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Revert "[AArch64] Optimize add/sub with immediate" 

This reverts commit 3de3ca3137.
This commit is contained in:
Ben Shi 2021-11-03 14:15:21 +08:00
parent 5a8b196340
commit 59c3b48d99
3 changed files with 66 additions and 234 deletions
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199
llvm/lib/Target/AArch64/AArch64MIPeepholeOpt.cpp
View File

@ -11,19 +11,12 @@
// 1. MOVi32imm + ANDWrr ==> ANDWri + ANDWri
// MOVi64imm + ANDXrr ==> ANDXri + ANDXri
//
// 2. MOVi32imm + ADDWrr ==> ADDWRi + ADDWRi
// MOVi64imm + ADDXrr ==> ANDXri + ANDXri
//
// 3. MOVi32imm + SUBWrr ==> SUBWRi + SUBWRi
// MOVi64imm + SUBXrr ==> SUBXri + SUBXri
//
// The mov pseudo instruction could be expanded to multiple mov instructions
// later. In this case, we could try to split the constant operand of mov
// instruction into two immediates which can be directly encoded into
// *Wri/*Xri instructions. It makes two AND/ADD/SUB instructions instead of
// multiple `mov` + `and/add/sub` instructions.
// instruction into two bitmask immediates. It makes two AND instructions
// intead of multiple `mov` + `and` instructions.
//
// 4. Remove redundant ORRWrs which is generated by zero-extend.
// 2. Remove redundant ORRWrs which is generated by zero-extend.
//
// %3:gpr32 = ORRWrs $wzr, %2, 0
// %4:gpr64 = SUBREG_TO_REG 0, %3, %subreg.sub_32
@ -58,12 +51,6 @@ struct AArch64MIPeepholeOpt : public MachineFunctionPass {
MachineLoopInfo *MLI;
MachineRegisterInfo *MRI;
bool checkMovImmInstr(MachineInstr &MI, MachineInstr *&MovMI,
MachineInstr *&SubregToRegMI);
template <typename T>
bool visitADDSUB(MachineInstr &MI,
SmallSetVector<MachineInstr *, 8> &ToBeRemoved, bool IsAdd);
template <typename T>
bool visitAND(MachineInstr &MI,
SmallSetVector<MachineInstr *, 8> &ToBeRemoved);
@ -144,9 +131,36 @@ bool AArch64MIPeepholeOpt::visitAND(
assert((RegSize == 32 || RegSize == 64) &&
"Invalid RegSize for AND bitmask peephole optimization");
// Perform several essential checks against current MI.
MachineInstr *MovMI = nullptr, *SubregToRegMI = nullptr;
if (!checkMovImmInstr(MI, MovMI, SubregToRegMI))
// Check whether AND's MBB is in loop and the AND is loop invariant.
MachineBasicBlock *MBB = MI.getParent();
MachineLoop *L = MLI->getLoopFor(MBB);
if (L && !L->isLoopInvariant(MI))
return false;
// Check whether AND's operand is MOV with immediate.
MachineInstr *MovMI = MRI->getUniqueVRegDef(MI.getOperand(2).getReg());
if (!MovMI)
return false;
MachineInstr *SubregToRegMI = nullptr;
// If it is SUBREG_TO_REG, check its operand.
if (MovMI->getOpcode() == TargetOpcode::SUBREG_TO_REG) {
SubregToRegMI = MovMI;
MovMI = MRI->getUniqueVRegDef(MovMI->getOperand(2).getReg());
if (!MovMI)
return false;
}
if (MovMI->getOpcode() != AArch64::MOVi32imm &&
MovMI->getOpcode() != AArch64::MOVi64imm)
return false;
// If the MOV has multiple uses, do not split the immediate because it causes
// more instructions.
if (!MRI->hasOneUse(MovMI->getOperand(0).getReg()))
return false;
if (SubregToRegMI && !MRI->hasOneUse(SubregToRegMI->getOperand(0).getReg()))
return false;
// Split the bitmask immediate into two.
@ -163,7 +177,6 @@ bool AArch64MIPeepholeOpt::visitAND(
// Create new AND MIs.
DebugLoc DL = MI.getDebugLoc();
MachineBasicBlock *MBB = MI.getParent();
const TargetRegisterClass *ANDImmRC =
(RegSize == 32) ? &AArch64::GPR32spRegClass : &AArch64::GPR64spRegClass;
Register DstReg = MI.getOperand(0).getReg();
@ -238,139 +251,6 @@ bool AArch64MIPeepholeOpt::visitORR(
return true;
}
template <typename T>
static bool splitAddSubImm(T Imm, unsigned RegSize, T &Imm0, T &Imm1) {
// The immediate must be in the form of ((imm0 << 12) + imm1), in which both
// imm0 and imm1 are non-zero 12-bit unsigned int.
if ((Imm & 0xfff000) == 0 || (Imm & 0xfff) == 0 ||
(Imm & ~static_cast<T>(0xffffff)) != 0)
return false;
// The immediate can not be composed via a single instruction.
SmallVector<AArch64_IMM::ImmInsnModel, 4> Insn;
AArch64_IMM::expandMOVImm(Imm, RegSize, Insn);
if (Insn.size() == 1)
return false;
// Split Imm into (Imm0 << 12) + Imm1;
Imm0 = (Imm >> 12) & 0xfff;
Imm1 = Imm & 0xfff;
return true;
}
template <typename T>
bool AArch64MIPeepholeOpt::visitADDSUB(
MachineInstr &MI, SmallSetVector<MachineInstr *, 8> &ToBeRemoved,
bool IsAdd) {
// Try below transformation.
//
// MOVi32imm + ADDWrr ==> ANDWri + ANDWri
// MOVi64imm + ADDXrr ==> ANDXri + ANDXri
//
// MOVi32imm + SUBWrr ==> SUBWri + SUBWri
// MOVi64imm + SUBXrr ==> SUBXri + SUBXri
//
// The mov pseudo instruction could be expanded to multiple mov instructions
// later. Let's try to split the constant operand of mov instruction into two
// legal add/sub immediates. It makes only two ADD/SUB instructions intead of
// multiple `mov` + `and/sub` instructions.
unsigned RegSize = sizeof(T) * 8;
assert((RegSize == 32 || RegSize == 64) &&
"Invalid RegSize for legal add/sub immediate peephole optimization");
// Perform several essential checks against current MI.
MachineInstr *MovMI, *SubregToRegMI;
if (!checkMovImmInstr(MI, MovMI, SubregToRegMI))
return false;
// Split the immediate to Imm0 and Imm1, and calculate the Opcode.
T Imm = static_cast<T>(MovMI->getOperand(1).getImm()), Imm0, Imm1;
unsigned Opcode;
if (splitAddSubImm(Imm, RegSize, Imm0, Imm1)) {
if (IsAdd)
Opcode = RegSize == 32 ? AArch64::ADDWri : AArch64::ADDXri;
else
Opcode = RegSize == 32 ? AArch64::SUBWri : AArch64::SUBXri;
} else if (splitAddSubImm(-Imm, RegSize, Imm0, Imm1)) {
if (IsAdd)
Opcode = RegSize == 32 ? AArch64::SUBWri : AArch64::SUBXri;
else
Opcode = RegSize == 32 ? AArch64::ADDWri : AArch64::ADDXri;
} else {
return false;
}
// Create new ADD/SUB MIs.
DebugLoc DL = MI.getDebugLoc();
MachineBasicBlock *MBB = MI.getParent();
const TargetRegisterClass *RC =
(RegSize == 32) ? &AArch64::GPR32spRegClass : &AArch64::GPR64spRegClass;
Register DstReg = MI.getOperand(0).getReg();
Register SrcReg = MI.getOperand(1).getReg();
Register TmpReg = MRI->createVirtualRegister(RC);
MRI->constrainRegClass(SrcReg, RC);
BuildMI(*MBB, MI, DL, TII->get(Opcode), TmpReg)
.addReg(SrcReg)
.addImm(Imm0)
.addImm(12);
MRI->constrainRegClass(DstReg, RC);
BuildMI(*MBB, MI, DL, TII->get(Opcode), DstReg)
.addReg(TmpReg)
.addImm(Imm1)
.addImm(0);
// Record the MIs need to be removed.
ToBeRemoved.insert(&MI);
if (SubregToRegMI)
ToBeRemoved.insert(SubregToRegMI);
ToBeRemoved.insert(MovMI);
return true;
}
// Checks if the corresponding MOV immediate instruction is applicable for
// this peephole optimization.
bool AArch64MIPeepholeOpt::checkMovImmInstr(MachineInstr &MI,
MachineInstr *&MovMI,
MachineInstr *&SubregToRegMI) {
// Check whether current MBB is in loop and the AND is loop invariant.
MachineBasicBlock *MBB = MI.getParent();
MachineLoop *L = MLI->getLoopFor(MBB);
if (L && !L->isLoopInvariant(MI))
return false;
// Check whether current MI's operand is MOV with immediate.
MovMI = MRI->getUniqueVRegDef(MI.getOperand(2).getReg());
if (!MovMI)
return false;
// If it is SUBREG_TO_REG, check its operand.
SubregToRegMI = nullptr;
if (MovMI->getOpcode() == TargetOpcode::SUBREG_TO_REG) {
SubregToRegMI = MovMI;
MovMI = MRI->getUniqueVRegDef(MovMI->getOperand(2).getReg());
if (!MovMI)
return false;
}
if (MovMI->getOpcode() != AArch64::MOVi32imm &&
MovMI->getOpcode() != AArch64::MOVi64imm)
return false;
// If the MOV has multiple uses, do not split the immediate because it causes
// more instructions.
if (!MRI->hasOneUse(MovMI->getOperand(0).getReg()))
return false;
if (SubregToRegMI && !MRI->hasOneUse(SubregToRegMI->getOperand(0).getReg()))
return false;
// It is OK to perform this peephole optimization.
return true;
}
bool AArch64MIPeepholeOpt::runOnMachineFunction(MachineFunction &MF) {
if (skipFunction(MF.getFunction()))
return false;
@ -398,19 +278,6 @@ bool AArch64MIPeepholeOpt::runOnMachineFunction(MachineFunction &MF) {
break;
case AArch64::ORRWrs:
Changed = visitORR(MI, ToBeRemoved);
break;
case AArch64::ADDWrr:
Changed = visitADDSUB<uint32_t>(MI, ToBeRemoved, true);
break;
case AArch64::SUBWrr:
Changed = visitADDSUB<uint32_t>(MI, ToBeRemoved, false);
break;
case AArch64::ADDXrr:
Changed = visitADDSUB<uint64_t>(MI, ToBeRemoved, true);
break;
case AArch64::SUBXrr:
Changed = visitADDSUB<uint64_t>(MI, ToBeRemoved, false);
break;
}
}
}

96
llvm/test/CodeGen/AArch64/addsub.ll
View File

@ -152,8 +152,9 @@ define void @sub_med() {
define i64 @add_two_parts_imm_i64(i64 %a) {
; CHECK-LABEL: add_two_parts_imm_i64:
; CHECK: // %bb.0:
; CHECK-NEXT: add x8, x0, #2730, lsl #12 // =11182080
; CHECK-NEXT: add x0, x8, #1365
; CHECK-NEXT: mov w8, #42325
; CHECK-NEXT: movk w8, #170, lsl #16
; CHECK-NEXT: add x0, x0, x8
; CHECK-NEXT: ret
%b = add i64 %a, 11183445
ret i64 %b
@ -162,8 +163,9 @@ define i64 @add_two_parts_imm_i64(i64 %a) {
define i32 @add_two_parts_imm_i32(i32 %a) {
; CHECK-LABEL: add_two_parts_imm_i32:
; CHECK: // %bb.0:
; CHECK-NEXT: add w8, w0, #2730, lsl #12 // =11182080
; CHECK-NEXT: add w0, w8, #1365
; CHECK-NEXT: mov w8, #42325
; CHECK-NEXT: movk w8, #170, lsl #16
; CHECK-NEXT: add w0, w0, w8
; CHECK-NEXT: ret
%b = add i32 %a, 11183445
ret i32 %b
@ -172,8 +174,9 @@ define i32 @add_two_parts_imm_i32(i32 %a) {
define i64 @add_two_parts_imm_i64_neg(i64 %a) {
; CHECK-LABEL: add_two_parts_imm_i64_neg:
; CHECK: // %bb.0:
; CHECK-NEXT: sub x8, x0, #2730, lsl #12 // =11182080
; CHECK-NEXT: sub x0, x8, #1365
; CHECK-NEXT: mov x8, #-42325
; CHECK-NEXT: movk x8, #65365, lsl #16
; CHECK-NEXT: add x0, x0, x8
; CHECK-NEXT: ret
%b = add i64 %a, -11183445
ret i64 %b
@ -182,8 +185,9 @@ define i64 @add_two_parts_imm_i64_neg(i64 %a) {
define i32 @add_two_parts_imm_i32_neg(i32 %a) {
; CHECK-LABEL: add_two_parts_imm_i32_neg:
; CHECK: // %bb.0:
; CHECK-NEXT: sub w8, w0, #2730, lsl #12 // =11182080
; CHECK-NEXT: sub w0, w8, #1365
; CHECK-NEXT: mov w8, #23211
; CHECK-NEXT: movk w8, #65365, lsl #16
; CHECK-NEXT: add w0, w0, w8
; CHECK-NEXT: ret
%b = add i32 %a, -11183445
ret i32 %b
@ -192,8 +196,9 @@ define i32 @add_two_parts_imm_i32_neg(i32 %a) {
define i64 @sub_two_parts_imm_i64(i64 %a) {
; CHECK-LABEL: sub_two_parts_imm_i64:
; CHECK: // %bb.0:
; CHECK-NEXT: sub x8, x0, #2730, lsl #12 // =11182080
; CHECK-NEXT: sub x0, x8, #1365
; CHECK-NEXT: mov x8, #-42325
; CHECK-NEXT: movk x8, #65365, lsl #16
; CHECK-NEXT: add x0, x0, x8
; CHECK-NEXT: ret
%b = sub i64 %a, 11183445
ret i64 %b
@ -202,8 +207,9 @@ define i64 @sub_two_parts_imm_i64(i64 %a) {
define i32 @sub_two_parts_imm_i32(i32 %a) {
; CHECK-LABEL: sub_two_parts_imm_i32:
; CHECK: // %bb.0:
; CHECK-NEXT: sub w8, w0, #2730, lsl #12 // =11182080
; CHECK-NEXT: sub w0, w8, #1365
; CHECK-NEXT: mov w8, #23211
; CHECK-NEXT: movk w8, #65365, lsl #16
; CHECK-NEXT: add w0, w0, w8
; CHECK-NEXT: ret
%b = sub i32 %a, 11183445
ret i32 %b
@ -212,8 +218,9 @@ define i32 @sub_two_parts_imm_i32(i32 %a) {
define i64 @sub_two_parts_imm_i64_neg(i64 %a) {
; CHECK-LABEL: sub_two_parts_imm_i64_neg:
; CHECK: // %bb.0:
; CHECK-NEXT: add x8, x0, #2730, lsl #12 // =11182080
; CHECK-NEXT: add x0, x8, #1365
; CHECK-NEXT: mov w8, #42325
; CHECK-NEXT: movk w8, #170, lsl #16
; CHECK-NEXT: add x0, x0, x8
; CHECK-NEXT: ret
%b = sub i64 %a, -11183445
ret i64 %b
@ -222,57 +229,14 @@ define i64 @sub_two_parts_imm_i64_neg(i64 %a) {
define i32 @sub_two_parts_imm_i32_neg(i32 %a) {
; CHECK-LABEL: sub_two_parts_imm_i32_neg:
; CHECK: // %bb.0:
; CHECK-NEXT: add w8, w0, #2730, lsl #12 // =11182080
; CHECK-NEXT: add w0, w8, #1365
; CHECK-NEXT: mov w8, #42325
; CHECK-NEXT: movk w8, #170, lsl #16
; CHECK-NEXT: add w0, w0, w8
; CHECK-NEXT: ret
%b = sub i32 %a, -11183445
ret i32 %b
}
define i32 @add_27962026(i32 %a) {
; CHECK-LABEL: add_27962026:
; CHECK: // %bb.0:
; CHECK-NEXT: mov w8, #43690
; CHECK-NEXT: movk w8, #426, lsl #16
; CHECK-NEXT: add w0, w0, w8
; CHECK-NEXT: ret
%b = add i32 %a, 27962026
ret i32 %b
}
define i32 @add_65534(i32 %a) {
; CHECK-LABEL: add_65534:
; CHECK: // %bb.0:
; CHECK-NEXT: mov w8, #65534
; CHECK-NEXT: add w0, w0, w8
; CHECK-NEXT: ret
%b = add i32 %a, 65534
ret i32 %b
}
declare i32 @foox(i32)
define void @add_in_loop(i32 %0) {
; CHECK-LABEL: add_in_loop:
; CHECK: // %bb.0:
; CHECK-NEXT: stp x30, x19, [sp, #-16]! // 16-byte Folded Spill
; CHECK-NEXT: .cfi_def_cfa_offset 16
; CHECK-NEXT: .cfi_offset w19, -8
; CHECK-NEXT: .cfi_offset w30, -16
; CHECK-NEXT: mov w19, #43690
; CHECK-NEXT: movk w19, #170, lsl #16
; CHECK-NEXT: .LBB15_1: // =>This Inner Loop Header: Depth=1
; CHECK-NEXT: add w0, w0, w19
; CHECK-NEXT: bl foox
; CHECK-NEXT: b .LBB15_1
br label %2
2:
%3 = phi i32 [ %0, %1 ], [ %5, %2 ]
%4 = add nsw i32 %3, 11184810
%5 = tail call i32 @foox(i32 %4) #2
br label %2
}
define void @testing() {
; CHECK-LABEL: testing:
; CHECK: // %bb.0:
@ -280,7 +244,7 @@ define void @testing() {
; CHECK-NEXT: ldr x8, [x8, :got_lo12:var_i32]
; CHECK-NEXT: ldr w9, [x8]
; CHECK-NEXT: cmp w9, #4095
; CHECK-NEXT: b.ne .LBB16_6
; CHECK-NEXT: b.ne .LBB13_6
; CHECK-NEXT: // %bb.1: // %test2
; CHECK-NEXT: adrp x10, :got:var2_i32
; CHECK-NEXT: add w11, w9, #1
@ -288,26 +252,26 @@ define void @testing() {
; CHECK-NEXT: str w11, [x8]
; CHECK-NEXT: ldr w10, [x10]
; CHECK-NEXT: cmp w10, #3567, lsl #12 // =14610432
; CHECK-NEXT: b.lo .LBB16_6
; CHECK-NEXT: b.lo .LBB13_6
; CHECK-NEXT: // %bb.2: // %test3
; CHECK-NEXT: add w11, w9, #2
; CHECK-NEXT: cmp w9, #123
; CHECK-NEXT: str w11, [x8]
; CHECK-NEXT: b.lt .LBB16_6
; CHECK-NEXT: b.lt .LBB13_6
; CHECK-NEXT: // %bb.3: // %test4
; CHECK-NEXT: add w11, w9, #3
; CHECK-NEXT: cmp w10, #321
; CHECK-NEXT: str w11, [x8]
; CHECK-NEXT: b.gt .LBB16_6
; CHECK-NEXT: b.gt .LBB13_6
; CHECK-NEXT: // %bb.4: // %test5
; CHECK-NEXT: add w11, w9, #4
; CHECK-NEXT: cmn w10, #443
; CHECK-NEXT: str w11, [x8]
; CHECK-NEXT: b.ge .LBB16_6
; CHECK-NEXT: b.ge .LBB13_6
; CHECK-NEXT: // %bb.5: // %test6
; CHECK-NEXT: add w9, w9, #5
; CHECK-NEXT: str w9, [x8]
; CHECK-NEXT: .LBB16_6: // %common.ret
; CHECK-NEXT: .LBB13_6: // %common.ret
; CHECK-NEXT: ret
%val = load i32, i32* @var_i32
%val2 = load i32, i32* @var2_i32

5
llvm/test/Transforms/CodeGenPrepare/AArch64/large-offset-gep.ll
View File

@ -214,9 +214,10 @@ define void @test5([65536 x i32]** %s, i32 %n) {
; CHECK-LABEL: test5:
; CHECK: // %bb.0: // %entry
; CHECK-NEXT: ldr x9, [x0]
; CHECK-NEXT: mov w10, #14464
; CHECK-NEXT: movk w10, #1, lsl #16
; CHECK-NEXT: mov w8, wzr
; CHECK-NEXT: add x9, x9, #19, lsl #12 // =77824
; CHECK-NEXT: add x9, x9, #2176
; CHECK-NEXT: add x9, x9, x10
; CHECK-NEXT: cmp w8, w1
; CHECK-NEXT: b.ge .LBB4_2
; CHECK-NEXT: .LBB4_1: // %while_body