https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109186
Bug ID: 109186
Summary: nearest(huge(x),-1.0_kind(x)) half of correct value
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: john.harper at vuw dot ac.nz
Target Milestone: ---
With all four real kinds available in gfortran_12 nearest(x,y) with x = huge
and y = -1 this program gave about half the correct result. Ifort gave correct
results for the 3 different kinds it has: sp,dp,qp.
The program:
implicit none
integer,parameter::sp = kind(1.0), dp=kind(1d0), ncases = 2, &
ep = selected_real_kind(18),qp = selected_real_kind(33)
character(*),parameter:: fmt(4) = &
"(A,ES"//["16.08E2","26.17E3","30.20E4","44.34E4"]//")"
character(24),dimension(2):: splist,dplist,eplist,qplist
integer n
real(sp),parameter::sp1 = 1.0_sp
real(sp):: spx(ncases) = [huge(sp1),nearest(huge(sp1),-sp1)]
data splist/'huge(sp1)','nearest(huge(sp1),-sp1)'/
real(dp),parameter::dp1 = 1.0_dp
real(dp):: dpx(ncases) = [huge(dp1),nearest(huge(dp1),-dp1)]
data dplist/'huge(dp1)','nearest(huge(dp1),-dp1)'/
real(ep),parameter::ep1 = 1.0_ep
real(ep):: epx(ncases) = [huge(ep1),nearest(huge(ep1),-ep1)]
data eplist/'huge(ep1)','nearest(huge(ep1),-ep1)'/
real(qp),parameter::qp1 = 1.0_qp
real(qp):: qpx(ncases) = [huge(qp1),nearest(huge(qp1),-qp1)]
data qplist/'huge(qp1)','nearest(huge(qp1),-qp1)'/
print fmt(1),(splist(n),spx(n),n=1,ncases)
print fmt(2),(dplist(n),dpx(n),n=1,ncases)
print fmt(3),(eplist(n),epx(n),n=1,ncases)
print fmt(4),(qplist(n),qpx(n),n=1,ncases)
end program
The output on ubuntu (Linux 86_64)
huge(sp1) 3.40282347E+38
nearest(huge(sp1),-sp1) 1.70141173E+38
huge(dp1) 1.79769313486231571E+308
nearest(huge(dp1),-dp1) 8.98846567431157854E+307
huge(ep1) 1.18973149535723176502E+4932
nearest(huge(ep1),-ep1) 5.94865747678615882511E+4931
huge(qp1) 1.1897314953572317650857593266280070E+4932
nearest(huge(qp1),-qp1) 5.9486574767861588254287966331400351E+4931
