I am using LLVM 3.5 and Mac OS X 10.10.2 Yosemite. It is consistent using a simple Hello World program.
Hardware Overview:
Model Name: MacBook Pro
Model Identifier: MacBookPro11,1
Processor Name: Intel Core i5
Processor Speed: 2.4 GHz
Number of Processors: 1
Total Number of Cores: 2
L2 Cache (per Core): 256 KB
L3 Cache: 3 MB
Memory: 8 GB
Boot ROM Version: MBP111.0138.B14
SMC Version (system): 2.16f68
I'm not sure if this is relevant or not, but I was running into a similar problem on Linux. It wasn't a crash, but the IDE would hang on shutdown, forcing me to manually terminate the process. Eventually I realized it was waiting on wget, which is used to check for version updates. I could also manually kill the wget process and then the IDE would gracefully shutdown. I disabled this option in Settings > Global Editor > Misc and the problem went away. I might have been impatient, perhaps if wget can't successfully connect it would timeout eventually, but once it was stuck it appeared to stay stuck. Hope this helps.