- 14 May, 2020 1 commit
-
-
Omer Katz authored
The existing non-builtin implementation is returning wrong results. For example, given the value 63 as a uint8_t it returns 38 (should be 6). The new implementation follows the naive algorithm presented in figure 5-1 in Hacker's Delight section 5-1. Note that the algorithm in the book is designed for 32 bit numbers, so we extended it to support 64 bit as well. Bug: chromium:1056170 Change-Id: I8fed9c449f80b01b8cc93d339529c0e1e0863fc0 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2199345Reviewed-by: Clemens Backes <clemensb@chromium.org> Reviewed-by: Michael Lippautz <mlippautz@chromium.org> Reviewed-by: Anton Bikineev <bikineev@chromium.org> Commit-Queue: Omer Katz <omerkatz@chromium.org> Cr-Commit-Position: refs/heads/master@{#67801}
-
- 08 Nov, 2019 1 commit
-
-
Clemens Backes authored
{WhichPowerOf2} is basically the same as {CountTrailingZeros}, with a restriction to powers of two. Since it does not use or depend on any v8 internals, it can be moved to src/base/bits.h. This CL also changes the implementation to use the CTZ builtin if available, and falls back to popcnt otherwise. Drive-by: Make it constexpr, and rename to {WhichPowerOfTwo}. R=sigurds@chromium.org Bug: v8:9810, v8:8912 Change-Id: I8368d098f9ab1247f3b9f036f1385a38de10cc6a Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1903966Reviewed-by: Yang Guo <yangguo@chromium.org> Commit-Queue: Clemens Backes <clemensb@chromium.org> Cr-Commit-Position: refs/heads/master@{#64851}
-
- 02 Dec, 2017 1 commit
-
-
Mathias Bynens authored
This patch normalizes the casing of hexadecimal digits in escape sequences of the form `\xNN` and integer literals of the form `0xNNNN`. Previously, the V8 code base used an inconsistent mixture of uppercase and lowercase. Google’s C++ style guide uses uppercase in its examples: https://google.github.io/styleguide/cppguide.html#Non-ASCII_Characters Moreover, uppercase letters more clearly stand out from the lowercase `x` (or `u`) characters at the start, as well as lowercase letters elsewhere in strings. BUG=v8:7109 TBR=marja@chromium.org,titzer@chromium.org,mtrofin@chromium.org,mstarzinger@chromium.org,rossberg@chromium.org,yangguo@chromium.org,mlippautz@chromium.org NOPRESUBMIT=true Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_chromium_rel_ng Change-Id: I790e21c25d96ad5d95c8229724eb45d2aa9e22d6 Reviewed-on: https://chromium-review.googlesource.com/804294 Commit-Queue: Mathias Bynens <mathias@chromium.org> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org> Cr-Commit-Position: refs/heads/master@{#49810}
-
- 01 Dec, 2017 1 commit
-
-
Clemens Hammacher authored
V8_INT64_C will be cleaned up in a follow-up CL. R=tebbi@chromium.org,mlippautz@chromium.org Bug: v8:7109 Change-Id: I6af97e7266039eb443896b404b77b8e2b5de5adb Reviewed-on: https://chromium-review.googlesource.com/803294Reviewed-by: Michael Lippautz <mlippautz@chromium.org> Reviewed-by: Tobias Tebbi <tebbi@chromium.org> Commit-Queue: Clemens Hammacher <clemensh@chromium.org> Cr-Commit-Position: refs/heads/master@{#49790}
-
- 06 Nov, 2017 1 commit
-
-
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: Michael Starzinger <mstarzinger@chromium.org> Commit-Queue: Clemens Hammacher <clemensh@chromium.org> Cr-Commit-Position: refs/heads/master@{#49138}
-
- 04 Nov, 2017 1 commit
-
-
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: Michael Achenbach <machenbach@chromium.org> Cr-Commit-Position: refs/heads/master@{#49123}
-
- 03 Nov, 2017 1 commit
-
-
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: Michael Starzinger <mstarzinger@chromium.org> Commit-Queue: Clemens Hammacher <clemensh@chromium.org> Cr-Commit-Position: refs/heads/master@{#49106}
-
- 18 Oct, 2017 1 commit
-
-
Clemens Hammacher authored
This makes the function constexpr and implements it for arbitrary unsigned integer types (up to 64 bits, but this can be extended if needed). R=mstarzinger@chromium.org Bug: v8:6600, v8:6921 Change-Id: I86d427238fadd55abb5a27f31ed648d4b02fc358 Reviewed-on: https://chromium-review.googlesource.com/718457 Commit-Queue: Clemens Hammacher <clemensh@chromium.org> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org> Cr-Commit-Position: refs/heads/master@{#48696}
-
- 13 Jul, 2017 1 commit
-
-
Clemens Hammacher authored
There is just one version now, called IsPowerOfTwo. It accepts any integral type. There is one slight semantical change: Called with kMinInt, it previously returned true, because the argument was implicitly casted to an unsigned. It's now (correctly) returning false, so I had to add special handlings of kMinInt in machine-operator-reducer before calling IsPowerOfTwo on that value. R=mlippautz@chromium.org,mstarzinger@chromium.org,jgruber@chromium.org,ishell@chromium.org,yangguo@chromium.org Change-Id: Idc112a89034cdc8c03365b778b33b1c29fefb38d Reviewed-on: https://chromium-review.googlesource.com/568140Reviewed-by: Igor Sheludko <ishell@chromium.org> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org> Reviewed-by: Michael Lippautz <mlippautz@chromium.org> Reviewed-by: Yang Guo <yangguo@chromium.org> Commit-Queue: Clemens Hammacher <clemensh@chromium.org> Cr-Commit-Position: refs/heads/master@{#46627}
-
- 12 Jul, 2017 1 commit
-
-
Daniel Clifford authored
This makes it possible for automated tests to distinguish between CHECK failures and DCHECK failures, the latter of which will continue to run in release builds after the assertion failure point. Change-Id: Ie26978c0342d401a8c85f3261749739195087579 Reviewed-on: https://chromium-review.googlesource.com/565515 Commit-Queue: Daniel Clifford <danno@chromium.org> Reviewed-by: Jochen Eisinger <jochen@chromium.org> Reviewed-by: Adam Klein <adamk@chromium.org> Cr-Commit-Position: refs/heads/master@{#46596}
-
- 27 Apr, 2017 3 commits
-
-
Clemens Hammacher authored
With fix for architectures where x<<32 != x. Original change's description: > [base] Introduce RoundUpToPowerOfTwo64 > > And fix RoundUpToPowerOfTwo32 to return 1 for the input 0. > 0 is no power of two. > Beside being the correct value, this also avoids a special case in the > (new) fast path using the number of leading zeros. > > R=jochen@chromium.org, ahaas@chromium.org > > Change-Id: I87173495e13b334954bcebbb55724fb666dfa809 > Reviewed-on: https://chromium-review.googlesource.com/488143 > Reviewed-by: Jochen Eisinger <jochen@chromium.org> > Reviewed-by: Andreas Haas <ahaas@chromium.org> > Commit-Queue: Clemens Hammacher <clemensh@chromium.org> > Cr-Commit-Position: refs/heads/master@{#44925} TBR=ahaas@chromium.org,jochen@chromium.org,clemensh@chromium.org,v8-reviews@googlegroups.com Change-Id: I7b4719d84a419bb7b38e3b5c9d6d183275087ace Reviewed-on: https://chromium-review.googlesource.com/488981 Commit-Queue: Clemens Hammacher <clemensh@chromium.org> Reviewed-by: Clemens Hammacher <clemensh@chromium.org> Cr-Commit-Position: refs/heads/master@{#44951}
-
Clemens Hammacher authored
This reverts commit 9ceaf212. Reason for revert: Fails on arm: http://build.chromium.org/p/client.v8.ports/builders/V8%20Arm%20-%20debug/builds/2950/steps/Check/logs/Bits.RoundUpToPowerOf.. Original change's description: > [base] Introduce RoundUpToPowerOfTwo64 > > And fix RoundUpToPowerOfTwo32 to return 1 for the input 0. > 0 is no power of two. > Beside being the correct value, this also avoids a special case in the > (new) fast path using the number of leading zeros. > > R=jochen@chromium.org, ahaas@chromium.org > > Change-Id: I87173495e13b334954bcebbb55724fb666dfa809 > Reviewed-on: https://chromium-review.googlesource.com/488143 > Reviewed-by: Jochen Eisinger <jochen@chromium.org> > Reviewed-by: Andreas Haas <ahaas@chromium.org> > Commit-Queue: Clemens Hammacher <clemensh@chromium.org> > Cr-Commit-Position: refs/heads/master@{#44925} TBR=ahaas@chromium.org,jochen@chromium.org,clemensh@chromium.org,v8-reviews@googlegroups.com,wasm-v8@google.com NOPRESUBMIT=true NOTREECHECKS=true NOTRY=true Change-Id: Ib353ee0a944316da6f919bac3bb88d4f95d98ea0 Reviewed-on: https://chromium-review.googlesource.com/488365Reviewed-by: Clemens Hammacher <clemensh@chromium.org> Commit-Queue: Clemens Hammacher <clemensh@chromium.org> Cr-Commit-Position: refs/heads/master@{#44935}
-
Clemens Hammacher authored
And fix RoundUpToPowerOfTwo32 to return 1 for the input 0. 0 is no power of two. Beside being the correct value, this also avoids a special case in the (new) fast path using the number of leading zeros. R=jochen@chromium.org, ahaas@chromium.org Change-Id: I87173495e13b334954bcebbb55724fb666dfa809 Reviewed-on: https://chromium-review.googlesource.com/488143Reviewed-by: Jochen Eisinger <jochen@chromium.org> Reviewed-by: Andreas Haas <ahaas@chromium.org> Commit-Queue: Clemens Hammacher <clemensh@chromium.org> Cr-Commit-Position: refs/heads/master@{#44925}
-
- 12 Jun, 2015 1 commit
-
-
bmeurer authored
Up until now we used int32_t for NodeId, but that was not ideal because negative values are invalid for NodeId and we use it as an array index for example in the NodeMarker class, where C++ compilers on x64 have to generate code that does proper sign extension for the indices, which is completely unnecessary. R=svenpanne@chromium.org Review URL: https://codereview.chromium.org/1178403004 Cr-Commit-Position: refs/heads/master@{#28997}
-
- 26 Oct, 2014 1 commit
-
-
bmeurer@chromium.org authored
Also fix the sdiv/udiv instructions on ARM as a nice side effect. TEST=cctest,unittests R=jarin@chromium.org Review URL: https://codereview.chromium.org/677483005 Cr-Commit-Position: refs/heads/master@{#24888} git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24888 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
-
- 14 Oct, 2014 2 commits
-
-
bmeurer@chromium.org authored
Apparently SMMLS r, b, c, a computes r = ((a << 32) - b * c) >> 32 while the documentation is kinda misleading and states that it should compute r = a - ((b * c) >> 32) The actual behavior is kinda useless, so we drop the instruction again. TEST=cctest,unittests TBR=dcarney@chromium.org Review URL: https://codereview.chromium.org/654653004 git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24577 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
-
bmeurer@chromium.org authored
TEST=cctest,unittests R=hpayer@chromium.org Review URL: https://codereview.chromium.org/648283002 git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24575 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
-
- 09 Oct, 2014 1 commit
-
-
bmeurer@chromium.org authored
Support selecting Ubfx for shift-mask and mask-shift operations. Also, rename the shifts to match the instruction names. BUG= R=bmeurer@chromium.org Review URL: https://codereview.chromium.org/633123002 Patch from Martyn Capewell <m.m.capewell@googlemail.com>. git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24482 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
-
- 01 Oct, 2014 1 commit
-
-
bmeurer@chromium.org authored
As per discussion on the V8 team, this is the place we want them to live, not following the Chrome Style Guide for this. BUG=v8:3489 LOG=y R=svenpanne@chromium.org Review URL: https://codereview.chromium.org/615393002 git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24350 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
-
- 09 Sep, 2014 1 commit
-
-
bmeurer@chromium.org authored
TEST=base-unittests,compiler-unittests,cctest R=svenpanne@chromium.org Review URL: https://codereview.chromium.org/555833002 git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23809 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
-
- 02 Sep, 2014 3 commits
-
-
jarin@chromium.org authored
R=mstarzinger@chromium.org BUG= Review URL: https://codereview.chromium.org/527273003 git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23625 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
-
mstarzinger@chromium.org authored
TBR=bmeurer@chromium.org TEST=base-unittests/BitsDeathTest.RoundUpToPowerOfTwo32 Review URL: https://codereview.chromium.org/532713002 git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23621 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
-
bmeurer@chromium.org authored
TEST=base-unittests,cctest,mjsunit R=svenpanne@chromium.org Review URL: https://codereview.chromium.org/528993002 git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23617 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
-
- 29 Aug, 2014 1 commit
-
-
bmeurer@chromium.org authored
We still need the test/base-unittests folder until the test driver is updated to handle unittests without the boilerplate. TEST=base-unittests R=svenpanne@chromium.org BUG=v8:3489 LOG=n Review URL: https://codereview.chromium.org/520503004 git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23516 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
-
- 25 Aug, 2014 1 commit
-
-
bmeurer@chromium.org authored
R=machenbach@chromium.org Review URL: https://codereview.chromium.org/502803002 git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23330 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
-
- 20 Aug, 2014 1 commit
-
-
bmeurer@chromium.org authored
The bit counting functions provided by CompilerIntrinsics were undefined for zero, which was easily overlooked and unsafe in general. Also their implementation was kinda hacky and mostly untested. Fixed the implementation and moved the functions to base/bits.h. TEST=base-unittests,cctest,compiler-unittests,mjsunit R=hpayer@chromium.org Review URL: https://codereview.chromium.org/494633002 git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23229 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
-
- 14 Aug, 2014 1 commit
-
-
bmeurer@chromium.org authored
Move recognition of rotate-right operations to the MachineOperatorReducer, so we don't need to repeat that in the InstructionSelector for every backend. TEST=base-unittests,compiler-unittests,cctests R=jarin@chromium.org Review URL: https://codereview.chromium.org/469213002 git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23121 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
-