Fix error in the Win32 implementation pointed out by Howard Su.

[oota-llvm.git] / lib / CodeGen / LiveVariables.cpp

diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp
index c33d81e8a875fb7d165250202d50d3a0c4e16b03..bd845085bbf5ce427f9f4d667582fef74bed2a1a 100644 (file)
--- a/lib/CodeGen/LiveVariables.cpp
+++ b/lib/CodeGen/LiveVariables.cpp
@@ -242,20 +242,6 @@ void LiveVariables::HandlePhysRegUse(unsigned Reg, MachineInstr *MI) {
     }
   }
 
-  // There was an earlier def of a super-register. Add implicit def to that MI.
-  //
-  //   A: EAX = ...
-  //   B: ... = AX
-  //
-  // Add implicit def to A if there isn't a use of AX (or EAX) before B.
-  if (!PhysRegUse[Reg]) {
-    MachineInstr *Def = PhysRegDef[Reg];
-    if (Def && !Def->modifiesRegister(Reg))
-      Def->addOperand(MachineOperand::CreateReg(Reg,
-                                                true  /*IsDef*/,
-                                                true  /*IsImp*/));
-  }
-  
   // Remember this use.
   PhysRegUse[Reg]  = MI;
   for (const unsigned *SubRegs = TRI->getSubRegisters(Reg);
@@ -373,12 +359,11 @@ bool LiveVariables::HandlePhysRegKill(unsigned Reg, MachineInstr *MI) {
     // That is, unless we are currently processing the last reference itself.
     LastRefOrPartRef->addRegisterDead(Reg, TRI, true);
 
-  /* Partial uses. Mark register def dead and add implicit def of
-     sub-registers which are used.
-    FIXME: LiveIntervalAnalysis can't handle this yet!
-    EAX<dead>  = op  AL<imp-def>
-    That is, EAX def is dead but AL def extends pass it.
-    Enable this after live interval analysis is fixed to improve codegen!
+  // Partial uses. Mark register def dead and add implicit def of
+  // sub-registers which are used.
+  // EAX<dead>  = op  AL<imp-def>
+  // That is, EAX def is dead but AL def extends pass it.
+  // Enable this after live interval analysis is fixed to improve codegen!
   else if (!PhysRegUse[Reg]) {
     PhysRegDef[Reg]->addRegisterDead(Reg, TRI, true);
     for (const unsigned *SubRegs = TRI->getSubRegisters(Reg);
@@ -391,7 +376,7 @@ bool LiveVariables::HandlePhysRegKill(unsigned Reg, MachineInstr *MI) {
           PartUses.erase(*SS);
       }
     }
-  } */
+  }
   else
     LastRefOrPartRef->addRegisterKilled(Reg, TRI, true);
   return true;