diff --git a/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp b/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp index e065b104db4eb3..d0a81673d6528c 100644 --- a/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp +++ b/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp @@ -2432,10 +2432,13 @@ bool SIRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator MI, if (Offset == 0) { unsigned OpCode = IsSALU && !LiveSCC ? AMDGPU::S_LSHR_B32 : AMDGPU::V_LSHRREV_B32_e64; - // XXX - This never happens because of emergency scavenging slot at 0? - auto Shift = BuildMI(*MBB, MI, DL, TII->get(OpCode), ResultReg) - .addImm(ST.getWavefrontSizeLog2()) - .addReg(FrameReg); + auto Shift = BuildMI(*MBB, MI, DL, TII->get(OpCode), ResultReg); + if (OpCode == AMDGPU::V_LSHRREV_B32_e64) + // For V_LSHRREV, the operands are reversed (the shift count goes + // first). + Shift.addImm(ST.getWavefrontSizeLog2()).addReg(FrameReg); + else + Shift.addReg(FrameReg).addImm(ST.getWavefrontSizeLog2()); if (IsSALU && !LiveSCC) Shift.getInstr()->getOperand(3).setIsDead(); // Mark SCC as dead. if (IsSALU && LiveSCC) { diff --git a/llvm/test/CodeGen/AMDGPU/frame-index.mir b/llvm/test/CodeGen/AMDGPU/frame-index.mir index 31bc2b04dde8c1..d8736c5276a26d 100644 --- a/llvm/test/CodeGen/AMDGPU/frame-index.mir +++ b/llvm/test/CodeGen/AMDGPU/frame-index.mir @@ -53,7 +53,7 @@ body: | ; GCN-LABEL: name: func_add_constant_to_fi_uniform_i32 ; GCN: liveins: $sgpr30_sgpr31 ; GCN-NEXT: {{ $}} - ; GCN-NEXT: $sgpr0 = S_LSHR_B32 6, $sgpr32, implicit-def dead $scc + ; GCN-NEXT: $sgpr0 = S_LSHR_B32 $sgpr32, 6, implicit-def dead $scc ; GCN-NEXT: renamable $sgpr4 = nuw S_ADD_I32 killed $sgpr0, 4, implicit-def dead $scc ; GCN-NEXT: renamable $vgpr0 = COPY killed renamable $sgpr4, implicit $exec ; GCN-NEXT: $m0 = S_MOV_B32 -1 @@ -89,7 +89,7 @@ body: | ; GCN-LABEL: name: func_add_constant_to_fi_uniform_SCC_clobber_i32 ; GCN: liveins: $sgpr30_sgpr31 ; GCN-NEXT: {{ $}} - ; GCN-NEXT: $sgpr0 = S_LSHR_B32 6, $sgpr32, implicit-def dead $scc + ; GCN-NEXT: $sgpr0 = S_LSHR_B32 $sgpr32, 6, implicit-def dead $scc ; GCN-NEXT: renamable $sgpr4 = nuw S_ADD_U32 killed $sgpr0, 4, implicit-def $scc ; GCN-NEXT: renamable $sgpr5 = S_ADDC_U32 $sgpr4, 1234567, implicit-def $scc, implicit $scc ; GCN-NEXT: $sgpr0 = S_LSHR_B32 $sgpr32, 6, implicit-def $scc