[ARM] Introduce i8neg and i8pos addressing modes

[dmgreen]

Summary

Some instructions with i8 immediate ranges can only hold negative values (like t2LDRHi8), only hold positive values (like t2STRT) or hold +/- depending on the U bit (like the pre/post inc instructions. e.g t2LDRH_POST). This patch splits the AddrModeT2_i8 into AddrModeT2_i8, AddrModeT2_i8pos and AddrModeT2_i8neg to make this clear.

This allows us to get the offset ranges of t2LDRHi8 correct in the load/store optimizer, fixing issues where we could end up creating instructions with positive offsets (which may then be encoded as ldrht).

[SjoerdMeijer]

Looks like an improvement to me.

[glandium]

FYI, I filed https://github.com/llvm/llvm-project/issues/52681 for a crash that this patch causes.

llvm/lib/Target/ARM/ARMBaseInstrInfo.h

inline bool isLegalAddressImm(unsigned Opcode, int Imm,
   case ARMII::AddrModeT2_i7:
     return std::abs(Imm) < ((1 << 7) * 1);
   case ARMII::AddrModeT2_i7s2:
     return std::abs(Imm) < ((1 << 7) * 2) && Imm % 2 == 0;
   case ARMII::AddrModeT2_i7s4:
     return std::abs(Imm) < ((1 << 7) * 4) && Imm % 4 == 0;
   case ARMII::AddrModeT2_i8:
     return std::abs(Imm) < ((1 << 8) * 1);
+  case ARMII::AddrModeT2_i8pos:
+    return Imm >= 0 && Imm < ((1 << 8) * 1);
+  case ARMII::AddrModeT2_i8neg:
+    return Imm < 0 && -Imm < ((1 << 8) * 1);
   case ARMII::AddrModeT2_i8s4:
     return std::abs(Imm) < ((1 << 8) * 4) && Imm % 4 == 0;
   case ARMII::AddrModeT2_i12:
     return Imm >= 0 && Imm < ((1 << 12) * 1);
   case ARMII::AddrMode2:
     return std::abs(Imm) < ((1 << 12) * 1);
   default:
     llvm_unreachable("Unhandled Addressing mode");

llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp

if (SPIdx < 0)
     // No SP operand
     return true;
   else if (SPIdx != 1 && (AddrMode != ARMII::AddrModeT2_i8s4 || SPIdx != 2))
     // If SP is not the base register we can't do much
     return false;
 
   // Stack might be involved but addressing mode doesn't handle any offset.
   // Rq: AddrModeT1_[1|2|4] don't operate on SP
-  if (AddrMode == ARMII::AddrMode1        // Arithmetic instructions
-      || AddrMode == ARMII::AddrMode4     // Load/Store Multiple
-      || AddrMode == ARMII::AddrMode6     // Neon Load/Store Multiple
-      || AddrMode == ARMII::AddrModeT2_so // SP can't be used as based register
-      || AddrMode == ARMII::AddrModeT2_pc // PCrel access
-      || AddrMode == ARMII::AddrMode2     // Used by PRE and POST indexed LD/ST
-      || AddrMode == ARMII::AddrModeT2_i7 // v8.1-M MVE
-      || AddrMode == ARMII::AddrModeT2_i7s2 // v8.1-M MVE
-      || AddrMode == ARMII::AddrModeT2_i7s4 // v8.1-M sys regs VLDR/VSTR
-      || AddrMode == ARMII::AddrModeNone)
+  if (AddrMode == ARMII::AddrMode1 ||       // Arithmetic instructions
+      AddrMode == ARMII::AddrMode4 ||       // Load/Store Multiple
+      AddrMode == ARMII::AddrMode6 ||       // Neon Load/Store Multiple
+      AddrMode == ARMII::AddrModeT2_so ||   // SP can't be used as based register
+      AddrMode == ARMII::AddrModeT2_pc ||   // PCrel access
+      AddrMode == ARMII::AddrMode2 ||       // Used by PRE and POST indexed LD/ST
+      AddrMode == ARMII::AddrModeT2_i7 ||   // v8.1-M MVE
+      AddrMode == ARMII::AddrModeT2_i7s2 || // v8.1-M MVE
+      AddrMode == ARMII::AddrModeT2_i7s4 || // v8.1-M sys regs VLDR/VSTR
+      AddrMode == ARMII::AddrModeNone ||
+      AddrMode == ARMII::AddrModeT2_i8 ||   // Pre/Post inc instructions
+      AddrMode == ARMII::AddrModeT2_i8neg)  // Always negative imm
     return false;
 
   unsigned NumOps = MI->getDesc().getNumOperands();
   unsigned ImmIdx = NumOps - 3;
 
   const MachineOperand &Offset = MI->getOperand(ImmIdx);
   assert(Offset.isImm() && "Is not an immediate");
   int64_t OffVal = Offset.getImm();
case ARMII::AddrMode5:
     break;
   case ARMII::AddrMode5FP16:
     if (ARM_AM::getAM5FP16Op(OffVal) == ARM_AM::sub)
       return false;
     OffVal = ARM_AM::getAM5FP16Offset(OffVal);
     NumBits = 8;
     Scale = 2;
     break;
-  case ARMII::AddrModeT2_i8:
+  case ARMII::AddrModeT2_i8pos:
     NumBits = 8;
     break;
   case ARMII::AddrModeT2_i8s4:
     // FIXME: Values are already scaled in this addressing mode.
     assert((Fixup & 3) == 0 && "Can't encode this offset!");
     NumBits = 10;
     break;
   case ARMII::AddrModeT2_ldrex:

llvm/lib/Target/ARM/ARMFrameLowering.cpp

for (auto &MI : MBB) {
 
         // Otherwise check the addressing mode.
         switch (MI.getDesc().TSFlags & ARMII::AddrModeMask) {
         case ARMII::AddrMode_i12:
         case ARMII::AddrMode2:
           // Default 12 bit limit.
           break;
         case ARMII::AddrMode3:
-        case ARMII::AddrModeT2_i8:
+        case ARMII::AddrModeT2_i8neg:
           Limit = std::min(Limit, (1U << 8) - 1);
           break;
         case ARMII::AddrMode5FP16:
           Limit = std::min(Limit, ((1U << 8) - 1) * 2);
           break;
         case ARMII::AddrMode5:
         case ARMII::AddrModeT2_i8s4:
         case ARMII::AddrModeT2_ldrex:

llvm/lib/Target/ARM/ARMInstrFormats.td

 def AddrMode5       : AddrMode<5>;
 def AddrMode6       : AddrMode<6>;
 def AddrModeT1_1    : AddrMode<7>;
 def AddrModeT1_2    : AddrMode<8>;
 def AddrModeT1_4    : AddrMode<9>;
 def AddrModeT1_s    : AddrMode<10>;
 def AddrModeT2_i12  : AddrMode<11>;
 def AddrModeT2_i8   : AddrMode<12>;
-def AddrModeT2_so   : AddrMode<13>;
-def AddrModeT2_pc   : AddrMode<14>;
-def AddrModeT2_i8s4 : AddrMode<15>;
-def AddrMode_i12    : AddrMode<16>;
-def AddrMode5FP16   : AddrMode<17>;
-def AddrModeT2_ldrex : AddrMode<18>;
-def AddrModeT2_i7s4 : AddrMode<19>;
-def AddrModeT2_i7s2 : AddrMode<20>;
-def AddrModeT2_i7   : AddrMode<21>;
+def AddrModeT2_i8pos : AddrMode<13>;
+def AddrModeT2_i8neg : AddrMode<14>;
+def AddrModeT2_so   : AddrMode<15>;
+def AddrModeT2_pc   : AddrMode<16>;
+def AddrModeT2_i8s4 : AddrMode<17>;
+def AddrMode_i12    : AddrMode<18>;
+def AddrMode5FP16   : AddrMode<19>;
+def AddrModeT2_ldrex : AddrMode<20>;
+def AddrModeT2_i7s4 : AddrMode<21>;
+def AddrModeT2_i7s2 : AddrMode<22>;
+def AddrModeT2_i7   : AddrMode<23>;
 
 // Load / store index mode.
 class IndexMode<bits<2> val> {
   bits<2> Value = val;
 }
 def IndexModeNone : IndexMode<0>;
 def IndexModePre  : IndexMode<1>;
 def IndexModePost : IndexMode<2>;

 }
 
 class T2I<dag oops, dag iops, InstrItinClass itin,
           string opc, string asm, list<dag> pattern, AddrMode am = AddrModeNone>
   : Thumb2I<oops, iops, am, 4, itin, opc, asm, "", pattern>;
 class T2Ii12<dag oops, dag iops, InstrItinClass itin,
              string opc, string asm, list<dag> pattern>
   : Thumb2I<oops, iops, AddrModeT2_i12, 4, itin, opc, asm, "",pattern>;
-class T2Ii8<dag oops, dag iops, InstrItinClass itin,
+class T2Ii8p<dag oops, dag iops, InstrItinClass itin,
              string opc, string asm, list<dag> pattern>
-  : Thumb2I<oops, iops, AddrModeT2_i8, 4, itin, opc, asm, "", pattern>;
+  : Thumb2I<oops, iops, AddrModeT2_i8pos, 4, itin, opc, asm, "", pattern>;
+class T2Ii8n<dag oops, dag iops, InstrItinClass itin,
+             string opc, string asm, list<dag> pattern>
+  : Thumb2I<oops, iops, AddrModeT2_i8neg, 4, itin, opc, asm, "", pattern>;
 class T2Iso<dag oops, dag iops, InstrItinClass itin,
             string opc, string asm, list<dag> pattern>
   : Thumb2I<oops, iops, AddrModeT2_so, 4, itin, opc, asm, "", pattern>;
 class T2Ipc<dag oops, dag iops, InstrItinClass itin,
             string opc, string asm, list<dag> pattern>
   : Thumb2I<oops, iops, AddrModeT2_pc, 4, itin, opc, asm, "", pattern>;
 class T2Ii8s4<bit P, bit W, bit isLoad, dag oops, dag iops, InstrItinClass itin,
               string opc, string asm, string cstr, list<dag> pattern>

llvm/lib/Target/ARM/ARMInstrThumb2.td

def i12 : T2Ii12<(outs target:$Rt), (ins t2addrmode_imm12:$addr), iii,
     let Inst{22-21} = opcod;
     let Inst{20} = 1; // load
     let Inst{19-16} = addr{16-13}; // Rn
     let Inst{15-12} = Rt;
     let Inst{11-0}  = addr{11-0};  // imm
 
     let DecoderMethod = "DecodeT2LoadImm12";
   }
-  def i8  : T2Ii8 <(outs target:$Rt), (ins t2addrmode_negimm8:$addr), iii,
+  def i8  : T2Ii8n <(outs target:$Rt), (ins t2addrmode_negimm8:$addr), iii,
                     opc, "\t$Rt, $addr",
                     [(set target:$Rt, (opnode t2addrmode_negimm8:$addr))]>,
             Sched<[WriteLd]> {
     bits<4> Rt;
     bits<13> addr;
     let Inst{31-27} = 0b11111;
     let Inst{26-25} = 0b00;
     let Inst{24} = signed;
     let Inst{23} = 0;
     let Inst{22-21} = opcod;
def i12 : T2Ii12<(outs), (ins target:$Rt, t2addrmode_imm12:$addr), iii,
     let Inst{15-12} = Rt;
 
     bits<17> addr;
     let addr{12}    = 1;           // add = TRUE
     let Inst{19-16} = addr{16-13}; // Rn
     let Inst{23}    = addr{12};    // U
     let Inst{11-0}  = addr{11-0};  // imm
   }
-  def i8  : T2Ii8 <(outs), (ins target:$Rt, t2addrmode_negimm8:$addr), iii,
+  def i8  : T2Ii8n <(outs), (ins target:$Rt, t2addrmode_negimm8:$addr), iii,
                     opc, "\t$Rt, $addr",
                     [(opnode target:$Rt, t2addrmode_negimm8:$addr)]>,
             Sched<[WriteST]> {
     let Inst{31-27} = 0b11111;
     let Inst{26-23} = 0b0000;
     let Inst{22-21} = opcod;
     let Inst{20} = 0; // !load
     let Inst{11} = 1;
     // Offset: index==TRUE, wback==FALSE
     let Inst{10} = 1; // The P bit.

 def t2LDR_PRE_imm : t2AsmPseudo<"ldr${p}.w $Rt, $addr!",
                          (ins GPR:$Rt, t2addrmode_imm8_pre:$addr, pred:$p)>;
 def t2LDR_POST_imm : t2AsmPseudo<"ldr${p}.w $Rt, $Rn, $imm",
                          (ins GPR:$Rt, addr_offset_none:$Rn, t2am_imm8_offset:$imm, pred:$p)>;
 
 // LDRT, LDRBT, LDRHT, LDRSBT, LDRSHT all have offset mode (PUW=0b110).
 // Ref: A8.6.57 LDR (immediate, Thumb) Encoding T4
 class T2IldT<bit signed, bits<2> type, string opc, InstrItinClass ii>
-  : T2Ii8<(outs rGPR:$Rt), (ins t2addrmode_posimm8:$addr), ii, opc,
+  : T2Ii8p<(outs rGPR:$Rt), (ins t2addrmode_posimm8:$addr), ii, opc,
            "\t$Rt, $addr", []>, Sched<[WriteLd]> {
   bits<4> Rt;
   bits<13> addr;
   let Inst{31-27} = 0b11111;
   let Inst{26-25} = 0b00;
   let Inst{24} = signed;
   let Inst{23} = 0;
   let Inst{22-21} = type;
   let Inst{20} = 1; // load
def t2STR_PRE_imm : t2AsmPseudo<"str${p}.w $Rt, $addr!",
   (ins GPR:$Rt, t2addrmode_imm8_pre:$addr, pred:$p)>;
 def t2STR_POST_imm : t2AsmPseudo<"str${p}.w $Rt, $Rn, $imm",
   (ins GPR:$Rt, addr_offset_none:$Rn, t2am_imm8_offset:$imm, pred:$p)>;
 
 // STRT, STRBT, STRHT all have offset mode (PUW=0b110) and are for disassembly
 // only.
 // Ref: A8.6.193 STR (immediate, Thumb) Encoding T4
 class T2IstT<bits<2> type, string opc, InstrItinClass ii>
-  : T2Ii8<(outs), (ins rGPR:$Rt, t2addrmode_imm8:$addr), ii, opc,
+  : T2Ii8p<(outs), (ins rGPR:$Rt, t2addrmode_posimm8:$addr), ii, opc,
            "\t$Rt, $addr", []>, Sched<[WriteST]> {
   let Inst{31-27} = 0b11111;
   let Inst{26-25} = 0b00;
   let Inst{24} = 0; // not signed
   let Inst{23} = 0;
   let Inst{22-21} = type;
   let Inst{20} = 0; // store
   let Inst{11} = 1;
   let Inst{10-8} = 0b110; // PUW
def i12 : T2Ii12<(outs), (ins t2addrmode_imm12:$addr), IIC_Preload, opc,
 
     bits<17> addr;
     let Inst{19-16} = addr{16-13}; // Rn
     let Inst{11-0}  = addr{11-0};  // imm12
 
     let DecoderMethod = "DecodeT2LoadImm12";
   }
 
-  def i8 : T2Ii8<(outs), (ins t2addrmode_negimm8:$addr), IIC_Preload, opc,
+  def i8 : T2Ii8n<(outs), (ins t2addrmode_negimm8:$addr), IIC_Preload, opc,
                  "\t$addr",
             [(ARMPreload t2addrmode_negimm8:$addr, (i32 write), (i32 instr))]>,
             Sched<[WritePreLd]> {
     let Inst{31-25} = 0b1111100;
     let Inst{24} = instr;
     let Inst{23} = 0; // U = 0
     let Inst{22} = 0;
     let Inst{21} = write;
     let Inst{20} = 1;

llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp

 // t2LDRi12 to t2LDRi8 for negative offsets. Works in conjunction with
 // AdjustBaseAndOffset below.
 static bool isLegalOrConvertableAddressImm(unsigned Opcode, int Imm,
                                            const TargetInstrInfo *TII,
                                            int &CodesizeEstimate) {
   if (isLegalAddressImm(Opcode, Imm, TII))
     return true;
 
-  // We can convert AddrModeT2_i12 to AddrModeT2_i8.
+  // We can convert AddrModeT2_i12 to AddrModeT2_i8neg.
   const MCInstrDesc &Desc = TII->get(Opcode);
   unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
   switch (AddrMode) {
   case ARMII::AddrModeT2_i12:
     CodesizeEstimate += 1;
-    return std::abs(Imm) < (((1 << 8) * 1) - 1);
+    return Imm < 0 && -Imm < ((1 << 8) * 1);
   }
   return false;
 }
 
 // Given an MI adjust its address BaseReg to use NewBaseReg and address offset
 // by -Offset. This can either happen in-place or be a replacement as MI is
 // converted to another instruction type.
 static void AdjustBaseAndOffset(MachineInstr *MI, Register NewBaseReg,

llvm/lib/Target/ARM/MCTargetDesc/ARMBaseInfo.h

enum AddrMode {
     AddrMode4       = 4,
     AddrMode5       = 5,
     AddrMode6       = 6,
     AddrModeT1_1    = 7,
     AddrModeT1_2    = 8,
     AddrModeT1_4    = 9,
     AddrModeT1_s    = 10, // i8 * 4 for pc and sp relative data
     AddrModeT2_i12  = 11,
-    AddrModeT2_i8   = 12,
-    AddrModeT2_so   = 13,
-    AddrModeT2_pc   = 14, // +/- i12 for pc relative data
-    AddrModeT2_i8s4 = 15, // i8 * 4
-    AddrMode_i12    = 16,
-    AddrMode5FP16   = 17,  // i8 * 2
-    AddrModeT2_ldrex = 18, // i8 * 4, with unscaled offset in MCInst
-    AddrModeT2_i7s4 = 19, // i7 * 4
-    AddrModeT2_i7s2 = 20, // i7 * 2
-    AddrModeT2_i7   = 21, // i7 * 1
+    AddrModeT2_i8   = 12, // +/- i8
+    AddrModeT2_i8pos = 13, // + i8
+    AddrModeT2_i8neg = 14, // - i8
+    AddrModeT2_so   = 15,
+    AddrModeT2_pc   = 16, // +/- i12 for pc relative data
+    AddrModeT2_i8s4 = 17, // i8 * 4
+    AddrMode_i12    = 18,
+    AddrMode5FP16   = 19,  // i8 * 2
+    AddrModeT2_ldrex = 20, // i8 * 4, with unscaled offset in MCInst
+    AddrModeT2_i7s4 = 21, // i7 * 4
+    AddrModeT2_i7s2 = 22, // i7 * 2
+    AddrModeT2_i7   = 23, // i7 * 1
   };
 
   inline static const char *AddrModeToString(AddrMode addrmode) {
     switch (addrmode) {
     case AddrModeNone:    return "AddrModeNone";
     case AddrMode1:       return "AddrMode1";
     case AddrMode2:       return "AddrMode2";
     case AddrMode3:       return "AddrMode3";
     case AddrMode4:       return "AddrMode4";
     case AddrMode5:       return "AddrMode5";
     case AddrMode5FP16:   return "AddrMode5FP16";
     case AddrMode6:       return "AddrMode6";
     case AddrModeT1_1:    return "AddrModeT1_1";
     case AddrModeT1_2:    return "AddrModeT1_2";
     case AddrModeT1_4:    return "AddrModeT1_4";
     case AddrModeT1_s:    return "AddrModeT1_s";
     case AddrModeT2_i12:  return "AddrModeT2_i12";
     case AddrModeT2_i8:   return "AddrModeT2_i8";
+    case AddrModeT2_i8pos: return "AddrModeT2_i8pos";
+    case AddrModeT2_i8neg: return "AddrModeT2_i8neg";
     case AddrModeT2_so:   return "AddrModeT2_so";
     case AddrModeT2_pc:   return "AddrModeT2_pc";
     case AddrModeT2_i8s4: return "AddrModeT2_i8s4";
     case AddrMode_i12:    return "AddrMode_i12";
     case AddrModeT2_ldrex:return "AddrModeT2_ldrex";
     case AddrModeT2_i7s4: return "AddrModeT2_i7s4";
     case AddrModeT2_i7s2: return "AddrModeT2_i7s2";
     case AddrModeT2_i7:   return "AddrModeT2_i7";

llvm/lib/Target/ARM/Thumb2InstrInfo.cpp

if (AddrMode == ARMII::AddrModeT2_so) {
       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) {
+    if (AddrMode == ARMII::AddrModeT2_i8neg ||
+        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;

llvm/test/CodeGen/ARM/machine-outliner-stack-fixup-thumb.mir

 tracksRegLiveness: true
 
 body:             |
   bb.0:
     liveins: $r1
     ;CHECK-LABEL: name:           CheckAddrModeT2_i8
     ;CHECK: $r0 = tMOVr $r1, 14 /* CC::al */, $noreg
     ;CHECK-NEXT: tBL 14 /* CC::al */, $noreg, @OUTLINED_FUNCTION_[[I8:[0-9]+]]
-    ;CHECK-NEXT: t2STRHi8 $r0, $sp, 248, 14 /* CC::al */, $noreg
+    ;CHECK-NEXT: t2STRHT $r0, $sp, 248, 14 /* CC::al */, $noreg
     $r0 = tMOVr $r1, 14, $noreg
     tBL 14, $noreg, @foo, implicit-def dead $lr, implicit $sp
-    t2STRHi8 $r0, $sp, 0, 14, $noreg
-    t2STRHi8 $r0, $sp, 4, 14, $noreg
-    t2STRHi8 $r0, $sp, 247, 14, $noreg
-    t2STRHi8 $r0, $sp, 248, 14, $noreg
-    tBL 14, $noreg, @foo, implicit-def dead $lr, implicit $sp
-    t2STRHi8 $r0, $sp, 0, 14, $noreg
-    t2STRHi8 $r0, $sp, 4, 14, $noreg
-    t2STRHi8 $r0, $sp, 247, 14, $noreg
-    t2STRHi8 $r0, $sp, 248, 14, $noreg
-    tBL 14, $noreg, @foo, implicit-def dead $lr, implicit $sp
-    t2STRHi8 $r0, $sp, 0, 14, $noreg
-    t2STRHi8 $r0, $sp, 4, 14, $noreg
-    t2STRHi8 $r0, $sp, 247, 14, $noreg
-    t2STRHi8 $r0, $sp, 248, 14, $noreg
+    t2STRHT $r0, $sp, 0, 14, $noreg
+    t2STRHT $r0, $sp, 4, 14, $noreg
+    t2STRHT $r0, $sp, 247, 14, $noreg
+    t2STRHT $r0, $sp, 248, 14, $noreg
+    tBL 14, $noreg, @foo, implicit-def dead $lr, implicit $sp
+    t2STRHT $r0, $sp, 0, 14, $noreg
+    t2STRHT $r0, $sp, 4, 14, $noreg
+    t2STRHT $r0, $sp, 247, 14, $noreg
+    t2STRHT $r0, $sp, 248, 14, $noreg
+    tBL 14, $noreg, @foo, implicit-def dead $lr, implicit $sp
+    t2STRHT $r0, $sp, 0, 14, $noreg
+    t2STRHT $r0, $sp, 4, 14, $noreg
+    t2STRHT $r0, $sp, 247, 14, $noreg
+    t2STRHT $r0, $sp, 248, 14, $noreg
     BX_RET 14, $noreg
 ...
 ---
 
 name:           CheckAddrModeT2_i8s4
 tracksRegLiveness: true
 
 body:             |
bb.0:
     ;CHECK-NEXT: $r1 = t2LDREX $sp, 255, 14 /* CC::al */, $noreg
     ;CHECK-NEXT: $lr, $sp = t2LDR_POST $sp, 8, 14 /* CC::al */, $noreg
 
     ;CHECK: name:           OUTLINED_FUNCTION_[[I8]]
     ;CHECK: early-clobber $sp = t2STR_PRE killed $lr, $sp, -8, 14 /* CC::al */, $noreg
     ;CHECK-NEXT: frame-setup CFI_INSTRUCTION def_cfa_offset 8
     ;CHECK-NEXT: frame-setup CFI_INSTRUCTION offset $lr, -8
     ;CHECK-NEXT: tBL 14 /* CC::al */, $noreg, @foo, implicit-def dead $lr, implicit $sp
-    ;CHECK-NEXT: t2STRHi8 $r0, $sp, 8, 14 /* CC::al */, $noreg
-    ;CHECK-NEXT: t2STRHi8 $r0, $sp, 12, 14 /* CC::al */, $noreg
-    ;CHECK-NEXT: t2STRHi8 $r0, $sp, 255, 14 /* CC::al */, $noreg
+    ;CHECK-NEXT: t2STRHT $r0, $sp, 8, 14 /* CC::al */, $noreg
+    ;CHECK-NEXT: t2STRHT $r0, $sp, 12, 14 /* CC::al */, $noreg
+    ;CHECK-NEXT: t2STRHT $r0, $sp, 255, 14 /* CC::al */, $noreg
     ;CHECK-NEXT: $lr, $sp = t2LDR_POST $sp, 8, 14 /* CC::al */, $noreg
 
     ;CHECK: name:           OUTLINED_FUNCTION_[[I8S4]]
     ;CHECK: early-clobber $sp = t2STR_PRE killed $lr, $sp, -8, 14 /* CC::al */, $noreg
     ;CHECK-NEXT: frame-setup CFI_INSTRUCTION def_cfa_offset 8
     ;CHECK-NEXT: frame-setup CFI_INSTRUCTION offset $lr, -8
     ;CHECK-NEXT: tBL 14 /* CC::al */, $noreg, @foo, implicit-def dead $lr, implicit $sp
     ;CHECK-NEXT: t2STRDi8 $r0, $r1, $sp, 8, 14 /* CC::al */, $noreg

llvm/test/CodeGen/Thumb2/postinc-distribute.mir

 body:             |
   bb.0:
     liveins: $r0
 
     ; CHECK-LABEL: name: t2LDRHi12_negoff
     ; CHECK: liveins: $r0
     ; CHECK-NEXT: {{  $}}
     ; CHECK-NEXT: [[COPY:%[0-9]+]]:gprnopc = COPY $r0
-    ; CHECK-NEXT: [[t2LDRH_POST:%[0-9]+]]:rgpr, [[t2LDRH_POST1:%[0-9]+]]:rgpr = t2LDRH_POST [[COPY]], -32, 14 /* CC::al */, $noreg :: (load (s32))
-    ; CHECK-NEXT: [[t2LDRHi12_:%[0-9]+]]:rgpr = t2LDRHi12 [[t2LDRH_POST1]], 36, 14 /* CC::al */, $noreg :: (load (s32))
-    ; CHECK-NEXT: [[t2LDRHi8_:%[0-9]+]]:rgpr = t2LDRHi8 [[t2LDRH_POST1]], 24, 14 /* CC::al */, $noreg :: (load (s32))
-    ; CHECK-NEXT: [[t2LDRSHi12_:%[0-9]+]]:rgpr = t2LDRSHi12 [[t2LDRH_POST1]], 44, 14 /* CC::al */, $noreg :: (load (s32))
-    ; CHECK-NEXT: $r0 = COPY [[t2LDRH_POST1]]
+    ; CHECK-NEXT: [[t2LDRHi12_:%[0-9]+]]:rgpr = t2LDRHi12 [[COPY]], 0, 14 /* CC::al */, $noreg :: (load (s32))
+    ; CHECK-NEXT: [[t2SUBri:%[0-9]+]]:rgpr = nuw t2SUBri [[COPY]], 32, 14 /* CC::al */, $noreg, $noreg
+    ; CHECK-NEXT: [[t2LDRHi12_1:%[0-9]+]]:rgpr = t2LDRHi12 [[COPY]], 4, 14 /* CC::al */, $noreg :: (load (s32))
+    ; CHECK-NEXT: [[t2LDRHi8_:%[0-9]+]]:rgpr = t2LDRHi8 [[COPY]], -8, 14 /* CC::al */, $noreg :: (load (s32))
+    ; CHECK-NEXT: [[t2LDRSHi12_:%[0-9]+]]:rgpr = t2LDRSHi12 [[COPY]], 12, 14 /* CC::al */, $noreg :: (load (s32))
+    ; CHECK-NEXT: $r0 = COPY [[t2SUBri]]
     ; CHECK-NEXT: tBX_RET 14 /* CC::al */, $noreg, implicit $r0
     %0:gprnopc = COPY $r0
     %1:rgpr = t2LDRHi12 %0, 0, 14, $noreg :: (load (s32), align 4)
     %2:rgpr = nuw t2SUBri %0, 32, 14, $noreg, $noreg
     %3:rgpr = t2LDRHi12 %0, 4, 14, $noreg :: (load (s32), align 4)
     %4:rgpr = t2LDRHi8 %0, -8, 14, $noreg :: (load (s32), align 4)
     %5:rgpr = t2LDRSHi12 %0, 12, 14, $noreg :: (load (s32), align 4)
     $r0 = COPY %2

 body:             |
   bb.0:
     liveins: $r0
 
     ; CHECK-LABEL: name: t2LDRBi12_negoff
     ; CHECK: liveins: $r0
     ; CHECK-NEXT: {{  $}}
     ; CHECK-NEXT: [[COPY:%[0-9]+]]:gprnopc = COPY $r0
-    ; CHECK-NEXT: [[t2LDRB_POST:%[0-9]+]]:rgpr, [[t2LDRB_POST1:%[0-9]+]]:rgpr = t2LDRB_POST [[COPY]], -32, 14 /* CC::al */, $noreg :: (load (s32))
-    ; CHECK-NEXT: [[t2LDRBi12_:%[0-9]+]]:rgpr = t2LDRBi12 [[t2LDRB_POST1]], 36, 14 /* CC::al */, $noreg :: (load (s32))
-    ; CHECK-NEXT: [[t2LDRBi8_:%[0-9]+]]:rgpr = t2LDRBi8 [[t2LDRB_POST1]], 24, 14 /* CC::al */, $noreg :: (load (s32))
-    ; CHECK-NEXT: [[t2LDRSBi12_:%[0-9]+]]:rgpr = t2LDRSBi12 [[t2LDRB_POST1]], 44, 14 /* CC::al */, $noreg :: (load (s32))
-    ; CHECK-NEXT: $r0 = COPY [[t2LDRB_POST1]]
+    ; CHECK-NEXT: [[t2LDRBi12_:%[0-9]+]]:rgpr = t2LDRBi12 [[COPY]], 0, 14 /* CC::al */, $noreg :: (load (s32))
+    ; CHECK-NEXT: [[t2SUBri:%[0-9]+]]:rgpr = nuw t2SUBri [[COPY]], 32, 14 /* CC::al */, $noreg, $noreg
+    ; CHECK-NEXT: [[t2LDRBi12_1:%[0-9]+]]:rgpr = t2LDRBi12 [[COPY]], 4, 14 /* CC::al */, $noreg :: (load (s32))
+    ; CHECK-NEXT: [[t2LDRBi8_:%[0-9]+]]:rgpr = t2LDRBi8 [[COPY]], -8, 14 /* CC::al */, $noreg :: (load (s32))
+    ; CHECK-NEXT: [[t2LDRSBi12_:%[0-9]+]]:rgpr = t2LDRSBi12 [[COPY]], 12, 14 /* CC::al */, $noreg :: (load (s32))
+    ; CHECK-NEXT: $r0 = COPY [[t2SUBri]]
     ; CHECK-NEXT: tBX_RET 14 /* CC::al */, $noreg, implicit $r0
     %0:gprnopc = COPY $r0
     %1:rgpr = t2LDRBi12 %0, 0, 14, $noreg :: (load (s32), align 4)
     %2:rgpr = nuw t2SUBri %0, 32, 14, $noreg, $noreg
     %3:rgpr = t2LDRBi12 %0, 4, 14, $noreg :: (load (s32), align 4)
     %4:rgpr = t2LDRBi8 %0, -8, 14, $noreg :: (load (s32), align 4)
     %12:rgpr = t2LDRSBi12 %0, 12, 14, $noreg :: (load (s32), align 4)
     $r0 = COPY %2
body:             |
   bb.0:
     liveins: $r0, $r1
 
     ; CHECK-LABEL: name: t2STRHi12_negoff
     ; CHECK: liveins: $r0, $r1
     ; CHECK-NEXT: {{  $}}
     ; CHECK-NEXT: [[COPY:%[0-9]+]]:gprnopc = COPY $r0
     ; CHECK-NEXT: [[COPY1:%[0-9]+]]:rgpr = COPY $r1
-    ; CHECK-NEXT: early-clobber %2:rgpr = t2STRH_POST [[COPY1]], [[COPY]], -32, 14 /* CC::al */, $noreg :: (store (s32))
-    ; CHECK-NEXT: t2STRHi12 [[COPY1]], %2, 36, 14 /* CC::al */, $noreg :: (store (s32))
-    ; CHECK-NEXT: t2STRHi8 [[COPY1]], %2, 24, 14 /* CC::al */, $noreg :: (store (s32))
-    ; CHECK-NEXT: $r0 = COPY %2
+    ; CHECK-NEXT: t2STRHi12 [[COPY1]], [[COPY]], 0, 14 /* CC::al */, $noreg :: (store (s32))
+    ; CHECK-NEXT: [[t2SUBri:%[0-9]+]]:rgpr = nuw t2SUBri [[COPY]], 32, 14 /* CC::al */, $noreg, $noreg
+    ; CHECK-NEXT: t2STRHi12 [[COPY1]], [[COPY]], 4, 14 /* CC::al */, $noreg :: (store (s32))
+    ; CHECK-NEXT: t2STRHi8 [[COPY1]], [[COPY]], -8, 14 /* CC::al */, $noreg :: (store (s32))
+    ; CHECK-NEXT: $r0 = COPY [[t2SUBri]]
     ; CHECK-NEXT: tBX_RET 14 /* CC::al */, $noreg, implicit $r0
     %0:gprnopc = COPY $r0
     %1:rgpr = COPY $r1
     t2STRHi12 %1:rgpr, %0, 0, 14, $noreg :: (store (s32), align 4)
     %2:rgpr = nuw t2SUBri %0, 32, 14, $noreg, $noreg
     t2STRHi12 %1:rgpr, %0, 4, 14, $noreg :: (store (s32), align 4)
     t2STRHi8 %1:rgpr, %0, -8, 14, $noreg :: (store (s32), align 4)
     $r0 = COPY %2
body:             |
   bb.0:
     liveins: $r0, $r1
 
     ; CHECK-LABEL: name: t2STRBi12_negoff
     ; CHECK: liveins: $r0, $r1
     ; CHECK-NEXT: {{  $}}
     ; CHECK-NEXT: [[COPY:%[0-9]+]]:gprnopc = COPY $r0
     ; CHECK-NEXT: [[COPY1:%[0-9]+]]:rgpr = COPY $r1
-    ; CHECK-NEXT: early-clobber %2:rgpr = t2STRB_POST [[COPY1]], [[COPY]], -32, 14 /* CC::al */, $noreg :: (store (s32))
-    ; CHECK-NEXT: t2STRBi12 [[COPY1]], %2, 36, 14 /* CC::al */, $noreg :: (store (s32))
-    ; CHECK-NEXT: t2STRBi8 [[COPY1]], %2, 24, 14 /* CC::al */, $noreg :: (store (s32))
-    ; CHECK-NEXT: $r0 = COPY %2
+    ; CHECK-NEXT: t2STRBi12 [[COPY1]], [[COPY]], 0, 14 /* CC::al */, $noreg :: (store (s32))
+    ; CHECK-NEXT: [[t2SUBri:%[0-9]+]]:rgpr = nuw t2SUBri [[COPY]], 32, 14 /* CC::al */, $noreg, $noreg
+    ; CHECK-NEXT: t2STRBi12 [[COPY1]], [[COPY]], 4, 14 /* CC::al */, $noreg :: (store (s32))
+    ; CHECK-NEXT: t2STRBi8 [[COPY1]], [[COPY]], -8, 14 /* CC::al */, $noreg :: (store (s32))
+    ; CHECK-NEXT: $r0 = COPY [[t2SUBri]]
     ; CHECK-NEXT: tBX_RET 14 /* CC::al */, $noreg, implicit $r0
     %0:gprnopc = COPY $r0
     %1:rgpr = COPY $r1
     t2STRBi12 %1:rgpr, %0, 0, 14, $noreg :: (store (s32), align 4)
     %2:rgpr = nuw t2SUBri %0, 32, 14, $noreg, $noreg
     t2STRBi12 %1:rgpr, %0, 4, 14, $noreg :: (store (s32), align 4)
     t2STRBi8 %1:rgpr, %0, -8, 14, $noreg :: (store (s32), align 4)
     $r0 = COPY %2
     tBX_RET 14, $noreg, implicit $r0
 
 ...