[llvm-dev] Should Verifier be an analysis?

Chijun Sima via llvm-dev
Thu, 12 Jul 2018 17:43:23 -0000

Hi,

I am wondering whether it is feasible to preserve the DominatorTree
which is recalculated in the Verifier by making Verifier into an
analysis. This recalculation actually consumes an approximately 7% of
the time used by the whole DominatorTree related calculations when
optimizing SQLite with opt -O3.

Best,
Chijun Sima

On Thu, Jul 12, 2018 at 11:19 PM Son Tuan VU via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
>
> Hello all,
>
> I came across the code of Verifier, and see that it doesn't modify the
IR at all. Why it is not considered as an analysis pass?
>
> Actually, this will have impact on debugify-each and
print-before/after-all: we are not supposed to print/debugify Verifier pass, but
since Verifier is declared as a transformation (well, a non-analysis) pass, we
actually do print/debugify it.