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

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

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-subzero.git;a=commit;h=8835b89

[wala, 2014-08-11 19:25:04]

This change is useful for testing constant blinding of memory operands, as it
provides a way to form a memory operand with a constant offset.

[jvoung (off chromium), 2014-08-12 00:34:58]

LGTM

https://codereview.chromium.org/459133002/diff/60001/src/IceTargetLoweringX86...
File src/IceTargetLoweringX8632.cpp (right):

https://codereview.chromium.org/459133002/diff/60001/src/IceTargetLoweringX86...
src/IceTargetLoweringX8632.cpp:3392: //   Index=Var, Shift+=Const
Could you move these comments for the << opts, to below the Base=Var+Const opts?
It seems like these are part of a TODO block, while the Base=Var+Const won't be
a TODO anymore =)

https://codereview.chromium.org/459133002/diff/60001/tests_lit/llvm2ice_tests...
File tests_lit/llvm2ice_tests/address-mode-opt.ll (right):

https://codereview.chromium.org/459133002/diff/60001/tests_lit/llvm2ice_tests...
tests_lit/llvm2ice_tests/address-mode-opt.ll:60: ; CHECK:
address_mode_opt_chaining:
could CHECK-LABEL this too

[wala, 2014-08-12 00:46:54]

https://codereview.chromium.org/459133002/diff/60001/src/IceTargetLoweringX86...
File src/IceTargetLoweringX8632.cpp (right):

https://codereview.chromium.org/459133002/diff/60001/src/IceTargetLoweringX86...
src/IceTargetLoweringX8632.cpp:3392: //   Index=Var, Shift+=Const
On 2014/08/12 00:34:57, jvoung wrote:
> Could you move these comments for the << opts, to below the Base=Var+Const
opts?
> It seems like these are part of a TODO block, while the Base=Var+Const won't
be
> a TODO anymore =)

Done.

https://codereview.chromium.org/459133002/diff/60001/tests_lit/llvm2ice_tests...
File tests_lit/llvm2ice_tests/address-mode-opt.ll (right):

https://codereview.chromium.org/459133002/diff/60001/tests_lit/llvm2ice_tests...
tests_lit/llvm2ice_tests/address-mode-opt.ll:60: ; CHECK:
address_mode_opt_chaining:
On 2014/08/12 00:34:57, jvoung wrote:
> could CHECK-LABEL this too

Done.

[wala, 2014-08-12 00:47:04]

Committed patchset #3 manually as 8835b89 (presubmit successful).