------- Comment #2 from jb at gcc dot gnu dot org 2008-04-14 18:09 -------
Well, your test case is invalid anyway (i0 is referenced before being defined).
Here's a standard conforming portable version that compiles with "-Wall
-pedantic -std=f2003":
program short_test_inf
implicit none
integer, parameter :: dp = selected_real_kind (15)
complex(dp) nan_inf, normal_number, cmplx_test, i0
real(dp) tth, pi, zero
data tth /6.66666666666666667e-01_dp/
data pi /3.1415926535897932385_dp/
data zero /0.0_dp/
normal_number = cmplx(tth, zero, dp)
nan_inf = cmplx(pi/zero, zero/zero, dp)
i0 = cmplx(0, 0, dp)
cmplx_test = nan_inf * normal_number
C print *,'nan_inf ',nan_inf
print *,'cmplx_test (inf+iNan)*(2/3+i0) ',cmplx_test
cmplx_test = nan_inf * tth
C print *,'tth ',tth
print *,'cmplx_test (inf+iNan)*(2/3)',cmplx_test
end program
Results with this program comparing 4.1 and 4.4 (trunk):
$ ./gf41-opt
cmplx_test (inf+iNan)*(2/3+i0) ( NaN,
NaN)
cmplx_test (inf+iNan)*(2/3) ( +Infinity, NaN)
$ ./gf41-nonopt
cmplx_test (inf+iNan)*(2/3+i0) ( NaN,
NaN)
cmplx_test (inf+iNan)*(2/3) ( NaN, NaN)
$ ./gf44-opt
cmplx_test (inf+iNan)*(2/3+i0) ( +Infinity,
NaN)
cmplx_test (inf+iNan)*(2/3) ( +Infinity,
NaN)
$ ./gf44-nonopt
cmplx_test (inf+iNan)*(2/3+i0) ( NaN,
NaN)
cmplx_test (inf+iNan)*(2/3) ( NaN,
NaN)
Basically, I'd like to close this as wontfix. IIRC once you get an FP
exception, all bets are off and the result of further computation can be
anything. Of course it would be nice if results were the same regardless of
optimization level.
For a related issue where being excessively anal about complex arithmetic
resulted in a factor of 5 slowdown, see PR 29549
--
jb at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jb at gcc dot gnu dot org
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Last reconfirmed|0000-00-00 00:00:00 |2008-04-14 18:09:38
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35877
