Register usage cleanup

I plan to enable some of the old-world basic block optimizations.
Those care about temp register status, so we needed a bit of
cleanup on the temp tracking.

Change-Id: I317bce1b91a73ec9589c20ed5bfe00d53994991a
diff --git a/src/compiler/codegen/arm/ArmLIR.h b/src/compiler/codegen/arm/ArmLIR.h
index 5308f7c..20fa0a2 100644
--- a/src/compiler/codegen/arm/ArmLIR.h
+++ b/src/compiler/codegen/arm/ArmLIR.h
@@ -840,9 +840,10 @@
     struct {
         bool isNop:1;           // LIR is optimized away
         bool insertWrapper:1;   // insert branch to emulate memory accesses
+        bool squashed:1;        // Elminated def
         unsigned int age:4;     // default is 0, set lazily by the optimizer
         unsigned int size:3;    // bytes (2 for thumb, 2/4 for thumb2)
-        unsigned int unused:23;
+        unsigned int unused:22;
     } flags;
     int aliasInfo;              // For Dalvik register & litpool disambiguation
     u8 useMask;                 // Resource mask for use