Index: lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
===================================================================
--- lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
+++ lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
@@ -925,6 +925,8 @@
 
   switch (getLexer().getKind()) {
   default:
+    if (HadParens)
+      getLexer().UnLex(AsmToken(AsmToken::LParen, "("));
     return MatchOperand_NoMatch;
   case AsmToken::Identifier:
     StringRef Name = getLexer().getTok().getIdentifier();
@@ -933,7 +935,7 @@
       RegNo = MatchRegisterAltName(Name);
       if (RegNo == 0) {
         if (HadParens)
-          getLexer().UnLex(Buf[0]);
+          getLexer().UnLex(AsmToken(AsmToken::LParen, "("));
         return MatchOperand_NoMatch;
       }
     }
Index: test/MC/RISCV/rv32i-valid.s
===================================================================
--- test/MC/RISCV/rv32i-valid.s
+++ test/MC/RISCV/rv32i-valid.s
@@ -128,6 +128,9 @@
 lb s3, 4(ra)
 # CHECK-ASM-AND-OBJ: lb s3, 4(ra)
 # CHECK-ASM: encoding: [0x83,0x89,0x40,0x00]
+lb s3, (4)(ra)
+# CHECK-ASM-AND-OBJ: lb s3, 4(ra)
+# CHECK-ASM: encoding: [0x83,0x89,0x40,0x00]
 lb s3, +4(ra)
 # CHECK-ASM-AND-OBJ: lh t1, -2048(zero)
 # CHECK-ASM: encoding: [0x03,0x13,0x00,0x80]