[patch, fortran] PR66310 Problems with intrinsic repeat for large number of copies

[Dominique d'Humières]

> Le 18 juil. 2016 à 02:02, Jerry DeLisle <jvdelisle@charter.net> a écrit :
> 
> Please test this revised patch. See my comments in the PR.
> 
> I think we should commit this one.
> 
> Jerry

Jerry,

As said on IRC I think the limit should be documented and a TODO comment added to gcc/fortran/gfortran.h.

While trying to bootstrap with the patch I got

/opt/gcc/build_w/./prev-gcc/xg++ -B/opt/gcc/build_w/./prev-gcc/ -B/opt/gcc/gcc7w/x86_64-apple-darwin15.5.0/bin/ -nostdinc++ -B/opt/gcc/build_w/prev-x86_64-apple-darwin15.5.0/libstdc++-v3/src/.libs -B/opt/gcc/build_w/prev-x86_64-apple-darwin15.5.0/libstdc++-v3/libsupc++/.libs  -I/opt/gcc/build_w/prev-x86_64-apple-darwin15.5.0/libstdc++-v3/include/x86_64-apple-darwin15.5.0  -I/opt/gcc/build_w/prev-x86_64-apple-darwin15.5.0/libstdc++-v3/include  -I/opt/gcc/work/libstdc++-v3/libsupc++ -L/opt/gcc/build_w/prev-x86_64-apple-darwin15.5.0/libstdc++-v3/src/.libs -L/opt/gcc/build_w/prev-x86_64-apple-darwin15.5.0/libstdc++-v3/libsupc++/.libs -fno-PIE -c  -DIN_GCC_FRONTEND -g -O2   -gtoggle -DIN_GCC     -fno-exceptions -fno-rtti -fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrite-strings -Wcast-qual -Wmissing-format-attribute -Woverloaded-virtual -pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings -Werror -fno-common  -DHAVE_CONFIG_H -I. -Ifortran -I../../work/gcc -I../../work/gcc/fortran -I../../work/gcc/../include -I./../intl -I../../work/gcc/../libcpp/include -I/opt/mp-new/include  -I../../work/gcc/../libdecnumber -I../../work/gcc/../libdecnumber/dpd -I../libdecnumber -I../../work/gcc/../libbacktrace -I/opt/mp-new/include  -o fortran/simplify.o -MT fortran/simplify.o -MMD -MP -MF fortran/.deps/simplify.TPo ../../work/gcc/fortran/simplify.c
../../work/gcc/fortran/simplify.c: In function 'gfc_expr* gfc_simplify_repeat(gfc_expr*, gfc_expr*)':
../../work/gcc/fortran/simplify.c:5089:11: error: variable 'i' set but not used [-Werror=unused-but-set-variable]
       int i;
           ^
cc1plus: all warnings being treated as errors

i.e., the lines

       int i;

and

       i = gfc_validate_kind (BT_INTEGER, gfc_charlen_int_kind, false);

must be deleted. also the comment

      /* Compute the maximum value allowed for NCOPIES:
	    huge(cl) - 1 / len.  */

should be updated.

Last point I have found, the limit does not seem to take into account CHARACTER(KIND=4):

[Book15] f90/bug% cat pr66310_par_4.f90
   program p
      character(len=2,kind=4), parameter :: z = 'yz'
      print *, repeat(z, 2**25)
   end
[Book15] f90/bug% gfc pr66310_par_4.f90
f951(3881,0x7fff74e38000) malloc: *** mach_vm_map(size=18446744073441116160) failed (error code=3)
*** error: can't allocate region
*** set a breakpoint in malloc_error_break to debug

f951: out of memory allocating 18446744073441116160 bytes after a total of 0 bytes

Thanks for working on this PR.

Dominique