4 files changed, 35 insertions, 7 deletions

diff --git a/include/llvm/MC/MCInstrDesc.h b/include/llvm/MC/MCInstrDesc.h
index 7061fcb012..aafa800c1a 100644
--- a/include/llvm/MC/MCInstrDesc.h
+++ b/include/llvm/MC/MCInstrDesc.h
@@ -97,6 +97,7 @@ namespace MCID {
   enum {
     Variadic = 0,
     HasOptionalDef,
+    Pseudo,
     Return,
     Call,
     Barrier,
@@ -275,6 +276,13 @@ public:
     return Size;
   }
 
+  /// isPseudo - Return true if this is a pseudo instruction that doesn't
+  /// correspond to a real machine instruction.
+  ///
+  bool isPseudo() const {
+    return Flags & (1 << MCID::Pseudo);
+  }
+
   bool isReturn() const {
     return Flags & (1 << MCID::Return);
   }
diff --git a/include/llvm/Target/TargetInstrInfo.h b/include/llvm/Target/TargetInstrInfo.h
index e6e963c03e..bbe5897821 100644
--- a/include/llvm/Target/TargetInstrInfo.h
+++ b/include/llvm/Target/TargetInstrInfo.h
@@ -386,6 +386,16 @@ public:
   assert(0 && "Target didn't implement TargetInstrInfo::loadRegFromStackSlot!");
   }
 
+  /// expandPostRAPseudo - This function is called for all pseudo instructions
+  /// that remain after register allocation. Many pseudo instructions are
+  /// created to help register allocation. This is the place to convert them
+  /// into real instructions. The target can edit MI in place, or it can insert
+  /// new instructions and erase MI. The function should return true if
+  /// anything was changed.
+  bool expandPostRAPseudo(MachineBasicBlock::iterator MI) const {
+    return false;
+  }
+
   /// emitFrameIndexDebugValue - Emit a target-dependent form of
   /// DBG_VALUE encoding the address of a frame index.  Addresses would
   /// normally be lowered the same way as other addresses on the target,
diff --git a/lib/CodeGen/ExpandPostRAPseudos.cpp b/lib/CodeGen/ExpandPostRAPseudos.cpp
index 78382f548c..623b67ddcd 100644
--- a/lib/CodeGen/ExpandPostRAPseudos.cpp
+++ b/lib/CodeGen/ExpandPostRAPseudos.cpp
@@ -202,17 +202,26 @@ bool ExpandPostRA::runOnMachineFunction(MachineFunction &MF) {
        mbbi != mbbe; ++mbbi) {
     for (MachineBasicBlock::iterator mi = mbbi->begin(), me = mbbi->end();
          mi != me;) {
-      MachineBasicBlock::iterator nmi = llvm::next(mi);
       MachineInstr *MI = mi;
-      assert(!MI->isInsertSubreg() && "INSERT_SUBREG should no longer appear");
-      assert(MI->getOpcode() != TargetOpcode::EXTRACT_SUBREG &&
-             "EXTRACT_SUBREG should no longer appear");
-      if (MI->isSubregToReg()) {
+      // Advance iterator here because MI may be erased.
+      ++mi;
+      switch (MI->getOpcode()) {
+      case TargetOpcode::SUBREG_TO_REG:
         MadeChange |= LowerSubregToReg(MI);
-      } else if (MI->isCopy()) {
+        break;
+      case TargetOpcode::COPY:
         MadeChange |= LowerCopy(MI);
+        break;
+      case TargetOpcode::DBG_VALUE:
+        continue;
+      case TargetOpcode::INSERT_SUBREG:
+      case TargetOpcode::EXTRACT_SUBREG:
+        llvm_unreachable("Sub-register pseudos should have been eliminated.");
+      default:
+        if (MI->getDesc().isPseudo())
+          MadeChange |= TII->expandPostRAPseudo(MI);
+        break;
       }
-      mi = nmi;
     }
   }
 
diff --git a/utils/TableGen/InstrInfoEmitter.cpp b/utils/TableGen/InstrInfoEmitter.cpp
index 1cf7c90496..35fe728f9e 100644
--- a/utils/TableGen/InstrInfoEmitter.cpp
+++ b/utils/TableGen/InstrInfoEmitter.cpp
@@ -268,6 +268,7 @@ void InstrInfoEmitter::emitRecord(const CodeGenInstruction &Inst, unsigned Num,
      << Inst.TheDef->getName() << "\", 0";
 
   // Emit all of the target indepedent flags...
+  if (Inst.isPseudo)           OS << "|(1<<MCID::Pseudo)";
   if (Inst.isReturn)           OS << "|(1<<MCID::Return)";
   if (Inst.isBranch)           OS << "|(1<<MCID::Branch)";
   if (Inst.isIndirectBranch)   OS << "|(1<<MCID::IndirectBranch)";