[ARMv8] Prevent generation of deprecated IT blocks on ARMv8 in Thumb mode.
IT blocks can only be one instruction lonf, and can only contain a subset of
the 16 instructions.
Patch by Artyom Skrobov!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190309 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMBaseInstrInfo.cpp b/lib/Target/ARM/ARMBaseInstrInfo.cpp
index 62e8063..696d039 100644
--- a/lib/Target/ARM/ARMBaseInstrInfo.cpp
+++ b/lib/Target/ARM/ARMBaseInstrInfo.cpp
@@ -513,6 +513,74 @@
return Found;
}
+static bool isV8EligibleForIT(MachineInstr *MI) {
+ switch (MI->getOpcode()) {
+ default:
+ return false;
+ case ARM::tADC:
+ case ARM::tADDi3:
+ case ARM::tADDi8:
+ case ARM::tADDrSPi:
+ case ARM::tADDrr:
+ case ARM::tAND:
+ case ARM::tASRri:
+ case ARM::tASRrr:
+ case ARM::tBIC:
+ case ARM::tCMNz:
+ case ARM::tCMPi8:
+ case ARM::tCMPr:
+ case ARM::tEOR:
+ case ARM::tLDRBi:
+ case ARM::tLDRBr:
+ case ARM::tLDRHi:
+ case ARM::tLDRHr:
+ case ARM::tLDRSB:
+ case ARM::tLDRSH:
+ case ARM::tLDRi:
+ case ARM::tLDRr:
+ case ARM::tLDRspi:
+ case ARM::tLSLri:
+ case ARM::tLSLrr:
+ case ARM::tLSRri:
+ case ARM::tLSRrr:
+ case ARM::tMOVi8:
+ case ARM::tMUL:
+ case ARM::tMVN:
+ case ARM::tORR:
+ case ARM::tROR:
+ case ARM::tRSB:
+ case ARM::tSBC:
+ case ARM::tSTRBi:
+ case ARM::tSTRBr:
+ case ARM::tSTRHi:
+ case ARM::tSTRHr:
+ case ARM::tSTRi:
+ case ARM::tSTRr:
+ case ARM::tSTRspi:
+ case ARM::tSUBi3:
+ case ARM::tSUBi8:
+ case ARM::tSUBrr:
+ case ARM::tTST:
+ return true;
+// there are some "conditionally deprecated" opcodes
+ case ARM::tADDspr:
+ return MI->getOperand(2).getReg() != ARM::PC;
+ case ARM::tADDrSP:
+ case ARM::tBX:
+ case ARM::tBLXr:
+ // ADD PC, SP and BLX PC were always unpredictable,
+ // now on top of it they're deprecated
+ return MI->getOperand(0).getReg() != ARM::PC;
+ case ARM::tADDhirr:
+ return MI->getOperand(0).getReg() != ARM::PC &&
+ MI->getOperand(2).getReg() != ARM::PC;
+ case ARM::tCMPhir:
+ case ARM::tMOVr:
+ return MI->getOperand(0).getReg() != ARM::PC &&
+ MI->getOperand(1).getReg() != ARM::PC;
+ }
+}
+
/// isPredicable - Return true if the specified instruction can be predicated.
/// By default, this returns true for every instruction with a
/// PredicateOperand.
@@ -520,11 +588,17 @@
if (!MI->isPredicable())
return false;
- if ((MI->getDesc().TSFlags & ARMII::DomainMask) == ARMII::DomainNEON) {
- ARMFunctionInfo *AFI =
- MI->getParent()->getParent()->getInfo<ARMFunctionInfo>();
- return AFI->isThumb2Function();
+ ARMFunctionInfo *AFI =
+ MI->getParent()->getParent()->getInfo<ARMFunctionInfo>();
+
+ if (AFI->isThumb2Function()) {
+ if (getSubtarget().hasV8Ops())
+ return isV8EligibleForIT(MI);
+ } else { // non-Thumb
+ if ((MI->getDesc().TSFlags & ARMII::DomainMask) == ARMII::DomainNEON)
+ return false;
}
+
return true;
}
diff --git a/lib/Target/ARM/ARMFastISel.cpp b/lib/Target/ARM/ARMFastISel.cpp
index 3cbb9a8..f3a74c7 100644
--- a/lib/Target/ARM/ARMFastISel.cpp
+++ b/lib/Target/ARM/ARMFastISel.cpp
@@ -254,10 +254,10 @@
bool ARMFastISel::isARMNEONPred(const MachineInstr *MI) {
const MCInstrDesc &MCID = MI->getDesc();
- // If we're a thumb2 or not NEON function we were handled via isPredicable.
+ // If we're a thumb2 or not NEON function we'll be handled via isPredicable.
if ((MCID.TSFlags & ARMII::DomainMask) != ARMII::DomainNEON ||
AFI->isThumb2Function())
- return false;
+ return MI->isPredicable();
for (unsigned i = 0, e = MCID.getNumOperands(); i != e; ++i)
if (MCID.OpInfo[i].isPredicate())
@@ -278,7 +278,7 @@
// Do we use a predicate? or...
// Are we NEON in ARM mode and have a predicate operand? If so, I know
// we're not predicable but add it anyways.
- if (TII.isPredicable(MI) || isARMNEONPred(MI))
+ if (isARMNEONPred(MI))
AddDefaultPred(MIB);
// Do we optionally set a predicate? Preds is size > 0 iff the predicate
diff --git a/lib/Target/ARM/ARMTargetMachine.cpp b/lib/Target/ARM/ARMTargetMachine.cpp
index 1ba78e4..c78db54 100644
--- a/lib/Target/ARM/ARMTargetMachine.cpp
+++ b/lib/Target/ARM/ARMTargetMachine.cpp
@@ -196,8 +196,13 @@
addPass(createARMExpandPseudoPass());
if (getOptLevel() != CodeGenOpt::None) {
- if (!getARMSubtarget().isThumb1Only())
+ if (!getARMSubtarget().isThumb1Only()) {
+ // in v8, IfConversion depends on Thumb instruction widths
+ if (getARMSubtarget().hasV8Ops() &&
+ !getARMSubtarget().prefers32BitThumb())
+ addPass(createThumb2SizeReductionPass());
addPass(&IfConverterID);
+ }
}
if (getARMSubtarget().isThumb2())
addPass(createThumb2ITBlockPass());
diff --git a/lib/Target/ARM/Thumb2ITBlockPass.cpp b/lib/Target/ARM/Thumb2ITBlockPass.cpp
index d8596d7..8f1ae2e 100644
--- a/lib/Target/ARM/Thumb2ITBlockPass.cpp
+++ b/lib/Target/ARM/Thumb2ITBlockPass.cpp
@@ -28,6 +28,7 @@
static char ID;
Thumb2ITBlockPass() : MachineFunctionPass(ID) {}
+ bool hasV8Ops;
const Thumb2InstrInfo *TII;
const TargetRegisterInfo *TRI;
ARMFunctionInfo *AFI;
@@ -192,37 +193,41 @@
// Form IT block.
ARMCC::CondCodes OCC = ARMCC::getOppositeCondition(CC);
unsigned Mask = 0, Pos = 3;
- // Branches, including tricky ones like LDM_RET, need to end an IT
- // block so check the instruction we just put in the block.
- for (; MBBI != E && Pos &&
- (!MI->isBranch() && !MI->isReturn()) ; ++MBBI) {
- if (MBBI->isDebugValue())
- continue;
- MachineInstr *NMI = &*MBBI;
- MI = NMI;
-
- unsigned NPredReg = 0;
- ARMCC::CondCodes NCC = getITInstrPredicate(NMI, NPredReg);
- if (NCC == CC || NCC == OCC) {
- Mask |= (NCC & 1) << Pos;
- // Add implicit use of ITSTATE.
- NMI->addOperand(MachineOperand::CreateReg(ARM::ITSTATE, false/*ifDef*/,
- true/*isImp*/, false/*isKill*/));
- LastITMI = NMI;
- } else {
- if (NCC == ARMCC::AL &&
- MoveCopyOutOfITBlock(NMI, CC, OCC, Defs, Uses)) {
- --MBBI;
- MBB.remove(NMI);
- MBB.insert(InsertPos, NMI);
- ++NumMovedInsts;
+ // v8 IT blocks are limited to one conditional op: skip the loop
+ if (!hasV8Ops) {
+ // Branches, including tricky ones like LDM_RET, need to end an IT
+ // block so check the instruction we just put in the block.
+ for (; MBBI != E && Pos &&
+ (!MI->isBranch() && !MI->isReturn()) ; ++MBBI) {
+ if (MBBI->isDebugValue())
continue;
+
+ MachineInstr *NMI = &*MBBI;
+ MI = NMI;
+
+ unsigned NPredReg = 0;
+ ARMCC::CondCodes NCC = getITInstrPredicate(NMI, NPredReg);
+ if (NCC == CC || NCC == OCC) {
+ Mask |= (NCC & 1) << Pos;
+ // Add implicit use of ITSTATE.
+ NMI->addOperand(MachineOperand::CreateReg(ARM::ITSTATE, false/*ifDef*/,
+ true/*isImp*/, false/*isKill*/));
+ LastITMI = NMI;
+ } else {
+ if (NCC == ARMCC::AL &&
+ MoveCopyOutOfITBlock(NMI, CC, OCC, Defs, Uses)) {
+ --MBBI;
+ MBB.remove(NMI);
+ MBB.insert(InsertPos, NMI);
+ ++NumMovedInsts;
+ continue;
+ }
+ break;
}
- break;
+ TrackDefUses(NMI, Defs, Uses, TRI);
+ --Pos;
}
- TrackDefUses(NMI, Defs, Uses, TRI);
- --Pos;
}
// Finalize IT mask.
@@ -250,6 +255,7 @@
AFI = Fn.getInfo<ARMFunctionInfo>();
TII = static_cast<const Thumb2InstrInfo*>(TM.getInstrInfo());
TRI = TM.getRegisterInfo();
+ hasV8Ops = TM.getSubtarget<ARMSubtarget>().hasV8Ops();
if (!AFI->isThumbFunction())
return false;