Index: lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp =================================================================== --- lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp +++ lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp @@ -1639,16 +1639,13 @@ return; } - if (isCBranchSCC(N)) { - // This brcond will use S_CBRANCH_SCC*, so let tablegen handle it. - SelectCode(N); - return; - } - + bool UseSCCBr = isCBranchSCC(N) && isUniformBr(N); + unsigned BrOp = UseSCCBr ? AMDGPU::S_CBRANCH_SCC1 : AMDGPU::S_CBRANCH_VCCNZ; + unsigned CondReg = UseSCCBr ? AMDGPU::SCC : AMDGPU::VCC; SDLoc SL(N); - SDValue VCC = CurDAG->getCopyToReg(N->getOperand(0), SL, AMDGPU::VCC, Cond); - CurDAG->SelectNodeTo(N, AMDGPU::S_CBRANCH_VCCNZ, MVT::Other, + SDValue VCC = CurDAG->getCopyToReg(N->getOperand(0), SL, CondReg, Cond); + CurDAG->SelectNodeTo(N, BrOp, MVT::Other, N->getOperand(2), // Basic Block VCC.getValue(0)); } Index: lib/Target/AMDGPU/SIInstrInfo.td =================================================================== --- lib/Target/AMDGPU/SIInstrInfo.td +++ lib/Target/AMDGPU/SIInstrInfo.td @@ -232,16 +232,6 @@ return true; }]>; -def si_uniform_br : PatFrag < - (ops node:$cond, node:$bb), (brcond node:$cond, node:$bb), [{ - return isUniformBr(N); -}]>; - -def si_uniform_br_scc : PatFrag < - (ops node:$cond, node:$bb), (si_uniform_br node:$cond, node:$bb), [{ - return isCBranchSCC(N); -}]>; - def lshr_rev : PatFrag < (ops node:$src1, node:$src0), (srl $src0, $src1) Index: lib/Target/AMDGPU/SOPInstructions.td =================================================================== --- lib/Target/AMDGPU/SOPInstructions.td +++ lib/Target/AMDGPU/SOPInstructions.td @@ -817,8 +817,7 @@ >; def S_CBRANCH_SCC1 : SOPP < 0x00000005, (ins sopp_brtarget:$simm16), - "s_cbranch_scc1 $simm16", - [(si_uniform_br_scc SCC, bb:$simm16)] + "s_cbranch_scc1 $simm16" >; } // End Uses = [SCC] Index: test/CodeGen/AMDGPU/control-flow-optnone.ll =================================================================== --- /dev/null +++ test/CodeGen/AMDGPU/control-flow-optnone.ll @@ -0,0 +1,54 @@ +; RUN: llc -mtriple=amdgcn-amd-amdhsa -verify-machineinstrs < %s | FileCheck -check-prefix=GCN %s + +; optnone disables AMDGPUAnnotateUniformValues, so no branch is known +; to be uniform during instruction selection. The custom selection for +; brcond was not checking if the branch was uniform, relying on the +; selection pattern to check that. That would fail, so then the branch +; would fail to select. + +; GCN-LABEL: {{^}}copytoreg_divergent_brcond: +; GCN: s_branch + +; GCN-DAG: v_cmp_lt_i32 +; GCN-DAG: v_cmp_gt_i32 +; GCN: s_and_b64 +; GCN: s_and_saveexec_b64 + +; GCN: s_or_b64 exec, exec +; GCN: v_cmp_eq_u32 +; GCN: s_cbranch_vccnz +; GCN-NEXT: s_branch +define amdgpu_kernel void @copytoreg_divergent_brcond(i32 %arg, i32 %arg1, i32 %arg2) #0 { +bb: + %tmp = tail call i32 @llvm.amdgcn.workitem.id.x() + %tmp3 = zext i32 %tmp to i64 + %tmp5 = add i64 %tmp3, undef + %tmp6 = trunc i64 %tmp5 to i32 + %tmp7 = mul nsw i32 %tmp6, %arg2 + br label %bb8 + +bb8.loopexit: ; preds = %bb14 + br label %bb8 + +bb8: ; preds = %bb8.loopexit, %bb + br label %bb9 + +bb9: ; preds = %bb14, %bb8 + %tmp10 = icmp slt i32 %tmp7, %arg1 + %tmp11 = icmp sgt i32 %arg, 0 + %tmp12 = and i1 %tmp10, %tmp11 + br i1 %tmp12, label %bb13, label %bb14 + +bb13: ; preds = %bb9 + store volatile i32 0, i32 addrspace(1)* undef, align 4 + br label %bb14 + +bb14: ; preds = %bb13, %bb9 + %tmp15 = icmp eq i32 %arg2, 1 + br i1 %tmp15, label %bb8.loopexit, label %bb9 +} + +declare i32 @llvm.amdgcn.workitem.id.x() #1 + +attributes #0 = { nounwind optnone noinline } +attributes #1 = { nounwind readnone speculatable }