svn commit: r312765 - in head/contrib/llvm: include/llvm/Analysis lib/Analysis

[Antoine Brodin]

On Wed, Jan 25, 2017 at 6:59 PM, Dimitry Andric <dim at freebsd.org> wrote:
> Author: dim
> Date: Wed Jan 25 17:59:22 2017
> New Revision: 312765
> URL: https://svnweb.freebsd.org/changeset/base/312765
>
> Log:
>   Pull in r276136 from upstream llvm trunk (by Wei Mi):
>
>     Use ValueOffsetPair to enhance value reuse during SCEV expansion.
>
>     In D12090, the ExprValueMap was added to reuse existing value during
>     SCEV expansion. However, const folding and sext/zext distribution can
>     make the reuse still difficult.
>
>     A simplified case is: suppose we know S1 expands to V1 in
>     ExprValueMap, and
>       S1 = S2 + C_a
>       S3 = S2 + C_b
>     where C_a and C_b are different SCEVConstants. Then we'd like to
>     expand S3 as V1 - C_a + C_b instead of expanding S2 literally. It is
>     helpful when S2 is a complex SCEV expr and S2 has no entry in
>     ExprValueMap, which is usually caused by the fact that S3 is
>     generated from S1 after const folding.
>
>     In order to do that, we represent ExprValueMap as a mapping from SCEV
>     to ValueOffsetPair. We will save both S1->{V1, 0} and S2->{V1, C_a}
>     into the ExprValueMap when we create SCEV for V1. When S3 is
>     expanded, it will first expand S2 to V1 - C_a because of S2->{V1,
>     C_a} in the map, then expand S3 to V1 - C_a + C_b.
>
>     Differential Revision: https://reviews.llvm.org/D21313
>
>   This should fix assertion failures when building OpenCV >= 3.1.
>
>   PR:           215649
>   MFC after:    3 days

Hi,

I don't know if it's this commit,  but there is now an assertion
failure when trying to build lang/spidermonkey24  (It was building
fine with base/head at 312672)

http://beefy12.nyi.freebsd.org/data/head-amd64-default/p432463_s312786/logs/errors/spidermonkey24-24.2.0_4.log

Cheers,

Antoine