https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88678
Peter Bergner <bergner at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2019-01-08
CC| |bergner at gcc dot gnu.org
Ever confirmed|0 |1
--- Comment #4 from Peter Bergner <bergner at gcc dot gnu.org> ---
Confirmed. I don't think the mentioned revision caused the problem, other than
adding a new test case that fails the same way. I simplified test case fails
for me with gcc 7.3. I don't have anything older to test with.
bergner@pike:~/gcc/BUGS/PR88678$ cat bug.f90
program foo
use ieee_arithmetic
implicit none
real x
x = ieee_value(x, ieee_signaling_nan)
if (.not. ieee_is_nan(x)) stop 1
end program foo
bergner@pike:~/gcc/BUGS/PR88678$ gfortran -ffpe-trap=invalid -static bug.f90
bergner@pike:~/gcc/BUGS/PR88678$ ./a.out
Program received signal SIGFPE: Floating-point exception - erroneous arithmetic
operation.
Backtrace for this error:
#0 0x10001b1b
Floating point exception
bergner@pike:~/gcc/BUGS/PR88678$ gdb ./a.out
(gdb) break * 0x1000aad8
Breakpoint 1 at 0x1000aad8
(gdb) run
Starting program: /home/bergner/gcc/BUGS/PR88678/a.out
Breakpoint 1, 0x000000001000aad8 in __ieee_arithmetic_MOD_ieee_value_4 ()
1: x/i $pc
=> 0x1000aad8 <__ieee_arithmetic_MOD_ieee_value_4+120>: fsqrts f1,f1
(gdb) info registers f1
f1 -1 (raw 0xbff0000000000000)
(gdb) stepi
Program received signal SIGFPE, Arithmetic exception.
0x000000001000aad8 in __ieee_arithmetic_MOD_ieee_value_4 ()
1: x/i $pc
=> 0x1000aad8 <__ieee_arithmetic_MOD_ieee_value_4+120>: fsqrts f1,f1
So it seems, we still have floating point exceptions enabled when we try and
generate the signaling nan value which is causing the SIGFPE. Who was supposed
to disable them before we execute the fsqrt with -1 as the source value?
