[llvm-commits] [llvm] r103737 - in /llvm/trunk: include/llvm/CodeGen/MachineInstr.h lib/CodeGen/MachineInstr.cpp lib/CodeGen/MachineLICM.cpp lib/CodeGen/MachineSink.cpp

[Dan Gohman]

Author: djg
Date: Thu May 13 15:34:42 2010
New Revision: 103737

URL: http://llvm.org/viewvc/llvm-project?rev=103737&view=rev
Log:
Teach MachineLICM and MachineSink how to clear kill flags conservatively
when they move instructions.

Modified:
    llvm/trunk/include/llvm/CodeGen/MachineInstr.h
    llvm/trunk/lib/CodeGen/MachineInstr.cpp
    llvm/trunk/lib/CodeGen/MachineLICM.cpp
    llvm/trunk/lib/CodeGen/MachineSink.cpp

Modified: llvm/trunk/include/llvm/CodeGen/MachineInstr.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/MachineInstr.h?rev=103737&r1=103736&r2=103737&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/MachineInstr.h (original)
+++ llvm/trunk/include/llvm/CodeGen/MachineInstr.h Thu May 13 15:34:42 2010
@@ -302,6 +302,10 @@
   /// reference if DefOpIdx is not null.
   bool isRegTiedToDefOperand(unsigned UseOpIdx, unsigned *DefOpIdx = 0) const;
 
+  /// clearKillInfo - Clears kill flags on all operands.
+  ///
+  void clearKillInfo();
+
   /// copyKillDeadInfo - Copies kill / dead operand properties from MI.
   ///
   void copyKillDeadInfo(const MachineInstr *MI);

Modified: llvm/trunk/lib/CodeGen/MachineInstr.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineInstr.cpp?rev=103737&r1=103736&r2=103737&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineInstr.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineInstr.cpp Thu May 13 15:34:42 2010
@@ -938,6 +938,16 @@
   return true;
 }
 
+/// clearKillInfo - Clears kill flags on all operands.
+///
+void MachineInstr::clearKillInfo() {
+  for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
+    MachineOperand &MO = getOperand(i);
+    if (MO.isReg() && MO.isUse())
+      MO.setIsKill(false);
+  }
+}
+
 /// copyKillDeadInfo - Copies kill / dead operand properties from MI.
 ///
 void MachineInstr::copyKillDeadInfo(const MachineInstr *MI) {

Modified: llvm/trunk/lib/CodeGen/MachineLICM.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineLICM.cpp?rev=103737&r1=103736&r2=103737&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineLICM.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineLICM.cpp Thu May 13 15:34:42 2010
@@ -738,8 +738,10 @@
              "Instructions with different phys regs are not identical!");
 
       if (MO.isReg() && MO.isDef() &&
-          !TargetRegisterInfo::isPhysicalRegister(MO.getReg()))
+          !TargetRegisterInfo::isPhysicalRegister(MO.getReg())) {
         RegInfo->replaceRegWith(MO.getReg(), Dup->getOperand(i).getReg());
+        RegInfo->clearKillFlags(Dup->getOperand(i).getReg());
+      }
     }
     MI->eraseFromParent();
     ++NumCSEed;
@@ -784,6 +786,15 @@
     // Otherwise, splice the instruction to the preheader.
     CurPreheader->splice(CurPreheader->getFirstTerminator(),MI->getParent(),MI);
 
+    // Clear the kill flags of any register this instruction defines,
+    // since they may need to be live throughout the entire loop
+    // rather than just live for part of it.
+    for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+      MachineOperand &MO = MI->getOperand(i);
+      if (MO.isReg() && MO.isDef() && !MO.isDead())
+        RegInfo->clearKillFlags(MO.getReg());
+    }
+
     // Add to the CSE map.
     if (CI != CSEMap.end())
       CI->second.push_back(MI);

Modified: llvm/trunk/lib/CodeGen/MachineSink.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineSink.cpp?rev=103737&r1=103736&r2=103737&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineSink.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineSink.cpp Thu May 13 15:34:42 2010
@@ -314,5 +314,10 @@
   // Move the instruction.
   SuccToSinkTo->splice(InsertPos, ParentBlock, MI,
                        ++MachineBasicBlock::iterator(MI));
+
+  // Conservatively, clear any kill flags, since it's possible that
+  // they are no longer correct.
+  MI->clearKillInfo();
+
   return true;
 }