[llvm] r296009 - Correct register pressure calculation in presence of subregs
Rui Ueyama via llvm-commits
llvm-commits at lists.llvm.org
Thu Feb 23 12:50:27 PST 2017
Hi,
This seems to have caused this warnings. Can you take a look?
Building CXX object /ssd/b/lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.
dir/SIOptimizeExecMasking.cpp.o
In file included from /ssd/llvm-project/llvm/lib/Target/AMDGPU/
SIOptimizeExecMasking.cpp:11:
In file included from //ssd/llvm-project/llvm/lib/
Target/AMDGPU/AMDGPUSubtarget.h:22:
In file included from //ssd/llvm-project/llvm/lib/
Target/AMDGPU/SIInstrInfo.h:21:
//ssd/llvm-project/llvm/lib/Target/AMDGPU/SIRegisterInfo.h:231:12: warning:
'llvm::SIRegisterInfo::getRegUnitWeight' hides overloaded virtual function
[-Woverloaded-virtual]
unsigned getRegUnitWeight(const MachineRegisterInfo &MRI,
^
//ssd/b/lib/Target/AMDGPU/AMDGPUGenRegisterInfo.inc:17362:12: note: hidden
overloaded virtual function 'llvm::AMDGPUGenRegisterInfo::getRegUnitWeight'
declared here: different number of parameters (1 vs 3)
unsigned getRegUnitWeight(unsigned RegUnit) const override;
^
1 warning generated.
On Thu, Feb 23, 2017 at 12:19 PM, Stanislav Mekhanoshin via llvm-commits <
llvm-commits at lists.llvm.org> wrote:
> Author: rampitec
> Date: Thu Feb 23 14:19:44 2017
> New Revision: 296009
>
> URL: http://llvm.org/viewvc/llvm-project?rev=296009&view=rev
> Log:
> Correct register pressure calculation in presence of subregs
>
> If a subreg is used in an instruction it counts as a whole superreg
> for the purpose of register pressure calculation. This patch corrects
> improper register pressure calculation by examining operand's lane mask.
>
> Differential Revision: https://reviews.llvm.org/D29835
>
> Added:
> llvm/trunk/test/CodeGen/AMDGPU/schedule-regpressure-subregs.mir
> Modified:
> llvm/trunk/include/llvm/CodeGen/RegisterPressure.h
> llvm/trunk/include/llvm/Target/TargetRegisterInfo.h
> llvm/trunk/lib/CodeGen/MachineScheduler.cpp
> llvm/trunk/lib/CodeGen/RegisterPressure.cpp
> llvm/trunk/lib/CodeGen/TargetRegisterInfo.cpp
> llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.cpp
> llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.h
> llvm/trunk/test/CodeGen/AMDGPU/load-global-i32.ll
>
> Modified: llvm/trunk/include/llvm/CodeGen/RegisterPressure.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/
> llvm/CodeGen/RegisterPressure.h?rev=296009&r1=296008&r2=296009&view=diff
> ============================================================
> ==================
> --- llvm/trunk/include/llvm/CodeGen/RegisterPressure.h (original)
> +++ llvm/trunk/include/llvm/CodeGen/RegisterPressure.h Thu Feb 23
> 14:19:44 2017
> @@ -156,7 +156,7 @@ public:
> const_iterator begin() const { return &PressureChanges[0]; }
> const_iterator end() const { return &PressureChanges[MaxPSets]; }
>
> - void addPressureChange(unsigned RegUnit, bool IsDec,
> + void addPressureChange(RegisterMaskPair P, bool IsDec,
> const MachineRegisterInfo *MRI);
>
> void dump(const TargetRegisterInfo &TRI) const;
>
> Modified: llvm/trunk/include/llvm/Target/TargetRegisterInfo.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/
> TargetRegisterInfo.h?rev=296009&r1=296008&r2=296009&view=diff
> ============================================================
> ==================
> --- llvm/trunk/include/llvm/Target/TargetRegisterInfo.h (original)
> +++ llvm/trunk/include/llvm/Target/TargetRegisterInfo.h Thu Feb 23
> 14:19:44 2017
> @@ -30,6 +30,7 @@ namespace llvm {
>
> class BitVector;
> class MachineFunction;
> +class MachineRegisterInfo;
> class RegScavenger;
> template<class T> class SmallVectorImpl;
> class VirtRegMap;
> @@ -719,6 +720,12 @@ public:
> /// Get the weight in units of pressure for this register unit.
> virtual unsigned getRegUnitWeight(unsigned RegUnit) const = 0;
>
> + /// Get the weight in units of pressure for a sub register of this
> register
> + /// unit given a lane mask.
> + virtual unsigned getRegUnitWeight(const MachineRegisterInfo &MRI,
> + unsigned RegUnit,
> + LaneBitmask LaneMask) const;
> +
> /// Get the number of dimensions of register pressure.
> virtual unsigned getNumRegPressureSets() const = 0;
>
>
> Modified: llvm/trunk/lib/CodeGen/MachineScheduler.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/
> CodeGen/MachineScheduler.cpp?rev=296009&r1=296008&r2=296009&view=diff
> ============================================================
> ==================
> --- llvm/trunk/lib/CodeGen/MachineScheduler.cpp (original)
> +++ llvm/trunk/lib/CodeGen/MachineScheduler.cpp Thu Feb 23 14:19:44 2017
> @@ -1085,7 +1085,7 @@ void ScheduleDAGMILive::updatePressureDi
> continue;
>
> PressureDiff &PDiff = getPressureDiff(&SU);
> - PDiff.addPressureChange(Reg, Decrement, &MRI);
> + PDiff.addPressureChange(P, Decrement, &MRI);
> DEBUG(
> dbgs() << " UpdateRegP: SU(" << SU.NodeNum << ") "
> << PrintReg(Reg, TRI) << ':' << PrintLaneMask(P.LaneMask)
> @@ -1123,7 +1123,7 @@ void ScheduleDAGMILive::updatePressureDi
> LI.Query(LIS->getInstructionIndex(*SU->getInstr()));
> if (LRQ.valueIn() == VNI) {
> PressureDiff &PDiff = getPressureDiff(SU);
> - PDiff.addPressureChange(Reg, true, &MRI);
> + PDiff.addPressureChange(P, true, &MRI);
> DEBUG(
> dbgs() << " UpdateRegP: SU(" << SU->NodeNum << ") "
> << *SU->getInstr();
>
> Modified: llvm/trunk/lib/CodeGen/RegisterPressure.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/
> CodeGen/RegisterPressure.cpp?rev=296009&r1=296008&r2=296009&view=diff
> ============================================================
> ==================
> --- llvm/trunk/lib/CodeGen/RegisterPressure.cpp (original)
> +++ llvm/trunk/lib/CodeGen/RegisterPressure.cpp Thu Feb 23 14:19:44 2017
> @@ -46,16 +46,29 @@
>
> using namespace llvm;
>
> +/// Clamp lane masks to maximum posible value.
> +static void clampMasks(const MachineRegisterInfo &MRI, unsigned Reg,
> + LaneBitmask& LaneMask1, LaneBitmask& LaneMask2) {
> + if (TargetRegisterInfo::isVirtualRegister(Reg)) {
> + LaneBitmask Max = MRI.getMaxLaneMaskForVReg(Reg);
> + LaneMask1 &= Max;
> + LaneMask2 &= Max;
> + }
> +}
> +
> /// Increase pressure for each pressure set provided by
> TargetRegisterInfo.
> static void increaseSetPressure(std::vector<unsigned> &CurrSetPressure,
> const MachineRegisterInfo &MRI, unsigned
> Reg,
> LaneBitmask PrevMask, LaneBitmask
> NewMask) {
> assert((PrevMask & ~NewMask).none() && "Must not remove bits");
> - if (PrevMask.any() || NewMask.none())
> +
> + clampMasks(MRI, Reg, PrevMask, NewMask);
> + if ((NewMask & ~PrevMask).none())
> return;
>
> + const TargetRegisterInfo *TRI = MRI.getTargetRegisterInfo();
> + unsigned Weight = TRI->getRegUnitWeight(MRI, Reg, NewMask & ~PrevMask);
> PSetIterator PSetI = MRI.getPressureSets(Reg);
> - unsigned Weight = PSetI.getWeight();
> for (; PSetI.isValid(); ++PSetI)
> CurrSetPressure[*PSetI] += Weight;
> }
> @@ -65,11 +78,13 @@ static void decreaseSetPressure(std::vec
> const MachineRegisterInfo &MRI, unsigned
> Reg,
> LaneBitmask PrevMask, LaneBitmask
> NewMask) {
> //assert((NewMask & !PrevMask) == 0 && "Must not add bits");
> - if (NewMask.any() || PrevMask.none())
> + clampMasks(MRI, Reg, PrevMask, NewMask);
> + if ((~NewMask & PrevMask).none())
> return;
>
> + const TargetRegisterInfo *TRI = MRI.getTargetRegisterInfo();
> + unsigned Weight = TRI->getRegUnitWeight(MRI, Reg, ~NewMask & PrevMask);
> PSetIterator PSetI = MRI.getPressureSets(Reg);
> - unsigned Weight = PSetI.getWeight();
> for (; PSetI.isValid(); ++PSetI) {
> assert(CurrSetPressure[*PSetI] >= Weight && "register pressure
> underflow");
> CurrSetPressure[*PSetI] -= Weight;
> @@ -139,11 +154,14 @@ void PressureDiff::dump(const TargetRegi
> void RegPressureTracker::increaseRegPressure(unsigned RegUnit,
> LaneBitmask PreviousMask,
> LaneBitmask NewMask) {
> - if (PreviousMask.any() || NewMask.none())
> + clampMasks(*MRI, RegUnit, PreviousMask, NewMask);
> + if ((NewMask & ~PreviousMask).none())
> return;
>
> + const TargetRegisterInfo *TRI = MRI->getTargetRegisterInfo();
> + unsigned Weight = TRI->getRegUnitWeight(*MRI, RegUnit,
> + NewMask & ~PreviousMask);
> PSetIterator PSetI = MRI->getPressureSets(RegUnit);
> - unsigned Weight = PSetI.getWeight();
> for (; PSetI.isValid(); ++PSetI) {
> CurrSetPressure[*PSetI] += Weight;
> P.MaxSetPressure[*PSetI] =
> @@ -644,17 +662,19 @@ void PressureDiffs::addInstruction(unsig
> PressureDiff &PDiff = (*this)[Idx];
> assert(!PDiff.begin()->isValid() && "stale PDiff");
> for (const RegisterMaskPair &P : RegOpers.Defs)
> - PDiff.addPressureChange(P.RegUnit, true, &MRI);
> + PDiff.addPressureChange(P, true, &MRI);
>
> for (const RegisterMaskPair &P : RegOpers.Uses)
> - PDiff.addPressureChange(P.RegUnit, false, &MRI);
> + PDiff.addPressureChange(P, false, &MRI);
> }
>
> /// Add a change in pressure to the pressure diff of a given instruction.
> -void PressureDiff::addPressureChange(unsigned RegUnit, bool IsDec,
> +void PressureDiff::addPressureChange(RegisterMaskPair P, bool IsDec,
> const MachineRegisterInfo *MRI) {
> - PSetIterator PSetI = MRI->getPressureSets(RegUnit);
> - int Weight = IsDec ? -PSetI.getWeight() : PSetI.getWeight();
> + const TargetRegisterInfo *TRI = MRI->getTargetRegisterInfo();
> + int Weight = (int)TRI->getRegUnitWeight(*MRI, P.RegUnit, P.LaneMask);
> + PSetIterator PSetI = MRI->getPressureSets(P.RegUnit);
> + if (IsDec) Weight = -Weight;
> for (; PSetI.isValid(); ++PSetI) {
> // Find an existing entry in the pressure diff for this PSet.
> PressureDiff::iterator I = nonconst_begin(), E = nonconst_end();
>
> Modified: llvm/trunk/lib/CodeGen/TargetRegisterInfo.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/
> CodeGen/TargetRegisterInfo.cpp?rev=296009&r1=296008&r2=296009&view=diff
> ============================================================
> ==================
> --- llvm/trunk/lib/CodeGen/TargetRegisterInfo.cpp (original)
> +++ llvm/trunk/lib/CodeGen/TargetRegisterInfo.cpp Thu Feb 23 14:19:44 2017
> @@ -412,6 +412,15 @@ bool TargetRegisterInfo::regmaskSubsetEq
> return true;
> }
>
> +/// Get the weight in units of pressure for a sub register of this
> register
> +/// unit given a lane mask.
> +unsigned TargetRegisterInfo::getRegUnitWeight(const MachineRegisterInfo
> &MRI,
> + unsigned RegUnit,
> + LaneBitmask LaneMask) const
> {
> + PSetIterator PSetI = MRI.getPressureSets(RegUnit);
> + return PSetI.getWeight();
> +}
> +
> #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
> LLVM_DUMP_METHOD
> void TargetRegisterInfo::dumpReg(unsigned Reg, unsigned SubRegIndex,
>
> Modified: llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/
> AMDGPU/SIRegisterInfo.cpp?rev=296009&r1=296008&r2=296009&view=diff
> ============================================================
> ==================
> --- llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.cpp (original)
> +++ llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.cpp Thu Feb 23 14:19:44
> 2017
> @@ -21,6 +21,7 @@
> #include "llvm/CodeGen/RegisterScavenging.h"
> #include "llvm/IR/Function.h"
> #include "llvm/IR/LLVMContext.h"
> +#include "llvm/Support/MathExtras.h"
>
> using namespace llvm;
>
> @@ -1408,3 +1409,18 @@ const int *SIRegisterInfo::getRegUnitPre
> return Empty;
> return AMDGPURegisterInfo::getRegUnitPressureSets(RegUnit);
> }
> +
> +unsigned SIRegisterInfo::getRegUnitWeight(const MachineRegisterInfo &MRI,
> + unsigned RegUnit,
> + LaneBitmask LaneMask) const {
> + unsigned Weight = TargetRegisterInfo::getRegUnitWeight(MRI, RegUnit,
> + LaneMask);
> + if (Weight > 1 && LaneMask.any() && !LaneMask.all() &&
> + isVirtualRegister(RegUnit)) {
> + LaneBitmask Max = MRI.getMaxLaneMaskForVReg(RegUnit);
> + if (Max != LaneMask && !Max.all() && !Max.none())
> + Weight = (Weight * countPopulation(LaneMask.getAsInteger())) /
> + countPopulation(Max.getAsInteger());
> + }
> + return Weight;
> +}
>
> Modified: llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/
> AMDGPU/SIRegisterInfo.h?rev=296009&r1=296008&r2=296009&view=diff
> ============================================================
> ==================
> --- llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.h (original)
> +++ llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.h Thu Feb 23 14:19:44 2017
> @@ -228,6 +228,10 @@ public:
>
> const int *getRegUnitPressureSets(unsigned RegUnit) const override;
>
> + unsigned getRegUnitWeight(const MachineRegisterInfo &MRI,
> + unsigned RegUnit,
> + LaneBitmask LaneMask) const override;
> +
> private:
> void buildSpillLoadStore(MachineBasicBlock::iterator MI,
> unsigned LoadStoreOp,
>
> Modified: llvm/trunk/test/CodeGen/AMDGPU/load-global-i32.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
> CodeGen/AMDGPU/load-global-i32.ll?rev=296009&r1=296008&r2=296009&view=diff
> ============================================================
> ==================
> --- llvm/trunk/test/CodeGen/AMDGPU/load-global-i32.ll (original)
> +++ llvm/trunk/test/CodeGen/AMDGPU/load-global-i32.ll Thu Feb 23 14:19:44
> 2017
> @@ -424,25 +424,25 @@ define void @global_zextload_v16i32_to_v
> ; GCN-NOHSA: buffer_store_dwordx4
> ; GCN-NOHSA: buffer_store_dwordx4
>
> -; GCN-HSA: flat_store_dwordx4
> -; GCN-HSA: flat_store_dwordx4
> -; GCN-HSA: flat_store_dwordx4
> -; GCN-HSA: flat_store_dwordx4
> +; GCN-HSA-DAG: flat_store_dwordx4
> +; GCN-HSA-DAG: flat_store_dwordx4
> +; GCN-HSA-DAG: flat_store_dwordx4
> +; GCN-HSA-DAG: flat_store_dwordx4
>
> -; GCN-HSA: flat_store_dwordx4
> -; GCN-HSA: flat_store_dwordx4
> -; GCN-HSA: flat_store_dwordx4
> -; GCN-HSA: flat_store_dwordx4
> +; GCN-HSA-DAG: flat_store_dwordx4
> +; GCN-HSA-DAG: flat_store_dwordx4
> +; GCN-HSA-DAG: flat_store_dwordx4
> +; GCN-HSA-DAG: flat_store_dwordx4
>
> -; GCN-HSA: flat_store_dwordx4
> -; GCN-HSA: flat_store_dwordx4
> -; GCN-HSA: flat_store_dwordx4
> -; GCN-HSA: flat_store_dwordx4
> +; GCN-HSA-DAG: flat_store_dwordx4
> +; GCN-HSA-DAG: flat_store_dwordx4
> +; GCN-HSA-DAG: flat_store_dwordx4
> +; GCN-HSA-DAG: flat_store_dwordx4
>
> -; GCN-HSA: flat_store_dwordx4
> -; GCN-HSA: flat_store_dwordx4
> -; GCN-HSA: flat_store_dwordx4
> -; GCN-HSA: flat_store_dwordx4
> +; GCN-HSA-DAG: flat_store_dwordx4
> +; GCN-HSA-DAG: flat_store_dwordx4
> +; GCN-HSA-DAG: flat_store_dwordx4
> +; GCN-HSA-DAG: flat_store_dwordx4
>
> define void @global_sextload_v32i32_to_v32i64(<32 x i64> addrspace(1)*
> %out, <32 x i32> addrspace(1)* %in) #0 {
> %ld = load <32 x i32>, <32 x i32> addrspace(1)* %in
>
> Added: llvm/trunk/test/CodeGen/AMDGPU/schedule-regpressure-subregs.mir
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
> CodeGen/AMDGPU/schedule-regpressure-subregs.mir?rev=296009&view=auto
> ============================================================
> ==================
> --- llvm/trunk/test/CodeGen/AMDGPU/schedule-regpressure-subregs.mir
> (added)
> +++ llvm/trunk/test/CodeGen/AMDGPU/schedule-regpressure-subregs.mir Thu
> Feb 23 14:19:44 2017
> @@ -0,0 +1,67 @@
> +# RUN: llc -march=amdgcn -misched=converge -run-pass machine-scheduler
> -verify-misched %s -o - -debug-only=misched 2>&1 | FileCheck %s
> +# REQUIRES: asserts
> +
> +# CHECK-LABEL: ScheduleDAGMILive::schedule starting
> +
> +# Check that def and use subregs count with the same weight
> +# CHECK: %vreg9:sub1<def> = V_MUL_LO_I32 %vreg6:sub1, 3
> +# CHECK: Pressure Diff : {{$}}
> +
> +# Check that a subreg does not count as a whole superreg
> +# CHECK: %vreg9:sub0<def> = V_MUL_LO_I32 %vreg6:sub0, %vreg9:sub1
> +# CHECK: Pressure Diff : VGPR_32 1{{$}}
> +
> +# Check that two subregs of the same register count as a whole register
> +# CHECK: DS_WRITE2_B32 %vreg7, %vreg9:sub0, %vreg9:sub1
> +# CHECK: Pressure Diff : VGPR_32 3{{$}}
> +
> +---
> +name: mo_pset
> +alignment: 0
> +exposesReturnsTwice: false
> +legalized: false
> +regBankSelected: false
> +selected: false
> +tracksRegLiveness: true
> +registers:
> + - { id: 0, class: sreg_128 }
> + - { id: 1, class: sgpr_64 }
> + - { id: 2, class: sreg_32_xm0 }
> + - { id: 3, class: sgpr_32 }
> + - { id: 4, class: vgpr_32 }
> + - { id: 5, class: sreg_32_xm0_xexec }
> + - { id: 6, class: vreg_64 }
> + - { id: 7, class: vgpr_32 }
> + - { id: 8, class: vgpr_32 }
> + - { id: 9, class: vreg_64 }
> +liveins:
> + - { reg: '%sgpr4_sgpr5', virtual-reg: '%1' }
> +frameInfo:
> + isFrameAddressTaken: false
> + isReturnAddressTaken: false
> + hasStackMap: false
> + hasPatchPoint: false
> + stackSize: 0
> + offsetAdjustment: 0
> + maxAlignment: 0
> + adjustsStack: false
> + hasCalls: false
> + maxCallFrameSize: 0
> + hasOpaqueSPAdjustment: false
> + hasVAStart: false
> + hasMustTailInVarArgFunc: false
> +body: |
> + bb.0:
> + liveins: %sgpr4_sgpr5
> +
> + %1 = COPY %sgpr4_sgpr5
> + %5 = S_LOAD_DWORD_IMM %1, 0, 0 :: (non-temporal dereferenceable
> invariant load 4 from `i32 addrspace(2)* undef`)
> + %m0 = S_MOV_B32 -1
> + %7 = COPY %5
> + %6 = DS_READ2_B32 %7, 0, 1, 0, implicit %m0, implicit %exec
> + undef %9.sub1 = V_MUL_LO_I32 %6.sub1, 3, implicit %exec
> + %9.sub0 = V_MUL_LO_I32 %6.sub0, %9.sub1, implicit %exec
> + DS_WRITE2_B32 %7, %9.sub0, %9.sub1, 4, 5, 0, implicit killed %m0,
> implicit %exec
> + S_ENDPGM
> +
> +...
>
>
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