[AMDGPU][MC] Corrected parsing of optional operands for ds_swizzle_b32

See bug 35645: https://bugs.llvm.org/show_bug.cgi?id=35645

Reviewers: artem.tamazov, arsenm

Differential Revision: https://reviews.llvm.org/D41186

llvm-svn: 321367

1 files changed, 3 insertions, 1 deletions

diff --git a/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp b/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
index 7ecaf0bf87c..25a4420a331 100644
--- a/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
+++ b/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
@@ -3852,7 +3852,9 @@ AMDGPUAsmParser::parseSwizzleOp(OperandVector &Operands) {
 
     return Ok? MatchOperand_Success : MatchOperand_ParseFail;
   } else {
-    return MatchOperand_NoMatch;
+    // Swizzle "offset" operand is optional.
+    // If it is omitted, try parsing other optional operands.
+    return parseOptionalOperand(Operands);
   }
 }