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ARMLoadStoreOptimizer: Create LDRD/STRD on thumb2

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Re-apply r241926 with an additional check that r13 and r15 are not used
for LDRD/STRD. See http://llvm.org/PR24190. This also already includes
the fix from r241951.

Differential Revision: http://reviews.llvm.org/D10623

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242742 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Matthias Braun 2015-07-21 00:18:59 +00:00
parent 4f50f9eba4
commit 361054b1fa
7 changed files with 138 additions and 47 deletions
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133
lib/Target/ARM/ARMLoadStoreOptimizer.cpp
View File

@ -111,8 +111,12 @@ namespace {
/// Index into the basic block where the merged instruction will be
/// inserted. (See MemOpQueueEntry.Position)
unsigned InsertPos;
/// Whether the instructions can be merged into a ldm/stm instruction.
bool CanMergeToLSMulti;
/// Whether the instructions can be merged into a ldrd/strd instruction.
bool CanMergeToLSDouble;
};
BumpPtrAllocator Allocator;
SpecificBumpPtrAllocator<MergeCandidate> Allocator;
SmallVector<const MergeCandidate*,4> Candidates;
void moveLiveRegsBefore(const MachineBasicBlock &MBB,
@ -122,11 +126,14 @@ namespace {
MachineBasicBlock::iterator MBBI,
DebugLoc DL, unsigned Base, unsigned WordOffset,
ARMCC::CondCodes Pred, unsigned PredReg);
MachineInstr *MergeOps(MachineBasicBlock &MBB,
MachineBasicBlock::iterator InsertBefore, int Offset,
unsigned Base, bool BaseKill, unsigned Opcode,
ARMCC::CondCodes Pred, unsigned PredReg, DebugLoc DL,
ArrayRef<std::pair<unsigned, bool>> Regs);
MachineInstr *CreateLoadStoreMulti(MachineBasicBlock &MBB,
MachineBasicBlock::iterator InsertBefore, int Offset, unsigned Base,
bool BaseKill, unsigned Opcode, ARMCC::CondCodes Pred, unsigned PredReg,
DebugLoc DL, ArrayRef<std::pair<unsigned, bool>> Regs);
MachineInstr *CreateLoadStoreDouble(MachineBasicBlock &MBB,
MachineBasicBlock::iterator InsertBefore, int Offset, unsigned Base,
bool BaseKill, unsigned Opcode, ARMCC::CondCodes Pred, unsigned PredReg,
DebugLoc DL, ArrayRef<std::pair<unsigned, bool>> Regs) const;
void FormCandidates(const MemOpQueue &MemOps);
MachineInstr *MergeOpsUpdate(const MergeCandidate &Cand);
bool FixInvalidRegPairOp(MachineBasicBlock &MBB,
@ -555,12 +562,10 @@ static bool ContainsReg(const ArrayRef<std::pair<unsigned, bool>> &Regs,
/// Create and insert a LDM or STM with Base as base register and registers in
/// Regs as the register operands that would be loaded / stored. It returns
/// true if the transformation is done.
MachineInstr *
ARMLoadStoreOpt::MergeOps(MachineBasicBlock &MBB,
MachineBasicBlock::iterator InsertBefore, int Offset,
unsigned Base, bool BaseKill, unsigned Opcode,
ARMCC::CondCodes Pred, unsigned PredReg, DebugLoc DL,
ArrayRef<std::pair<unsigned, bool>> Regs) {
MachineInstr *ARMLoadStoreOpt::CreateLoadStoreMulti(MachineBasicBlock &MBB,
MachineBasicBlock::iterator InsertBefore, int Offset, unsigned Base,
bool BaseKill, unsigned Opcode, ARMCC::CondCodes Pred, unsigned PredReg,
DebugLoc DL, ArrayRef<std::pair<unsigned, bool>> Regs) {
unsigned NumRegs = Regs.size();
assert(NumRegs > 1);
@ -749,6 +754,28 @@ ARMLoadStoreOpt::MergeOps(MachineBasicBlock &MBB,
return MIB.getInstr();
}
MachineInstr *ARMLoadStoreOpt::CreateLoadStoreDouble(MachineBasicBlock &MBB,
MachineBasicBlock::iterator InsertBefore, int Offset, unsigned Base,
bool BaseKill, unsigned Opcode, ARMCC::CondCodes Pred, unsigned PredReg,
DebugLoc DL, ArrayRef<std::pair<unsigned, bool>> Regs) const {
bool IsLoad = isi32Load(Opcode);
assert((IsLoad || isi32Store(Opcode)) && "Must have integer load or store");
unsigned LoadStoreOpcode = IsLoad ? ARM::t2LDRDi8 : ARM::t2STRDi8;
assert(Regs.size() == 2);
MachineInstrBuilder MIB = BuildMI(MBB, InsertBefore, DL,
TII->get(LoadStoreOpcode));
if (IsLoad) {
MIB.addReg(Regs[0].first, RegState::Define)
.addReg(Regs[1].first, RegState::Define);
} else {
MIB.addReg(Regs[0].first, getKillRegState(Regs[0].second))
.addReg(Regs[1].first, getKillRegState(Regs[1].second));
}
MIB.addReg(Base).addImm(Offset).addImm(Pred).addReg(PredReg);
return MIB.getInstr();
}
/// Call MergeOps and update MemOps and merges accordingly on success.
MachineInstr *ARMLoadStoreOpt::MergeOpsUpdate(const MergeCandidate &Cand) {
const MachineInstr *First = Cand.Instrs.front();
@ -799,7 +826,12 @@ MachineInstr *ARMLoadStoreOpt::MergeOpsUpdate(const MergeCandidate &Cand) {
unsigned PredReg = 0;
ARMCC::CondCodes Pred = getInstrPredicate(First, PredReg);
DebugLoc DL = First->getDebugLoc();
MachineInstr *Merged = MergeOps(MBB, InsertBefore, Offset, Base, BaseKill,
MachineInstr *Merged = nullptr;
if (Cand.CanMergeToLSDouble)
Merged = CreateLoadStoreDouble(MBB, InsertBefore, Offset, Base, BaseKill,
Opcode, Pred, PredReg, DL, Regs);
if (!Merged && Cand.CanMergeToLSMulti)
Merged = CreateLoadStoreMulti(MBB, InsertBefore, Offset, Base, BaseKill,
Opcode, Pred, PredReg, DL, Regs);
if (!Merged)
return nullptr;
@ -861,6 +893,13 @@ MachineInstr *ARMLoadStoreOpt::MergeOpsUpdate(const MergeCandidate &Cand) {
return Merged;
}
static bool isValidLSDoubleOffset(int Offset) {
unsigned Value = abs(Offset);
// t2LDRDi8/t2STRDi8 supports an 8 bit immediate which is internally
// multiplied by 4.
return (Value % 4) == 0 && Value < 1024;
}
/// Find candidates for load/store multiple merge in list of MemOpQueueEntries.
void ARMLoadStoreOpt::FormCandidates(const MemOpQueue &MemOps) {
const MachineInstr *FirstMI = MemOps[0].MI;
@ -880,29 +919,55 @@ void ARMLoadStoreOpt::FormCandidates(const MemOpQueue &MemOps) {
unsigned Latest = SIndex;
unsigned Earliest = SIndex;
unsigned Count = 1;
bool CanMergeToLSDouble =
STI->isThumb2() && isNotVFP && isValidLSDoubleOffset(Offset);
// ARM errata 602117: LDRD with base in list may result in incorrect base
// register when interrupted or faulted.
if (STI->isCortexM3() && isi32Load(Opcode) &&
PReg == getLoadStoreBaseOp(*MI).getReg())
CanMergeToLSDouble = false;
// Merge additional instructions fulfilling LDM/STM constraints.
bool CanMergeToLSMulti = true;
// On swift vldm/vstm starting with an odd register number as that needs
// more uops than single vldrs.
if (STI->isSwift() && !isNotVFP && (PRegNum % 2) == 1)
CanMergeToLSMulti = false;
// LDRD/STRD do not allow SP/PC. LDM/STM do not support it or have it
// deprecated; LDM to PC is fine but cannot happen here.
if (PReg == ARM::SP || PReg == ARM::PC)
CanMergeToLSMulti = CanMergeToLSDouble = false;
// Merge following instructions where possible.
for (unsigned I = SIndex+1; I < EIndex; ++I, ++Count) {
int NewOffset = MemOps[I].Offset;
if (NewOffset != Offset + (int)Size)
break;
const MachineOperand &MO = getLoadStoreRegOp(*MemOps[I].MI);
unsigned Reg = MO.getReg();
if (Reg == ARM::SP)
break;
unsigned RegNum = MO.isUndef() ? UINT_MAX : TRI->getEncodingValue(Reg);
// Register numbers must be in ascending order.
if (RegNum <= PRegNum)
break;
// For VFP / NEON load/store multiples, the registers must be consecutive
// and within the limit on the number of registers per instruction.
if (!isNotVFP && RegNum != PRegNum+1)
break;
// On Swift we don't want vldm/vstm to start with a odd register num
// because Q register unaligned vldm/vstm need more uops.
if (!isNotVFP && STI->isSwift() && Count == 1 && (PRegNum % 2) == 1)
if (Reg == ARM::SP || Reg == ARM::PC)
break;
// See if the current load/store may be part of a multi load/store.
unsigned RegNum = MO.isUndef() ? UINT_MAX : TRI->getEncodingValue(Reg);
bool PartOfLSMulti = CanMergeToLSMulti;
if (PartOfLSMulti) {
// Register numbers must be in ascending order.
if (RegNum <= PRegNum)
PartOfLSMulti = false;
// For VFP / NEON load/store multiples, the registers must be
// consecutive and within the limit on the number of registers per
// instruction.
else if (!isNotVFP && RegNum != PRegNum+1)
PartOfLSMulti = false;
}
// See if the current load/store may be part of a double load/store.
bool PartOfLSDouble = CanMergeToLSDouble && Count <= 1;
if (!PartOfLSMulti && !PartOfLSDouble)
break;
CanMergeToLSMulti &= PartOfLSMulti;
CanMergeToLSDouble &= PartOfLSDouble;
// Track MemOp with latest and earliest position (Positions are
// counted in reverse).
unsigned Position = MemOps[I].Position;
@ -916,12 +981,16 @@ void ARMLoadStoreOpt::FormCandidates(const MemOpQueue &MemOps) {
}
// Form a candidate from the Ops collected so far.
MergeCandidate *Candidate = new(Allocator) MergeCandidate;
MergeCandidate *Candidate = new(Allocator.Allocate()) MergeCandidate;
for (unsigned C = SIndex, CE = SIndex + Count; C < CE; ++C)
Candidate->Instrs.push_back(MemOps[C].MI);
Candidate->LatestMIIdx = Latest - SIndex;
Candidate->EarliestMIIdx = Earliest - SIndex;
Candidate->InsertPos = MemOps[Latest].Position;
if (Count == 1)
CanMergeToLSMulti = CanMergeToLSDouble = false;
Candidate->CanMergeToLSMulti = CanMergeToLSMulti;
Candidate->CanMergeToLSDouble = CanMergeToLSDouble;
Candidates.push_back(Candidate);
// Continue after the chain.
SIndex += Count;
@ -1653,12 +1722,14 @@ bool ARMLoadStoreOpt::LoadStoreMultipleOpti(MachineBasicBlock &MBB) {
// Go through list of candidates and merge.
bool Changed = false;
for (const MergeCandidate *Candidate : Candidates) {
if (Candidate->Instrs.size() > 1) {
if (Candidate->CanMergeToLSMulti || Candidate->CanMergeToLSDouble) {
MachineInstr *Merged = MergeOpsUpdate(*Candidate);
// Merge preceding/trailing base inc/dec into the merged op.
if (Merged) {
MergeBaseUpdateLSMultiple(Merged);
Changed = true;
unsigned Opcode = Merged->getOpcode();
if (Opcode != ARM::t2STRDi8 && Opcode != ARM::t2LDRDi8)
MergeBaseUpdateLSMultiple(Merged);
} else {
for (MachineInstr *MI : Candidate->Instrs) {
if (MergeBaseUpdateLoadStore(MI))
@ -1738,7 +1809,7 @@ bool ARMLoadStoreOpt::runOnMachineFunction(MachineFunction &Fn) {
Modified |= MergeReturnIntoLDM(MBB);
}
Allocator.Reset();
Allocator.DestroyAll();
return Modified;
}

3
test/CodeGen/ARM/2013-05-02-AAPCS-ByVal-Structs-C4-C5-VFP.ll
View File

@ -25,8 +25,7 @@ entry:
;CHECK: push {r7, lr}
;CHECK: sub sp, #4
;CHECK: add r0, sp, #12
;CHECK: str r2, [sp, #16]
;CHECK: str r1, [sp, #12]
;CHECK: strd r1, r2, [sp, #12]
;CHECK: bl fooUseStruct
call void @fooUseStruct(%st_t* %p1)
ret void

3
test/CodeGen/ARM/byval-align.ll
View File

@ -28,8 +28,7 @@ define i32 @test_align8(i8*, [4 x i32]* byval align 8 %b) {
; CHECK: push {r4, r7, lr}
; CHECK: add r7, sp, #4
; CHECK-DAG: str r2, [r7, #8]
; CHECK-DAG: str r3, [r7, #12]
; CHECK: strd r2, r3, [r7, #8]
; CHECK: ldr r0, [r7, #8]

21
test/CodeGen/ARM/ldrd.ll
View File

@ -3,6 +3,7 @@
; rdar://6949835
; RUN: llc < %s -mtriple=thumbv7-apple-ios -mcpu=cortex-a8 -regalloc=basic | FileCheck %s -check-prefix=BASIC -check-prefix=CHECK
; RUN: llc < %s -mtriple=thumbv7-apple-ios -mcpu=cortex-a8 -regalloc=greedy | FileCheck %s -check-prefix=GREEDY -check-prefix=CHECK
; RUN: llc < %s -mtriple=thumbv7-apple-ios -mcpu=swift | FileCheck %s -check-prefix=SWIFT -check-prefix=CHECK
; Magic ARM pair hints works best with linearscan / fast.
@ -110,5 +111,25 @@ entry:
ret void
}
; CHECK-LABEL: strd_spill_ldrd_reload:
; A8: strd r1, r0, [sp]
; M3: strd r1, r0, [sp]
; BASIC: strd r1, r0, [sp]
; GREEDY: strd r0, r1, [sp]
; CHECK: @ InlineAsm Start
; CHECK: @ InlineAsm End
; A8: ldrd r2, r1, [sp]
; M3: ldrd r2, r1, [sp]
; BASIC: ldrd r2, r1, [sp]
; GREEDY: ldrd r1, r2, [sp]
; CHECK: bl{{x?}} _extfunc
define void @strd_spill_ldrd_reload(i32 %v0, i32 %v1) {
; force %v0 and %v1 to be spilled
call void asm sideeffect "", "~{r0},~{r1},~{r2},~{r3},~{r4},~{r5},~{r6},~{r7},~{r8},~{r9},~{r10},~{r11},~{r12},~{lr}"()
; force the reloaded %v0, %v1 into different registers
call void @extfunc(i32 0, i32 %v0, i32 %v1, i32 7)
ret void
}
declare void @llvm.lifetime.start(i64, i8* nocapture) nounwind
declare void @llvm.lifetime.end(i64, i8* nocapture) nounwind

3
test/CodeGen/ARM/memset-inline.ll
View File

@ -4,8 +4,7 @@ define void @t1(i8* nocapture %c) nounwind optsize {
entry:
; CHECK-LABEL: t1:
; CHECK: movs r1, #0
; CHECK: str r1, [r0]
; CHECK: str r1, [r0, #4]
; CHECK: strd r1, r1, [r0]
; CHECK: str r1, [r0, #8]
call void @llvm.memset.p0i8.i64(i8* %c, i8 0, i64 12, i32 8, i1 false)
ret void

16
test/CodeGen/ARM/wrong-t2stmia-size-opt.ll
View File

@ -5,16 +5,20 @@ target triple = "thumbv7--linux-gnueabi"
declare i8* @llvm.returnaddress(i32)
define i32* @wrong-t2stmia-size-reduction(i32* %addr, i32 %val0) minsize {
define i32* @wrong-t2stmia-size-reduction(i32* %addr, i32 %val0, i32 %val1) minsize {
store i32 %val0, i32* %addr
%addr1 = getelementptr i32, i32* %addr, i32 1
%addr2 = getelementptr i32, i32* %addr, i32 2
%lr = call i8* @llvm.returnaddress(i32 0)
%lr32 = ptrtoint i8* %lr to i32
store i32 %lr32, i32* %addr1
%addr2 = getelementptr i32, i32* %addr1, i32 1
ret i32* %addr2
store i32 %val1, i32* %addr1
store i32 %lr32, i32* %addr2
%addr3 = getelementptr i32, i32* %addr, i32 3
ret i32* %addr3
}
; Check that stm writes two registers. The bug caused one of registers (LR,
; Check that stm writes three registers. The bug caused one of registers (LR,
; which invalid for Thumb1 form of STMIA instruction) to be dropped.
; CHECK: stm{{[^,]*}}, {{{.*,.*}}}
; CHECK-LABEL: wrong-t2stmia-size-reduction:
; CHECK: stm{{[^,]*}}, {{{.*,.*,.*}}}

6
test/CodeGen/Thumb2/aapcs.ll
View File

@ -33,8 +33,7 @@ define float @float_on_stack(double %a, double %b, double %c, double %d, double
define double @double_on_stack(double %a, double %b, double %c, double %d, double %e, double %f, double %g, double %h, double %i) {
; CHECK-LABEL: double_on_stack:
; SOFT: ldr r0, [sp, #48]
; SOFT: ldr r1, [sp, #52]
; SOFT: ldrd r0, r1, [sp, #48]
; HARD: vldr d0, [sp]
; CHECK-NEXT: bx lr
ret double %i
@ -42,8 +41,7 @@ define double @double_on_stack(double %a, double %b, double %c, double %d, doubl
define double @double_not_split(double %a, double %b, double %c, double %d, double %e, double %f, double %g, float %h, double %i) {
; CHECK-LABEL: double_not_split:
; SOFT: ldr r0, [sp, #48]
; SOFT: ldr r1, [sp, #52]
; SOFT: ldrd r0, r1, [sp, #48]
; HARD: vldr d0, [sp]
; CHECK-NEXT: bx lr
ret double %i