Roll r123609 back in with two changes that fix test failures with expensive

checks enabled:

1) Use '<' to compare integers in a comparison function rather than '<='.

2) Use the uniqued set DefBlocks rather than Info.DefiningBlocks to initialize
the priority queue.

The speedup of scalarrepl on test-suite + SPEC2000 + SPEC2006 is a bit less, at
just under 16% rather than 17%.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123662 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Transforms/Utils/PromoteMemToReg.h

@@ -38,8 +38,7 @@ bool isAllocaPromotable(const AllocaInst *AI);
 /// made to the IR.
 ///
 void PromoteMemToReg(const std::vector<AllocaInst*> &Allocas,
-                     DominatorTree &DT, DominanceFrontier &DF,
-                     AliasSetTracker *AST = 0);
+                     DominatorTree &DT, AliasSetTracker *AST = 0);
 
 } // End llvm namespace