Unable to find the possible suspect using Code Search, Find it and CL.
Assigning to the concern owner who previously worked on similar issues --

@cwallez -- Could you please look into the issue, kindly re-assign if this is not related to your changes.
Thank You.

Fix up for review at https://chromium-review.googlesource.com/c/414305/

The following revision refers to this bug:
  https://chromium.googlesource.com/angle/angle/+/1212bcacb32c0f34be737a88377defbc02096b04

commit 1212bcacb32c0f34be737a88377defbc02096b04
Author: Corentin Wallez <cwallez@chromium.org>
Date: Wed Nov 23 18:44:05 2016

translator: separate declarations after rewriting loops

Otherwise when trying to add the declarations back, things might fail
because the loop initialization is a sequence and not a block.

BUG= 668028 

Change-Id: I8d84a25c25765e9655c16ce56604ae08f0f8176c
Reviewed-on: https://chromium-review.googlesource.com/414305
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Olli Etuaho <oetuaho@nvidia.com>

[modify] https://crrev.com/1212bcacb32c0f34be737a88377defbc02096b04/src/compiler/translator/SimplifyLoopConditions.cpp
[modify] https://crrev.com/1212bcacb32c0f34be737a88377defbc02096b04/src/compiler/translator/IntermNodePatternMatcher.h
[modify] https://crrev.com/1212bcacb32c0f34be737a88377defbc02096b04/src/compiler/translator/TranslatorHLSL.cpp
[modify] https://crrev.com/1212bcacb32c0f34be737a88377defbc02096b04/src/compiler/translator/IntermNodePatternMatcher.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9038bcb2f30582773c59986e9f6c42e656b7679d

commit 9038bcb2f30582773c59986e9f6c42e656b7679d
Author: geofflang <geofflang@chromium.org>
Date: Thu Dec 08 22:35:38 2016

Roll ANGLE b5e997f..dceacf5

https://chromium.googlesource.com/angle/angle.git/+log/b5e997f..dceacf5

BUG= 668028 , 668223 , chromium:661857 

TBR=jmadill@chromium.org

TEST=bots

CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.win:win_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.android:android_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2562813002
Cr-Commit-Position: refs/heads/master@{#437368}

[modify] https://crrev.com/9038bcb2f30582773c59986e9f6c42e656b7679d/DEPS

ClusterFuzz has detected this issue as fixed in range 437309:437451.

Detailed report: https://cluster-fuzz.appspot.com/testcase?key=4883104264355840

Fuzzer: libfuzzer_angle_translator_fuzzer
Job Type: libfuzzer_chrome_asan
Platform Id: linux

Crash Type: UNKNOWN READ
Crash Address: 0x000000000000
Crash State:
  sh::TIntermAggregateBase::replaceChildNodeWithMultiple
  sh::TIntermTraverser::updateTree
  sh::SeparateDeclarationsTraverser::apply
  
Regressed: https://cluster-fuzz.appspot.com/revisions?job=libfuzzer_chrome_asan&range=423381:423433
Fixed: https://cluster-fuzz.appspot.com/revisions?job=libfuzzer_chrome_asan&range=437309:437451

Minimized Testcase (0.98 Kb): https://cluster-fuzz.appspot.com/download/AMIfv94B8pZ-MEY4-4EkmTHmvV9GYziNuTQaANwKA8RabjfF02NXakU_tDMiBbI8rndceOO_4bhAwOw0u__pvNMMDMXjTR8aCr7DebtJcc3OHKgx_2ATdLw49wzk0fmEEX-W8iYyNXDSjwn3VVjtrPHYFkfzy3auaA?testcase_id=4883104264355840

See https://chromium.googlesource.com/chromium/src/+/master/testing/libfuzzer/reproducing.md for more information.

If you suspect that the result above is incorrect, try re-doing that job on the test case report page.

ClusterFuzz testcase 4883104264355840 is verified as fixed, so closing issue.

If this is incorrect, please add ClusterFuzz-Wrong label and re-open the issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/angle/angle/+/36fd100d480e51c742ed7cf95f82876b016c998d

commit 36fd100d480e51c742ed7cf95f82876b016c998d
Author: Corentin Wallez <cwallez@chromium.org>
Date: Thu Dec 08 16:30:44 2016

GLSLTest: test interaction of declaration splitting with other passes

In TranslatorHLSL a number of AST simplifications are done, that must
happen in a precise order for things to be correct:
 - First for-loops must be split
 - Then multideclarations must be split
 - Finally comma operators must be split

This adds tests for interaction between this passes to make sure they
are done in the right order.

BUG= 668028 

Change-Id: I306915b51011bb5467d117352becfd60cbe77be4
Reviewed-on: https://chromium-review.googlesource.com/417989
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Olli Etuaho <oetuaho@nvidia.com>

[modify] https://crrev.com/36fd100d480e51c742ed7cf95f82876b016c998d/src/compiler/translator/SimplifyLoopConditions.cpp
[modify] https://crrev.com/36fd100d480e51c742ed7cf95f82876b016c998d/src/tests/gl_tests/GLSLTest.cpp
[modify] https://crrev.com/36fd100d480e51c742ed7cf95f82876b016c998d/src/compiler/translator/IntermNode.cpp
[modify] https://crrev.com/36fd100d480e51c742ed7cf95f82876b016c998d/src/compiler/translator/IntermNode.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d398b797dbcd4e88c229f0ba535198c087e15c2b

commit d398b797dbcd4e88c229f0ba535198c087e15c2b
Author: qiankun.miao <qiankun.miao@intel.com>
Date: Tue Dec 13 14:16:12 2016

Roll ANGLE d023939..c31b741

https://chromium.googlesource.com/angle/angle.git/+log/d023939..c31b741

BUG= 308366 ,  672380 ,  668028 ,  668223 , angleproject:1523,  angleproject:523 

TEST=bots

CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.win:win_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.android:android_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2567173003
Cr-Commit-Position: refs/heads/master@{#438161}

[modify] https://crrev.com/d398b797dbcd4e88c229f0ba535198c087e15c2b/DEPS