[mips][microMIPSr6] Implement BITSWAP instruction

[jkolek]

Summary

This patch implements BITSWAP instruction using mapping.

[dsanders]

LGTM

llvm/trunk/lib/Target/Mips/MicroMips32r6InstrFormats.td

 // This file describes microMIPS32r6 instruction formats.
 //
 //===----------------------------------------------------------------------===//
 
 class MMR6Arch<string opstr> {
   string Arch = "micromipsr6";
   string BaseOpcode = opstr;
 }
+
+class POOL32A_BITSWAP_FM_MMR6<bits<6> funct> : MipsR6Inst {
+  bits<5> rd;
+  bits<5> rt;
+
+  bits<32> Inst;
+
+  let Inst{31-26} = 0b000000;
+  let Inst{25-21} = rt;
+  let Inst{20-16} = rd;
+  let Inst{15-12} = 0b0000;
+  let Inst{11-6} = funct;
+  let Inst{5-0} = 0b111100;
+}

llvm/trunk/lib/Target/Mips/MicroMips32r6InstrInfo.td

 //===----------------------------------------------------------------------===//
 //
 // Instruction Encodings
 //
 //===----------------------------------------------------------------------===//
 
 class BALC_MMR6_ENC  : BRANCH_OFF26_FM<0b101101>;
 class BC_MMR6_ENC : BRANCH_OFF26_FM<0b100101>;
+class BITSWAP_MMR6_ENC : POOL32A_BITSWAP_FM_MMR6<0b101100>;
 
 //===----------------------------------------------------------------------===//
 //
 // Instruction Descriptions
 //
 //===----------------------------------------------------------------------===//
 
 class BC_MMR6_DESC_BASE<string instr_asm, DAGOperand opnd>
     : BRANCH_DESC_BASE, MMR6Arch<instr_asm> {
   dag InOperandList = (ins opnd:$offset);
   dag OutOperandList = (outs);
   string AsmString = !strconcat(instr_asm, "\t$offset");
   bit isBarrier = 1;
 }
 
 class BALC_MMR6_DESC : BC_MMR6_DESC_BASE<"balc", brtarget26> {
   bit isCall = 1;
   list<Register> Defs = [RA];
 }
 class BC_MMR6_DESC : BC_MMR6_DESC_BASE<"bc", brtarget26>;
 
+class BITSWAP_MMR6_DESC_BASE<string instr_asm, RegisterOperand GPROpnd>
+    : MMR6Arch<instr_asm> {
+  dag OutOperandList = (outs GPROpnd:$rd);
+  dag InOperandList = (ins GPROpnd:$rt);
+  string AsmString = !strconcat(instr_asm, "\t$rd, $rt");
+  list<dag> Pattern = [];
+}
+
+class BITSWAP_MMR6_DESC : BITSWAP_MMR6_DESC_BASE<"bitswap", GPR32Opnd>;
+
 //===----------------------------------------------------------------------===//
 //
 // Instruction Definitions
 //
 //===----------------------------------------------------------------------===//
 
 let DecoderNamespace = "MicroMips32r6" in {
 def BALC_MMR6 : R6MMR6Rel, BALC_MMR6_ENC, BALC_MMR6_DESC, ISA_MICROMIPS32R6;
 def BC_MMR6 : R6MMR6Rel, BC_MMR6_ENC, BC_MMR6_DESC, ISA_MICROMIPS32R6;
+def BITSWAP_MMR6 : R6MMR6Rel, BITSWAP_MMR6_ENC, BITSWAP_MMR6_DESC,
+                   ISA_MICROMIPS32R6;
 }

llvm/trunk/lib/Target/Mips/Mips32r6InstrInfo.td

 class JR_HB_R6_DESC : JR_HB_DESC_BASE<"jr.hb", GPR32Opnd> {
   bit isBranch = 1;
   bit isIndirectBranch = 1;
   bit hasDelaySlot = 1;
   bit isTerminator=1;
   bit isBarrier=1;
 }
 
-class BITSWAP_DESC_BASE<string instr_asm, RegisterOperand GPROpnd> {
+class BITSWAP_DESC_BASE<string instr_asm, RegisterOperand GPROpnd>
+    : MipsR6Arch<instr_asm> {
   dag OutOperandList = (outs GPROpnd:$rd);
   dag InOperandList = (ins GPROpnd:$rt);
   string AsmString = !strconcat(instr_asm, "\t$rd, $rt");
   list<dag> Pattern = [];
 }
 
 class BITSWAP_DESC : BITSWAP_DESC_BASE<"bitswap", GPR32Opnd>;
 

 def BEQZALC : BEQZALC_ENC, BEQZALC_DESC, ISA_MIPS32R6;
 def BEQZC : BEQZC_ENC, BEQZC_DESC, ISA_MIPS32R6;
 def BGEC : BGEC_ENC, BGEC_DESC, ISA_MIPS32R6;
 def BGEUC : BGEUC_ENC, BGEUC_DESC, ISA_MIPS32R6;
 def BGEZALC : BGEZALC_ENC, BGEZALC_DESC, ISA_MIPS32R6;
 def BGEZC : BGEZC_ENC, BGEZC_DESC, ISA_MIPS32R6;
 def BGTZALC : BGTZALC_ENC, BGTZALC_DESC, ISA_MIPS32R6;
 def BGTZC : BGTZC_ENC, BGTZC_DESC, ISA_MIPS32R6;
-def BITSWAP : BITSWAP_ENC, BITSWAP_DESC, ISA_MIPS32R6;
+def BITSWAP : R6MMR6Rel, BITSWAP_ENC, BITSWAP_DESC, ISA_MIPS32R6;
 def BLEZALC : BLEZALC_ENC, BLEZALC_DESC, ISA_MIPS32R6;
 def BLEZC : BLEZC_ENC, BLEZC_DESC, ISA_MIPS32R6;
 def BLTC : BLTC_ENC, BLTC_DESC, ISA_MIPS32R6;
 def BLTUC : BLTUC_ENC, BLTUC_DESC, ISA_MIPS32R6;
 def BLTZALC : BLTZALC_ENC, BLTZALC_DESC, ISA_MIPS32R6;
 def BLTZC : BLTZC_ENC, BLTZC_DESC, ISA_MIPS32R6;
 def BNEC : BNEC_ENC, BNEC_DESC, ISA_MIPS32R6;
 def BNEZALC : BNEZALC_ENC, BNEZALC_DESC, ISA_MIPS32R6;

llvm/trunk/test/MC/Disassembler/Mips/micromips32r6.txt

 # RUN: llvm-mc --disassemble %s -triple=mips-unknown-linux -mcpu=mips32r6 -mattr=micromips | FileCheck %s
 
 # CHECK: balc 14572256
 0xb4 0x37 0x96 0xb8
 
 # CHECK: bc 14572256
 0x94 0x37 0x96 0xb8
+
+# CHECK: bitswap $4, $2
+0x00 0x44 0x0b 0x3c

llvm/trunk/test/MC/Mips/micromips32r6/valid.s

 # RUN: llvm-mc %s -triple=mips-unknown-linux -show-encoding -mcpu=mips32r6 -mattr=micromips | FileCheck %s
 
   .set noat
   balc 14572256            # CHECK: balc 14572256       # encoding: [0xb4,0x37,0x96,0xb8]
   bc 14572256              # CHECK: bc 14572256         # encoding: [0x94,0x37,0x96,0xb8]
+  bitswap $4, $2           # CHECK: bitswap $4, $2      # encoding: [0x00,0x44,0x0b,0x3c]