MachineOperand/MIParser: Do not print debug-use flag, infer it

The debug-use flag must be set exactly for uses on DBG_VALUEs.  This is
so obvious that it can be trivially inferred while parsing. This will
reduce noise when printing while omitting an information that has little
value to the user.

The parser will keep recognizing the flag for compatibility with old
`.mir` files.

Differential Revision: https://reviews.llvm.org/D53903

llvm-svn: 345671

2 files changed, 4 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/MIRParser/MIParser.cpp b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
index da758da873c..1a6174bf9ee 100644
--- a/llvm/lib/CodeGen/MIRParser/MIParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
@@ -752,6 +752,8 @@ bool MIParser::parse(MachineInstr *&MI) {
     Optional<unsigned> TiedDefIdx;
     if (parseMachineOperandAndTargetFlags(MO, TiedDefIdx))
       return true;
+    if (OpCode == TargetOpcode::DBG_VALUE && MO.isReg())
+      MO.setIsDebug();
     Operands.push_back(
         ParsedMachineOperand(MO, Loc, Token.location(), TiedDefIdx));
     if (Token.isNewlineOrEOF() || Token.is(MIToken::coloncolon) ||
diff --git a/llvm/lib/CodeGen/MachineOperand.cpp b/llvm/lib/CodeGen/MachineOperand.cpp
index 97d32a5d66a..4fe51f66248 100644
--- a/llvm/lib/CodeGen/MachineOperand.cpp
+++ b/llvm/lib/CodeGen/MachineOperand.cpp
@@ -744,10 +744,10 @@ void MachineOperand::print(raw_ostream &OS, ModuleSlotTracker &MST,
       OS << "undef ";
     if (isEarlyClobber())
       OS << "early-clobber ";
-    if (isDebug())
-      OS << "debug-use ";
     if (TargetRegisterInfo::isPhysicalRegister(getReg()) && isRenamable())
       OS << "renamable ";
+    // isDebug() is exactly true for register operands of a DBG_VALUE. So we
+    // simply infer it when parsing and do not need to print it.
 
     const MachineRegisterInfo *MRI = nullptr;
     if (TargetRegisterInfo::isVirtualRegister(Reg)) {