Subzero: address mode opt: Transform *(reg+const) into [reg+const].

Teach address mode optimization about Base=Base+Const,
Base=Const+Base, and Base=Base-Const patterns.

Change ConstantInteger::emit() to emit signed values.

BUG=none
R=jvoung@chromium.org

Review URL: https://codereview.chromium.org/459133002
2 files changed