MIPS: Optimize load/store with large offset

MIPS: Optimize load/store with large offset

Currently, we are using the following sequence for load/store with large offset (offset > 16b):

    lui at, 0x1234
    ori at, at, 0x5678
    add at, s0, at
    lw  a0, 0(at)

This sequence can be optimized in the following way:

    lui at, 0x1234
    add at, s0, at
    lw  a0, 0x5678(at)

BUG=

Committed: https://crrev.com/6d054f765815e923a851f4a1ddaff3217ee57b58
Cr-Commit-Position: refs/heads/master@{#40953}

[dusan.simicic, 2016-11-10 15:51:13]

dusan.simicic@imgtec.com changed reviewers:
+ ivica.bogosavljevic@imgtec.com, miran.karic@imgtec.com,
v8-mips-ports@googlegroups.com

[dusan.simicic, 2016-11-10 15:51:14]

PTAL

[ivica.bogosavljevic, 2016-11-14 08:43:39]

lgtm

[dusan.simicic, 2016-11-14 09:32:26]

The CQ bit was checked by dusan.simicic@imgtec.com

[commit-bot: I haz the power, 2016-11-14 09:32:33]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-14 09:57:11]

Committed patchset #1 (id:1)

[Benedikt Meurer, 2016-11-14 11:43:20]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/2500863003/ by bmeurer@chromium.org.

The reason for reverting is: Breaks CQ trybots now, i.e.
https://build.chromium.org/p/tryserver.v8/builders/v8_linux_mipsel_compile_re....

[commit-bot: I haz the power, 2016-11-17 22:32:00]

Description was changed from

==========
MIPS: Optimize load/store with large offset

Currently, we are using the following sequence for load/store with large offset
(offset > 16b):

    lui at, 0x1234
    ori at, at, 0x5678
    add at, s0, at
    lw  a0, 0(at)

This sequence can be optimized in the following way:

    lui at, 0x1234
    add at, s0, at
    lw  a0, 0x5678(at)

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

to

==========
MIPS: Optimize load/store with large offset

Currently, we are using the following sequence for load/store with large offset
(offset > 16b):

    lui at, 0x1234
    ori at, at, 0x5678
    add at, s0, at
    lw  a0, 0(at)

This sequence can be optimized in the following way:

    lui at, 0x1234
    add at, s0, at
    lw  a0, 0x5678(at)

BUG=

Committed: https://crrev.com/6d054f765815e923a851f4a1ddaff3217ee57b58
Cr-Commit-Position: refs/heads/master@{#40953}
==========

[commit-bot: I haz the power, 2016-11-17 22:32:01]

Patchset 1 (id:??) landed as
https://crrev.com/6d054f765815e923a851f4a1ddaff3217ee57b58
Cr-Commit-Position: refs/heads/master@{#40953}