Fix ScalarEvolutionExpander step scaling bug

The expandAddRecExprLiterally function incorrectly transforms
`[Start + Step * X]` into `Step * [Start + X]` instead of the correct
transform of `[Step * X] + Start`.

This caused https://github.com/JuliaLang/julia/issues/14704#issuecomment-174126219
due to what appeared to be sufficiently complicated loop interactions.

Patch by Jameson Nash (jameson@juliacomputing.com).

Reviewers: sanjoy
Differential Revision: http://reviews.llvm.org/D16505

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275239 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed