[Bug fortran/71544] gfortran compiler optimization bug when dealing with c-style pointers

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71544

--- Comment #5 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
> I do not observe correct behavior with the options that the previous comment
> list s as being turned on by -O1 (this is on OS X 10.10, macports gfortran
> 4.9.3):

gfortran-fsf-5: error: unrecognized command line option '-fssa-backprop'
gfortran-fsf-4.9: error: unrecognized command line option '-fssa-phiopt'

So these options are not available for 4.9 and older. For 4.8.5 and 4.9.3 on
x86_64-apple-darwin15 (fink builds or mine ones), I get

[Book15] f90/bug% gfortran-fsf-4.8 pr71544.f90 -fauto-inc-dec
-fbranch-count-reg -fcombine-stack-adjustments -fcompare-elim -fcprop-registers
-fdce -fdefer-pop -fdse -fforward-propagate -fguess-branch-probability
-fif-conversion2 -fif-conversion -finline-functions-called-once
-fipa-pure-const -fipa-profile -fipa-reference -fmerge-constants
-fmove-loop-invariants -freorder-blocks -fshrink-wrap -fsplit-wide-types
-ftree-bit-ccp -ftree-ccp -ftree-ch -ftree-coalesce-vars -ftree-copy-prop
-ftree-dce -ftree-dominator-opts -ftree-dse -ftree-forwprop -ftree-fre
-ftree-phiprop -ftree-sink -ftree-slsr -ftree-sra -ftree-pta -ftree-ter
-funit-at-a-time -fomit-frame-pointer
[Book15] f90/bug% ./a.out                                                      
                                                                         The
following line should print 100
         100