Revert "[AArch64] Optimize when storing symmetry constants" (#105474)

vitalybuka · web-flow · commit 7f7f4feaf07d · 2024-08-20T23:37:19.000-07:00
Reverts #93717 Introduce stack use after return https://lab.llvm.org/buildbot/#/builders/24/builds/1003
diff --git a/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp b/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp
@@ -226,14 +226,6 @@ struct AArch64LoadStoreOpt : public MachineFunctionPass {
   // Find and merge an index ldr/st instruction into a base ld/st instruction.
   bool tryToMergeIndexLdSt(MachineBasicBlock::iterator &MBBI, int Scale);
 
-  // Finds and collapses loads of symmetric constant value.
-  bool tryFoldSymmetryConstantLoad(MachineBasicBlock::iterator &I,
-                                   unsigned Limit);
-  MachineBasicBlock::iterator
-  doFoldSymmetryConstantLoad(MachineInstr &MI,
-                             SmallVectorImpl<MachineBasicBlock::iterator> &MIs,
-                             int UpperLoadIdx, int Accumulated);
-
   bool optimizeBlock(MachineBasicBlock &MBB, bool EnableNarrowZeroStOpt);
 
   bool runOnMachineFunction(MachineFunction &Fn) override;
@@ -2451,155 +2443,6 @@ AArch64LoadStoreOpt::findMatchingConstOffsetBackward(
   return E;
 }
 
-static bool isSymmetricLoadCandidate(MachineInstr &MI, Register BaseReg) {
-  auto MatchBaseReg = [&](unsigned Count) {
-    for (unsigned I = 0; I < Count; I++) {
-      auto OpI = MI.getOperand(I);
-      if (OpI.isReg() && OpI.getReg() != BaseReg)
-        return false;
-    }
-    return true;
-  };
-
-  unsigned Opc = MI.getOpcode();
-  switch (Opc) {
-  default:
-    return false;
-  case AArch64::MOVZXi:
-    return MatchBaseReg(1);
-  case AArch64::MOVKXi:
-    return MatchBaseReg(2);
-  case AArch64::ORRXrs:
-    MachineOperand &Imm = MI.getOperand(3);
-    // Fourth operand of ORR must be 32 which mean
-    // 32bit symmetric constant load.
-    // ex) renamable $x8 = ORRXrs $x8, $x8, 32
-    if (MatchBaseReg(3) && Imm.isImm() && Imm.getImm() == 32)
-      return true;
-  }
-
-  return false;
-}
-
-MachineBasicBlock::iterator AArch64LoadStoreOpt::doFoldSymmetryConstantLoad(
-    MachineInstr &MI, SmallVectorImpl<MachineBasicBlock::iterator> &MIs,
-    int UpperLoadIdx, int Accumulated) {
-  MachineBasicBlock::iterator I = MI.getIterator();
-  MachineBasicBlock::iterator E = I->getParent()->end();
-  MachineBasicBlock::iterator NextI = next_nodbg(I, E);
-  MachineBasicBlock *MBB = MI.getParent();
-
-  if (!UpperLoadIdx) {
-    // ORR ensures that previous instructions load lower 32-bit constants.
-    // Remove ORR only.
-    (*MIs.begin())->eraseFromParent();
-  } else {
-    // We need to remove MOV for upper of 32bit because we know these instrs
-    // is part of symmetric constant.
-    int Index = 0;
-    for (auto MI = MIs.begin(); Index < UpperLoadIdx; ++MI, Index++) {
-      (*MI)->eraseFromParent();
-    }
-  }
-
-  Register BaseReg = getLdStRegOp(MI).getReg();
-  const MachineOperand MO = AArch64InstrInfo::getLdStBaseOp(MI);
-  Register DstRegW = TRI->getSubReg(BaseReg, AArch64::sub_32);
-  unsigned DstRegState = getRegState(MI.getOperand(0));
-  int Offset = AArch64InstrInfo::getLdStOffsetOp(MI).getImm();
-  BuildMI(*MBB, MI, MI.getDebugLoc(), TII->get(AArch64::STPWi))
-      .addReg(DstRegW, DstRegState)
-      .addReg(DstRegW, DstRegState)
-      .addReg(MO.getReg(), getRegState(MO))
-      .addImm(Offset * 2)
-      .setMemRefs(MI.memoperands())
-      .setMIFlags(MI.getFlags());
-  I->eraseFromParent();
-  return NextI;
-}
-
-bool AArch64LoadStoreOpt::tryFoldSymmetryConstantLoad(
-    MachineBasicBlock::iterator &I, unsigned Limit) {
-  MachineInstr &MI = *I;
-  if (MI.getOpcode() != AArch64::STRXui)
-    return false;
-
-  MachineBasicBlock::iterator MBBI = I;
-  MachineBasicBlock::iterator B = I->getParent()->begin();
-  if (MBBI == B)
-    return false;
-
-  TypeSize Scale(0U, false), Width(0U, false);
-  int64_t MinOffset, MaxOffset;
-  if (!AArch64InstrInfo::getMemOpInfo(AArch64::STPWi, Scale, Width, MinOffset,
-                                      MaxOffset))
-    return false;
-
-  // We replace the STRX instruction, which stores 64 bits, with the STPW
-  // instruction, which stores two consecutive 32 bits. Therefore, we compare
-  // the offset range with multiplied by two.
-  int Offset = AArch64InstrInfo::getLdStOffsetOp(MI).getImm();
-  if (Offset * 2 < MinOffset || Offset * 2 > MaxOffset)
-    return false;
-
-  Register BaseReg = getLdStRegOp(MI).getReg();
-  unsigned Count = 0, UpperLoadIdx = 0;
-  uint64_t Accumulated = 0, Mask = 0xFFFFUL;
-  bool hasORR = false, Found = false;
-  SmallVector<MachineBasicBlock::iterator> MIs;
-  ModifiedRegUnits.clear();
-  UsedRegUnits.clear();
-  do {
-    MBBI = prev_nodbg(MBBI, B);
-    MachineInstr &MI = *MBBI;
-    if (!MI.isTransient())
-      ++Count;
-    if (!isSymmetricLoadCandidate(MI, BaseReg)) {
-      LiveRegUnits::accumulateUsedDefed(MI, ModifiedRegUnits, UsedRegUnits,
-                                        TRI);
-      if (!ModifiedRegUnits.available(BaseReg) ||
-          !UsedRegUnits.available(BaseReg))
-        return false;
-      continue;
-    }
-
-    unsigned Opc = MI.getOpcode();
-    if (Opc == AArch64::ORRXrs) {
-      hasORR = true;
-      MIs.push_back(MBBI);
-      continue;
-    }
-    unsigned ValueOrder = Opc == AArch64::MOVZXi ? 1 : 2;
-    MachineOperand Value = MI.getOperand(ValueOrder);
-    MachineOperand Shift = MI.getOperand(ValueOrder + 1);
-    if (!Value.isImm() || !Shift.isImm())
-      return false;
-
-    uint64_t IValue = Value.getImm();
-    uint64_t IShift = Shift.getImm();
-    uint64_t Adder = IValue << IShift;
-    MIs.push_back(MBBI);
-    if (Adder >> 32)
-      UpperLoadIdx = MIs.size();
-
-    Accumulated -= Accumulated & (Mask << IShift);
-    Accumulated += Adder;
-    if (Accumulated != 0 &&
-        (((Accumulated >> 32) == (Accumulated & 0xffffffffULL)) ||
-         (hasORR && (Accumulated >> 32 == 0)))) {
-      Found = true;
-      break;
-    }
-  } while (MBBI != B && Count < Limit);
-
-  if (Found) {
-    I = doFoldSymmetryConstantLoad(MI, MIs, UpperLoadIdx, Accumulated);
-    return true;
-  }
-
-  return false;
-}
-
 bool AArch64LoadStoreOpt::tryToPromoteLoadFromStore(
     MachineBasicBlock::iterator &MBBI) {
   MachineInstr &MI = *MBBI;
@@ -2910,27 +2753,6 @@ bool AArch64LoadStoreOpt::optimizeBlock(MachineBasicBlock &MBB,
       ++MBBI;
   }
 
-  // We have an opportunity to optimize the `STRXui` instruction, which loads
-  // the same 32-bit value into a register twice. The `STPXi` instruction allows
-  // us to load a 32-bit value only once.
-  // Considering :
-  // renamable $x8 = MOVZXi 49370, 0
-  // renamable $x8 = MOVKXi $x8, 320, 16
-  // renamable $x8 = ORRXrs $x8, $x8, 32
-  // STRXui killed renamable $x8, killed renamable $x0, 0
-  // Transform :
-  // $w8 = MOVZWi 49370, 0
-  // $w8 = MOVKWi $w8, 320, 16
-  // STPWi killed renamable $w8, killed renamable $w8, killed renamable $x0, 0
-  for (MachineBasicBlock::iterator MBBI = MBB.begin(), E = MBB.end();
-       MBBI != E;) {
-    if (isMergeableLdStUpdate(*MBBI) &&
-        tryFoldSymmetryConstantLoad(MBBI, UpdateLimit))
-      Modified = true;
-    else
-      ++MBBI;
-  }
-
   return Modified;
 }
 
diff --git a/llvm/test/CodeGen/AArch64/movimm-expand-ldst.ll b/llvm/test/CodeGen/AArch64/movimm-expand-ldst.ll
@@ -93,183 +93,3 @@ define i64 @testuu0xf555f555f555f555() {
 ; CHECK-NEXT:    ret
   ret i64 u0xf555f555f555f555
 }
-
-define void @test_store_0x1234567812345678(ptr %x) {
-; CHECK-LABEL: test_store_0x1234567812345678:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #22136 // =0x5678
-; CHECK-NEXT:    movk x8, #4660, lsl #16
-; CHECK-NEXT:    stp w8, w8, [x0]
-; CHECK-NEXT:    ret
-  store i64 u0x1234567812345678, ptr %x
-  ret void
-}
-
-define void @test_store_0xff3456ffff3456ff(ptr %x) {
-; CHECK-LABEL: test_store_0xff3456ffff3456ff:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #22271 // =0x56ff
-; CHECK-NEXT:    movk x8, #65332, lsl #16
-; CHECK-NEXT:    stp w8, w8, [x0]
-; CHECK-NEXT:    ret
-  store i64 u0xff3456ffff3456ff, ptr %x
-  ret void
-}
-
-define void @test_store_0x00345600345600(ptr %x) {
-; CHECK-LABEL: test_store_0x00345600345600:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #22016 // =0x5600
-; CHECK-NEXT:    movk x8, #52, lsl #16
-; CHECK-NEXT:    movk x8, #13398, lsl #32
-; CHECK-NEXT:    str x8, [x0]
-; CHECK-NEXT:    ret
-  store i64 u0x00345600345600, ptr %x
-  ret void
-}
-
-define void @test_store_0x5555555555555555(ptr %x) {
-; CHECK-LABEL: test_store_0x5555555555555555:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #6148914691236517205 // =0x5555555555555555
-; CHECK-NEXT:    str x8, [x0]
-; CHECK-NEXT:    ret
-  store i64 u0x5555555555555555, ptr %x
-  ret void
-}
-
-define void @test_store_0x5055555550555555(ptr %x) {
-; CHECK-LABEL: test_store_0x5055555550555555:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #6148914691236517205 // =0x5555555555555555
-; CHECK-NEXT:    and x8, x8, #0xf0fffffff0ffffff
-; CHECK-NEXT:    str x8, [x0]
-; CHECK-NEXT:    ret
-  store i64 u0x5055555550555555, ptr %x
-  ret void
-}
-
-define void @test_store_0x0000555555555555(ptr %x) {
-; CHECK-LABEL: test_store_0x0000555555555555:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #6148914691236517205 // =0x5555555555555555
-; CHECK-NEXT:    movk x8, #0, lsl #48
-; CHECK-NEXT:    str x8, [x0]
-; CHECK-NEXT:    ret
-  store i64 u0x0000555555555555, ptr %x
-  ret void
-}
-
-define void @test_store_0x0000555500005555(ptr %x) {
-; CHECK-LABEL: test_store_0x0000555500005555:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #21845 // =0x5555
-; CHECK-NEXT:    stp w8, w8, [x0]
-; CHECK-NEXT:    ret
-  store i64 u0x0000555500005555, ptr %x
-  ret void
-}
-
-define void @test_store_0x5555000055550000(ptr %x) {
-; CHECK-LABEL: test_store_0x5555000055550000:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #1431633920 // =0x55550000
-; CHECK-NEXT:    stp w8, w8, [x0]
-; CHECK-NEXT:    ret
-  store i64 u0x5555000055550000, ptr %x
-  ret void
-}
-
-define void @test_store_u0xffff5555ffff5555(ptr %x) {
-; CHECK-LABEL: test_store_u0xffff5555ffff5555:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #-43691 // =0xffffffffffff5555
-; CHECK-NEXT:    movk x8, #21845, lsl #32
-; CHECK-NEXT:    str x8, [x0]
-; CHECK-NEXT:    ret
-  store i64 u0xffff5555ffff5555, ptr %x
-  ret void
-}
-
-define void @test_store_0x8888ffff8888ffff(ptr %x) {
-; CHECK-LABEL: test_store_0x8888ffff8888ffff:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #-2004287489 // =0xffffffff8888ffff
-; CHECK-NEXT:    movk x8, #34952, lsl #48
-; CHECK-NEXT:    str x8, [x0]
-; CHECK-NEXT:    ret
-  store i64 u0x8888ffff8888ffff, ptr %x
-  ret void
-}
-
-define void @test_store_uu0xfffff555f555f555(ptr %x) {
-; CHECK-LABEL: test_store_uu0xfffff555f555f555:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #-2731 // =0xfffffffffffff555
-; CHECK-NEXT:    movk x8, #62805, lsl #16
-; CHECK-NEXT:    movk x8, #62805, lsl #32
-; CHECK-NEXT:    str x8, [x0]
-; CHECK-NEXT:    ret
-  store i64 u0xfffff555f555f555, ptr %x
-  ret void
-}
-
-define void @test_store_uu0xf555f555f555f555(ptr %x) {
-; CHECK-LABEL: test_store_uu0xf555f555f555f555:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #6148914691236517205 // =0x5555555555555555
-; CHECK-NEXT:    orr x8, x8, #0xe001e001e001e001
-; CHECK-NEXT:    str x8, [x0]
-; CHECK-NEXT:    ret
-  store i64 u0xf555f555f555f555, ptr %x
-  ret void
-}
-
-define void @test_store_0x1234567812345678_offset_range(ptr %x) {
-; CHECK-LABEL: test_store_0x1234567812345678_offset_range:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #22136 // =0x5678
-; CHECK-NEXT:    movk x8, #4660, lsl #16
-; CHECK-NEXT:    stp w8, w8, [x0, #32]
-; CHECK-NEXT:    ret
-  %g = getelementptr i64, ptr %x, i64 4
-  store i64 u0x1234567812345678, ptr %g
-  ret void
-}
-
-define void @test_store_0x1234567812345678_offset_min(ptr %x) {
-; CHECK-LABEL: test_store_0x1234567812345678_offset_min:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #22136 // =0x5678
-; CHECK-NEXT:    movk x8, #4660, lsl #16
-; CHECK-NEXT:    stp w8, w8, [x0]
-; CHECK-NEXT:    ret
-  %g = getelementptr i8, ptr %x, i32 0
-  store i64 u0x1234567812345678, ptr %g
-  ret void
-}
-
-define void @test_store_0x1234567812345678_offset_max(ptr %x) {
-; CHECK-LABEL: test_store_0x1234567812345678_offset_max:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #22136 // =0x5678
-; CHECK-NEXT:    movk x8, #4660, lsl #16
-; CHECK-NEXT:    stp w8, w8, [x0, #248]
-; CHECK-NEXT:    ret
-  %g = getelementptr i8, ptr %x, i32 248
-  store i64 u0x1234567812345678, ptr %g
-  ret void
-}
-
-define void @test_store_0x1234567812345678_offset_max_over(ptr %x) {
-; CHECK-LABEL: test_store_0x1234567812345678_offset_max_over:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x8, #22136 // =0x5678
-; CHECK-NEXT:    movk x8, #4660, lsl #16
-; CHECK-NEXT:    orr x8, x8, x8, lsl #32
-; CHECK-NEXT:    stur x8, [x0, #249]
-; CHECK-NEXT:    ret
-  %g = getelementptr i8, ptr %x, i32 249
-  store i64 u0x1234567812345678, ptr %g
-  ret void
-}
diff --git a/llvm/test/CodeGen/AArch64/movimm-expand-ldst.mir b/llvm/test/CodeGen/AArch64/movimm-expand-ldst.mir
