Vendor import of llvm tags/RELEASE_33/final r183502 (effectively, 3.3

release):
http://llvm.org/svn/llvm-project/llvm/tags/RELEASE_33/final@183502

1 files changed, 10 insertions, 6 deletions

diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp
index e6dfe10..7ca2bee 100644
--- a/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -43,6 +43,7 @@
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/IR/Function.h"
 #include "llvm/MC/MCInstrItineraries.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Target/TargetInstrInfo.h"
@@ -58,6 +59,12 @@ STATISTIC(Num3AddrSunk,        "Number of 3-address instructions sunk");
 STATISTIC(NumReSchedUps,       "Number of instructions re-scheduled up");
 STATISTIC(NumReSchedDowns,     "Number of instructions re-scheduled down");
 
+// Temporary flag to disable rescheduling.
+static cl::opt<bool>
+EnableRescheduling("twoaddr-reschedule",
+                   cl::desc("Coalesce copies by rescheduling (default=true)"),
+                   cl::init(true), cl::Hidden);
+
 namespace {
 class TwoAddressInstructionPass : public MachineFunctionPass {
   MachineFunction *MF;
@@ -426,10 +433,7 @@ static bool isKilled(MachineInstr &MI, unsigned Reg,
 /// isTwoAddrUse - Return true if the specified MI uses the specified register
 /// as a two-address use. If so, return the destination register by reference.
 static bool isTwoAddrUse(MachineInstr &MI, unsigned Reg, unsigned &DstReg) {
-  const MCInstrDesc &MCID = MI.getDesc();
-  unsigned NumOps = MI.isInlineAsm()
-    ? MI.getNumOperands() : MCID.getNumOperands();
-  for (unsigned i = 0; i != NumOps; ++i) {
+  for (unsigned i = 0, NumOps = MI.getNumOperands(); i != NumOps; ++i) {
     const MachineOperand &MO = MI.getOperand(i);
     if (!MO.isReg() || !MO.isUse() || MO.getReg() != Reg)
       continue;
@@ -1144,7 +1148,7 @@ tryInstructionTransform(MachineBasicBlock::iterator &mi,
 
   // If there is one more use of regB later in the same MBB, consider
   // re-schedule this MI below it.
-  if (rescheduleMIBelowKill(mi, nmi, regB)) {
+  if (EnableRescheduling && rescheduleMIBelowKill(mi, nmi, regB)) {
     ++NumReSchedDowns;
     return true;
   }
@@ -1163,7 +1167,7 @@ tryInstructionTransform(MachineBasicBlock::iterator &mi,
 
   // If there is one more use of regB later in the same MBB, consider
   // re-schedule it before this MI if it's legal.
-  if (rescheduleKillAboveMI(mi, nmi, regB)) {
+  if (EnableRescheduling && rescheduleKillAboveMI(mi, nmi, regB)) {
     ++NumReSchedUps;
     return true;
   }