In assignments, such as string = trim(string) string(n1:n2) = trim(string) the trim has no effect and can be optimized away.
(Note: With Fortran 2003 and allocatable strings with "len=:", the first version cannot be optimized as on length mismatch the LHS is reallocated.) Such code can easily be present in real-world code and causes unnecessarily a large overhead, cf. e.g. http://www.tddft.org/trac/octopus/changeset/5672 -- Summary: Assignment using "= trim(string)": Optimize "trim" away Product: gcc Version: 4.5.0 Status: UNCONFIRMED Keywords: missed-optimization Severity: normal Priority: P3 Component: fortran AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: burnus at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40628
