Link to Builder
===============
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/mac%20trunk/builds/48698

Link to Log Files
=================
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/mac%20trunk/builds/48698/steps/compile/logs/stdio

Error Log
=========
clang: error: unable to execute command: Abort trap: 6
clang: error: clang frontend command failed due to signal (use -v to see invocation)
clang version 5.0.0 (trunk 301274)
Target: x86_64-apple-darwin13.4.0
Thread model: posix
InstalledDir: /b/build/slave/mac_trunk/build/src/out/Release/../../third_party/llvm-build/Release+Asserts/bin
clang: note: diagnostic msg: PLEASE submit a bug report to http://llvm.org/bugs/ and include the crash backtrace, preprocessed source, and associated run script.

clang: note: diagnostic msg: 
****************************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang: note: diagnostic msg: /var/folders/wc/20wzxxhn72l60f65wv0s39j00000gm/T/SelectionDAGBuilder-54b6a6.cpp
clang: note: diagnostic msg: /var/folders/wc/20wzxxhn72l60f65wv0s39j00000gm/T/SelectionDAGBuilder-54b6a6.sh
clang: note: diagnostic msg: /var/folders/wc/20wzxxhn72l60f65wv0s39j00000gm/T/SelectionDAGBuilder-54b6a6.crash

Possible suspect
================
https://chromium.googlesource.com/chromium/src/+/09a607ae4637ace31251bd434527772c0aed313f

Looks like clang roll broke the build.

Assigning to hans@ for resolving this ASAP.