http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53787
Bug #: 53787 Summary: Possible lto improvement Classification: Unclassified Product: gcc Version: 4.8.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: lto AssignedTo: unassig...@gcc.gnu.org ReportedBy: izamya...@gmail.com For following Fortan test t.f90 icc can propagate loop counter value and then perform complete unroll and gcc doesn't do it real x(10) n = 10 call init(x,n) print *, x end subroutine init(x, n) real x(10) do i=1,n x(i) = i*i + 1 enddo return end Not sure it's completely lto problem though... ifort flags - -O3 -ipo -inline-level=0 gfortran flags - -O3 -flto -fwhole-program -fno-inline