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  1. 06 Nov, 2017 1 commit
    • Clemens Hammacher's avatar
      Reland "[bits] Consolidate Count{Leading,Trailing}Zeros" · 27ffc624
      Clemens Hammacher authored 
      This is a reland of 7d231e57, fixed to
avoid instantiating CountLeadingZeros for bits==0.

Original change's description:
> [bits] Consolidate Count{Leading,Trailing}Zeros
> 
> Instead of having one method for 32 bit integers and one for 64 bit,
> plus a templatized version to choose from those two, just implement one
> version which handles unsigned integers of any size. Also, make them
> constexpr.
> The Count{Leading,Trailing}Zeros{32,64} methods are kept for now in
> order to keep the amount of code changes small. Also, sometimes it
> improves readability by stating exactly the size of the argument,
> especially for leading zeros (where zero-extending would add more
> leading zeros).
> 
> CountLeadingZeros now uses a binary search inspired implementation
> as proposed in Hacker's Delight. It's more than 20% faster on x64 if
> the builtins are disabled.
> CountTrailingZeros falls back to CountPopulation instead of counting in
> a naive loop. This is ~50% faster.
> 
> R=mstarzinger@chromium.org
> 
> Change-Id: I1d8bf1d7295b930724163248150444bd17fbb34e
> Reviewed-on: https://chromium-review.googlesource.com/741231
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#49106}

Change-Id: Icdff2510ec66d1c96a1912cef29d77d8550994ee
Reviewed-on: https://chromium-review.googlesource.com/753903Reviewed-by: 's avatarMichael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49138}
      27ffc624
  3. 04 Nov, 2017 1 commit
    • Michael Achenbach's avatar
      Revert "[bits] Consolidate Count{Leading,Trailing}Zeros" · 1a1968fe
      Michael Achenbach authored 
      This reverts commit 7d231e57.

Reason for revert: Breaks revert for win-clang:
https://build.chromium.org/p/tryserver.chromium.win/builders/win_clang/builds/342755

Original change's description:
> [bits] Consolidate Count{Leading,Trailing}Zeros
> 
> Instead of having one method for 32 bit integers and one for 64 bit,
> plus a templatized version to choose from those two, just implement one
> version which handles unsigned integers of any size. Also, make them
> constexpr.
> The Count{Leading,Trailing}Zeros{32,64} methods are kept for now in
> order to keep the amount of code changes small. Also, sometimes it
> improves readability by stating exactly the size of the argument,
> especially for leading zeros (where zero-extending would add more
> leading zeros).
> 
> CountLeadingZeros now uses a binary search inspired implementation
> as proposed in Hacker's Delight. It's more than 20% faster on x64 if
> the builtins are disabled.
> CountTrailingZeros falls back to CountPopulation instead of counting in
> a naive loop. This is ~50% faster.
> 
> R=​mstarzinger@chromium.org
> 
> Change-Id: I1d8bf1d7295b930724163248150444bd17fbb34e
> Reviewed-on: https://chromium-review.googlesource.com/741231
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#49106}

TBR=mstarzinger@chromium.org,clemensh@chromium.org

Change-Id: Iceeb35bf9c7539a1013c9bdbc47118008611bef2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/753463Reviewed-by: 's avatarMichael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49123}
      1a1968fe
  5. 03 Nov, 2017 1 commit
    • Clemens Hammacher's avatar
      [bits] Consolidate Count{Leading,Trailing}Zeros · 7d231e57
      Clemens Hammacher authored 
      Instead of having one method for 32 bit integers and one for 64 bit,
plus a templatized version to choose from those two, just implement one
version which handles unsigned integers of any size. Also, make them
constexpr.
The Count{Leading,Trailing}Zeros{32,64} methods are kept for now in
order to keep the amount of code changes small. Also, sometimes it
improves readability by stating exactly the size of the argument,
especially for leading zeros (where zero-extending would add more
leading zeros).

CountLeadingZeros now uses a binary search inspired implementation
as proposed in Hacker's Delight. It's more than 20% faster on x64 if
the builtins are disabled.
CountTrailingZeros falls back to CountPopulation instead of counting in
a naive loop. This is ~50% faster.

R=mstarzinger@chromium.org

Change-Id: I1d8bf1d7295b930724163248150444bd17fbb34e
Reviewed-on: https://chromium-review.googlesource.com/741231Reviewed-by: 's avatarMichael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49106}
      7d231e57
  7. 27 Apr, 2017 3 commits
  9. 14 Jul, 2016 1 commit
  11. 06 May, 2016 1 commit
    • lpy's avatar
      Create TimeBase for time related classes. · 5cbe0f5d
      lpy authored 
      Currently we have Time and TimeTicks sharing some methods. This patch
creates TimeBase, and makes Time and TimeTicks inherits from it, so that time
related classes won't have to implement common methods and it's easier to
introduce new time related classes.

BUG=v8:4990
LOG=n

Review-Url: https://codereview.chromium.org/1952843002
Cr-Commit-Position: refs/heads/master@{#36088}
      5cbe0f5d
  13. 26 Oct, 2014 1 commit
  15. 14 Oct, 2014 2 commits
  17. 02 Sep, 2014 1 commit