[PATCH] Disable indvar widening if arithmetics on the wider type are more expensive

[Jingyue Wu]

Thanks Andrew! 

I don't like that either. I saw there's effort on making DataLayout mandatory, and think maybe the same thing will eventually happen to TargetTransformInfo. We already have a default "boring" NoTTI, so the switch wouldn't be too hard. 

Jingyue

http://reviews.llvm.org/D6196