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Shrink ldr / str [sp, imm0-1024] to 16-bit instructions.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89326 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2009-11-19 06:32:27 +00:00
parent a64ce45917
commit 5b397c93a5
2 changed files with 32 additions and 8 deletions
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34
lib/Target/ARM/Thumb2SizeReduction.cpp
View File

@ -105,7 +105,7 @@ namespace {
// FIXME: Clean this up after splitting each Thumb load / store opcode
// into multiple ones.
{ ARM::t2LDRi12,ARM::tLDR, 0, 5, 0, 1, 0, 0,0, 1 },
{ ARM::t2LDRi12,ARM::tLDR, ARM::tLDRspi, 5, 8, 1, 0, 0,0, 1 },
{ ARM::t2LDRs, ARM::tLDR, 0, 0, 0, 1, 0, 0,0, 1 },
{ ARM::t2LDRBi12,ARM::tLDRB, 0, 5, 0, 1, 0, 0,0, 1 },
{ ARM::t2LDRBs, ARM::tLDRB, 0, 0, 0, 1, 0, 0,0, 1 },
@ -113,7 +113,7 @@ namespace {
{ ARM::t2LDRHs, ARM::tLDRH, 0, 0, 0, 1, 0, 0,0, 1 },
{ ARM::t2LDRSBs,ARM::tLDRSB, 0, 0, 0, 1, 0, 0,0, 1 },
{ ARM::t2LDRSHs,ARM::tLDRSH, 0, 0, 0, 1, 0, 0,0, 1 },
{ ARM::t2STRi12,ARM::tSTR, 0, 5, 0, 1, 0, 0,0, 1 },
{ ARM::t2STRi12,ARM::tSTR, ARM::tSTRspi, 5, 8, 1, 0, 0,0, 1 },
{ ARM::t2STRs, ARM::tSTR, 0, 0, 0, 1, 0, 0,0, 1 },
{ ARM::t2STRBi12,ARM::tSTRB, 0, 5, 0, 1, 0, 0,0, 1 },
{ ARM::t2STRBs, ARM::tSTRB, 0, 0, 0, 1, 0, 0,0, 1 },
@ -244,8 +244,13 @@ static bool VerifyLowRegs(MachineInstr *MI) {
continue;
if (isLROk && Reg == ARM::LR)
continue;
if (isSPOk && Reg == ARM::SP)
continue;
if (Reg == ARM::SP) {
if (isSPOk)
continue;
if (i == 1 && (Opc == ARM::t2LDRi12 || Opc == ARM::t2STRi12))
// Special case for these ldr / str with sp as base register.
continue;
}
if (!isARMLowRegister(Reg))
return false;
}
@ -261,17 +266,26 @@ Thumb2SizeReduce::ReduceLoadStore(MachineBasicBlock &MBB, MachineInstr *MI,
unsigned Scale = 1;
bool HasImmOffset = false;
bool HasShift = false;
bool HasOffReg = true;
bool isLdStMul = false;
unsigned Opc = Entry.NarrowOpc1;
unsigned OpNum = 3; // First 'rest' of operands.
uint8_t ImmLimit = Entry.Imm1Limit;
switch (Entry.WideOpc) {
default:
llvm_unreachable("Unexpected Thumb2 load / store opcode!");
case ARM::t2LDRi12:
case ARM::t2STRi12:
case ARM::t2STRi12: {
unsigned BaseReg = MI->getOperand(1).getReg();
if (BaseReg == ARM::SP) {
Opc = Entry.NarrowOpc2;
ImmLimit = Entry.Imm2Limit;
HasOffReg = false;
}
Scale = 4;
HasImmOffset = true;
break;
}
case ARM::t2LDRBi12:
case ARM::t2STRBi12:
HasImmOffset = true;
@ -325,7 +339,7 @@ Thumb2SizeReduce::ReduceLoadStore(MachineBasicBlock &MBB, MachineInstr *MI,
unsigned OffsetImm = 0;
if (HasImmOffset) {
OffsetImm = MI->getOperand(2).getImm();
unsigned MaxOffset = ((1 << Entry.Imm1Limit) - 1) * Scale;
unsigned MaxOffset = ((1 << ImmLimit) - 1) * Scale;
if ((OffsetImm & (Scale-1)) || OffsetImm > MaxOffset)
// Make sure the immediate field fits.
return false;
@ -337,7 +351,7 @@ Thumb2SizeReduce::ReduceLoadStore(MachineBasicBlock &MBB, MachineInstr *MI,
MachineInstrBuilder MIB = BuildMI(MBB, *MI, dl, TII->get(Opc));
if (!isLdStMul) {
MIB.addOperand(MI->getOperand(0)).addOperand(MI->getOperand(1));
if (Entry.NarrowOpc1 != ARM::tLDRSB && Entry.NarrowOpc1 != ARM::tLDRSH) {
if (Opc != ARM::tLDRSB && Opc != ARM::tLDRSH) {
// tLDRSB and tLDRSH do not have an immediate offset field. On the other
// hand, it must have an offset register.
// FIXME: Remove this special case.
@ -345,13 +359,17 @@ Thumb2SizeReduce::ReduceLoadStore(MachineBasicBlock &MBB, MachineInstr *MI,
}
assert((!HasShift || OffsetReg) && "Invalid so_reg load / store address!");
MIB.addReg(OffsetReg, getKillRegState(OffsetKill));
if (HasOffReg)
MIB.addReg(OffsetReg, getKillRegState(OffsetKill));
}
// Transfer the rest of operands.
for (unsigned e = MI->getNumOperands(); OpNum != e; ++OpNum)
MIB.addOperand(MI->getOperand(OpNum));
// Transfer memoperands.
(*MIB).setMemRefs(MI->memoperands_begin(), MI->memoperands_end());
DEBUG(errs() << "Converted 32-bit: " << *MI << " to 16-bit: " << *MIB);
MBB.erase(MI);

6
test/CodeGen/Thumb2/ldr-str-imm12.ll
View File

@ -49,6 +49,12 @@ bb119: ; preds = %bb20, %bb20
unreachable
bb420: ; preds = %bb20, %bb20
; CHECK: bb420
; CHECK: str r{{[0-7]}}, [sp]
; CHECK: str r{{[0-7]}}, [sp, #+4]
; CHECK: str r{{[0-7]}}, [sp, #+8]
; CHECK: ldr r{{[0-7]}}, [sp, #+28]
; CHECK: str r{{[0-7]}}, [sp, #+24]
store %union.rec* null, %union.rec** @zz_hold, align 4
store %union.rec* null, %union.rec** @zz_res, align 4
store %union.rec* %x, %union.rec** @zz_hold, align 4