Code clean up. The peephole pass should be the one updating the instruction

iterator, not TII->OptimizeCompareInstr.

llvm-svn: 119186

include/llvm/Target/TargetInstrInfo.h

@@ -602,12 +602,10 @@ public:
 
   /// OptimizeCompareInstr - See if the comparison instruction can be converted
   /// into something more efficient. E.g., on ARM most instructions can set the
-  /// flags register, obviating the need for a separate CMP. Update the iterator
+  /// flags register, obviating the need for a separate CMP.
-  /// *only* if a transformation took place.
   virtual bool OptimizeCompareInstr(MachineInstr *CmpInstr,
                                     unsigned SrcReg, int Mask, int Value,
-                                    const MachineRegisterInfo *MRI,
+                                    const MachineRegisterInfo *MRI) const {
-                                    MachineBasicBlock::iterator &) const {
     return false;
   }
 

lib/CodeGen/PeepholeOptimizer.cpp

@@ -82,8 +82,7 @@ namespace {
     }
 
   private:
-    bool OptimizeCmpInstr(MachineInstr *MI, MachineBasicBlock *MBB,
+    bool OptimizeCmpInstr(MachineInstr *MI, MachineBasicBlock *MBB);
-                          MachineBasicBlock::iterator &MII);
     bool OptimizeExtInstr(MachineInstr *MI, MachineBasicBlock *MBB,
                           SmallPtrSet<MachineInstr*, 8> &LocalMIs);
   };
@@ -112,8 +111,6 @@ FunctionPass *llvm::createPeepholeOptimizerPass() {
 bool PeepholeOptimizer::
 OptimizeExtInstr(MachineInstr *MI, MachineBasicBlock *MBB,
                  SmallPtrSet<MachineInstr*, 8> &LocalMIs) {
-  LocalMIs.insert(MI);
-
   unsigned SrcReg, DstReg, SubIdx;
   if (!TII->isCoalescableExtInstr(*MI, SrcReg, DstReg, SubIdx))
     return false;
@@ -242,8 +239,7 @@ OptimizeExtInstr(MachineInstr *MI, MachineBasicBlock *MBB,
 /// set) the same flag as the compare, then we can remove the comparison and use
 /// the flag from the previous instruction.
 bool PeepholeOptimizer::OptimizeCmpInstr(MachineInstr *MI,
-                                         MachineBasicBlock *MBB,
+                                         MachineBasicBlock *MBB){
-                                         MachineBasicBlock::iterator &NextIter){
   // If this instruction is a comparison against zero and isn't comparing a
   // physical register, we can try to optimize it.
   unsigned SrcReg;
@@ -253,7 +249,7 @@ bool PeepholeOptimizer::OptimizeCmpInstr(MachineInstr *MI,
     return false;
 
   // Attempt to optimize the comparison instruction.
-  if (TII->OptimizeCompareInstr(MI, SrcReg, CmpMask, CmpValue, MRI, NextIter)) {
+  if (TII->OptimizeCompareInstr(MI, SrcReg, CmpMask, CmpValue, MRI)) {
     ++NumEliminated;
     return true;
   }
@@ -262,6 +258,9 @@ bool PeepholeOptimizer::OptimizeCmpInstr(MachineInstr *MI,
 }
 
 bool PeepholeOptimizer::runOnMachineFunction(MachineFunction &MF) {
+  if (DisablePeephole)
+    return false;
+  
   TM  = &MF.getTarget();
   TII = TM->getInstrInfo();
   MRI = &MF.getRegInfo();
@@ -276,17 +275,16 @@ bool PeepholeOptimizer::runOnMachineFunction(MachineFunction &MF) {
 
     for (MachineBasicBlock::iterator
            MII = I->begin(), MIE = I->end(); MII != MIE; ) {
-      MachineInstr *MI = &*MII;
+      MachineInstr *MI = &*MII++;
+      LocalMIs.insert(MI);
 
-      if (MI->getDesc().isCompare() &&
+      if (MI->getDesc().hasUnmodeledSideEffects())
-          !MI->getDesc().hasUnmodeledSideEffects()) {
+        continue;
-        if (!DisablePeephole && OptimizeCmpInstr(MI, MBB, MII))
+
-          Changed = true;
+      if (MI->getDesc().isCompare()) {
-        else
+        Changed |= OptimizeCmpInstr(MI, MBB);
-          ++MII;
       } else {
         Changed |= OptimizeExtInstr(MI, MBB, LocalMIs);
-        ++MII;
       }
     }
   }

lib/Target/ARM/ARMBaseInstrInfo.cpp

@@ -1484,12 +1484,10 @@ static bool isSuitableForMask(MachineInstr *&MI, unsigned SrcReg,
 }
 
 /// OptimizeCompareInstr - Convert the instruction supplying the argument to the
-/// comparison into one that sets the zero bit in the flags register. Update the
+/// comparison into one that sets the zero bit in the flags register.
-/// iterator *only* if a transformation took place.
 bool ARMBaseInstrInfo::
 OptimizeCompareInstr(MachineInstr *CmpInstr, unsigned SrcReg, int CmpMask,
-                     int CmpValue, const MachineRegisterInfo *MRI,
+                     int CmpValue, const MachineRegisterInfo *MRI) const {
-                     MachineBasicBlock::iterator &MII) const {
   if (CmpValue != 0)
     return false;
 
@@ -1561,7 +1559,6 @@ OptimizeCompareInstr(MachineInstr *CmpInstr, unsigned SrcReg, int CmpMask,
     MI->RemoveOperand(5);
     MachineInstrBuilder(MI)
       .addReg(ARM::CPSR, RegState::Define | RegState::Implicit);
-    MII = llvm::next(MachineBasicBlock::iterator(CmpInstr));
     CmpInstr->eraseFromParent();
     return true;
   }

lib/Target/ARM/ARMBaseInstrInfo.h

@@ -344,8 +344,7 @@ public:
   /// that we can remove a "comparison with zero".
   virtual bool OptimizeCompareInstr(MachineInstr *CmpInstr, unsigned SrcReg,
                                     int CmpMask, int CmpValue,
-                                    const MachineRegisterInfo *MRI,
+                                    const MachineRegisterInfo *MRI) const;
-                                    MachineBasicBlock::iterator &MII) const;
 
   virtual unsigned getNumMicroOps(const InstrItineraryData *ItinData,
                                   const MachineInstr *MI) const;