- More refactoring. This gets rid of all of the getOpcode calls.
- This change also makes it possible to switch between ARM / Thumb on a
per-function basis.
- Fixed thumb2 routine which expand reg + arbitrary immediate. It was using
using ARM so_imm logic.
- Use movw and movt to do reg + imm when profitable.
- Other code clean ups and minor optimizations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77300 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/Thumb2InstrInfo.cpp b/lib/Target/ARM/Thumb2InstrInfo.cpp
index ede8ab4..0c31820 100644
--- a/lib/Target/ARM/Thumb2InstrInfo.cpp
+++ b/lib/Target/ARM/Thumb2InstrInfo.cpp
@@ -13,6 +13,7 @@
#include "ARMInstrInfo.h"
#include "ARM.h"
+#include "ARMAddressingModes.h"
#include "ARMGenInstrInfo.inc"
#include "ARMMachineFunctionInfo.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
@@ -31,18 +32,6 @@
return 0;
}
-unsigned Thumb2InstrInfo::getOpcode(ARMII::Op Op) const {
- switch (Op) {
- case ARMII::ADDri: return ARM::t2ADDri;
- case ARMII::MOVr: return ARM::t2MOVr;
- case ARMII::SUBri: return ARM::t2SUBri;
- default:
- break;
- }
-
- return 0;
-}
-
bool
Thumb2InstrInfo::BlockHasNoFallThrough(const MachineBasicBlock &MBB) const {
if (MBB.empty()) return false;
@@ -124,3 +113,319 @@
ARMBaseInstrInfo::loadRegFromStackSlot(MBB, I, DestReg, FI, RC);
}
+
+
+void llvm::emitT2RegPlusImmediate(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator &MBBI, DebugLoc dl,
+ unsigned DestReg, unsigned BaseReg, int NumBytes,
+ ARMCC::CondCodes Pred, unsigned PredReg,
+ const ARMBaseInstrInfo &TII) {
+ bool isSub = NumBytes < 0;
+ if (isSub) NumBytes = -NumBytes;
+
+ // If profitable, use a movw or movt to materialize the offset.
+ // FIXME: Use the scavenger to grab a scratch register.
+ if (DestReg != ARM::SP && DestReg != BaseReg &&
+ NumBytes >= 4096 &&
+ ARM_AM::getT2SOImmVal(NumBytes) == -1) {
+ bool Fits = false;
+ if (NumBytes < 65536) {
+ // Use a movw to materialize the 16-bit constant.
+ BuildMI(MBB, MBBI, dl, TII.get(ARM::t2MOVi16), DestReg)
+ .addImm(NumBytes)
+ .addImm((unsigned)Pred).addReg(PredReg).addReg(0);
+ Fits = true;
+ } else if ((NumBytes & 0xffff) == 0) {
+ // Use a movt to materialize the 32-bit constant.
+ BuildMI(MBB, MBBI, dl, TII.get(ARM::t2MOVTi16), DestReg)
+ .addReg(DestReg)
+ .addImm(NumBytes >> 16)
+ .addImm((unsigned)Pred).addReg(PredReg).addReg(0);
+ Fits = true;
+ }
+
+ if (Fits) {
+ if (isSub) {
+ BuildMI(MBB, MBBI, dl, TII.get(ARM::t2SUBrr), DestReg)
+ .addReg(BaseReg, RegState::Kill)
+ .addReg(DestReg, RegState::Kill)
+ .addImm((unsigned)Pred).addReg(PredReg).addReg(0);
+ } else {
+ BuildMI(MBB, MBBI, dl, TII.get(ARM::t2ADDrr), DestReg)
+ .addReg(DestReg, RegState::Kill)
+ .addReg(BaseReg, RegState::Kill)
+ .addImm((unsigned)Pred).addReg(PredReg).addReg(0);
+ }
+ return;
+ }
+ }
+
+ while (NumBytes) {
+ unsigned Opc = isSub ? ARM::t2SUBri : ARM::t2ADDri;
+ unsigned ThisVal = NumBytes;
+ if (ARM_AM::getT2SOImmVal(NumBytes) != -1) {
+ NumBytes = 0;
+ } else if (ThisVal < 4096) {
+ Opc = isSub ? ARM::t2SUBri12 : ARM::t2ADDri12;
+ NumBytes = 0;
+ } else {
+ // FIXME: Move this to ARMAddressingModes.h?
+ unsigned RotAmt = CountLeadingZeros_32(ThisVal);
+ ThisVal = ThisVal & ARM_AM::rotr32(0xff000000U, RotAmt);
+ NumBytes &= ~ThisVal;
+ assert(ARM_AM::getT2SOImmVal(ThisVal) != -1 &&
+ "Bit extraction didn't work?");
+ }
+
+ // Build the new ADD / SUB.
+ BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg)
+ .addReg(BaseReg, RegState::Kill).addImm(ThisVal)
+ .addImm((unsigned)Pred).addReg(PredReg).addReg(0);
+ BaseReg = DestReg;
+ }
+}
+
+static unsigned
+negativeOffsetOpcode(unsigned opcode)
+{
+ switch (opcode) {
+ case ARM::t2LDRi12: return ARM::t2LDRi8;
+ case ARM::t2LDRHi12: return ARM::t2LDRHi8;
+ case ARM::t2LDRBi12: return ARM::t2LDRBi8;
+ case ARM::t2LDRSHi12: return ARM::t2LDRSHi8;
+ case ARM::t2LDRSBi12: return ARM::t2LDRSBi8;
+ case ARM::t2STRi12: return ARM::t2STRi8;
+ case ARM::t2STRBi12: return ARM::t2STRBi8;
+ case ARM::t2STRHi12: return ARM::t2STRHi8;
+
+ case ARM::t2LDRi8:
+ case ARM::t2LDRHi8:
+ case ARM::t2LDRBi8:
+ case ARM::t2LDRSHi8:
+ case ARM::t2LDRSBi8:
+ case ARM::t2STRi8:
+ case ARM::t2STRBi8:
+ case ARM::t2STRHi8:
+ return opcode;
+
+ default:
+ break;
+ }
+
+ return 0;
+}
+
+static unsigned
+positiveOffsetOpcode(unsigned opcode)
+{
+ switch (opcode) {
+ case ARM::t2LDRi8: return ARM::t2LDRi12;
+ case ARM::t2LDRHi8: return ARM::t2LDRHi12;
+ case ARM::t2LDRBi8: return ARM::t2LDRBi12;
+ case ARM::t2LDRSHi8: return ARM::t2LDRSHi12;
+ case ARM::t2LDRSBi8: return ARM::t2LDRSBi12;
+ case ARM::t2STRi8: return ARM::t2STRi12;
+ case ARM::t2STRBi8: return ARM::t2STRBi12;
+ case ARM::t2STRHi8: return ARM::t2STRHi12;
+
+ case ARM::t2LDRi12:
+ case ARM::t2LDRHi12:
+ case ARM::t2LDRBi12:
+ case ARM::t2LDRSHi12:
+ case ARM::t2LDRSBi12:
+ case ARM::t2STRi12:
+ case ARM::t2STRBi12:
+ case ARM::t2STRHi12:
+ return opcode;
+
+ default:
+ break;
+ }
+
+ return 0;
+}
+
+static unsigned
+immediateOffsetOpcode(unsigned opcode)
+{
+ switch (opcode) {
+ case ARM::t2LDRs: return ARM::t2LDRi12;
+ case ARM::t2LDRHs: return ARM::t2LDRHi12;
+ case ARM::t2LDRBs: return ARM::t2LDRBi12;
+ case ARM::t2LDRSHs: return ARM::t2LDRSHi12;
+ case ARM::t2LDRSBs: return ARM::t2LDRSBi12;
+ case ARM::t2STRs: return ARM::t2STRi12;
+ case ARM::t2STRBs: return ARM::t2STRBi12;
+ case ARM::t2STRHs: return ARM::t2STRHi12;
+
+ case ARM::t2LDRi12:
+ case ARM::t2LDRHi12:
+ case ARM::t2LDRBi12:
+ case ARM::t2LDRSHi12:
+ case ARM::t2LDRSBi12:
+ case ARM::t2STRi12:
+ case ARM::t2STRBi12:
+ case ARM::t2STRHi12:
+ case ARM::t2LDRi8:
+ case ARM::t2LDRHi8:
+ case ARM::t2LDRBi8:
+ case ARM::t2LDRSHi8:
+ case ARM::t2LDRSBi8:
+ case ARM::t2STRi8:
+ case ARM::t2STRBi8:
+ case ARM::t2STRHi8:
+ return opcode;
+
+ default:
+ break;
+ }
+
+ return 0;
+}
+
+int llvm::rewriteT2FrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
+ unsigned FrameReg, int Offset,
+ const ARMBaseInstrInfo &TII) {
+ unsigned Opcode = MI.getOpcode();
+ unsigned NewOpc = Opcode;
+ const TargetInstrDesc &Desc = MI.getDesc();
+ unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
+ bool isSub = false;
+
+ // Memory operands in inline assembly always use AddrModeT2_i12.
+ if (Opcode == ARM::INLINEASM)
+ AddrMode = ARMII::AddrModeT2_i12; // FIXME. mode for thumb2?
+
+ if (Opcode == ARM::t2ADDri || Opcode == ARM::t2ADDri12) {
+ Offset += MI.getOperand(FrameRegIdx+1).getImm();
+ if (Offset == 0) {
+ // Turn it into a move.
+ MI.setDesc(TII.get(ARM::t2MOVr));
+ MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
+ MI.RemoveOperand(FrameRegIdx+1);
+ return 0;
+ }
+
+ if (Offset < 0) {
+ Offset = -Offset;
+ isSub = true;
+ MI.setDesc(TII.get(ARM::t2SUBri));
+ }
+
+ // Common case: small offset, fits into instruction.
+ if (ARM_AM::getT2SOImmVal(Offset) != -1) {
+ NewOpc = isSub ? ARM::t2SUBri : ARM::t2ADDri;
+ if (NewOpc != Opcode)
+ MI.setDesc(TII.get(NewOpc));
+ MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
+ MI.getOperand(FrameRegIdx+1).ChangeToImmediate(Offset);
+ return 0;
+ }
+ // Another common case: imm12.
+ if (Offset < 4096) {
+ NewOpc = isSub ? ARM::t2SUBri12 : ARM::t2ADDri12;
+ if (NewOpc != Opcode)
+ MI.setDesc(TII.get(NewOpc));
+ MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
+ MI.getOperand(FrameRegIdx+1).ChangeToImmediate(Offset);
+ return 0;
+ }
+
+ // Otherwise, extract 8 adjacent bits from the immediate into this
+ // t2ADDri/t2SUBri.
+ unsigned RotAmt = CountLeadingZeros_32(Offset);
+ unsigned ThisImmVal = Offset & ARM_AM::rotr32(0xff000000U, RotAmt);
+
+ // We will handle these bits from offset, clear them.
+ Offset &= ~ThisImmVal;
+
+ assert(ARM_AM::getT2SOImmVal(ThisImmVal) != -1 &&
+ "Bit extraction didn't work?");
+ MI.getOperand(FrameRegIdx+1).ChangeToImmediate(ThisImmVal);
+ } else {
+ // AddrModeT2_so cannot handle any offset. If there is no offset
+ // register then we change to an immediate version.
+ NewOpc = Opcode;
+ if (AddrMode == ARMII::AddrModeT2_so) {
+ unsigned OffsetReg = MI.getOperand(FrameRegIdx+1).getReg();
+ if (OffsetReg != 0) {
+ MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
+ return Offset;
+ }
+
+ MI.RemoveOperand(FrameRegIdx+1);
+ MI.getOperand(FrameRegIdx+1).ChangeToImmediate(0);
+ NewOpc = immediateOffsetOpcode(Opcode);
+ AddrMode = ARMII::AddrModeT2_i12;
+ }
+
+ unsigned NumBits = 0;
+ unsigned Scale = 1;
+ if (AddrMode == ARMII::AddrModeT2_i8 || AddrMode == ARMII::AddrModeT2_i12) {
+ // i8 supports only negative, and i12 supports only positive, so
+ // based on Offset sign convert Opcode to the appropriate
+ // instruction
+ Offset += MI.getOperand(FrameRegIdx+1).getImm();
+ if (Offset < 0) {
+ NewOpc = negativeOffsetOpcode(Opcode);
+ NumBits = 8;
+ isSub = true;
+ Offset = -Offset;
+ } else {
+ NewOpc = positiveOffsetOpcode(Opcode);
+ NumBits = 12;
+ }
+ } else {
+ // VFP address modes.
+ assert(AddrMode == ARMII::AddrMode5);
+ int InstrOffs=ARM_AM::getAM5Offset(MI.getOperand(FrameRegIdx+1).getImm());
+ if (ARM_AM::getAM5Op(MI.getOperand(FrameRegIdx+1).getImm()) ==ARM_AM::sub)
+ InstrOffs *= -1;
+ NumBits = 8;
+ Scale = 4;
+ Offset += InstrOffs * 4;
+ assert((Offset & (Scale-1)) == 0 && "Can't encode this offset!");
+ if (Offset < 0) {
+ Offset = -Offset;
+ isSub = true;
+ }
+ }
+
+ if (NewOpc != Opcode)
+ MI.setDesc(TII.get(NewOpc));
+
+ MachineOperand &ImmOp = MI.getOperand(FrameRegIdx+1);
+
+ // Attempt to fold address computation
+ // Common case: small offset, fits into instruction.
+ int ImmedOffset = Offset / Scale;
+ unsigned Mask = (1 << NumBits) - 1;
+ if ((unsigned)Offset <= Mask * Scale) {
+ // Replace the FrameIndex with fp/sp
+ MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
+ if (isSub) {
+ if (AddrMode == ARMII::AddrMode5)
+ // FIXME: Not consistent.
+ ImmedOffset |= 1 << NumBits;
+ else
+ ImmedOffset = -ImmedOffset;
+ }
+ ImmOp.ChangeToImmediate(ImmedOffset);
+ return 0;
+ }
+
+ // Otherwise, offset doesn't fit. Pull in what we can to simplify
+ ImmedOffset = Offset & Mask;
+ if (isSub) {
+ if (AddrMode == ARMII::AddrMode5)
+ // FIXME: Not consistent.
+ ImmedOffset |= 1 << NumBits;
+ else
+ ImmedOffset = -ImmedOffset;
+ }
+ ImmOp.ChangeToImmediate(ImmedOffset);
+ Offset &= ~(Mask*Scale);
+ }
+
+ return (isSub) ? -Offset : Offset;
+}