[Arch64AsmParser] better diagnostic for isb

Instruction isb takes as an operand either 'sy' or an immediate value. This
improves the diagnostic when the string is not 'sy' and adds a test case for
this which was missing. This also adds tests to check invalid inputs for dsb
and dmb.

Differential Revision: https://reviews.llvm.org/D32227

llvm-svn: 301165

1 files changed, 5 insertions, 7 deletions

diff --git a/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp b/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
index d7bbc2bcd22..4dbcc9581a8 100644
--- a/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
+++ b/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
@@ -2473,16 +2473,14 @@ AArch64AsmParser::tryParseBarrierOperand(OperandVector &Operands) {
     return MatchOperand_ParseFail;
   }
 
-  auto DB = AArch64DB::lookupDBByName(Tok.getString());
-  if (!DB) {
-    TokError("invalid barrier option name");
-    return MatchOperand_ParseFail;
-  }
-
   // The only valid named option for ISB is 'sy'
-  if (Mnemonic == "isb" && DB->Encoding != AArch64DB::sy) {
+  auto DB = AArch64DB::lookupDBByName(Tok.getString());
+  if (Mnemonic == "isb" && (!DB || DB->Encoding != AArch64DB::sy)) {
     TokError("'sy' or #imm operand expected");
     return MatchOperand_ParseFail;
+  } else if (!DB) {
+    TokError("invalid barrier option name");
+    return MatchOperand_ParseFail;
   }
 
   Operands.push_back(AArch64Operand::CreateBarrier(