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

src/IceTargetLowering.h

Index: src/IceTargetLowering.h
diff --git a/src/IceTargetLowering.h b/src/IceTargetLowering.h
index da52adfcc7ae838a8781085a8cd2954d9d48823e..e0e95fb8e7aef7eeb13ec162897aa677c5bce5ab 100644
--- a/src/IceTargetLowering.h
+++ b/src/IceTargetLowering.h
@@ -46,6 +46,7 @@ public:
   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; }
@@ -65,11 +66,14 @@ private:
   // 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;
 };