[mips][microMIPS] Implement JR16 instruction

[jkolek]

Summary

Implement 16-bit microMIPS jump register instruction JR16.

[sstankovic]

LGTM

Closed by commit rL219498 (authored by zjovanovic).

llvm/trunk/lib/Target/Mips/MicroMipsInstrInfo.td

 class JumpLinkRegMM16<string opstr, RegisterOperand RO> :
   MicroMipsInst16<(outs), (ins RO:$rs), !strconcat(opstr, "\t$rs"),
            [(MipsJmpLink RO:$rs)], IIBranch, FrmR> {
   let isCall = 1;
   let hasDelaySlot = 1;
   let Defs = [RA];
 }
 
+// 16-bit Jump Reg
+class JumpRegMM16<string opstr, RegisterOperand RO> :
+  MicroMipsInst16<(outs), (ins RO:$rs), !strconcat(opstr, "\t$rs"),
+           [], IIBranch, FrmR> {
+  let hasDelaySlot = 1;
+  let isBranch = 1;
+  let isIndirectBranch = 1;
+}
+
 // Base class for JRADDIUSP instruction.
 class JumpRAddiuStackMM16 :
   MicroMipsInst16<(outs), (ins uimm5_lsl2:$imm), "jraddiusp\t$imm",
                   [], IIBranch, FrmR> {
   let isTerminator = 1;
   let isBarrier = 1;
   let hasDelaySlot = 1;
   let isBranch = 1;

 def ADDIUS5_MM : AddImmUS5<"addius5", GPR32Opnd>, ADDIUS5_FM_MM16;
 def MFHI16_MM : MoveFromHILOMM<"mfhi", GPR32Opnd, AC0>, MFHILO_FM_MM16<0x10>;
 def MFLO16_MM : MoveFromHILOMM<"mflo", GPR32Opnd, AC0>, MFHILO_FM_MM16<0x12>;
 def MOVE16_MM : MoveMM16<"move", GPR32Opnd>, MOVE_FM_MM16<0x03>;
 def JALR16_MM : JumpLinkRegMM16<"jalr", GPR32Opnd>, JALR_FM_MM16<0x0e>;
 def JALRS16_MM : JumpLinkRegSMM16<"jalrs16", GPR32Opnd>, JALR_FM_MM16<0x0f>;
 def JRC16_MM : JumpRegCMM16<"jrc", GPR32Opnd>, JALR_FM_MM16<0x0d>;
 def JRADDIUSP : JumpRAddiuStackMM16, JRADDIUSP_FM_MM16<0x18>;
+def JR16_MM : JumpRegMM16<"jr16", GPR32Opnd>, JALR_FM_MM16<0x0c>;
 
 class WaitMM<string opstr> :
   InstSE<(outs), (ins uimm10:$code_), !strconcat(opstr, "\t$code_"), [],
          NoItinerary, FrmOther, opstr>;
 
 let DecoderNamespace = "MicroMips", Predicates = [InMicroMips] in {
   /// Compact Branch Instructions
   def BEQZC_MM : CompactBranchMM<"beqzc", brtarget_mm, seteq, GPR32Opnd>,

llvm/trunk/test/MC/Mips/micromips-16-bit-instructions.s

 # CHECK-EL: mflo    $9              # encoding: [0x49,0x46]
 # CHECK-EL: move    $25, $1         # encoding: [0x21,0x0f]
 # CHECK-EL: jrc     $9              # encoding: [0xa9,0x45]
 # CHECK-NEXT: jalr    $9            # encoding: [0xc9,0x45]
 # CHECK-EL: jraddiusp 20            # encoding: [0x05,0x47]
 # CHECK-EL: nop                     # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EL: jalrs16 $9              # encoding: [0xe9,0x45]
 # CHECK-EL: move    $zero, $zero    # encoding: [0x00,0x0c]
+# CHECK-EL: jr16    $9              # encoding: [0x89,0x45]
+# CHECK-EL: nop                     # encoding: [0x00,0x00,0x00,0x00]
 #------------------------------------------------------------------------------
 # Big endian
 #------------------------------------------------------------------------------
 # CHECK-EB: addius5 $7, -2          # encoding: [0x4c,0xfc]
 # CHECK-EB: mfhi    $9              # encoding: [0x46,0x09]
 # CHECK-EB: mflo    $9              # encoding: [0x46,0x49]
 # CHECK-EB: move    $25, $1         # encoding: [0x0f,0x21]
 # CHECK-EB: jrc     $9              # encoding: [0x45,0xa9]
 # CHECK-NEXT: jalr    $9            # encoding: [0x45,0xc9]
 # CHECK-EB: jraddiusp 20            # encoding: [0x47,0x05]
 # CHECK-EB: nop                     # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EB: jalrs16 $9              # encoding: [0x45,0xe9]
 # CHECK-EB: move    $zero, $zero    # encoding: [0x0c,0x00]
+# CHECK-EB: jr16    $9              # encoding: [0x45,0x89]
+# CHECK-EB: nop                     # encoding: [0x00,0x00,0x00,0x00]
 
     addius5 $7, -2
     mfhi    $9
     mflo    $9
     move    $25, $1
     jrc     $9
     jalr    $9
     jraddiusp 20
     jalrs16 $9
+    jr16    $9