Log at places we fail to compile.

Useful when diagnosing some compiler issues / limitations.

Test: test.py

Change-Id: I8759d0e78b0682b300ddcadfe02793432cab2036
diff --git a/compiler/optimizing/block_builder.cc b/compiler/optimizing/block_builder.cc
index a6687fe..ed00032 100644
--- a/compiler/optimizing/block_builder.cc
+++ b/compiler/optimizing/block_builder.cc
@@ -58,6 +58,7 @@
         // cannot have any code afterwards.
       } else {
         // The TryItem spans beyond the end of the CodeItem. This is invalid code.
+        VLOG(compiler) << "Not compiled: TryItem spans beyond the end of the CodeItem";
         return false;
       }
     }
@@ -110,6 +111,7 @@
       if (next == instructions.end()) {
         // In the normal case we should never hit this but someone can artificially forge a dex
         // file to fall-through out the method code. In this case we bail out compilation.
+        VLOG(compiler) << "Not compiled: Fall-through beyond the CodeItem";
         return false;
       }
       MaybeCreateBlockAt(next.DexPc());