[turbofan] ARM64: Support shifted indexes in loads and stores

[turbofan] ARM64: Support shifted indexes in loads and stores

This patch adds support for the `Operand2_R_LSL_I` addressing mode to
loads and stores. This allows merging a shift instruction into a
MemoryOperand. Since the shift immediate is restricted to the log2 of
the operation width, the opportunities to hit this are slim. However,
Ignition's bytecode handlers hit this case all the time:

kind = BYTECODE_HANDLER
name = Star
compiler = turbofan
Instructions (size = 44)
0x23e67280     0  add x1, x19, #0x1 (1)
0x23e67284     4  ldrsb x1, [x20, x1]
0x23e67288     8  sxtw x1, w1
0x23e6728c    12  mov x2, fp
0x23e67290    16  str x0, [x2, x1, lsl #3]
                  ^^^^^^^^^^^^^^^^^^^^^
0x23e67294    20  add x19, x19, #0x2 (2)
0x23e67298    24  ldrb w1, [x20, x19]
0x23e6729c    28  ldr x1, [x21, x1, lsl #3]
                  ^^^^^^^^^^^^^^^^^^^^^
0x23e672a0    32  br x1

Additionally, I noticed the optimisation occurs once in both the
`StringPrototypeCharAt` and `StringPrototypeCharCodeAt` turbofan stubs.

BUG=

Committed: https://crrev.com/60fb6ea1b83c47af64be2577a278f05158a1447f
Cr-Commit-Position: refs/heads/master@{#36227}

[Pierre Langlois, 2016-05-12 10:56:27]

Description was changed from

==========
[turbofan] ARM64: Support shifted indexes in loads and stores

This patch adds support for the `Operand2_R_LSL_I` addressing mode to
loads and stores. This allows merging a shift instruction into a
MemoryOperand. Since the shift immediate is restricted to the log2 of
the operation width, the opportunities to hit this are slim. However,
Ignition's bytecode handlers hit this case all the time:

kind = BYTECODE_HANDLER
name = Star
compiler = turbofan
Instructions (size = 44)
0x23e67280     0  add x1, x19, #0x1 (1)
0x23e67284     4  ldrsb x1, [x20, x1]
0x23e67288     8  sxtw x1, w1
0x23e6728c    12  mov x2, fp
0x23e67290    16  str x0, [x2, x1, lsl #3]
                  ^^^^^^^^^^^^^^^^^^^^^
0x23e67294    20  add x19, x19, #0x2 (2)
0x23e67298    24  ldrb w1, [x20, x19]
0x23e6729c    28  ldr x1, [x21, x1, lsl #3]
                  ^^^^^^^^^^^^^^^^^^^^^
0x23e672a0    32  br x1

Additionally, I noticed the optimisation occurs once in both the
`StringPrototypeCharAt` and `StringPrototypeCharCodeAt` turbofan stubs.

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

to

==========
[turbofan] ARM64: Support shifted indexes in loads and stores

This patch adds support for the `Operand2_R_LSL_I` addressing mode to
loads and stores. This allows merging a shift instruction into a
MemoryOperand. Since the shift immediate is restricted to the log2 of
the operation width, the opportunities to hit this are slim. However,
Ignition's bytecode handlers hit this case all the time:

kind = BYTECODE_HANDLER
name = Star
compiler = turbofan
Instructions (size = 44)
0x23e67280     0  add x1, x19, #0x1 (1)
0x23e67284     4  ldrsb x1, [x20, x1]
0x23e67288     8  sxtw x1, w1
0x23e6728c    12  mov x2, fp
0x23e67290    16  str x0, [x2, x1, lsl #3]
                  ^^^^^^^^^^^^^^^^^^^^^
0x23e67294    20  add x19, x19, #0x2 (2)
0x23e67298    24  ldrb w1, [x20, x19]
0x23e6729c    28  ldr x1, [x21, x1, lsl #3]
                  ^^^^^^^^^^^^^^^^^^^^^
0x23e672a0    32  br x1

Additionally, I noticed the optimisation occurs once in both the
`StringPrototypeCharAt` and `StringPrototypeCharCodeAt` turbofan stubs.

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

[Pierre Langlois, 2016-05-12 10:56:27]

pierre.langlois@arm.com changed reviewers:
+ bmeurer@chromium.org, jarin@chromium.org, rmcilroy@chromium.org

[Benedikt Meurer, 2016-05-12 17:40:26]

Nice, thanks for the patch. LGTM.

[Pierre Langlois, 2016-05-13 07:26:10]

The CQ bit was checked by pierre.langlois@arm.com

[commit-bot: I haz the power, 2016-05-13 07:26:15]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1972103002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1972103002/1

[rmcilroy, 2016-05-13 07:39:17]

Nice, thanks Pierre.

[commit-bot: I haz the power, 2016-05-13 07:56:30]

Description was changed from

==========
[turbofan] ARM64: Support shifted indexes in loads and stores

This patch adds support for the `Operand2_R_LSL_I` addressing mode to
loads and stores. This allows merging a shift instruction into a
MemoryOperand. Since the shift immediate is restricted to the log2 of
the operation width, the opportunities to hit this are slim. However,
Ignition's bytecode handlers hit this case all the time:

kind = BYTECODE_HANDLER
name = Star
compiler = turbofan
Instructions (size = 44)
0x23e67280     0  add x1, x19, #0x1 (1)
0x23e67284     4  ldrsb x1, [x20, x1]
0x23e67288     8  sxtw x1, w1
0x23e6728c    12  mov x2, fp
0x23e67290    16  str x0, [x2, x1, lsl #3]
                  ^^^^^^^^^^^^^^^^^^^^^
0x23e67294    20  add x19, x19, #0x2 (2)
0x23e67298    24  ldrb w1, [x20, x19]
0x23e6729c    28  ldr x1, [x21, x1, lsl #3]
                  ^^^^^^^^^^^^^^^^^^^^^
0x23e672a0    32  br x1

Additionally, I noticed the optimisation occurs once in both the
`StringPrototypeCharAt` and `StringPrototypeCharCodeAt` turbofan stubs.

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

to

==========
[turbofan] ARM64: Support shifted indexes in loads and stores

This patch adds support for the `Operand2_R_LSL_I` addressing mode to
loads and stores. This allows merging a shift instruction into a
MemoryOperand. Since the shift immediate is restricted to the log2 of
the operation width, the opportunities to hit this are slim. However,
Ignition's bytecode handlers hit this case all the time:

kind = BYTECODE_HANDLER
name = Star
compiler = turbofan
Instructions (size = 44)
0x23e67280     0  add x1, x19, #0x1 (1)
0x23e67284     4  ldrsb x1, [x20, x1]
0x23e67288     8  sxtw x1, w1
0x23e6728c    12  mov x2, fp
0x23e67290    16  str x0, [x2, x1, lsl #3]
                  ^^^^^^^^^^^^^^^^^^^^^
0x23e67294    20  add x19, x19, #0x2 (2)
0x23e67298    24  ldrb w1, [x20, x19]
0x23e6729c    28  ldr x1, [x21, x1, lsl #3]
                  ^^^^^^^^^^^^^^^^^^^^^
0x23e672a0    32  br x1

Additionally, I noticed the optimisation occurs once in both the
`StringPrototypeCharAt` and `StringPrototypeCharCodeAt` turbofan stubs.

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

[commit-bot: I haz the power, 2016-05-13 07:56:32]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-05-13 07:59:03]

Description was changed from

==========
[turbofan] ARM64: Support shifted indexes in loads and stores

This patch adds support for the `Operand2_R_LSL_I` addressing mode to
loads and stores. This allows merging a shift instruction into a
MemoryOperand. Since the shift immediate is restricted to the log2 of
the operation width, the opportunities to hit this are slim. However,
Ignition's bytecode handlers hit this case all the time:

kind = BYTECODE_HANDLER
name = Star
compiler = turbofan
Instructions (size = 44)
0x23e67280     0  add x1, x19, #0x1 (1)
0x23e67284     4  ldrsb x1, [x20, x1]
0x23e67288     8  sxtw x1, w1
0x23e6728c    12  mov x2, fp
0x23e67290    16  str x0, [x2, x1, lsl #3]
                  ^^^^^^^^^^^^^^^^^^^^^
0x23e67294    20  add x19, x19, #0x2 (2)
0x23e67298    24  ldrb w1, [x20, x19]
0x23e6729c    28  ldr x1, [x21, x1, lsl #3]
                  ^^^^^^^^^^^^^^^^^^^^^
0x23e672a0    32  br x1

Additionally, I noticed the optimisation occurs once in both the
`StringPrototypeCharAt` and `StringPrototypeCharCodeAt` turbofan stubs.

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

to

==========
[turbofan] ARM64: Support shifted indexes in loads and stores

This patch adds support for the `Operand2_R_LSL_I` addressing mode to
loads and stores. This allows merging a shift instruction into a
MemoryOperand. Since the shift immediate is restricted to the log2 of
the operation width, the opportunities to hit this are slim. However,
Ignition's bytecode handlers hit this case all the time:

kind = BYTECODE_HANDLER
name = Star
compiler = turbofan
Instructions (size = 44)
0x23e67280     0  add x1, x19, #0x1 (1)
0x23e67284     4  ldrsb x1, [x20, x1]
0x23e67288     8  sxtw x1, w1
0x23e6728c    12  mov x2, fp
0x23e67290    16  str x0, [x2, x1, lsl #3]
                  ^^^^^^^^^^^^^^^^^^^^^
0x23e67294    20  add x19, x19, #0x2 (2)
0x23e67298    24  ldrb w1, [x20, x19]
0x23e6729c    28  ldr x1, [x21, x1, lsl #3]
                  ^^^^^^^^^^^^^^^^^^^^^
0x23e672a0    32  br x1

Additionally, I noticed the optimisation occurs once in both the
`StringPrototypeCharAt` and `StringPrototypeCharCodeAt` turbofan stubs.

BUG=

Committed: https://crrev.com/60fb6ea1b83c47af64be2577a278f05158a1447f
Cr-Commit-Position: refs/heads/master@{#36227}
==========

[commit-bot: I haz the power, 2016-05-13 07:59:04]

Patchset 1 (id:??) landed as
https://crrev.com/60fb6ea1b83c47af64be2577a278f05158a1447f
Cr-Commit-Position: refs/heads/master@{#36227}