Implement irreducible loop support in optimizing.

So we don't fallback to the interpreter in the presence of
irreducible loops.

Implications:
- A loop pre-header does not necessarily dominate a loop header.
- Non-constant redundant phis will be kept in loop headers, to
  satisfy our linear scan register allocation algorithm.
- while-graph optimizations, such as gvn, licm, lse, and dce
  need to know when they are dealing with irreducible loops.

Change-Id: I2cea8934ce0b40162d215353497c7f77d6c9137e

1 files changed, 0 insertions, 2 deletions

diff --git a/compiler/optimizing/optimizing_compiler_stats.h b/compiler/optimizing/optimizing_compiler_stats.h
index bca1632e31..f8035aae34 100644
--- a/compiler/optimizing/optimizing_compiler_stats.h
+++ b/compiler/optimizing/optimizing_compiler_stats.h
@@ -38,7 +38,6 @@ enum MethodCompilationStat {
   kRemovedDeadInstruction,
   kRemovedNullCheck,
   kNotCompiledBranchOutsideMethodCode,
-  kNotCompiledNonNaturalLoop,
   kNotCompiledThrowCatchLoop,
   kNotCompiledAmbiguousArrayOp,
   kNotCompiledHugeMethod,
@@ -106,7 +105,6 @@ class OptimizingCompilerStats {
       case kRemovedDeadInstruction: name = "RemovedDeadInstruction"; break;
       case kRemovedNullCheck: name = "RemovedNullCheck"; break;
       case kNotCompiledBranchOutsideMethodCode: name = "NotCompiledBranchOutsideMethodCode"; break;
-      case kNotCompiledNonNaturalLoop : name = "NotCompiledNonNaturalLoop"; break;
       case kNotCompiledThrowCatchLoop : name = "NotCompiledThrowCatchLoop"; break;
       case kNotCompiledAmbiguousArrayOp : name = "NotCompiledAmbiguousArrayOp"; break;
       case kNotCompiledHugeMethod : name = "NotCompiledHugeMethod"; break;