ifx issues with minloc

[Harald1]

Hello,

the following code shows some issues and surprising behavior with minloc:

program p
  use ieee_arithmetic
  implicit none
  real :: inf, nan
  inf = ieee_value (inf, ieee_positive_inf)
  nan = ieee_value (nan, ieee_quiet_nan)

  print *, "Testing minloc with zero-sized arrays"
  print *, minloc ([real ::]), "  <-- should be 0"
  print *, minloc ([inf],mask=.false.), "  <-- should be 0"
  print *
  print *, "Testing minval and minloc with ieee exceptional values"
  print *, minval ([inf,-inf])
  print *, minval ([nan, inf])
  print *, minval ([nan, nan]), "  <-- likely ok"
  print *
  print *, minloc ([inf, nan]), "  <-- should be 1 (ok)"
  print *, minloc ([inf, nan],back=.true.), "  <-- should be 1 (ok)"
  print *, minloc ([nan, inf]), "  <-- should be 2"
  print *, minloc ([nan, inf],back=.true.), "  <-- should be 2 (ok)"
  print *, minloc ([nan, nan]), "  <-- likely ok"
  print *, minloc ([nan, nan],back=.true.), "  <-- likely ok"
end

 ifx 2024.2.0 produces the following result:

 Testing minloc with zero-sized arrays
           1   <-- should be 0
           1   <-- should be 0
 
 Testing minval and minloc with ieee exceptional values
      -Infinity
       Infinity
       Infinity   <-- likely ok
 
           1   <-- should be 1 (ok)
           1   <-- should be 1 (ok)
           1   <-- should be 2
           2   <-- should be 2 (ok)
           1   <-- likely ok
           1   <-- likely ok

 First, the result for zero-sized arrays is defined by the standard to be 0; ifx clearly has a bug here.

Some of the other results may be surprising.  If there is no ieee finite array element, the result of minval could be expected to be Infinity or NaN in the third test (source line 15).

However, I don't understand why the result of minloc in source line 19 could be 1 instead of 2.  Does ifx confuse NaN with Infinity?  But then I do not understand why source line 21 and 22 give the same result.

Thanks for any insight.

Harald

[Devorah_H_Intel]

using -standard-semantics I got

Testing minloc with zero-sized arrays
0 <-- should be 0
0 <-- should be 0

We are investigating the issue with the rest of the output.