[llvm-commits] [llvm] r103519 - /llvm/trunk/lib/CodeGen/SelectionDAG/InstrEmitter.cpp

[Dan Gohman]

Author: djg
Date: Tue May 11 16:59:14 2010
New Revision: 103519

URL: http://llvm.org/viewvc/llvm-project?rev=103519&view=rev
Log:
Don't set kill flags on uses of CopyFromReg nodes. InstrEmitter doesn't
create separate virtual registers for CopyFromReg values, so uses of
them don't necessarily kill the value.

Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/InstrEmitter.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/InstrEmitter.cpp?rev=103519&r1=103518&r2=103519&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/InstrEmitter.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/InstrEmitter.cpp Tue May 11 16:59:14 2010
@@ -297,15 +297,22 @@
   }
 
   // If this value has only one use, that use is a kill. This is a
-  // conservative approximation. Tied operands are never killed, so we need
-  // to check that. And that means we need to determine the index of the
-  // operand.
-  unsigned Idx = MI->getNumOperands();
-  while (Idx > 0 &&
-         MI->getOperand(Idx-1).isReg() && MI->getOperand(Idx-1).isImplicit())
-    --Idx;
-  bool isTied = MI->getDesc().getOperandConstraint(Idx, TOI::TIED_TO) != -1;
-  bool isKill = Op.hasOneUse() && !isTied && !IsDebug;
+  // conservative approximation. InstrEmitter does trivial coalescing
+  // with CopyFromReg nodes, so don't emit kill flags for them.
+  // Tied operands are never killed, so we need to check that. And that
+  // means we need to determine the index of the operand.
+  bool isKill = Op.hasOneUse() &&
+                Op.getNode()->getOpcode() != ISD::CopyFromReg &&
+                !IsDebug;
+  if (isKill) {
+    unsigned Idx = MI->getNumOperands();
+    while (Idx > 0 &&
+           MI->getOperand(Idx-1).isReg() && MI->getOperand(Idx-1).isImplicit())
+      --Idx;
+    bool isTied = MI->getDesc().getOperandConstraint(Idx, TOI::TIED_TO) != -1;
+    if (isTied)
+      isKill = false;
+  }
 
   MI->addOperand(MachineOperand::CreateReg(VReg, isOptDef,
                                            false/*isImp*/, isKill,