[AMDGPU] add missing checks in processBaseWithConstOffset

llvm/lib/Target/AMDGPU/SILoadStoreOptimizer.cpp

@@ -2117,6 +2117,9 @@ void SILoadStoreOptimizer::processBaseWithConstOffset(const MachineOperand &Base
     BaseLo = *Src0;
   }
 
+  if (!BaseLo.isReg())
+    return;
+
   Src0 = TII->getNamedOperand(*BaseHiDef, AMDGPU::OpName::src0);
   Src1 = TII->getNamedOperand(*BaseHiDef, AMDGPU::OpName::src1);
 
@@ -2129,6 +2132,9 @@ void SILoadStoreOptimizer::processBaseWithConstOffset(const MachineOperand &Base
   uint64_t Offset1 = Src1->getImm();
   BaseHi = *Src0;
 
+  if (!BaseHi.isReg())
+    return;
+
   Addr.Base.LoReg = BaseLo.getReg();
   Addr.Base.HiReg = BaseHi.getReg();
   Addr.Base.LoSubReg = BaseLo.getSubReg();

llvm/test/CodeGen/AMDGPU/promote-constOffset-to-imm.ll

@@ -2562,4 +2562,99 @@ entry:
   ret void
 }
 
+define amdgpu_kernel void @negativeoffsetnullptr(ptr %buffer) {
+; GFX8-LABEL: negativeoffsetnullptr:
+; GFX8:       ; %bb.0: ; %entry
+; GFX8-NEXT:    s_load_dword s1, s[2:3], 0xec
+; GFX8-NEXT:    s_add_u32 s0, 0, -1
+; GFX8-NEXT:    s_waitcnt lgkmcnt(0)
+; GFX8-NEXT:    s_addc_u32 s1, s1, -1
+; GFX8-NEXT:    v_mov_b32_e32 v0, s0
+; GFX8-NEXT:    v_mov_b32_e32 v1, s1
+; GFX8-NEXT:    flat_load_ubyte v0, v[0:1]
+; GFX8-NEXT:    s_mov_b64 s[0:1], 0
+; GFX8-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX8-NEXT:    v_cmp_eq_u16_e32 vcc, 0, v0
+; GFX8-NEXT:  .LBB8_1: ; %branch
+; GFX8-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX8-NEXT:    s_and_b64 s[2:3], exec, vcc
+; GFX8-NEXT:    s_or_b64 s[0:1], s[2:3], s[0:1]
+; GFX8-NEXT:    s_andn2_b64 exec, exec, s[0:1]
+; GFX8-NEXT:    s_cbranch_execnz .LBB8_1
+; GFX8-NEXT:  ; %bb.2: ; %end
+; GFX8-NEXT:    s_endpgm
+;
+; GFX9-LABEL: negativeoffsetnullptr:
+; GFX9:       ; %bb.0: ; %entry
+; GFX9-NEXT:    s_mov_b64 s[0:1], src_private_base
+; GFX9-NEXT:    v_mov_b32_e32 v1, s1
+; GFX9-NEXT:    v_add_co_u32_e64 v0, vcc, -1, 0
+; GFX9-NEXT:    v_addc_co_u32_e32 v1, vcc, -1, v1, vcc
+; GFX9-NEXT:    flat_load_ubyte v0, v[0:1]
+; GFX9-NEXT:    s_mov_b64 s[0:1], 0
+; GFX9-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX9-NEXT:    v_cmp_eq_u16_e32 vcc, 0, v0
+; GFX9-NEXT:  .LBB8_1: ; %branch
+; GFX9-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX9-NEXT:    s_and_b64 s[2:3], exec, vcc
+; GFX9-NEXT:    s_or_b64 s[0:1], s[2:3], s[0:1]
+; GFX9-NEXT:    s_andn2_b64 exec, exec, s[0:1]
+; GFX9-NEXT:    s_cbranch_execnz .LBB8_1
+; GFX9-NEXT:  ; %bb.2: ; %end
+; GFX9-NEXT:    s_endpgm
+;
+; GFX10-LABEL: negativeoffsetnullptr:
+; GFX10:       ; %bb.0: ; %entry
+; GFX10-NEXT:    s_mov_b64 s[0:1], src_private_base
+; GFX10-NEXT:    s_add_u32 s0, 0, -1
+; GFX10-NEXT:    s_addc_u32 s1, s1, -1
+; GFX10-NEXT:    v_mov_b32_e32 v0, s0
+; GFX10-NEXT:    v_mov_b32_e32 v1, s1
+; GFX10-NEXT:    s_mov_b32 s0, 0
+; GFX10-NEXT:    flat_load_ubyte v0, v[0:1]
+; GFX10-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX10-NEXT:    v_cmp_eq_u16_e32 vcc_lo, 0, v0
+; GFX10-NEXT:  .LBB8_1: ; %branch
+; GFX10-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX10-NEXT:    s_and_b32 s1, exec_lo, vcc_lo
+; GFX10-NEXT:    s_or_b32 s0, s1, s0
+; GFX10-NEXT:    s_andn2_b32 exec_lo, exec_lo, s0
+; GFX10-NEXT:    s_cbranch_execnz .LBB8_1
+; GFX10-NEXT:  ; %bb.2: ; %end
+; GFX10-NEXT:    s_endpgm
+;
+; GFX11-LABEL: negativeoffsetnullptr:
+; GFX11:       ; %bb.0: ; %entry
+; GFX11-NEXT:    s_mov_b64 s[0:1], src_private_base
+; GFX11-NEXT:    v_add_co_u32 v0, s0, -1, 0
+; GFX11-NEXT:    s_delay_alu instid0(VALU_DEP_1)
+; GFX11-NEXT:    v_add_co_ci_u32_e64 v1, null, -1, s1, s0
+; GFX11-NEXT:    s_mov_b32 s0, 0
+; GFX11-NEXT:    flat_load_u8 v0, v[0:1]
+; GFX11-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
+; GFX11-NEXT:    v_cmp_eq_u16_e32 vcc_lo, 0, v0
+; GFX11-NEXT:  .LBB8_1: ; %branch
+; GFX11-NEXT:    ; =>This Inner Loop Header: Depth=1
+; GFX11-NEXT:    s_and_b32 s1, exec_lo, vcc_lo
+; GFX11-NEXT:    s_delay_alu instid0(SALU_CYCLE_1) | instskip(NEXT) | instid1(SALU_CYCLE_1)
+; GFX11-NEXT:    s_or_b32 s0, s1, s0
+; GFX11-NEXT:    s_and_not1_b32 exec_lo, exec_lo, s0
+; GFX11-NEXT:    s_cbranch_execnz .LBB8_1
+; GFX11-NEXT:  ; %bb.2: ; %end
+; GFX11-NEXT:    s_endpgm
+entry:
+  %null = select i1 false, ptr %buffer, ptr addrspacecast (ptr addrspace(5) null to ptr)
+  %gep = getelementptr i8, ptr %null, i64 -1
+  %ld = load i8, ptr %gep
+  %cmp = icmp eq i8 %ld, 0
+  br label %branch
+
+branch:
+  br i1 %cmp, label %end, label %branch
+
+end:
+  ret void
+}
+
+
 attributes #0 = { nounwind "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "target-cpu"="fiji" "uniform-work-group-size"="false" }

llvm/test/CodeGen/AMDGPU/promote-constOffset-to-imm.mir

@@ -447,3 +447,33 @@ body:             |
     %13:vreg_64 = REG_SEQUENCE %9, %subreg.sub0, %11, %subreg.sub1
     %15:vgpr_32 = FLAT_ATOMIC_ADD_RTN %13:vreg_64, %0.sub0, 0, 0, implicit $exec, implicit $flat_scr
 ...
+
+---
+# GCN-LABEL: name: negative_offset_nullptr
+# GCN: V_ADD_CO_U32_e64 -1, 0, 0
+# GCN: V_ADDC_U32_e64 -1, %{{[0-9]+}}, %{{[0-9]+}}, 0
+
+name:            negative_offset_nullptr
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:  
+    %15:sreg_64 = S_MOV_B64 $src_private_base
+    %17:sreg_32 = S_MOV_B32 0
+    %18:sreg_64 = REG_SEQUENCE %17, %subreg.sub0, %15.sub1, %subreg.sub1
+    %21:vgpr_32, %22:sreg_64_xexec = V_ADD_CO_U32_e64 -1, 0, 0, implicit $exec
+    %28:vgpr_32 = COPY %18.sub1
+    %25:vgpr_32, %26:sreg_64 = V_ADDC_U32_e64 -1, %28, %22, 0, implicit $exec
+    %29:vreg_64 = REG_SEQUENCE %21, %subreg.sub0, %25, %subreg.sub1
+    %30:vgpr_32 = FLAT_LOAD_UBYTE %29, 0, 0, implicit $exec, implicit $flat_scr
+    %32:sreg_64 = V_CMP_EQ_U16_e64 %30, 0, implicit $exec
+    %14:sreg_64 = S_MOV_B64 0
+
+  bb.1:  
+    %1:sreg_64 = PHI %14, %bb.0, %2, %bb.1
+    %2:sreg_64 = SI_IF_BREAK %32, %1, implicit-def dead $scc
+    SI_LOOP %2, %bb.1, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
+    S_BRANCH %bb.2
+
+  bb.2:
+    SI_END_CF %2, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
+    S_ENDPGM 0