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

Wed Feb 1 21:01:58 PST 2017

On 02/01/2017 04:07 PM, Hans Wennborg wrote:
> 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?

It should be safe to merge.

  -Hal

>
> 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

-- 
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory