[llvm-commits] [llvm] r159453 - in /llvm/trunk: include/llvm/CodeGen/MachineRegisterInfo.h lib/CodeGen/MachineRegisterInfo.cpp

[Manman Ren]

Author: mren
Date: Fri Jun 29 14:16:05 2012
New Revision: 159453

URL: http://llvm.org/viewvc/llvm-project?rev=159453&view=rev
Log:
Add getUniqueVRegDef to MachineRegisterInfo.
This comes in handy during peephole optimization.

Modified:
    llvm/trunk/include/llvm/CodeGen/MachineRegisterInfo.h
    llvm/trunk/lib/CodeGen/MachineRegisterInfo.cpp

Modified: llvm/trunk/include/llvm/CodeGen/MachineRegisterInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/MachineRegisterInfo.h?rev=159453&r1=159452&r2=159453&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/MachineRegisterInfo.h (original)
+++ llvm/trunk/include/llvm/CodeGen/MachineRegisterInfo.h Fri Jun 29 14:16:05 2012
@@ -237,6 +237,11 @@
   /// form, so there should only be one definition.
   MachineInstr *getVRegDef(unsigned Reg) const;
 
+  /// getUniqueVRegDef - Return the unique machine instr that defines the
+  /// specified virtual register or null if none is found.  If there are
+  /// multiple definitions or no definition, return null.
+  MachineInstr *getUniqueVRegDef(unsigned Reg) const;
+
   /// clearKillFlags - Iterate over all the uses of the given register and
   /// clear the kill flag from the MachineOperand. This function is used by
   /// optimization passes which extend register lifetimes and need only

Modified: llvm/trunk/lib/CodeGen/MachineRegisterInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineRegisterInfo.cpp?rev=159453&r1=159452&r2=159453&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineRegisterInfo.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineRegisterInfo.cpp Fri Jun 29 14:16:05 2012
@@ -165,6 +165,17 @@
   return !I.atEnd() ? &*I : 0;
 }
 
+/// getUniqueVRegDef - Return the unique machine instr that defines the
+/// specified virtual register or null if none is found.  If there are
+/// multiple definitions or no definition, return null.
+MachineInstr *MachineRegisterInfo::getUniqueVRegDef(unsigned Reg) const {
+  if (def_empty(Reg)) return 0;
+  def_iterator I = def_begin(Reg);
+  if (llvm::next(I) != def_end())
+    return 0;
+  return &*I;
+}
+
 bool MachineRegisterInfo::hasOneUse(unsigned RegNo) const {
   use_iterator UI = use_begin(RegNo);
   if (UI == use_end())