RISC-V: Fix bug in prior addi/c.nop patch.

gas/
	* config/tc-riscv.c (validate_riscv_insn) <'z'>: New.
	(riscv_ip) <'z'>: New.
	opcodes/
	* riscv-opc.c (riscv_opcodes) <addi>: Use z instead of 0.

gas/ChangeLog

@@ -1,3 +1,8 @@
+2018-01-17  Jim Wilson  <jimw@sifive.com>
+
+	* config/tc-riscv.c (validate_riscv_insn) <'z'>: New.
+	(riscv_ip) <'z'>: New.
+
 2018-01-17  Igor Tsimbalist  <igor.v.tsimbalist@intel.com>
 
 	* config/tc-i386.c (cpu_arch): Delete .cet. Add .ibt, .shstk.

gas/config/tc-riscv.c

@@ -570,6 +570,7 @@ validate_riscv_insn (const struct riscv_opcode *opc)
       case 'p':	used_bits |= ENCODE_SBTYPE_IMM (-1U); break;
       case 'q':	used_bits |= ENCODE_STYPE_IMM (-1U); break;
       case 'u':	used_bits |= ENCODE_UTYPE_IMM (-1U); break;
+      case 'z': break;
       case '[': break;
       case ']': break;
       case '0': break;
@@ -1712,6 +1713,15 @@ jump:
 		*imm_reloc = BFD_RELOC_RISCV_CALL;
 	      continue;
 
+	    case 'z':
+	      if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  || imm_expr->X_op != O_constant
+		  || imm_expr->X_add_number != 0)
+		break;
+	      s = expr_end;
+	      imm_expr->X_op = O_absent;
+	      continue;
+
 	    default:
 	      as_fatal (_("internal error: bad argument type %c"), *args);
 	    }

opcodes/ChangeLog

@@ -1,3 +1,7 @@
+2018-01-17  Jim Wilson  <jimw@sifive.com>
+
+	* riscv-opc.c (riscv_opcodes) <addi>: Use z instead of 0.
+
 2018-01-17  Igor Tsimbalist  <igor.v.tsimbalist@intel.com>
 
 	* i386-gen.c (cpu_flag_init): Delete CPU_CET_FLAGS, CpuCET.

opcodes/riscv-opc.c

@@ -232,7 +232,7 @@ const struct riscv_opcode riscv_opcodes[] =
 {"bne",       "I",   "s,t,p",  MATCH_BNE, MASK_BNE, match_opcode, 0 },
 {"addi",      "C",   "Ct,Cc,CK", MATCH_C_ADDI4SPN, MASK_C_ADDI4SPN, match_c_addi4spn, INSN_ALIAS },
 {"addi",      "C",   "d,CU,Cj",  MATCH_C_ADDI, MASK_C_ADDI, match_rd_nonzero, INSN_ALIAS },
-{"addi",      "C",   "d,CU,0",    MATCH_C_NOP, MASK_C_ADDI | MASK_RVC_IMM, match_c_nop, INSN_ALIAS },
+{"addi",      "C",   "d,CU,z",    MATCH_C_NOP, MASK_C_ADDI | MASK_RVC_IMM, match_c_nop, INSN_ALIAS },
 {"addi",      "C",   "Cc,Cc,CL", MATCH_C_ADDI16SP, MASK_C_ADDI16SP, match_c_addi16sp, INSN_ALIAS },
 {"addi",      "I",   "d,s,j",  MATCH_ADDI, MASK_ADDI, match_opcode, 0 },
 {"add",       "C",   "d,CU,CV",  MATCH_C_ADD, MASK_C_ADD, match_c_add, INSN_ALIAS },