Performance optimizations for Checked(Add|Sub|Mul|Div)

Performance optimizations for Checked(Add|Sub|Mul|Div)

This skips the more complicated math functions if we can can perform
the operations on a wider intermediate type.

R=tsepez@chromium.org

Committed: https://crrev.com/fc21258997b7cf8ca1fcf5e8d66af256815d5611
Cr-Commit-Position: refs/heads/master@{#432768}

[jschuh, 2016-11-16 21:04:15]

Patchset #2 (id:20001) has been deleted

[jschuh, 2016-11-16 21:05:18]

Description was changed from

==========
Performance optimization for Checked(Add|Sub|Mul)

This skips the more complicated math functions if we can can perform the
operations on a wider intermediate type.

R=tsepez@chromium.org
==========

to

==========
Performance optimizations for Checked(Add|Sub|Mul|Div)

This skips the more complicated math functions if we can can perform
the operations on a wider intermediate type.

R=tsepez@chromium.org
==========

[Tom Sepez, 2016-11-16 21:16:08]

https://codereview.chromium.org/2510793004/diff/50001/base/numerics/safe_math...
File base/numerics/safe_math_impl.h (right):

https://codereview.chromium.org/2510793004/diff/50001/base/numerics/safe_math...
base/numerics/safe_math_impl.h:284: is_valid &=
CheckedAddImpl(static_cast<Promotion>(x),
Do we maybe perform an operation here that we would have skipped in the old
code, and is it safe to do so without spewing UBSAN warninging.

[jschuh, 2016-11-16 21:22:28]

https://codereview.chromium.org/2510793004/diff/50001/base/numerics/safe_math...
File base/numerics/safe_math_impl.h (right):

https://codereview.chromium.org/2510793004/diff/50001/base/numerics/safe_math...
base/numerics/safe_math_impl.h:284: is_valid &=
CheckedAddImpl(static_cast<Promotion>(x),
On 2016/11/16 21:16:08, Tom Sepez wrote:
> Do we maybe perform an operation here that we would have skipped in the old
> code, and is it safe to do so without spewing UBSAN warninging.

The Impl functions should all be safe from undefined behavior. I went through
and cleaned them up a few months ago. If it hits any, file a bug and I'll fix
it.

[jschuh, 2016-11-16 21:27:58]

The CQ bit was checked by jschuh@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-11-16 21:28:51]

Dry run: 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, 2016-11-16 23:34:39]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-16 23:34:40]

Dry run: Try jobs failed on following builders:
  linux_chromium_chromeos_ozone_rel_ng on master.tryserver.chromium.linux
(JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_clobber_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[Tom Sepez, 2016-11-17 00:24:40]

lgtm

[jschuh, 2016-11-17 00:36:24]

The CQ bit was checked by jschuh@chromium.org

[commit-bot: I haz the power, 2016-11-17 00:38:07]

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, 2016-11-17 02:40:41]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-17 02:40:42]

Try jobs failed on following builders:
  android_arm64_dbg_recipe on master.tryserver.chromium.android (JOB_TIMED_OUT,
no build URL)
  android_clang_dbg_recipe on master.tryserver.chromium.android (JOB_TIMED_OUT,
no build URL)

[jschuh, 2016-11-17 03:57:01]

The CQ bit was checked by jschuh@chromium.org

[commit-bot: I haz the power, 2016-11-17 03:57:47]

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, 2016-11-17 05:40:59]

Description was changed from

==========
Performance optimizations for Checked(Add|Sub|Mul|Div)

This skips the more complicated math functions if we can can perform
the operations on a wider intermediate type.

R=tsepez@chromium.org
==========

to

==========
Performance optimizations for Checked(Add|Sub|Mul|Div)

This skips the more complicated math functions if we can can perform
the operations on a wider intermediate type.

R=tsepez@chromium.org
==========

[commit-bot: I haz the power, 2016-11-17 05:40:59]

Committed patchset #3 (id:50001)

[commit-bot: I haz the power, 2016-11-17 05:44:26]

Description was changed from

==========
Performance optimizations for Checked(Add|Sub|Mul|Div)

This skips the more complicated math functions if we can can perform
the operations on a wider intermediate type.

R=tsepez@chromium.org
==========

to

==========
Performance optimizations for Checked(Add|Sub|Mul|Div)

This skips the more complicated math functions if we can can perform
the operations on a wider intermediate type.

R=tsepez@chromium.org

Committed: https://crrev.com/fc21258997b7cf8ca1fcf5e8d66af256815d5611
Cr-Commit-Position: refs/heads/master@{#432768}
==========

[commit-bot: I haz the power, 2016-11-17 05:44:27]

Patchset 3 (id:??) landed as
https://crrev.com/fc21258997b7cf8ca1fcf5e8d66af256815d5611
Cr-Commit-Position: refs/heads/master@{#432768}