Hello,
I'm getting erroneous output for the following program when compiled with ifort -xHost using ifort version 13.1.3 on a computer with Xeon Intel 8-core Sandybridge processors.
The program checks the vector, which is comprised of pairs of numbers,
(/ 3,1, 3,2, 4,1, 5,1, 6,2, 7,1, 7,2 /)
to see which numbers occur only once in the first position in each pair. The second number in the pair is irrelevant but having pairs is required to produce the erroneous output. The first numbers in the pairs are 3,3,4,5,6,7,7. 4, 5, and 6 occur only once. The program should return
0 0 1 1 1 0 0
but returns
0 0 0 1 1 0 0
when compiled with -xHost. When it is so compiled, both loops are vectorized:
> ifort -xHost -vec-report bugtest.F90 -o bugtest
bugtest.F90(10): (col. 3) remark: LOOP WAS VECTORIZED.
bugtest.F90(15): (col. 6) remark: LOOP WAS VECTORIZED.
when it is not compiled with -xHost, only the first is:
> ifort -vec-report bugtest.F90 -o bugtest
bugtest.F90(10): (col. 3) remark: LOOP WAS VECTORIZED.
The program is below. I be removing -xHost from my makefile.
Best regards, Dan
program highspinorder
implicit none
integer,parameter :: ndof=14, numelec=7
integer :: configlist(ndof) = (/ 3,1, 3,2, 4,1, 5,1, 6,2, 7,1, 7,2 /)
integer :: ii,unpaired(numelec),jj
unpaired(1:numelec)=1
do ii=1,numelec !!ALWAYS VECTORIZED
!!!WORKS do jj=1,numelec
!!!WORKS if (jj.ne.ii) then
do jj=ii+1,numelec !!FAILS WHEN VECTORIZED (WITH -xHost)
if (configlist(jj*2-1).eq.configlist(ii*2-1)) then
unpaired(ii)=0
unpaired(jj)=0
endif
!!!WORKS endif
enddo
enddo
print *, unpaired(:); stop
end program highspinorder