Workaround for Issue 7250540

There's a problem (originating with Dalvik's failure to properly type constants) with
Dalvik vregs that are used in both reference and floating point situations.  In
particular, if a constant zero is used in a floating point context, the verifier in
some cases will treat it as a null pointer for the purposes generating the GC map.

If that vreg ends up promoted to a floating point value, the run-time value of that
vreg will not be found during garbage collection.  As a quick workaround, this
CL causes the compiler to detect this special case of an immediate zero being loaded
into a promoted floating point register and also store a zero in the core/ref identity
of that vreg.

Note, the CL also excludes references from store elimination.

Change-Id: I72f0a96744823ff9c5a2bd961a5e39ac4bbc707b
7 files changed
tree: a508e465a79ee97e00f9a5ff2ab35cd8efb636a6
  1. .gitignore
  3. build/
  4. jdwpspy/
  5. src/
  6. test/
  7. tools/