[Subzero][MIPS32] Add LowerStore implementation

- This patch implements lowerstore for i32, i64 types for mips32 arch.

- InstMIPS32Memory class is added to represent memory related instructions(load/store). I will add remaining load/store instructions if you are okay with this patch.

- Changed uncond_br.ll test as it was failing due to hardcoded label no. expected in output.

R=jpp@chromium.org, stichnot@chromium.org

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-subzero.git;a=commit;h=f3bc5cf730eaa6117a9d494ce61613a3118acd4d

[mohit.bhakkad, 2016-05-23 12:13:55]

Description was changed from

==========
[Subzero][MIPS32] Add LowerStore implementation

BUG=
==========

to

==========
- This patch implements lowerstore for i32, i64 types for mips32 arch.

- InstMIPS32Memory class is added to represent memory related
instructions(load/store). I will add remaining load/store instructions if you
are okay with this patch. 

- Changed uncond_br.ll test as it was failing due to hardcoded label no.
expected in output.
==========

[mohit.bhakkad, 2016-05-23 12:13:55]

mohit.bhakkad@imgtec.com changed reviewers:
+ eholk@chromium.org, jpp@chromium.org, kschimpf@google.com,
stichnot@chromium.org

[John, 2016-05-23 13:30:38]

lgtm

https://codereview.chromium.org/2005823002/diff/1/src/IceInstMIPS32.h
File src/IceInstMIPS32.h (right):

https://codereview.chromium.org/2005823002/diff/1/src/IceInstMIPS32.h#newcode311
src/IceInstMIPS32.h:311: // InstMIPS32Memory represents instructions which
loads/stores data on stack
not just stack memory, but also globals, right?

https://codereview.chromium.org/2005823002/diff/1/tests_lit/llvm2ice_tests/un...
File tests_lit/llvm2ice_tests/uncond_br.ll (right):

https://codereview.chromium.org/2005823002/diff/1/tests_lit/llvm2ice_tests/un...
tests_lit/llvm2ice_tests/uncond_br.ll:26: ; MIPS32:   b  10 <.Luncond1$target>
maybe use a regexp here: {{[0-9a-f]+}}

I am not sure about the syntax, though.

[Jim Stichnoth, 2016-05-23 17:12:19]

This is looking good.  Is there / can there be a MIPS store test in the lit
tests?

https://codereview.chromium.org/2005823002/diff/1/src/IceTargetLoweringMIPS32...
File src/IceTargetLoweringMIPS32.cpp (right):

https://codereview.chromium.org/2005823002/diff/1/src/IceTargetLoweringMIPS32...
src/IceTargetLoweringMIPS32.cpp:375: auto *Mem =
llvm::dyn_cast<OperandMIPS32Mem>(Operand);
Just use llvm::isa<> instead of testing the result of llvm::dyn_cast<>.

(unless the dyn_cast result is used other than just testing against nullptr)

https://codereview.chromium.org/2005823002/diff/1/src/IceTargetLoweringMIPS32...
src/IceTargetLoweringMIPS32.cpp:382: // If we didn't do address mode
optimization, then we only have a
reflow comment to 80-col

[mohit.bhakkad, 2016-05-31 06:04:46]

Hi Jim, could you please review this. 2021033002 is dependent on this.

[Jim Stichnoth, 2016-05-31 18:18:52]

lgtm

https://codereview.chromium.org/2005823002/diff/20001/src/IceTargetLoweringMI...
File src/IceTargetLoweringMIPS32.cpp (right):

https://codereview.chromium.org/2005823002/diff/20001/src/IceTargetLoweringMI...
src/IceTargetLoweringMIPS32.cpp:378: if (llvm::isa<OperandMIPS32Mem>(Operand)) {
Sorry, I was a bit off in my previous comment.  This should look more like the
following instead:

  if (auto *Mem = llvm::dyn_cast<OperandMIPS32Mem>(Operand)) {
    return Mem;
  }

(I went ahead and made the change to avoid another round of reviews just for
this.)

[Jim Stichnoth, 2016-05-31 18:19:06]

Description was changed from

==========
- This patch implements lowerstore for i32, i64 types for mips32 arch.

- InstMIPS32Memory class is added to represent memory related
instructions(load/store). I will add remaining load/store instructions if you
are okay with this patch. 

- Changed uncond_br.ll test as it was failing due to hardcoded label no.
expected in output.
==========

to

==========
- This patch implements lowerstore for i32, i64 types for mips32 arch.

- InstMIPS32Memory class is added to represent memory related
instructions(load/store). I will add remaining load/store instructions if you
are okay with this patch.

- Changed uncond_br.ll test as it was failing due to hardcoded label no.
expected in output.

R=jpp@chromium.org, stichnot@chromium.org

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

[Jim Stichnoth, 2016-05-31 18:19:08]

Committed patchset #2 (id:20001) manually as
f3bc5cf730eaa6117a9d494ce61613a3118acd4d (presubmit successful).