Add method to update livevar when an instruction moves
llvm-svn: 11625
diff --git a/llvm/lib/CodeGen/LiveVariables.cpp b/llvm/lib/CodeGen/LiveVariables.cpp
index 0554bae..c4c8d63 100644
--- a/llvm/lib/CodeGen/LiveVariables.cpp
+++ b/llvm/lib/CodeGen/LiveVariables.cpp
@@ -33,6 +33,7 @@
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/CFG.h"
#include "Support/DepthFirstIterator.h"
+#include "Support/STLExtras.h"
using namespace llvm;
static RegisterAnalysis<LiveVariables> X("livevars", "Live Variable Analysis");
@@ -313,3 +314,36 @@
return false;
}
+
+/// instructionChanged - When the address of an instruction changes, this
+/// method should be called so that live variables can update its internal
+/// data structures. This removes the records for OldMI, transfering them to
+/// the records for NewMI.
+void LiveVariables::instructionChanged(MachineInstr *OldMI,
+ MachineInstr *NewMI) {
+ // If the instruction defines any virtual registers, update the VarInfo for
+ // the instruction.
+ for (unsigned i = 0, e = NewMI->getNumOperands(); i != e; ++i) {
+ MachineOperand &MO = NewMI->getOperand(i);
+ if (MO.isRegister() && MO.isDef() &&
+ MRegisterInfo::isVirtualRegister(MO.getReg())) {
+ unsigned Reg = MO.getReg();
+ VarInfo &VI = getVarInfo(Reg);
+ if (VI.DefInst == OldMI)
+ VI.DefInst = NewMI;
+ }
+ }
+
+ // Move the killed information over...
+ killed_iterator I, E;
+ tie(I, E) = killed_range(OldMI);
+ for (killed_iterator A = I; A != E; ++A)
+ RegistersKilled.insert(std::make_pair(NewMI, A->second));
+ RegistersKilled.erase(I, E);
+
+ // Move the dead information over...
+ tie(I, E) = dead_range(OldMI);
+ for (killed_iterator A = I; A != E; ++A)
+ RegistersDead.insert(std::make_pair(NewMI, A->second));
+ RegistersDead.erase(I, E);
+}