: BB{{[0-9]+_[0-9]+}}:
 
 ; GCN: s_add_u32 s{{[0-9]+}}, s{{[0-9]+}}, [[LONG_BR_DEST0:BB[0-9]+_[0-9]+]]-(
 ; GCN-NEXT: s_addc_u32
 ; GCN-NEXT: s_setpc_b64
-
 ; GCN-NEXT: [[LONG_BR_0]]:
-; GCN: s_setpc_b64
 
-; GCN: [[LONG_BR_DEST0]]
+; GCN: [[LONG_BR_DEST0]]:
 
-; GCN: s_cbranch_vccnz
 ; GCN-DAG: v_cmp_lt_i32
 ; GCN-DAG: v_cmp_ge_i32
 
 ; GCN: s_cbranch_vccz
 ; GCN: s_setpc_b64
 
 ; GCN: s_endpgm
 define amdgpu_kernel void @long_branch_hang(i32 addrspace(1)* nocapture %arg, i32 %arg1, i32 %arg2, i32 %arg3, i32 %arg4, i64 %arg5) #0 {

llvm/test/CodeGen/AMDGPU/indirect-addressing-si.ll

 ; IDXMODE: s_set_gpr_idx_on
 ; IDXMODE: v_mov_b32_e32
 ; IDXMODE: s_set_gpr_idx_off
 
 ; GCN: s_cbranch_execnz [[REGLOOP]]
 
 ; GCN: {{^; %bb.[0-9]}}:
 ; GCN: s_mov_b64 exec,
-; GCN: s_cbranch_vccnz [[BB2]]
+; GCN: s_cbranch_execnz [[BB2]]
 
 define amdgpu_kernel void @broken_phi_bb(i32 %arg, i32 %arg1) #0 {
 bb:
   br label %bb2
 
 bb2:                                              ; preds = %bb4, %bb
   %tmp = phi i32 [ 8, %bb ], [ %tmp7, %bb4 ]
   %tmp3 = icmp slt i32 %tmp, %arg

llvm/test/CodeGen/AMDGPU/infinite-loop.ll

 ; SI-NEXT:    v_mov_b32_e32 v0, 0x3e7
 ; SI-NEXT:    s_waitcnt lgkmcnt(0)
 ; SI-NEXT:    buffer_store_dword v0, off, s[4:7], 0
 ; SI-NEXT:    s_andn2_b64 exec, exec, s[2:3]
 ; SI-NEXT:    s_cbranch_execnz BB3_3
 ; SI-NEXT:  ; %bb.4: ; %loop.exit.guard
 ; SI-NEXT:    ; in Loop: Header=BB3_2 Depth=1
 ; SI-NEXT:    s_or_b64 exec, exec, s[2:3]
 ; SI-NEXT:    s_and_b64 vcc, exec, 0
-; SI-NEXT:    s_cbranch_vccz BB3_2
+; SI-NEXT:    s_branch BB3_2
 ; SI-NEXT:  BB3_5: ; %UnifiedReturnBlock
 ; SI-NEXT:    s_endpgm
 ; IR-LABEL: @infinite_loop_nest_ret(
 ; IR-NEXT:  entry:
 ; IR-NEXT:    [[TMP:%.*]] = tail call i32 @llvm.amdgcn.workitem.id.x()
 ; IR-NEXT:    [[COND1:%.*]] = icmp eq i32 [[TMP]], 1
 ; IR-NEXT:    br i1 [[COND1]], label [[OUTER_LOOP:%.*]], label [[UNIFIEDRETURNBLOCK:%.*]]
 ; IR:       outer_loop:

llvm/test/CodeGen/AMDGPU/insert-skip-from-vcc.mir

bb.1:
     S_NOP 0
 
   bb.2:
     $sgpr0 = S_MOV_B32 -1
     $vcc_lo = S_AND_B32 $exec_lo, killed $sgpr0, implicit-def dead $scc
     S_CBRANCH_VCCZ %bb.1, implicit killed $vcc
     S_ENDPGM 0
 ...
+---
+# GCN-LABEL: name: andn2_execz_mov_vccz
+# GCN-NOT: S_MOV_
+# GCN-NOT: S_ANDN2_
+# GCN: S_CBRANCH_EXECZ %bb.1, implicit $exec
+name:            andn2_execz_mov_vccz
+body:             |
+  bb.0:
+    S_NOP 0
+
+  bb.1:
+    S_NOP 0
+
+  bb.2:
+    $sgpr0_sgpr1 = S_MOV_B64 0
+    $vcc = S_ANDN2_B64 $exec, killed $sgpr0_sgpr1, implicit-def dead $scc
+    S_CBRANCH_VCCZ %bb.1, implicit killed $vcc
+    S_ENDPGM 0
+...
+---
+# GCN-LABEL: name: andn2_branch_mov_vccz
+# GCN-NOT: S_MOV_
+# GCN-NOT: S_ANDN2_
+# GCN: S_BRANCH %bb.1
+name:            andn2_branch_mov_vccz
+body:             |
+  bb.0:
+    S_NOP 0
+
+  bb.1:
+    S_NOP 0
+
+  bb.2:
+    $sgpr0_sgpr1 = S_MOV_B64 -1
+    $vcc = S_ANDN2_B64 $exec, killed $sgpr0_sgpr1, implicit-def dead $scc
+    S_CBRANCH_VCCZ %bb.1, implicit killed $vcc
+    S_ENDPGM 0
+...
+---
+# GCN-LABEL: name: andn2_execnz_mov_vccnz
+# GCN-NOT: S_MOV_
+# GCN-NOT: S_ANDN2_
+# GCN: S_CBRANCH_EXECNZ %bb.1, implicit $exec
+name:            andn2_execnz_mov_vccnz
+body:             |
+  bb.0:
+    S_NOP 0
+
+  bb.1:
+    S_NOP 0
+
+  bb.2:
+    $sgpr0_sgpr1 = S_MOV_B64 0
+    $vcc = S_ANDN2_B64 $exec, killed $sgpr0_sgpr1, implicit-def dead $scc
+    S_CBRANCH_VCCNZ %bb.1, implicit killed $vcc
+    S_ENDPGM 0
+...
+---
+# GCN-LABEL: name: andn2_no_branch_mov_vccnz
+# GCN-NOT: S_MOV_
+# GCN-NOT: S_ANDN2_
+# GCN-NOT: S_CBRANCH
+# GCN-NOT: S_BRANCH
+name:            andn2_no_branch_mov_vccnz
+body:             |
+  bb.0:
+    S_NOP 0
+
+  bb.1:
+    S_NOP 0
+
+  bb.2:
+    $sgpr0_sgpr1 = S_MOV_B64 -1
+    $vcc = S_ANDN2_B64 $exec, killed $sgpr0_sgpr1, implicit-def dead $scc
+    S_CBRANCH_VCCNZ %bb.1, implicit killed $vcc
+    S_ENDPGM 0
+...

llvm/test/CodeGen/AMDGPU/insert_vector_elt.ll

 ; SI-NEXT:    s_load_dword s1, s[6:7], 0x1
 ; SI-NEXT:    s_mov_b64 s[2:3], 0
 ; SI-NEXT:    s_andn2_b64 vcc, exec, s[2:3]
 ; SI-NEXT:    s_waitcnt lgkmcnt(0)
 ; SI-NEXT:    s_mov_b64 vcc, vcc
 ; SI-NEXT:    s_cbranch_vccz BB26_3
 ; SI-NEXT:    s_branch BB26_4
 ; SI-NEXT:  BB26_2:
-; SI-NEXT:    s_mov_b64 s[2:3], -1
-; SI-NEXT:    s_andn2_b64 vcc, exec, s[2:3]
-; SI-NEXT:    s_cbranch_vccnz BB26_4
 ; SI-NEXT:  BB26_3: ; %if
 ; SI-NEXT:    s_load_dword s1, s[6:7], 0x0
 ; SI-NEXT:  BB26_4: ; %endif
 ; SI-NEXT:    s_waitcnt lgkmcnt(0)
 ; SI-NEXT:    v_mov_b32_e32 v0, s0
 ; SI-NEXT:    s_mov_b32 s7, 0x100f000
 ; SI-NEXT:    s_mov_b32 s6, -1
 ; SI-NEXT:    v_mov_b32_e32 v1, s1
 ; SI-NEXT:    buffer_store_dwordx2 v[0:1], off, s[4:7], 0
 ; SI-NEXT:    s_endpgm
 ;
 ; VI-LABEL: insert_split_bb:
 ; VI:       ; %bb.0: ; %entry
 ; VI-NEXT:    s_load_dword s0, s[4:5], 0x10
 ; VI-NEXT:    s_load_dwordx4 s[4:7], s[4:5], 0x0
 ; VI-NEXT:    s_waitcnt lgkmcnt(0)
 ; VI-NEXT:    s_cmp_lg_u32 s0, 0
 ; VI-NEXT:    s_cbranch_scc0 BB26_2
 ; VI-NEXT:  ; %bb.1: ; %else
 ; VI-NEXT:    s_load_dword s1, s[6:7], 0x4
-; VI-NEXT:    s_mov_b64 s[2:3], 0
-; VI-NEXT:    s_andn2_b64 vcc, exec, s[2:3]
-; VI-NEXT:    s_cbranch_vccz BB26_3
+; VI-NEXT:    s_cbranch_execz BB26_3
 ; VI-NEXT:    s_branch BB26_4
 ; VI-NEXT:  BB26_2:
-; VI-NEXT:    s_mov_b64 s[2:3], -1
-; VI-NEXT:    s_andn2_b64 vcc, exec, s[2:3]
-; VI-NEXT:    s_cbranch_vccnz BB26_4
 ; VI-NEXT:  BB26_3: ; %if
 ; VI-NEXT:    s_waitcnt lgkmcnt(0)
 ; VI-NEXT:    s_load_dword s1, s[6:7], 0x0
 ; VI-NEXT:  BB26_4: ; %endif
 ; VI-NEXT:    s_waitcnt lgkmcnt(0)
 ; VI-NEXT:    v_mov_b32_e32 v0, s0
 ; VI-NEXT:    s_mov_b32 s7, 0x1100f000
 ; VI-NEXT:    s_mov_b32 s6, -1

llvm/test/CodeGen/AMDGPU/multi-divergent-exit-region.ll

 
 ; GCN-LABEL: {{^}}uniform_branch_to_multi_divergent_region_exit_ret_ret_return_value:
 ; GCN: s_cmp_gt_i32 s0, 1
 ; GCN: s_cbranch_scc0 [[FLOW:BB[0-9]+_[0-9]+]]
 
 ; GCN: v_cmp_ne_u32_e32 vcc, 7, v0
 
 ; GCN: {{^}}[[FLOW]]:
-; GCN: s_cbranch_vccnz [[FLOW1:BB[0-9]+]]
 
 ; GCN: s_or_b64 exec, exec
 ; GCN: v_mov_b32_e32 v0, 2.0
 ; GCN-NOT: s_and_b64 exec, exec
 ; GCN: v_mov_b32_e32 v0, 1.0
 
 ; GCN: {{^BB[0-9]+_[0-9]+}}: ; %UnifiedReturnBlock
 ; GCN-NEXT: s_or_b64 exec, exec

llvm/test/CodeGen/AMDGPU/sgpr-control-flow.ll

 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc -march=amdgcn -mcpu=tahiti -verify-machineinstrs < %s | FileCheck -enable-var-scope -check-prefix=SI %s
 ;
 ; Most SALU instructions ignore control flow, so we need to make sure
 ; they don't overwrite values from other blocks.
 
 ; If the branch decision is made based on a value in an SGPR then all
 ; threads will execute the same code paths, so we don't need to worry
 ; about instructions in different blocks overwriting each other.
 
 define amdgpu_kernel void @sgpr_if_else_salu_br(i32 addrspace(1)* %out, i32 %a, i32 %b, i32 %c, i32 %d, i32 %e) {
 ; SI-LABEL: sgpr_if_else_salu_br:
 ; SI:       ; %bb.0: ; %entry
-; SI-NEXT:  s_load_dwordx4 s[4:7], s[0:1], 0xb
-; SI-NEXT:  s_load_dword s2, s[0:1], 0xf
-; SI-NEXT:  s_load_dwordx2 s[0:1], s[0:1], 0x9
-; SI-NEXT:  s_waitcnt lgkmcnt(0)
-; SI-NEXT:  s_cmp_lg_u32 s4, 0
-; SI-NEXT:  s_cbranch_scc0 BB0_2
-; SI-NEXT:; %bb.1:                                ; %else
-; SI-NEXT:  s_add_i32 s2, s7, s2
-; SI-NEXT:  s_mov_b64 s[8:9], 0
-; SI-NEXT:  s_andn2_b64 vcc, exec, s[8:9]
-; SI-NEXT:  s_cbranch_vccz BB0_3
-; SI-NEXT:  s_branch BB0_4
-; SI-NEXT:BB0_2:
-; SI-NEXT:  s_mov_b64 s[8:9], -1
-; SI-NEXT:                                        ; implicit-def: $sgpr2
-; SI-NEXT:  s_andn2_b64 vcc, exec, s[8:9]
-; SI-NEXT:  s_cbranch_vccnz BB0_4
-; SI-NEXT:BB0_3:                                  ; %if
-; SI-NEXT:  s_sub_i32 s2, s5, s6
-; SI-NEXT:BB0_4:                                  ; %endif
-; SI-NEXT:  s_add_i32 s4, s2, s4
-; SI-NEXT:  s_mov_b32 s3, 0xf000
-; SI-NEXT:  s_mov_b32 s2, -1
-; SI-NEXT:  v_mov_b32_e32 v0, s4
-; SI-NEXT:  buffer_store_dword v0, off, s[0:3], 0
-; SI-NEXT:  s_endpgm
+; SI-NEXT:    s_load_dwordx4 s[4:7], s[0:1], 0xb
+; SI-NEXT:    s_load_dword s2, s[0:1], 0xf
+; SI-NEXT:    s_load_dwordx2 s[0:1], s[0:1], 0x9
+; SI-NEXT:    s_waitcnt lgkmcnt(0)
+; SI-NEXT:    s_cmp_lg_u32 s4, 0
+; SI-NEXT:    s_cbranch_scc0 BB0_2
+; SI-NEXT:  ; %bb.1: ; %else
+; SI-NEXT:    s_add_i32 s2, s7, s2
+; SI-NEXT:    s_cbranch_execz BB0_3
+; SI-NEXT:    s_branch BB0_4
+; SI-NEXT:  BB0_2:
+; SI-NEXT:    ; implicit-def: $sgpr2
+; SI-NEXT:  BB0_3: ; %if
+; SI-NEXT:    s_sub_i32 s2, s5, s6
+; SI-NEXT:  BB0_4: ; %endif
+; SI-NEXT:    s_add_i32 s4, s2, s4
+; SI-NEXT:    s_mov_b32 s3, 0xf000
+; SI-NEXT:    s_mov_b32 s2, -1
+; SI-NEXT:    v_mov_b32_e32 v0, s4
+; SI-NEXT:    buffer_store_dword v0, off, s[0:3], 0
+; SI-NEXT:    s_endpgm
 entry:
   %0 = icmp eq i32 %a, 0
   br i1 %0, label %if, label %else
 
 if:
   %1 = sub i32 %b, %c
   br label %endif
 

 ; SI-NEXT:    s_waitcnt lgkmcnt(0)
 ; SI-NEXT:    s_cmp_lg_u32 s2, 0
 ; SI-NEXT:    s_cbranch_scc0 BB1_2
 ; SI-NEXT:  ; %bb.1: ; %else
 ; SI-NEXT:    s_load_dword s3, s[0:1], 0x2e
 ; SI-NEXT:    s_load_dword s6, s[0:1], 0x37
 ; SI-NEXT:    s_waitcnt lgkmcnt(0)
 ; SI-NEXT:    s_add_i32 s3, s3, s6
-; SI-NEXT:    s_mov_b64 s[6:7], 0
-; SI-NEXT:    s_andn2_b64 vcc, exec, s[6:7]
-; SI-NEXT:    s_cbranch_vccz BB1_3
+; SI-NEXT:    s_cbranch_execz BB1_3
 ; SI-NEXT:    s_branch BB1_4
 ; SI-NEXT:  BB1_2:
-; SI-NEXT:    s_mov_b64 s[6:7], -1
 ; SI-NEXT:    ; implicit-def: $sgpr3
-; SI-NEXT:    s_andn2_b64 vcc, exec, s[6:7]
-; SI-NEXT:    s_cbranch_vccnz BB1_4
 ; SI-NEXT:  BB1_3: ; %if
 ; SI-NEXT:    s_load_dword s3, s[0:1], 0x1c
 ; SI-NEXT:    s_load_dword s0, s[0:1], 0x25
 ; SI-NEXT:    s_waitcnt lgkmcnt(0)
 ; SI-NEXT:    s_add_i32 s3, s3, s0
 ; SI-NEXT:  BB1_4: ; %endif
 ; SI-NEXT:    s_add_i32 s0, s3, s2
 ; SI-NEXT:    s_mov_b32 s7, 0xf000

llvm/test/CodeGen/AMDGPU/wave32.ll

define amdgpu_gs void @test_kill_i1_terminator_i1(i32 %a, i32 %b, i32 %c, i32 %d) #0 {
   %x = or i1 %c1, %c2
   call void @llvm.amdgcn.kill(i1 %x)
   ret void
 }
 
 ; GCN-LABEL: {{^}}test_loop_vcc:
 ; GFX1032: v_cmp_lt_f32_e32 vcc_lo,
 ; GFX1064: v_cmp_lt_f32_e32 vcc,
-; GCN: s_cbranch_vccnz
+; GCN: s_cbranch_vccz
 define amdgpu_ps <4 x float> @test_loop_vcc(<4 x float> %in) #0 {
 entry:
   br label %loop
 
 loop:
   %ctr.iv = phi float [ 0.0, %entry ], [ %ctr.next, %body ]
   %c.iv = phi <4 x float> [ %in, %entry ], [ %c.next, %body ]
   %cc = fcmp ogt float %ctr.iv, 7.0

llvm/test/CodeGen/AMDGPU/wqm.ll

 ; CHECK-NEXT: s_mov_b64 [[LIVE:s\[[0-9]+:[0-9]+\]]], exec
 ; CHECK: s_wqm_b64 exec, exec
 ; CHECK: s_and_b64 exec, exec, [[LIVE]]
 ; CHECK: image_store
 ; CHECK: s_wqm_b64 exec, exec
 ; CHECK-DAG: v_mov_b32_e32 [[CTR:v[0-9]+]], 0
 ; CHECK-DAG: s_mov_b32 [[SEVEN:s[0-9]+]], 0x40e00000
 
-; CHECK: ; %body
+; CHECK: [[LOOPHDR:BB[0-9]+_[0-9]+]]: ; %body
 ; CHECK: v_add_f32_e32 [[CTR]], 2.0, [[CTR]]
-; CHECK: [[LOOPHDR:BB[0-9]+_[0-9]+]]: ; %loop
+; CHECK: [[LOOP:BB[0-9]+_[0-9]+]]: ; %loop
 ; CHECK: v_cmp_lt_f32_e32 vcc, [[SEVEN]], [[CTR]]
-; CHECK: s_cbranch_vccz
-
-; CHECK: s_cbranch_vccnz [[LOOPHDR]]
+; CHECK: s_cbranch_vccz [[LOOPHDR]]
 
 ; CHECK: ; %break
 ; CHECK: ; return
 define amdgpu_ps <4 x float> @test_loop_vcc(<4 x float> %in) nounwind {
 entry:
   call void @llvm.amdgcn.image.store.1d.v4f32.i32(<4 x float> %in, i32 15, i32 undef, <8 x i32> undef, i32 0, i32 0)
   br label %loop