reland Optimizations to IC stub for unoptimized code performance

reland Optimizations to IC stub for unoptimized code performance

R=vegorov@google.com
BUG=

Committed: https://github.com/dart-lang/sdk/commit/10796ae455b8bc660cee7156909d1fdab967600c

[erikcorry, 2017-01-30 12:17:49]

This is a reland of https://codereview.chromium.org/2647913002/

As far as I can tell, the issues that caused it to be reverted were just
flakiness.  None of them reproduce on my machine. The MIPS stub has been cleaned
up.

[Vyacheslav Egorov (Google), 2017-01-30 12:33:06]

lgtm

https://codereview.chromium.org/2660863002/diff/1/runtime/vm/stub_code_mips.cc
File runtime/vm/stub_code_mips.cc (right):

https://codereview.chromium.org/2660863002/diff/1/runtime/vm/stub_code_mips.c...
runtime/vm/stub_code_mips.cc:1489: __ LoadImmediate(TMP, Smi::RawValue(1));
Maybe this warrants a comment like "// load second argument cid"

TMP is already containing Smi::RawValue(1) here I think.

https://codereview.chromium.org/2660863002/diff/1/runtime/vm/stub_code_mips.c...
runtime/vm/stub_code_mips.cc:1490: __ subu(T5, T1, TMP);
Maybe this should not use a temp register at all.

https://codereview.chromium.org/2660863002/diff/1/runtime/vm/stub_code_mips.c...
runtime/vm/stub_code_mips.cc:1493: __ lw(T5, Address(T5));
also this can just be 

__ lw(T5, Address(T3, -8)) if it was not destroyed above.

https://codereview.chromium.org/2660863002/diff/1/runtime/vm/stub_code_mips.c...
runtime/vm/stub_code_mips.cc:1503: bool optimize = kind == Token::kILLEGAL;
maybe const bool.

[erikcorry, 2017-01-30 13:19:27]

Description was changed from

==========
reland Optimizations to IC stub for unoptimized code performance

R=vegorov@google.com
BUG=
==========

to

==========
reland Optimizations to IC stub for unoptimized code performance

R=vegorov@google.com
BUG=

Committed:
https://github.com/dart-lang/sdk/commit/10796ae455b8bc660cee7156909d1fdab967600c
==========

[erikcorry, 2017-01-30 13:19:29]

Committed patchset #2 (id:20001) manually as
10796ae455b8bc660cee7156909d1fdab967600c (presubmit successful).