https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91699
Bug ID: 91699 Summary: [10 Regression] Bogus warnings with -O3 -flto after revision r274997 Product: gcc Version: 10.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: dominiq at lps dot ens.fr CC: iains at gcc dot gnu.org, msebor at gcc dot gnu.org Target Milestone: --- After revision r274997 I see the following failures FAIL: gfortran.dg/argument_checking_1.f90 -g -O3 -fwhole-program -flto (test for excess errors) FAIL: gfortran.dg/argument_checking_8.f90 -g -O3 -fwhole-program -flto (test for excess errors) FAIL: gfortran.dg/arrayio_derived_1.f90 -g -O3 -fwhole-program -flto (test for excess errors) FAIL: gfortran.dg/dtio_25.f90 -g -O3 -fwhole-program -flto (test for excess errors) FAIL: gfortran.dg/dtio_28.f03 -g -O3 -fwhole-program -flto (test for excess errors) FAIL: gfortran.dg/dtio_30.f03 -g -O3 -fwhole-program -flto (test for excess errors) FAIL: gfortran.dg/pr39865.f90 -g -O3 -fwhole-program -flto (test for excess errors) % /opt/gcc/gcc10p-274996p1/bin/gfortran /opt/gcc/_clean/gcc/testsuite/gfortran.dg/argument_checking_1.f90 -O3 -flto % /opt/gcc/gcc10p-274997p1/bin/gfortran /opt/gcc/_clean/gcc/testsuite/gfortran.dg/argument_checking_1.f90 -O3 -flto In function 'copy2', inlined from 'MAIN__' at /opt/gcc/_clean/gcc/testsuite/gfortran.dg/argument_checking_1.f90:13:0, inlined from 'main' at /opt/gcc/_clean/gcc/testsuite/gfortran.dg/argument_checking_1.f90:18:0: /opt/gcc/_clean/gcc/testsuite/gfortran.dg/argument_checking_1.f90:28: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=] 28 | out(1:2,1:5) = in(1:2,1:5) | Note that pr39865.f90 requires -fwhole-program in order to give the warning. This is not fixed by the patch at https://gcc.gnu.org/ml/gcc-patches/2019-09/msg00425.html