https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79430
Bug ID: 79430 Summary: [7 Regression] action of statement incorrectly optimised away Product: gcc Version: 7.0.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran Assignee: unassigned at gcc dot gnu.org Reporter: juergen.reuter at desy dot de Target Milestone: --- Unfortunately this is only in a very large test case at the moment, which needs both gfortran and OCaml, using: http://whizard.hepforge.org/versions/unofficial/whizard-2.4.1_alpha-20170131.tar.gz and configuring with ./configure --with-precision=extended Then make and make check. In the test suite, the functional test mlm_matching_isr will show a discrepancy coming from the fact that in the function integral_over_z_isr in shower_core.f90 the if clause after 'call integral_over_z_part_isr', namely if (integral > final) then return end if is not correctly executed, either optimised away or scrambled. Funnily, this happens only if the default precision for real types is set to extended precision, for double and quadruple precision it works as in previous gfortran versions. The attempt to reduce this case made this behaviour disappear.