157     zero_reg,  in ToRegister()
572   Register nop_rt_reg = (type == 0) ? zero_reg : at;  in IsNop()
574               rd == static_cast<uint32_t>(ToNumber(zero_reg)) &&  in IsNop()
1143   beq(zero_reg, zero_reg, offset);  in b()
1149   bgezal(zero_reg, offset);  in bal()
1169   DCHECK(!(rt.is(zero_reg)));  in bgezc()
1176   DCHECK(!(rs.is(zero_reg)));  in bgeuc()
1177   DCHECK(!(rt.is(zero_reg)));  in bgeuc()
1185   DCHECK(!(rs.is(zero_reg)));  in bgec()
1186   DCHECK(!(rt.is(zero_reg)));  in bgec()
1193   DCHECK(kArchVariant != kMips64r6 || rs.is(zero_reg));  in bgezal()
1203   GenInstrImmediate(BGTZ, rs, zero_reg, offset);  in bgtz()
1210   DCHECK(!(rt.is(zero_reg)));  in bgtzc()
1211   GenInstrImmediate(BGTZL, zero_reg, rt, offset);  in bgtzc()
1217   GenInstrImmediate(BLEZ, rs, zero_reg, offset);  in blez()
1224   DCHECK(!(rt.is(zero_reg)));  in blezc()
1225   GenInstrImmediate(BLEZL, zero_reg, rt, offset);  in blezc()
1231   DCHECK(!(rt.is(zero_reg)));  in bltzc()
1238   DCHECK(!(rs.is(zero_reg)));  in bltuc()
1239   DCHECK(!(rt.is(zero_reg)));  in bltuc()
1247   DCHECK(!(rs.is(zero_reg)));  in bltc()
1248   DCHECK(!(rt.is(zero_reg)));  in bltc()
1262   DCHECK(kArchVariant != kMips64r6 || rs.is(zero_reg));  in bltzal()
1279   DCHECK(!(rs.is(zero_reg)));  in bovc()
1287   DCHECK(!(rs.is(zero_reg)));  in bnvc()
1295   DCHECK(!(rt.is(zero_reg)));  in blezalc()
1296   GenInstrImmediate(BLEZ, zero_reg, rt, offset);  in blezalc()
1302   DCHECK(!(rt.is(zero_reg)));  in bgezalc()
1309   DCHECK(!(rs.is(zero_reg)));  in bgezall()
1316   DCHECK(!(rt.is(zero_reg)));  in bltzalc()
1323   DCHECK(!(rt.is(zero_reg)));  in bgtzalc()
1324   GenInstrImmediate(BGTZ, zero_reg, rt, offset);  in bgtzalc()
1330   DCHECK(!(rt.is(zero_reg)));  in beqzalc()
1331   GenInstrImmediate(ADDI, zero_reg, rt, offset);  in beqzalc()
1337   DCHECK(!(rt.is(zero_reg)));  in bnezalc()
1338   GenInstrImmediate(DADDI, zero_reg, rt, offset);  in bnezalc()
1351   DCHECK(!(rs.is(zero_reg)));  in beqzc()
1366   DCHECK(!(rs.is(zero_reg)));  in bnezc()
1390     GenInstrRegister(SPECIAL, rs, zero_reg, zero_reg, 0, JR);  in jr()
1393     jalr(rs, zero_reg);  in jr()
1414   GenInstrRegister(SPECIAL, rs, zero_reg, rd, 0, JALR);  in jalr()
1517   GenInstrRegister(SPECIAL, rs, rt, zero_reg, 0, MULT);  in mult()
1523   GenInstrRegister(SPECIAL, rs, rt, zero_reg, 0, MULTU);  in multu()
1533   GenInstrRegister(SPECIAL, rs, rt, zero_reg, 0, DIV);  in div()
1550   GenInstrRegister(SPECIAL, rs, rt, zero_reg, 0, DIVU);  in divu()
1577   GenInstrRegister(SPECIAL, rs, rt, zero_reg, 0, DMULT);  in dmult()
1582   GenInstrRegister(SPECIAL, rs, rt, zero_reg, 0, DMULTU);  in dmultu()
1587   GenInstrRegister(SPECIAL, rs, rt, zero_reg, 0, DDIV);  in ddiv()
1604   GenInstrRegister(SPECIAL, rs, rt, zero_reg, 0, DDIVU);  in ddivu()
1669   DCHECK(coming_from_nop || !(rd.is(zero_reg) && rt.is(zero_reg)));  in sll()
1670   GenInstrRegister(SPECIAL, zero_reg, rt, rd, sa, SLL);  in sll()
1680   GenInstrRegister(SPECIAL, zero_reg, rt, rd, sa, SRL);  in srl()
1690   GenInstrRegister(SPECIAL, zero_reg, rt, rd, sa, SRA);  in sra()
1720   GenInstrRegister(SPECIAL, zero_reg, rt, rd, sa, DSLL);  in dsll()
1730   GenInstrRegister(SPECIAL, zero_reg, rt, rd, sa, DSRL);  in dsrl()
1756   GenInstrRegister(SPECIAL, zero_reg, rt, rd, sa, DSRA);  in dsra()
1766   GenInstrRegister(SPECIAL, zero_reg, rt, rd, sa, DSLL32);  in dsll32()
1771   GenInstrRegister(SPECIAL, zero_reg, rt, rd, sa, DSRL32);  in dsrl32()
1776   GenInstrRegister(SPECIAL, zero_reg, rt, rd, sa, DSRA32);  in dsra32()
1786   daddiu(at, zero_reg, (src.offset_ >> kLuiShift) & kImm16Mask);  in LoadRegPlusOffsetToAt()
1905   GenInstrImmediate(LUI, zero_reg, rd, j);  in lui()
2061   GenInstrRegister(SPECIAL, zero_reg, zero_reg, rd, 0, MFHI);  in mfhi()
2066   GenInstrRegister(SPECIAL, zero_reg, zero_reg, rd, 0, MFLO);  in mflo()
2174     GenInstrRegister(SPECIAL, rs, zero_reg, rd, 1, CLZ_R6);  in clz()
2533   mtc1(zero_reg, f14);  in fcmp()