v8/test/mjsunit/es9
Leszek Swirski 51afbd1a46 Revert "[regexp] Better quick checks on loop entry nodes"
This reverts commit 4b15b984ad.

Reason for revert: UBSan failure (https://logs.chromium.org/logs/v8/buildbucket/cr-buildbucket.appspot.com/8906578530303352544/+/steps/Check/0/logs/regress-126412/0).

Original change's description:
> [regexp] Better quick checks on loop entry nodes
> 
> Like the predecessor change https://crrev.com/c/v8/v8/+/1702125 , this
> change is inspired by attempting to exit earlier from generated RegExp
> code, when no further matches are possible because any match would be
> too long. The motivating example this time is the following expression,
> which tests whether a string of Unicode playing cards has five of the
> same suit in a row:
> 
> /([🂡-🂮]{5})|([🂱-🂾]{5})|([🃁-🃎]{5})|([🃑-🃞]{5})/u
> 
> A human reading this expression can readily see that any match requires
> at least 10 characters (5 surrogate pairs), but the LoopChoiceNode for
> each repeated option reports its minimum distance to the end of a match
> as zero. This is correct, because the LoopChoiceNode's behavior depends
> on additional state (the loop counter). However, the preceding node, a
> SET_REGISTER action that initializes the loop counter, could confidently
> state that it consumes at least 10 characters. Furthermore, when we try
> to emit a quick check for that action, we could follow only paths from
> the LoopChoiceNode that are possible based on the minimum iteration
> count. This change implements both of those "could"s.
> 
> I expect this improvement to apply pretty broadly to expressions that
> use minimum repetition counts and that don't meet the criteria for
> unrolling. In this particular case, I get about 12% improvement on the
> overall UniPoker test, due to reducing the execution time of this
> expression by 85% and the execution time of another similar expression
> that checks for n-of-a-kind by 20%.
> 
> Bug: v8:9305
> 
> Change-Id: I319e381743967bdf83324be75bae943fbb5dd496
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1704941
> Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#62963}

TBR=jgruber@chromium.org,seth.brenith@microsoft.com

Change-Id: Iac085b75e054fdf0d218987cfe449be1f1630545
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:9305
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1725621
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62977}
2019-07-30 09:48:31 +00:00
..
regress [Test] Add PrepareForOptimization to some mjsunit tests. 2019-05-03 13:32:32 +00:00
object-rest-basic.js
object-spread-basic.js [interpreter] Do ToObject implicitly as part of CloneObject. 2019-06-08 17:42:12 +00:00
object-spread-ic-dontenum-transition.js [CloneObjectIC] add CSA implementation of slow case 2018-09-11 20:43:53 +00:00
object-spread-ic-multiple-transitions.js [CloneObjectIC] add CSA implementation of slow case 2018-09-11 20:43:53 +00:00
object-spread-ic.js [CloneObjectIC] clone MutableHeapNumbers instead of referencing them 2018-11-07 03:15:45 +00:00
regexp-lookbehind.js Revert "[regexp] Better quick checks on loop entry nodes" 2019-07-30 09:48:31 +00:00
template-escapes.js Remove always-on --harmony-template-escapes flag 2017-11-28 18:36:41 +00:00