1 files changed, 39 insertions, 1 deletions

diff --git a/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp b/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
index ebf656c549ec..2e3a453f9c75 100644
--- a/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
+++ b/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
@@ -815,6 +815,10 @@ public:
 class AMDGPUAsmParser : public MCTargetAsmParser {
   MCAsmParser &Parser;
 
+  // Number of extra operands parsed after the first optional operand.
+  // This may be necessary to skip hardcoded mandatory operands.
+  static const unsigned MAX_OPR_LOOKAHEAD = 1;
+
   unsigned ForcedEncodingSize = 0;
   bool ForcedDPP = false;
   bool ForcedSDWA = false;
@@ -1037,6 +1041,7 @@ private:
 
 public:
   OperandMatchResultTy parseOptionalOperand(OperandVector &Operands);
+  OperandMatchResultTy parseOptionalOpr(OperandVector &Operands);
 
   OperandMatchResultTy parseExpTgt(OperandVector &Operands);
   OperandMatchResultTy parseSendMsgOp(OperandVector &Operands);
@@ -3859,7 +3864,7 @@ AMDGPUAsmParser::parseSwizzleOp(OperandVector &Operands) {
   } else {
     // Swizzle "offset" operand is optional.
     // If it is omitted, try parsing other optional operands.
-    return parseOptionalOperand(Operands);
+    return parseOptionalOpr(Operands);
   }
 }
 
@@ -4179,6 +4184,39 @@ static const OptionalOperand AMDGPUOptionalOperandTable[] = {
 };
 
 OperandMatchResultTy AMDGPUAsmParser::parseOptionalOperand(OperandVector &Operands) {
+  unsigned size = Operands.size();
+  assert(size > 0);
+
+  OperandMatchResultTy res = parseOptionalOpr(Operands);
+
+  // This is a hack to enable hardcoded mandatory operands which follow
+  // optional operands.
+  //
+  // Current design assumes that all operands after the first optional operand
+  // are also optional. However implementation of some instructions violates
+  // this rule (see e.g. flat/global atomic which have hardcoded 'glc' operands).
+  //
+  // To alleviate this problem, we have to (implicitly) parse extra operands
+  // to make sure autogenerated parser of custom operands never hit hardcoded
+  // mandatory operands.
+
+  if (size == 1 || ((AMDGPUOperand &)*Operands[size - 1]).isRegKind()) {
+
+    // We have parsed the first optional operand.
+    // Parse as many operands as necessary to skip all mandatory operands.
+
+    for (unsigned i = 0; i < MAX_OPR_LOOKAHEAD; ++i) {
+      if (res != MatchOperand_Success ||
+          getLexer().is(AsmToken::EndOfStatement)) break;
+      if (getLexer().is(AsmToken::Comma)) Parser.Lex();
+      res = parseOptionalOpr(Operands);
+    }
+  }
+
+  return res;
+}
+
+OperandMatchResultTy AMDGPUAsmParser::parseOptionalOpr(OperandVector &Operands) {
   OperandMatchResultTy res;
   for (const OptionalOperand &Op : AMDGPUOptionalOperandTable) {
     // try to parse any optional operand here