https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65819
Bug ID: 65819
Summary: overzealous checking in gfc_check_dependency for
identical=true
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: tkoenig at gcc dot gnu.org
Just ran across this while trying to cook up a test case for matrix inlining.
In the patch proposed for PR 37131, I have
if (gfc_check_dependency (expr1, matrix_a, true)
|| gfc_check_dependency (expr1, matrix_b, true))
return 0;
In the test case, I want to do
f(3,1:eight:2,:) = matmul(f(1,1:3,2:3), f(2,2:3,:))
where clearly the lhs does not depend on the rhs. However, specifying true to
gfc_dep_dependency leads to
if (identical)
return 1;
before any checking is done. I'm not sure if there is a real-world test
case yet, but there will be one soon, so I'll keep this PR as a reminder.
