llvm-mirror/test/FileCheck/check-dag-not-dag.txt
Joel E. Denny 9cdb8f503d [FileCheck] Fix search ranges for DAG-NOT-DAG
A DAG-NOT-DAG is a CHECK-DAG group, X, followed by a CHECK-NOT group,
N, followed by a CHECK-DAG group, Y.  Let y be the initial directive
of Y.  This patch makes the following changes to the behavior:

    1. Directives in N can no longer match within part of Y's match
       range just because y happens not to be the earliest match from
       Y.  Specifically, this patch withdraws N's search range end
       from y's match range start to Y's match range start.

    2. y can no longer match within X's match range, where a y match
       produced a reordering complaint, which is thus no longer
       possible.  Specifically, this patch withdraws y's search range
       start from X's permitted range start to X's match range end,
       which was already the search range start for other members of
       Y.

Both of these changes can only increase the number of test passes: #1
constrains the ability of CHECK-NOTs to match, and #2 expands the
ability of CHECK-DAGs to match without complaints.

These changes are based on discussions at:

   <http://lists.llvm.org/pipermail/llvm-dev/2018-May/123550.html>
   <https://reviews.llvm.org/D47106>

which conclude that:

    1. These changes simplify the FileCheck conceptual model.  First,
       it makes search ranges for DAG-NOT-DAG more consistent with
       other cases.  Second, it was confusing that y was treated
       differently from the rest of Y.

    2. These changes add theoretical use cases for DAG-NOT-DAG that
       had no obvious means to be expressed otherwise.  We can justify
       the first half of this assertion with the observation that
       these changes can only increase the number of test passes.

    3. Reordering detection for DAG-NOT-DAG had no obvious real
       benefit.

We don't have evidence from real uses cases to help us debate
conclusions #2 and #3, but #1 at least seems intuitive.

Reviewed By: probinson

Differential Revision: https://reviews.llvm.org/D48986

llvm-svn: 337605
2018-07-20 20:09:56 +00:00

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;---------------------------------------------------------------------
; RUN: FileCheck -input-file %s %s -check-prefix=NotSearchEnd
The search range for the NOTs used to end at the start of the match range for
the first DAG in the following DAG group. Now it ends at the start of the
match range for the entire following DAG group.
__NotSearchEnd
x0
x1
y1
foobar
y0
z2
foobar
z1
foobar
z0
__NotSearchEnd
; NotSearchEnd: {{^}}__NotSearchEnd
; NotSearchEnd-DAG: {{^}}x0
; NotSearchEnd-DAG: {{^}}x1
; NotSearchEnd-NOT: {{^}}foobar
; NotSearchEnd-DAG: {{^}}y0
; NotSearchEnd-DAG: {{^}}y1
; NotSearchEnd-NOT: {{^}}foobar
; NotSearchEnd-DAG: {{^}}z0
; NotSearchEnd-DAG: {{^}}z1
; NotSearchEnd-DAG: {{^}}z2
; NotSearchEnd: {{^}}__NotSearchEnd
;---------------------------------------------------------------------
; RUN: FileCheck -input-file %s %s -check-prefix=Dag2SearchStart
The start of the search range for the second or later DAG group used to be
different for its first DAG than its other DAGs. For the first DAG, it was
the start of the permitted range for the preceding DAG group, and there was a
reordering complaint if the match range was in the first DAG group's match
range. For the other DAGs, it was the end of the match range for the
preceding DAG group, so reordering detection wasn't possible. Now, the
first DAG behaves like the others, and so reordering detection is no longer
implemented. As a result, matches that used to produce the reordering
complaint are now skipped, permitting later matches to succeed.
__Dag2SearchStart
y0
y1
x0
y0
y1
x1
z1
z0
y1
z1
z0
y0
z0
z1
__Dag2SearchStart
; Dag2SearchStart: {{^}}__Dag2SearchStart
; Dag2SearchStart-DAG: {{^}}x0
; Dag2SearchStart-DAG: {{^}}x1
; Dag2SearchStart-NOT: {{^}}foobar
; Dag2SearchStart-DAG: {{^}}y0
; Dag2SearchStart-DAG: {{^}}y1
; Dag2SearchStart-NOT: {{^}}foobar
; Dag2SearchStart-DAG: {{^}}z0
; Dag2SearchStart-DAG: {{^}}z1
; Dag2SearchStart: {{^}}__Dag2SearchStart