Quick: Redefine the notion of back-egdes.

Redefine a back-edge to really mean an edge to a loop head
instead of comparing instruction offsets. Generate suspend
checks also on fall-through to a loop head; insert an extra
GOTO for these edges.

Add suspend checks to fused cmp instructions.

Rewrite suspend check elimination to track whether there is
an invoke on each path from the loop head to a given back
edge, instead of using domination info to look for a basic
block with invoke that must be on each path. Ignore invokes
to intrinsics and move the optimization to a its own pass.

The new loops in 109-suspend-check should prevent intrinsics
and fused cmp-related regressions.

Bug: 18522004
Change-Id: I96ac818f76ccf9419a6e70e9ec00555f9d487a9e
diff --git a/compiler/dex/quick/mir_to_lir.h b/compiler/dex/quick/mir_to_lir.h
index 5d78a6e..156d6fd 100644
--- a/compiler/dex/quick/mir_to_lir.h
+++ b/compiler/dex/quick/mir_to_lir.h
@@ -843,8 +843,8 @@
     virtual void GenArithOpLong(Instruction::Code opcode, RegLocation rl_dest,
                                 RegLocation rl_src1, RegLocation rl_src2, int flags);
     void GenConversionCall(QuickEntrypointEnum trampoline, RegLocation rl_dest, RegLocation rl_src);
-    virtual void GenSuspendTest(int opt_flags);
-    virtual void GenSuspendTestAndBranch(int opt_flags, LIR* target);
+    void GenSuspendTest(int opt_flags);
+    void GenSuspendTestAndBranch(int opt_flags, LIR* target);
 
     // This will be overridden by x86 implementation.
     virtual void GenConstWide(RegLocation rl_dest, int64_t value);