[llvm] r293635 - [DAGCombine] require UnsafeFPMath for re-association of addition

[Hans Wennborg via llvm-commits]

The bug was marked as a release-blocker for 4.0, but it sounds like
it's not technically a 3.9 regression. Hal, what do you think about
merging this?

On Tue, Jan 31, 2017 at 6:35 AM, Nicolai Haehnle via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
> Author: nha
> Date: Tue Jan 31 08:35:37 2017
> New Revision: 293635
>
> URL: http://llvm.org/viewvc/llvm-project?rev=293635&view=rev
> Log:
> [DAGCombine] require UnsafeFPMath for re-association of addition
>
> Summary:
> The affected transforms all implicitly use associativity of addition,
> for which we usually require unsafe math to be enabled.
>
> The "Aggressive" flag is only meant to convey information about the
> performance of the fused ops relative to a fmul+fadd sequence.
>
> Fixes Bug 31626.
>
> Reviewers: spatel, hfinkel, mehdi_amini, arsenm, tstellarAMD
>
> Subscribers: jholewinski, nemanjai, wdng, llvm-commits
>
> Differential Revision: https://reviews.llvm.org/D28675