[Bug tree-optimization/110311] [14 Regression] regression in tree-optimizer

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110311

--- Comment #41 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Uroš Bizjak from comment #39)
> (In reply to anlauf from comment #36)
> > Breakpoint 2, rng_stream.rng_stream_s::mmm_mod (x1=330289839997,
> > x2=4294967087) at rng_stream_sub.f90:336
> > 336         res = mod (x1, x2)
> > (gdb) info float
> >   R7: Valid   0x401be51fb57800000000 +480507567                 
> >   R6: Valid   0x401be51fb57800000000 +480507567                 
> >   R5: Zero    0x00000000000000000000 +0                         
> >   R4: Zero    0x00000000000000000000 +0                         
> >   R3: Zero    0x00000000000000000000 +0                         
> >   R2: Zero    0x00000000000000000000 +0                         
> >   R1: Zero    0x00000000000000000000 +0                         
> > =>R0: Special 0xffff0000000004f5dc90 Unsupported

0xffff0000000004f5dc90 is pseudo NaN:
Pseudo Not a Number. The sign bit is meaningless. The 8087 and 80287 treat this
as a Signaling Not a Number. The 80387 and later treat this as an invalid
operand.
So, if that comes from some random number generator, I'd say that random number
generator should be fixed not to create the erroneous cases for
https://en.wikipedia.org/wiki/Extended_precision