[llvm-dev] [RFC] Compiled regression tests.

[Joel E. Denny via llvm-dev]

On Thu, Jul 16, 2020 at 10:12 AM Robinson, Paul via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

>
>
> > -----Original Message-----
> > From: David Greene <david.greene at hpe.com>
> > Sent: Wednesday, July 15, 2020 3:11 PM
> > To: Robinson, Paul <paul.robinson at sony.com>; Michael Kruse
> > <llvmdev at meinersbur.de>; 'llvm-dev at lists.llvm.org' <llvm-
> > dev at lists.llvm.org>
> > Subject: Re: [llvm-dev] [RFC] Compiled regression tests.
> >
> > "Robinson, Paul via llvm-dev" <llvm-dev at lists.llvm.org> writes:
> >
> > >> My use-case is for metadata, where I wanted to do this:
> > >>
> > >> CHECK: %r1 = add %r2, %r3
> > >> CHECK-SAME: !some-metadata
> > >> CHECK-SAME: !some-other-metadata
> > >>
> > >> where some-metadata and some-other-metadata might be reordered within
> > >> the line (because some unrelated metadata got added to the
> > instruction).
> > >> In other words, all of these should match:
> > >>
> > >> %r1 = add %r2, %r3, !some-metadata !1, !some-other-metadata !2
> > >> %r1 = add %r2, %r3, !some-other-metadata !1, !some-metadata !2
> > >> %r1 = add %r2, %r3, !some-other-metadata !1, !some-unrelated-metadata
> > !3,
> > >> !some-metadata !2
> >
> > >
> > > I'd expect the following to do what you want:
> > >
> > > CHECK: %r1 = add %r2, %r3
> > > CHECK-DAG: !some-metadata
> > > CHECK-DAG: !some-other-metadata
> > > CHECK: {{$}}
> > >
> > > Interestingly, it does not; I filed PR46634 to figure this out.
> >
> > According to that PR this isn't supposed to work.  So I don't think we
> > have a solution to do what I want.
> >
> > And CHECK-DAG starts from the end of the previous match, and so can
> > match things on the same line?  I didn't expect that given the
> > documentation.
> >
> >                      -David
>
> Each CHECK-DAG starts from the end of the previous non-DAG match.
> CHECK-DAG directives in the same group can't have overlapping matches.
> Two successive CHECKs of any kind (other than CHECK-NEXT) are allowed
> to match on the same line; the effect of CHECK-SAME is to *require*
> that they are on the same line.
>
> If you're looking for a way to match two patterns in either order on
> a single line, I can think of two ways to do that.  One depends on
> having something distinctive that's guaranteed to be on the next line;
> then you can do CHECK-DAG/CHECK-DAG/CHECK-NEXT.  I suspect this is
> likely to be fragile.
>

It's fragile: the CHECK-NEXT complains if it doesn't match on the line
after whichever CHECK-DAG matches later in the input.  CHECK-NEXT does not
verify that its match is on the line after whichever CHECK-DAG matches
earlier in the input.

I wish we had a CHECK-DAG-SAME (and CHECK-DAG-NEXT) for cases like these.

Joel


>
> If you don't have a distinctive next-line pattern, then I can't think
> of a multi-directive way to achieve what you want.  You'd have to write
> a regex with alternatives, like this untested attempt:
> CHECK:
> {{(!some-metadata.*!other-metadata)|(!other-metadata.*!some-metadata)}}
>
> --paulr
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