Add dead loop elimination, which removes dead loops for which we can compute

the trip count.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50382 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/LinkAllPasses.h

@@ -114,6 +114,7 @@ namespace {
       (void) llvm::createCodeGenPreparePass();
       (void) llvm::createGVNPass();
       (void) llvm::createMemCpyOptPass();
+      (void) llvm::createDeadLoopEliminationPass();
 
       (void)new llvm::IntervalPartition();
       (void)new llvm::FindUsedTypes();

include/llvm/Transforms/Scalar.h

@@ -317,6 +317,13 @@ FunctionPass *createGVNPass();
 //
 FunctionPass *createMemCpyOptPass();
 
+//===----------------------------------------------------------------------===//
+//
+// DeadLoopElimination - This pass performs DCE of non-infinite loops that it
+// can prove are dead.
+//
+LoopPass *createDeadLoopEliminationPass();
+
 //===----------------------------------------------------------------------===//
 //
 // CodeGenPrepare - This pass prepares a function for instruction selection.