From ba38e6c2aedf1787e90fa01a0f18c7ab22ddbb3e Mon Sep 17 00:00:00 2001 From: Matt Arsenault Date: Tue, 14 Jul 2015 18:20:33 +0000 Subject: [PATCH] AMDGPU: Avoid using 64-bit shift for i64 (shl x, 32) This can be done only with moves which theoretically will optimize better later. Although this transform increases the instruction count, it should be code size / cycle count neutral in the worst VALU case. It also seems to slightly improve a couple of testcases due to other DAG combines this exposes. This is probably slightly worse for the SALU case, so it might be better to handle this during moveToVALU, although then you lose some simplifications like the load width reducing in the simple testcase. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242177 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/AMDGPU/AMDGPUISelLowering.cpp | 34 ++++++++++++++++++++ lib/Target/AMDGPU/AMDGPUISelLowering.h | 1 + test/CodeGen/AMDGPU/array-ptr-calc-i64.ll | 5 +-- test/CodeGen/AMDGPU/mul_uint24.ll | 20 ++++++------ test/CodeGen/AMDGPU/shl.ll | 38 +++++++++++++++++++++-- test/CodeGen/AMDGPU/srl.ll | 35 +++++++++++++++++++-- 6 files changed, 117 insertions(+), 16 deletions(-) diff --git a/lib/Target/AMDGPU/AMDGPUISelLowering.cpp b/lib/Target/AMDGPU/AMDGPUISelLowering.cpp index 3b68a92cd5f..3a65f3b5614 100644 --- a/lib/Target/AMDGPU/AMDGPUISelLowering.cpp +++ b/lib/Target/AMDGPU/AMDGPUISelLowering.cpp @@ -406,6 +406,7 @@ AMDGPUTargetLowering::AMDGPUTargetLowering(TargetMachine &TM, setOperationAction(ISD::FNEARBYINT, MVT::f32, Custom); setOperationAction(ISD::FNEARBYINT, MVT::f64, Custom); + setTargetDAGCombine(ISD::SHL); setTargetDAGCombine(ISD::MUL); setTargetDAGCombine(ISD::SELECT); setTargetDAGCombine(ISD::SELECT_CC); @@ -2415,6 +2416,33 @@ SDValue AMDGPUTargetLowering::performStoreCombine(SDNode *N, SN->getBasePtr(), SN->getMemOperand()); } +SDValue AMDGPUTargetLowering::performShlCombine(SDNode *N, + DAGCombinerInfo &DCI) const { + if (N->getValueType(0) != MVT::i64) + return SDValue(); + + // i64 (shl x, 32) -> (build_pair 0, x) + + // Doing this with moves theoretically helps MI optimizations that understand + // copies. 2 v_mov_b32_e32 will have the same code size / cycle count as + // v_lshl_b64. In the SALU case, I think this is slightly worse since it + // doubles the code size and I'm unsure about cycle count. + const ConstantSDNode *RHS = dyn_cast(N->getOperand(1)); + if (!RHS || RHS->getZExtValue() != 32) + return SDValue(); + + SDValue LHS = N->getOperand(0); + + SDLoc SL(N); + SelectionDAG &DAG = DCI.DAG; + + // Extract low 32-bits. + SDValue Lo = DAG.getNode(ISD::TRUNCATE, SL, MVT::i32, LHS); + + const SDValue Zero = DAG.getConstant(0, SL, MVT::i32); + return DAG.getNode(ISD::BUILD_PAIR, SL, MVT::i64, Zero, Lo); +} + SDValue AMDGPUTargetLowering::performMulCombine(SDNode *N, DAGCombinerInfo &DCI) const { EVT VT = N->getValueType(0); @@ -2454,6 +2482,12 @@ SDValue AMDGPUTargetLowering::PerformDAGCombine(SDNode *N, switch(N->getOpcode()) { default: break; + case ISD::SHL: { + if (DCI.getDAGCombineLevel() < AfterLegalizeDAG) + break; + + return performShlCombine(N, DCI); + } case ISD::MUL: return performMulCombine(N, DCI); case AMDGPUISD::MUL_I24: diff --git a/lib/Target/AMDGPU/AMDGPUISelLowering.h b/lib/Target/AMDGPU/AMDGPUISelLowering.h index bba303d3e4b..478b2035fd7 100644 --- a/lib/Target/AMDGPU/AMDGPUISelLowering.h +++ b/lib/Target/AMDGPU/AMDGPUISelLowering.h @@ -65,6 +65,7 @@ private: SDValue LowerSIGN_EXTEND_INREG(SDValue Op, SelectionDAG &DAG) const; SDValue performStoreCombine(SDNode *N, DAGCombinerInfo &DCI) const; + SDValue performShlCombine(SDNode *N, DAGCombinerInfo &DCI) const; SDValue performMulCombine(SDNode *N, DAGCombinerInfo &DCI) const; protected: diff --git a/test/CodeGen/AMDGPU/array-ptr-calc-i64.ll b/test/CodeGen/AMDGPU/array-ptr-calc-i64.ll index eae095eb844..a3ae3c3aea1 100644 --- a/test/CodeGen/AMDGPU/array-ptr-calc-i64.ll +++ b/test/CodeGen/AMDGPU/array-ptr-calc-i64.ll @@ -3,8 +3,9 @@ declare i32 @llvm.SI.tid() readnone ; SI-LABEL: {{^}}test_array_ptr_calc: -; SI: v_mul_lo_i32 -; SI: v_mul_hi_i32 +; SI-DAG: v_mul_lo_i32 +; SI-DAG: v_mul_hi_i32 +; SI: s_endpgm define void @test_array_ptr_calc(i32 addrspace(1)* noalias %out, [1025 x i32] addrspace(1)* noalias %inA, i32 addrspace(1)* noalias %inB) { %tid = call i32 @llvm.SI.tid() readnone %a_ptr = getelementptr [1025 x i32], [1025 x i32] addrspace(1)* %inA, i32 %tid, i32 0 diff --git a/test/CodeGen/AMDGPU/mul_uint24.ll b/test/CodeGen/AMDGPU/mul_uint24.ll index e640a7cd69f..8a0e71d739b 100644 --- a/test/CodeGen/AMDGPU/mul_uint24.ll +++ b/test/CodeGen/AMDGPU/mul_uint24.ll @@ -52,16 +52,18 @@ entry: ; FUNC_LABEL: {{^}}mul24_i64: ; EG; MUL_UINT24 ; EG: MULHI -; SI: v_mul_u32_u24 ; FIXME: SI support 24-bit mulhi -; SI: v_mul_hi_u32 -define void @mul24_i64(i64 addrspace(1)* %out, i64 %a, i64 %b) { + +; SI-DAG: v_mul_u32_u24 +; SI-DAG: v_mul_hi_u32 +; SI: s_endpgm +define void @mul24_i64(i64 addrspace(1)* %out, i64 %a, i64 %b, i64 %c) { entry: - %0 = shl i64 %a, 40 - %a_24 = lshr i64 %0, 40 - %1 = shl i64 %b, 40 - %b_24 = lshr i64 %1, 40 - %2 = mul i64 %a_24, %b_24 - store i64 %2, i64 addrspace(1)* %out + %tmp0 = shl i64 %a, 40 + %a_24 = lshr i64 %tmp0, 40 + %tmp1 = shl i64 %b, 40 + %b_24 = lshr i64 %tmp1, 40 + %tmp2 = mul i64 %a_24, %b_24 + store i64 %tmp2, i64 addrspace(1)* %out ret void } diff --git a/test/CodeGen/AMDGPU/shl.ll b/test/CodeGen/AMDGPU/shl.ll index 53b63dc4b8a..6f81a39ed96 100644 --- a/test/CodeGen/AMDGPU/shl.ll +++ b/test/CodeGen/AMDGPU/shl.ll @@ -1,6 +1,9 @@ -;RUN: llc < %s -march=r600 -mcpu=redwood | FileCheck --check-prefix=EG %s -;RUN: llc < %s -march=amdgcn -mcpu=verde -verify-machineinstrs | FileCheck --check-prefix=SI %s -;RUN: llc < %s -march=amdgcn -mcpu=tonga -verify-machineinstrs | FileCheck --check-prefix=VI %s +; RUN: llc < %s -march=r600 -mcpu=redwood | FileCheck --check-prefix=EG %s +; RUN: llc < %s -march=amdgcn -mcpu=verde -verify-machineinstrs | FileCheck -check-prefix=GCN -check-prefix=SI %s +; XUN: llc < %s -march=amdgcn -mcpu=tonga -verify-machineinstrs | FileCheck -check-prefix=GCN -check-prefix=VI %s + +declare i32 @llvm.r600.read.tidig.x() #0 + ;EG: {{^}}shl_v2i32: ;EG: LSHL {{\*? *}}T{{[0-9]+\.[XYZW], T[0-9]+\.[XYZW], T[0-9]+\.[XYZW]}} @@ -178,3 +181,32 @@ define void @shl_v4i64(<4 x i64> addrspace(1)* %out, <4 x i64> addrspace(1)* %in store <4 x i64> %result, <4 x i64> addrspace(1)* %out ret void } + +; Make sure load width gets reduced to i32 load. +; GCN-LABEL: {{^}}s_shl_32_i64: +; GCN-DAG: s_load_dword [[LO_A:s[0-9]+]], s{{\[[0-9]+:[0-9]+\]}}, 0xb{{$}} +; GCN-DAG: s_mov_b32 s[[SLO:[0-9]+]], 0{{$}} +; GCN-DAG: v_mov_b32_e32 v[[VLO:[0-9]+]], s[[SLO]] +; GCN-DAG: v_mov_b32_e32 v[[VHI:[0-9]+]], [[LO_A]] +; GCN: buffer_store_dwordx2 v{{\[}}[[VLO]]:[[VHI]]{{\]}} +define void @s_shl_32_i64(i64 addrspace(1)* %out, i64 %a) { + %result = shl i64 %a, 32 + store i64 %result, i64 addrspace(1)* %out + ret void +} + +; GCN-LABEL: {{^}}v_shl_32_i64: +; GCN-DAG: buffer_load_dword v[[LO_A:[0-9]+]], +; GCN-DAG: v_mov_b32_e32 v[[VLO:[0-9]+]], 0{{$}} +; GCN: buffer_store_dwordx2 v{{\[}}[[VLO]]:[[LO_A]]{{\]}} +define void @v_shl_32_i64(i64 addrspace(1)* %out, i64 addrspace(1)* %in) { + %tid = call i32 @llvm.r600.read.tidig.x() #0 + %gep.in = getelementptr i64, i64 addrspace(1)* %in, i32 %tid + %gep.out = getelementptr i64, i64 addrspace(1)* %out, i32 %tid + %a = load i64, i64 addrspace(1)* %gep.in + %result = shl i64 %a, 32 + store i64 %result, i64 addrspace(1)* %gep.out + ret void +} + +attributes #0 = { nounwind readnone } diff --git a/test/CodeGen/AMDGPU/srl.ll b/test/CodeGen/AMDGPU/srl.ll index 4904d7fa1bd..0dad91e709d 100644 --- a/test/CodeGen/AMDGPU/srl.ll +++ b/test/CodeGen/AMDGPU/srl.ll @@ -1,7 +1,9 @@ -; RUN: llc -march=amdgcn -mcpu=verde -verify-machineinstrs < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s -; RUN: llc -march=amdgcn -mcpu=tonga -verify-machineinstrs < %s | FileCheck -check-prefix=VI -check-prefix=FUNC %s +; RUN: llc -march=amdgcn -mcpu=verde -verify-machineinstrs < %s | FileCheck -check-prefix=SI -check-prefix=GCN -check-prefix=FUNC %s +; XUN: llc -march=amdgcn -mcpu=tonga -verify-machineinstrs < %s | FileCheck -check-prefix=VI -check-prefix=GCN -check-prefix=FUNC %s ; RUN: llc -march=r600 -mcpu=redwood < %s | FileCheck -check-prefix=EG -check-prefix=FUNC %s +declare i32 @llvm.r600.read.tidig.x() #0 + ; FUNC-LABEL: {{^}}lshr_i32: ; SI: v_lshrrev_b32_e32 v{{[0-9]+, v[0-9]+, v[0-9]+}} ; VI: v_lshrrev_b32_e32 v{{[0-9]+, v[0-9]+, v[0-9]+}} @@ -184,3 +186,32 @@ define void @lshr_v4i64(<4 x i64> addrspace(1)* %out, <4 x i64> addrspace(1)* %i store <4 x i64> %result, <4 x i64> addrspace(1)* %out ret void } + +; Make sure load width gets reduced to i32 load. +; GCN-LABEL: {{^}}s_lshr_32_i64: +; GCN-DAG: s_load_dword [[HI_A:s[0-9]+]], s{{\[[0-9]+:[0-9]+\]}}, 0xc{{$}} +; GCN-DAG: s_mov_b32 s[[SHI:[0-9]+]], 0{{$}} +; GCN-DAG: v_mov_b32_e32 v[[VHI:[0-9]+]], s[[SHI]] +; GCN-DAG: v_mov_b32_e32 v[[VLO:[0-9]+]], [[HI_A]] +; GCN: buffer_store_dwordx2 v{{\[}}[[VLO]]:[[VHI]]{{\]}} +define void @s_lshr_32_i64(i64 addrspace(1)* %out, i64 %a) { + %result = lshr i64 %a, 32 + store i64 %result, i64 addrspace(1)* %out + ret void +} + +; GCN-LABEL: {{^}}v_lshr_32_i64: +; GCN-DAG: buffer_load_dword v[[HI_A:[0-9]+]], v{{\[[0-9]+:[0-9]+\]}}, s{{\[[0-9]+:[0-9]+\]}}, 0 addr64 offset:4 +; GCN-DAG: v_mov_b32_e32 v[[VHI:[0-9]+]], 0{{$}} +; GCN: buffer_store_dwordx2 v{{\[}}[[HI_A]]:[[VHI]]{{\]}} +define void @v_lshr_32_i64(i64 addrspace(1)* %out, i64 addrspace(1)* %in) { + %tid = call i32 @llvm.r600.read.tidig.x() #0 + %gep.in = getelementptr i64, i64 addrspace(1)* %in, i32 %tid + %gep.out = getelementptr i64, i64 addrspace(1)* %out, i32 %tid + %a = load i64, i64 addrspace(1)* %gep.in + %result = lshr i64 %a, 32 + store i64 %result, i64 addrspace(1)* %gep.out + ret void +} + +attributes #0 = { nounwind readnone } -- 2.34.1