class LiveVariables;
class MCAsmInfo;
class MachineMemOperand;
+class MachineRegisterInfo;
class MDNode;
class MCInst;
class SDNode;
int getOperandLatency(const InstrItineraryData *ItinData,
SDNode *DefNode, unsigned DefIdx,
SDNode *UseNode, unsigned UseIdx) const;
+
+ /// hasHighOperandLatency - Compute operand latency between a def of 'Reg'
+ /// and an use in the current loop, return true if the target considered
+ /// it 'high'. This is used by optimization passes such as machine LICM to
+ /// determine whether it makes sense to hoist an instruction out even in
+ /// high register pressure situation.
+ virtual
+ bool hasHighOperandLatency(const InstrItineraryData *ItinData,
+ const MachineRegisterInfo *MRI,
+ const MachineInstr *DefMI, unsigned DefIdx,
+ const MachineInstr *UseMI, unsigned UseIdx) const {
+ return false;
+ }
};
/// TargetInstrInfoImpl - This is the default implementation of
using namespace llvm;
-static cl::opt<bool>
-TrackRegPressure("rp-aware-machine-licm",
- cl::desc("Register pressure aware machine LICM"),
- cl::init(false), cl::Hidden);
-
STATISTIC(NumHoisted,
"Number of machine instructions hoisted out of loops");
STATISTIC(NumLowRP,
RegSeen.clear();
RegPressure.clear();
RegLimit.clear();
+ BackTrace.clear();
for (DenseMap<unsigned,std::vector<const MachineInstr*> >::iterator
CI = CSEMap.begin(), CE = CSEMap.end(); CI != CE; ++CI)
CI->second.clear();
///
bool IsLoopInvariantInst(MachineInstr &I);
- /// ComputeOperandLatency - Compute operand latency between a def of 'Reg'
- /// and an use in the current loop.
- int ComputeOperandLatency(MachineInstr &MI, unsigned DefIdx, unsigned Reg);
+ /// HasHighOperandLatency - Compute operand latency between a def of 'Reg'
+ /// and an use in the current loop, return true if the target considered
+ /// it 'high'.
+ bool HasHighOperandLatency(MachineInstr &MI, unsigned DefIdx, unsigned Reg);
/// IncreaseHighRegPressure - Visit BBs from preheader to current BB, check
/// if hoisting an instruction of the given cost matrix can cause high
if (!Preheader)
return;
- if (TrackRegPressure) {
- if (IsHeader) {
- // Compute registers which are liveout of preheader.
- RegSeen.clear();
- BackTrace.clear();
- InitRegPressure(Preheader);
- }
-
- // Remember livein register pressure.
- BackTrace.push_back(RegPressure);
+ if (IsHeader) {
+ // Compute registers which are liveout of preheader.
+ RegSeen.clear();
+ BackTrace.clear();
+ InitRegPressure(Preheader);
}
+ // Remember livein register pressure.
+ BackTrace.push_back(RegPressure);
+
for (MachineBasicBlock::iterator
MII = BB->begin(), E = BB->end(); MII != E; ) {
MachineBasicBlock::iterator NextMII = MII; ++NextMII;
MachineInstr *MI = &*MII;
- if (TrackRegPressure)
- UpdateRegPressureBefore(MI);
+ UpdateRegPressureBefore(MI);
Hoist(MI, Preheader);
- if (TrackRegPressure)
- UpdateRegPressureAfter(MI);
+ UpdateRegPressureAfter(MI);
MII = NextMII;
}
HoistRegion(Children[I]);
}
- if (TrackRegPressure)
- BackTrace.pop_back();
+ BackTrace.pop_back();
}
/// InitRegPressure - Find all virtual register references that are liveout of
}
}
-/// ComputeOperandLatency - Compute operand latency between a def of 'Reg'
-/// and an use in the current loop.
-int MachineLICM::ComputeOperandLatency(MachineInstr &MI,
- unsigned DefIdx, unsigned Reg) {
+/// HasHighOperandLatency - Compute operand latency between a def of 'Reg'
+/// and an use in the current loop, return true if the target considered
+/// it 'high'.
+bool MachineLICM::HasHighOperandLatency(MachineInstr &MI,
+ unsigned DefIdx, unsigned Reg) {
if (MRI->use_nodbg_empty(Reg))
- // No use? Return arbitrary large number!
- return 300;
+ return false;
- int Latency = -1;
for (MachineRegisterInfo::use_nodbg_iterator I = MRI->use_nodbg_begin(Reg),
E = MRI->use_nodbg_end(); I != E; ++I) {
MachineInstr *UseMI = &*I;
if (MOReg != Reg)
continue;
- int UseCycle = TII->getOperandLatency(InstrItins, &MI, DefIdx, UseMI, i);
- Latency = std::max(Latency, UseCycle);
+ if (TII->hasHighOperandLatency(InstrItins, MRI, &MI, DefIdx, UseMI, i))
+ return true;
}
- if (Latency != -1)
- break;
+ // Only look at the first in loop use.
+ break;
}
- if (Latency == -1)
- Latency = InstrItins->getOperandCycle(MI.getDesc().getSchedClass(), DefIdx);
-
- return Latency;
+ return false;
}
/// IncreaseHighRegPressure - Visit BBs from preheader to current BB, check
if (MI.isImplicitDef())
return true;
- // FIXME: For now, only hoist re-materilizable instructions. LICM will
- // increase register pressure. We want to make sure it doesn't increase
- // spilling.
+ // If the instruction is cheap, only hoist if it is re-materilizable. LICM
+ // will increase register pressure. It's probably not worth it if the
+ // instruction is cheap.
// Also hoist loads from constant memory, e.g. load from stubs, GOT. Hoisting
// these tend to help performance in low register pressure situation. The
// trade off is it may cause spill in high pressure situation. It will end up
// adding a store in the loop preheader. But the reload is no more expensive.
// The side benefit is these loads are frequently CSE'ed.
- if (!TrackRegPressure || MI.getDesc().isAsCheapAsAMove()) {
- if (!TII->isTriviallyReMaterializable(&MI, AA) &&
- !isLoadFromConstantMemory(&MI))
+ if (MI.getDesc().isAsCheapAsAMove()) {
+ if (!TII->isTriviallyReMaterializable(&MI, AA))
return false;
} else {
+ // Estimate register pressure to determine whether to LICM the instruction.
// In low register pressure situation, we can be more aggressive about
// hoisting. Also, favors hoisting long latency instructions even in
// moderately high pressure situation.
if (!Reg || TargetRegisterInfo::isPhysicalRegister(Reg))
continue;
if (MO.isDef()) {
- if (InstrItins && !InstrItins->isEmpty()) {
- int Cycle = ComputeOperandLatency(MI, i, Reg);
- if (Cycle > 3) {
- // FIXME: Target specific high latency limit?
- ++NumHighLatency;
- return true;
- }
+ if (HasHighOperandLatency(MI, i, Reg)) {
+ ++NumHighLatency;
+ return true;
}
const TargetRegisterClass *RC = MRI->getRegClass(Reg);
return getOperandLatency(ItinData, DefTID, DefIdx, DefAlign,
UseTID, UseIdx, UseAlign);
}
+
+bool ARMBaseInstrInfo::
+hasHighOperandLatency(const InstrItineraryData *ItinData,
+ const MachineRegisterInfo *MRI,
+ const MachineInstr *DefMI, unsigned DefIdx,
+ const MachineInstr *UseMI, unsigned UseIdx) const {
+ unsigned DDomain = DefMI->getDesc().TSFlags & ARMII::DomainMask;
+ unsigned UDomain = UseMI->getDesc().TSFlags & ARMII::DomainMask;
+ if (Subtarget.isCortexA8() &&
+ (DDomain == ARMII::DomainVFP || UDomain == ARMII::DomainVFP))
+ // CortexA8 VFP instructions are not pipelined.
+ return true;
+
+ // Hoist VFP / NEON instructions with 4 or higher latency.
+ int Latency = getOperandLatency(ItinData, DefMI, DefIdx, UseMI, UseIdx);
+ if (Latency <= 3)
+ return false;
+ return DDomain == ARMII::DomainVFP || DDomain == ARMII::DomainNEON ||
+ UDomain == ARMII::DomainVFP || UDomain == ARMII::DomainNEON;
+}
unsigned DefIdx, unsigned DefAlign,
const TargetInstrDesc &UseTID,
unsigned UseIdx, unsigned UseAlign) const;
+
+ bool hasHighOperandLatency(const InstrItineraryData *ItinData,
+ const MachineRegisterInfo *MRI,
+ const MachineInstr *DefMI, unsigned DefIdx,
+ const MachineInstr *UseMI, unsigned UseIdx) const;
};
static inline
NopInst.setOpcode(X86::NOOP);
}
+bool X86InstrInfo::
+hasHighOperandLatency(const InstrItineraryData *ItinData,
+ const MachineRegisterInfo *MRI,
+ const MachineInstr *DefMI, unsigned DefIdx,
+ const MachineInstr *UseMI, unsigned UseIdx) const {
+ switch (DefMI->getOpcode()) {
+ default: return false;
+ case X86::DIVSDrm:
+ case X86::DIVSDrm_Int:
+ case X86::DIVSDrr:
+ case X86::DIVSDrr_Int:
+ case X86::DIVSSrm:
+ case X86::DIVSSrm_Int:
+ case X86::DIVSSrr:
+ case X86::DIVSSrr_Int:
+ case X86::SQRTPDm:
+ case X86::SQRTPDm_Int:
+ case X86::SQRTPDr:
+ case X86::SQRTPDr_Int:
+ case X86::SQRTPSm:
+ case X86::SQRTPSm_Int:
+ case X86::SQRTPSr:
+ case X86::SQRTPSr_Int:
+ case X86::SQRTSDm:
+ case X86::SQRTSDm_Int:
+ case X86::SQRTSDr:
+ case X86::SQRTSDr_Int:
+ case X86::SQRTSSm:
+ case X86::SQRTSSm_Int:
+ case X86::SQRTSSr:
+ case X86::SQRTSSr_Int:
+ return true;
+ }
+}
+
namespace {
/// CGBR - Create Global Base Reg pass. This initializes the PIC
/// global base register for x86-32.
unsigned OpNum,
const SmallVectorImpl<MachineOperand> &MOs,
unsigned Size, unsigned Alignment) const;
+
+ bool hasHighOperandLatency(const InstrItineraryData *ItinData,
+ const MachineRegisterInfo *MRI,
+ const MachineInstr *DefMI, unsigned DefIdx,
+ const MachineInstr *UseMI, unsigned UseIdx) const;
private:
MachineInstr * convertToThreeAddressWithLEA(unsigned MIOpc,
+++ /dev/null
-; RUN: llc < %s -march=arm -mattr=+v6,+vfp2 -o /dev/null -stats -info-output-file - | grep "Number of re-materialization"
-
-define i32 @main(i32 %argc, i8** nocapture %argv, double %d1, double %d2) nounwind {
-entry:
- br i1 undef, label %smvp.exit, label %bb.i3
-
-bb.i3: ; preds = %bb.i3, %bb134
- br i1 undef, label %smvp.exit, label %bb.i3
-
-smvp.exit: ; preds = %bb.i3
- %0 = fmul double %d1, 2.400000e-03 ; <double> [#uses=2]
- br i1 undef, label %bb138.preheader, label %bb159
-
-bb138.preheader: ; preds = %smvp.exit
- br label %bb138
-
-bb138: ; preds = %bb138, %bb138.preheader
- br i1 undef, label %bb138, label %bb145.loopexit
-
-bb142: ; preds = %bb.nph218.bb.nph218.split_crit_edge, %phi0.exit
- %1 = fmul double %d1, -1.200000e-03 ; <double> [#uses=1]
- %2 = fadd double %d2, %1 ; <double> [#uses=1]
- %3 = fmul double %2, %d2 ; <double> [#uses=1]
- %4 = fsub double 0.000000e+00, %3 ; <double> [#uses=1]
- br i1 %14, label %phi1.exit, label %bb.i35
-
-bb.i35: ; preds = %bb142
- %5 = call double @sin(double %15) nounwind readonly ; <double> [#uses=1]
- %6 = fmul double %5, 0x4031740AFA84AD8A ; <double> [#uses=1]
- %7 = fsub double 1.000000e+00, undef ; <double> [#uses=1]
- %8 = fdiv double %7, 6.000000e-01 ; <double> [#uses=1]
- br label %phi1.exit
-
-phi1.exit: ; preds = %bb.i35, %bb142
- %.pn = phi double [ %6, %bb.i35 ], [ 0.000000e+00, %bb142 ] ; <double> [#uses=1]
- %9 = phi double [ %8, %bb.i35 ], [ 0.000000e+00, %bb142 ] ; <double> [#uses=1]
- %10 = fmul double %.pn, %9 ; <double> [#uses=1]
- br i1 %14, label %phi0.exit, label %bb.i
-
-bb.i: ; preds = %phi1.exit
- unreachable
-
-phi0.exit: ; preds = %phi1.exit
- %11 = fsub double %4, %10 ; <double> [#uses=1]
- %12 = fadd double 0.000000e+00, %11 ; <double> [#uses=1]
- store double %12, double* undef, align 4
- br label %bb142
-
-bb145.loopexit: ; preds = %bb138
- br i1 undef, label %bb.nph218.bb.nph218.split_crit_edge, label %bb159
-
-bb.nph218.bb.nph218.split_crit_edge: ; preds = %bb145.loopexit
- %13 = fmul double %0, 0x401921FB54442D18 ; <double> [#uses=1]
- %14 = fcmp ugt double %0, 6.000000e-01 ; <i1> [#uses=2]
- %15 = fdiv double %13, 6.000000e-01 ; <double> [#uses=1]
- br label %bb142
-
-bb159: ; preds = %bb145.loopexit, %smvp.exit, %bb134
- unreachable
-
-bb166: ; preds = %bb127
- unreachable
-}
-
-declare double @sin(double) nounwind readonly
; RUN: llc < %s -mtriple=thumbv7-apple-darwin -mcpu=cortex-a8 -relocation-model=pic -disable-fp-elim -arm-vdup-splat | FileCheck %s
; Modified version of machine-licm.ll with -arm-vdup-splat turned on, 8003375.
; Eventually this should become the default and be moved into machine-licm.ll.
-; FIXME: the vdup should be hoisted out of the loop, 8248029.
define void @t2(i8* %ptr1, i8* %ptr2) nounwind {
entry:
; CHECK: t2:
; CHECK: mov.w r3, #1065353216
+; CHECK: vdup.32 q{{.*}}, r3
br i1 undef, label %bb1, label %bb2
bb1:
; CHECK-NEXT: %bb1
-; CHECK: vdup.32 q{{.*}}, r3
%indvar = phi i32 [ %indvar.next, %bb1 ], [ 0, %entry ]
%tmp1 = shl i32 %indvar, 2
%gep1 = getelementptr i8* %ptr1, i32 %tmp1
-; RUN: llc < %s -march=x86 -mattr=+sse2 -stats |& not grep {Number of register spills}
+; RUN: llc < %s -mtriple=i386-apple-darwin -mattr=+sse2 -stats |& FileCheck %s
+; Now this test spills one register. But a reload in the loop is cheaper than
+; the divsd so it's a win.
define fastcc void @fourn(double* %data, i32 %isign) nounwind {
+; CHECK: fourn
entry:
br label %bb
%1 = icmp sgt i32 %0, 2 ; <i1> [#uses=1]
br i1 %1, label %bb30.loopexit, label %bb
+; CHECK: %bb30.loopexit
+; CHECK: divsd %xmm0
+; CHECK: movsd %xmm0, 16(%esp)
+; CHECK: .align
+; CHECK-NEXT: %bb3
bb3: ; preds = %bb30.loopexit, %bb25, %bb3
%2 = load i32* null, align 4 ; <i32> [#uses=1]
%3 = mul i32 %2, 0 ; <i32> [#uses=1]
-; RUN: llc < %s -march=x86-64 -mattr=+sse3,+sse41 -stats |& grep {6 machine-licm}
+; RUN: llc < %s -march=x86-64 -mattr=+sse3,+sse41 -stats |& grep {7 machine-licm}
; RUN: llc < %s -march=x86-64 -mattr=+sse3,+sse41 | FileCheck %s
; rdar://6627786
; rdar://7792037
projects / oota-llvm.git / commitdiff