X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FDeadMachineInstructionElim.cpp;h=f3be2abacd70529b4bb8421ccb7ce38d98515cf0;hb=fe0bf8fbf9d401a67a1842da6cefbb58aa8975a3;hp=bbb4da8330598d6bbb7a40964f071c96caa224e8;hpb=9f998de8918c1dd5a8b8ec564af00107859898e0;p=oota-llvm.git

diff --git a/lib/CodeGen/DeadMachineInstructionElim.cpp b/lib/CodeGen/DeadMachineInstructionElim.cpp
index bbb4da83305..f3be2abacd7 100644
--- a/lib/CodeGen/DeadMachineInstructionElim.cpp
+++ b/lib/CodeGen/DeadMachineInstructionElim.cpp
@@ -11,7 +11,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#define DEBUG_TYPE "codegen-dce"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
@@ -21,8 +20,12 @@
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetSubtargetInfo.h"
+
 using namespace llvm;
 
+#define DEBUG_TYPE "codegen-dce"
+
 STATISTIC(NumDeletes,          "Number of dead instructions deleted");
 
 namespace {
@@ -59,7 +62,7 @@ bool DeadMachineInstructionElim::isDead(const MachineInstr *MI) const {
 
   // Don't delete instructions with side effects.
   bool SawStore = false;
-  if (!MI->isSafeToMove(TII, 0, SawStore) && !MI->isPHI())
+  if (!MI->isSafeToMove(TII, nullptr, SawStore) && !MI->isPHI())
     return false;
 
   // Examine each operand.
@@ -84,10 +87,13 @@ bool DeadMachineInstructionElim::isDead(const MachineInstr *MI) const {
 }
 
 bool DeadMachineInstructionElim::runOnMachineFunction(MachineFunction &MF) {
+  if (skipOptnoneFunction(*MF.getFunction()))
+    return false;
+
   bool AnyChanges = false;
   MRI = &MF.getRegInfo();
-  TRI = MF.getTarget().getRegisterInfo();
-  TII = MF.getTarget().getInstrInfo();
+  TRI = MF.getSubtarget().getRegisterInfo();
+  TII = MF.getSubtarget().getInstrInfo();
 
   // Loop over all instructions in all blocks, from bottom to top, so that it's
   // more likely that chains of dependent but ultimately dead instructions will
@@ -118,29 +124,10 @@ bool DeadMachineInstructionElim::runOnMachineFunction(MachineFunction &MF) {
       if (isDead(MI)) {
         DEBUG(dbgs() << "DeadMachineInstructionElim: DELETING: " << *MI);
         // It is possible that some DBG_VALUE instructions refer to this
-        // instruction.  Examine each def operand for such references;
-        // if found, mark the DBG_VALUE as undef (but don't delete it).
-        for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
-          const MachineOperand &MO = MI->getOperand(i);
-          if (!MO.isReg() || !MO.isDef())
-            continue;
-          unsigned Reg = MO.getReg();
-          if (!TargetRegisterInfo::isVirtualRegister(Reg))
-            continue;
-          MachineRegisterInfo::use_iterator nextI;
-          for (MachineRegisterInfo::use_iterator I = MRI->use_begin(Reg),
-               E = MRI->use_end(); I!=E; I=nextI) {
-            nextI = std::next(I);  // I is invalidated by the setReg
-            MachineOperand& Use = I.getOperand();
-            MachineInstr *UseMI = Use.getParent();
-            if (UseMI==MI)
-              continue;
-            assert(Use.isDebug());
-            UseMI->getOperand(0).setReg(0U);
-          }
-        }
+        // instruction.  They get marked as undef and will be deleted
+        // in the live debug variable analysis.
+        MI->eraseFromParentAndMarkDBGValuesForRemoval();
         AnyChanges = true;
-        MI->eraseFromParent();
         ++NumDeletes;
         MIE = MBB->rend();
         // MII is now pointing to the next instruction to process,