[CodeGen] Use MachineOperand::print in the MIRPrinter for MO_Register.

Work towards the unification of MIR and debug output by refactoring the
interfaces.

For MachineOperand::print, keep a simple version that can be easily called
from `dump()`, and a more complex one which will be called from both the
MIRPrinter and MachineInstr::print.

Add extra checks inside MachineOperand for detached operands (operands
with getParent() == nullptr).

https://reviews.llvm.org/D40836

* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/kill: ([^ ]+) ([^ ]+)<def> ([^ ]+)/kill: \1 def \2 \3/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/kill: ([^ ]+) ([^ ]+) ([^ ]+)<def>/kill: \1 \2 def \3/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/kill: def ([^ ]+) ([^ ]+) ([^ ]+)<def>/kill: def \1 \2 def \3/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/<def>//g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<kill>/killed \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<imp-use,kill>/implicit killed \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<dead>/dead \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<def[ ]*,[ ]*dead>/dead \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<imp-def[ ]*,[ ]*dead>/implicit-def dead \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<imp-def>/implicit-def \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<imp-use>/implicit \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<internal>/internal \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<undef>/undef \1/g'

llvm-svn: 320022
diff --git a/llvm/lib/CodeGen/LiveVariables.cpp b/llvm/lib/CodeGen/LiveVariables.cpp
index f9c5652..1c2bbc3 100644
--- a/llvm/lib/CodeGen/LiveVariables.cpp
+++ b/llvm/lib/CodeGen/LiveVariables.cpp
@@ -235,7 +235,7 @@
     // Otherwise, the last sub-register def implicitly defines this register.
     // e.g.
     // AH =
-    // AL = ... <imp-def EAX>, <imp-kill AH>
+    // AL = ... implicit-def EAX, implicit killed AH
     //    = AH
     // ...
     //    = EAX
@@ -321,17 +321,17 @@
   // AH =
   //
   //    = AX
-  //    = AL, AX<imp-use, kill>
+  //    = AL, implicit killed AX
   // AX =
   //
   // Or whole register is defined, but not used at all.
-  // AX<dead> =
+  // dead AX =
   // ...
   // AX =
   //
   // Or whole register is defined, but only partly used.
-  // AX<dead> = AL<imp-def>
-  //    = AL<kill>
+  // dead AX = implicit-def AL
+  //    = killed AL
   // AX =
   MachineInstr *LastPartDef = nullptr;
   unsigned LastPartDefDist = 0;
@@ -364,7 +364,7 @@
   if (!PhysRegUse[Reg]) {
     // Partial uses. Mark register def dead and add implicit def of
     // sub-registers which are used.
-    // EAX<dead>  = op  AL<imp-def>
+    // dead EAX  = op  implicit-def AL
     // That is, EAX def is dead but AL def extends pass it.
     PhysRegDef[Reg]->addRegisterDead(Reg, TRI, true);
     for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs) {