[llvm] 22a5cde - [SCEV] Separate out constant folding in mul expr creation

[Nikita Popov via llvm-commits]

On Sun, Jun 20, 2021 at 12:24 PM Florian Hahn <florian_hahn at apple.com>
wrote:

> Hi,
>
> On Oct 25, 2020, at 17:47, Nikita Popov via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
>
> Author: Nikita Popov
> Date: 2020-10-25T18:46:50+01:00
> New Revision: 22a5cde541c3306e53279fd02c6d60ae6178ef10
>
> URL:
> https://github.com/llvm/llvm-project/commit/22a5cde541c3306e53279fd02c6d60ae6178ef10
> DIFF:
> https://github.com/llvm/llvm-project/commit/22a5cde541c3306e53279fd02c6d60ae6178ef10.diff
>
> LOG: [SCEV] Separate out constant folding in mul expr creation
>
> Separate out the code handling constant folding into a separate
> block, that is independent of other folds that need a constant
> first operand. Also make some minor adjustments to make the
> constant folding look nearly identical to the same code in
> getAddExpr().
>
> The only reason this change is not strictly NFC is that the
> C1*(C2+V) fold is moved below the constant folding, which means
> that it now also applies to C1*C2*(C3+V), as it should.
>
> Added:
>
>
>
> It looks like this change may cause a crash in LoopStrengthReduce:
> https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=35400
>
> To reproduce, run `llc` on
> https://oss-fuzz.com/download?testcase_id=5243727227518976
>

Looks like this is https://bugs.llvm.org/show_bug.cgi?id=50765.

Nikita
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