Fix bug when atomic load is fused with an arith op (and not in the entry BB)

src/IceTargetLowering.h

 //===- subzero/src/IceTargetLowering.h - Lowering interface -----*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares the TargetLowering and LoweringContext
@@ skipping 28 matching lines @@
   Inst *getNextInst() const {
     if (Next == End)
       return NULL;
     return *Next;
   }
   CfgNode *getNode() const { return Node; }
   bool atEnd() const { return Cur == End; }
   InstList::iterator getCur() const { return Cur; }
   InstList::iterator getEnd() const { return End; }
   void insert(Inst *Inst);
+  Inst *getLastInserted() const;
   void advanceCur() { Cur = Next; }
   void advanceNext() { advance(Next); }
   void setInsertPoint(const InstList::iterator &Position) { Next = Position; }
 
 private:
   // Node is the argument to Inst::updateVars().
   CfgNode *Node;
   // Cur points to the current instruction being considered.  It is
   // guaranteed to point to a non-deleted instruction, or to be End.
   InstList::iterator Cur;
   // Next doubles as a pointer to the next valid instruction (if any),
   // and the new-instruction insertion point.  It is also updated for
   // the caller in case the lowering consumes more than one high-level
   // instruction.  It is guaranteed to point to a non-deleted
   // instruction after Cur, or to be End.  TODO: Consider separating
   // the notion of "next valid instruction" and "new instruction
   // insertion point", to avoid confusion when previously-deleted
   // instructions come between the two points.
   InstList::iterator Next;
+  // Begin is a copy of Insts.begin(), used if iterators need to be rewinded.

[Jim Stichnoth, 2014/07/29 17:54:09]

rewound

[jvoung (off chromium), 2014/07/30 15:17:14]

Done, used the "backward" language to match the new method name.

+  InstList::iterator Begin;
   // End is a copy of Insts.end(), used if Next needs to be advanced.
   InstList::iterator End;
 
   void skipDeleted(InstList::iterator &I);
   void advance(InstList::iterator &I);
+  void rewind(InstList::iterator &I) const;

[Jim Stichnoth, 2014/07/29 17:54:09]

I assumed on first read that "rewind" meant "rewind back to the beginning".  Is
there a clearer name?  The best I can think of so far is advanceForward() and
advanceBackward(), or advanceNext() and advancePrev().

[jvoung (off chromium), 2014/07/30 15:17:13]

Good point, hmm... going to go with advanceForward() and advanceBackward().
There's already a method called "advanceNext()" for moving the "Next" iterator,
so I didn't go with that.

There's also the shorter, "next()" and "previous()" naming scheme, but "next()"
might be a confusing name alongside the Next field, unless Next is renamed to
InsertPoint.

   LoweringContext(const LoweringContext &) LLVM_DELETED_FUNCTION;
   LoweringContext &operator=(const LoweringContext &) LLVM_DELETED_FUNCTION;
 };
 
 class TargetLowering {
 public:
   static TargetLowering *createLowering(TargetArch Target, Cfg *Func);
   void translate() {
     switch (Ctx->getOptLevel()) {
     case Opt_m1:
@@ skipping 142 matching lines @@
 private:
   TargetGlobalInitLowering(const TargetGlobalInitLowering &)
   LLVM_DELETED_FUNCTION;
   TargetGlobalInitLowering &
   operator=(const TargetGlobalInitLowering &) LLVM_DELETED_FUNCTION;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERING_H