4 files changed, 63 insertions, 10 deletions

diff --git a/llvm/lib/CodeGen/MIRParser/MILexer.cpp b/llvm/lib/CodeGen/MIRParser/MILexer.cpp
index 450d318f8c8..5ae1b10afd6 100644
--- a/llvm/lib/CodeGen/MIRParser/MILexer.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MILexer.cpp
@@ -454,6 +454,10 @@ static MIToken::TokenKind symbolToken(char C) {
     return MIToken::lparen;
   case ')':
     return MIToken::rparen;
+  case '{':
+    return MIToken::lbrace;
+  case '}':
+    return MIToken::rbrace;
   case '+':
     return MIToken::plus;
   case '-':
diff --git a/llvm/lib/CodeGen/MIRParser/MILexer.h b/llvm/lib/CodeGen/MIRParser/MILexer.h
index 07bdc3e4549..2f55ae4f0db 100644
--- a/llvm/lib/CodeGen/MIRParser/MILexer.h
+++ b/llvm/lib/CodeGen/MIRParser/MILexer.h
@@ -41,6 +41,8 @@ struct MIToken {
     exclaim,
     lparen,
     rparen,
+    lbrace,
+    rbrace,
     plus,
     minus,
 
diff --git a/llvm/lib/CodeGen/MIRParser/MIParser.cpp b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
index 3a0e52491ca..36b34395d4d 100644
--- a/llvm/lib/CodeGen/MIRParser/MIParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
@@ -351,6 +351,7 @@ bool MIParser::parseBasicBlockDefinitions(
     return Token.isError();
   if (Token.isNot(MIToken::MachineBasicBlockLabel))
     return error("expected a basic block definition before instructions");
+  unsigned BraceDepth = 0;
   do {
     if (parseBasicBlockDefinition(MBBSlots))
       return true;
@@ -363,12 +364,23 @@ bool MIParser::parseBasicBlockDefinitions(
       else if (Token.is(MIToken::MachineBasicBlockLabel))
         return error("basic block definition should be located at the start of "
                      "the line");
-      if (Token.is(MIToken::Newline))
+      else if (consumeIfPresent(MIToken::Newline)) {
         IsAfterNewline = true;
-      else
-        IsAfterNewline = false;
+        continue;
+      }
+      IsAfterNewline = false;
+      if (Token.is(MIToken::lbrace))
+        ++BraceDepth;
+      if (Token.is(MIToken::rbrace)) {
+        if (!BraceDepth)
+          return error("extraneous closing brace ('}')");
+        --BraceDepth;
+      }
       lex();
     }
+    // Verify that we closed all of the '{' at the end of a file or a block.
+    if (!Token.isError() && BraceDepth)
+      return error("expected '}'"); // FIXME: Report a note that shows '{'.
   } while (!Token.isErrorOrEOF());
   return Token.isError();
 }
@@ -458,15 +470,40 @@ bool MIParser::parseBasicBlock(MachineBasicBlock &MBB) {
   }
 
   // Parse the instructions.
+  bool IsInBundle = false;
+  MachineInstr *PrevMI = nullptr;
   while (true) {
     if (Token.is(MIToken::MachineBasicBlockLabel) || Token.is(MIToken::Eof))
       return false;
     else if (consumeIfPresent(MIToken::Newline))
       continue;
+    if (consumeIfPresent(MIToken::rbrace)) {
+      // The first parsing pass should verify that all closing '}' have an
+      // opening '{'.
+      assert(IsInBundle);
+      IsInBundle = false;
+      continue;
+    }
     MachineInstr *MI = nullptr;
     if (parse(MI))
       return true;
     MBB.insert(MBB.end(), MI);
+    if (IsInBundle) {
+      PrevMI->setFlag(MachineInstr::BundledSucc);
+      MI->setFlag(MachineInstr::BundledPred);
+    }
+    PrevMI = MI;
+    if (Token.is(MIToken::lbrace)) {
+      if (IsInBundle)
+        return error("nested instruction bundles are not allowed");
+      lex();
+      // This instruction is the start of the bundle.
+      MI->setFlag(MachineInstr::BundledSucc);
+      IsInBundle = true;
+      if (!Token.is(MIToken::Newline))
+        // The next instruction can be on the same line.
+        continue;
+    }
     assert(Token.isNewlineOrEOF() && "MI is not fully parsed");
     lex();
   }
@@ -516,16 +553,15 @@ bool MIParser::parse(MachineInstr *&MI) {
   if (Token.isError() || parseInstruction(OpCode, Flags))
     return true;
 
-  // TODO: Parse the bundle instruction flags.
-
   // Parse the remaining machine operands.
   while (!Token.isNewlineOrEOF() && Token.isNot(MIToken::kw_debug_location) &&
-         Token.isNot(MIToken::coloncolon)) {
+         Token.isNot(MIToken::coloncolon) && Token.isNot(MIToken::lbrace)) {
     auto Loc = Token.location();
     if (parseMachineOperandAndTargetFlags(MO))
       return true;
     Operands.push_back(MachineOperandWithLocation(MO, Loc, Token.location()));
-    if (Token.isNewlineOrEOF() || Token.is(MIToken::coloncolon))
+    if (Token.isNewlineOrEOF() || Token.is(MIToken::coloncolon) ||
+        Token.is(MIToken::lbrace))
       break;
     if (Token.isNot(MIToken::comma))
       return error("expected ',' before the next machine operand");
diff --git a/llvm/lib/CodeGen/MIRPrinter.cpp b/llvm/lib/CodeGen/MIRPrinter.cpp
index a4de62899e4..8bb5203c507 100644
--- a/llvm/lib/CodeGen/MIRPrinter.cpp
+++ b/llvm/lib/CodeGen/MIRPrinter.cpp
@@ -439,11 +439,23 @@ void MIPrinter::print(const MachineBasicBlock &MBB) {
 
   if (HasLineAttributes)
     OS << "\n";
-  for (const auto &MI : MBB) {
-    OS.indent(2);
+  bool IsInBundle = false;
+  for (auto I = MBB.instr_begin(), E = MBB.instr_end(); I != E; ++I) {
+    const MachineInstr &MI = *I;
+    if (IsInBundle && !MI.isInsideBundle()) {
+      OS.indent(2) << "}\n";
+      IsInBundle = false;
+    }
+    OS.indent(IsInBundle ? 4 : 2);
     print(MI);
+    if (!IsInBundle && MI.getFlag(MachineInstr::BundledSucc)) {
+      OS << " {";
+      IsInBundle = true;
+    }
     OS << "\n";
   }
+  if (IsInBundle)
+    OS.indent(2) << "}\n";
 }
 
 void MIPrinter::print(const MachineInstr &MI) {
@@ -469,7 +481,6 @@ void MIPrinter::print(const MachineInstr &MI) {
   if (MI.getFlag(MachineInstr::FrameSetup))
     OS << "frame-setup ";
   OS << TII->getName(MI.getOpcode());
-  // TODO: Print the bundling instruction flags.
   if (I < E)
     OS << ' ';