Segmentation fault when using -r8

[wesarmour]

Hi All,

I'm having a problem with ifort. If I compile my code using...

ifort -D_LINUX -static -openmp -funroll-loops -parallel -ipo -O3 -axS x3.f -o x3_42_omp

I have no problems running it.

If I add the -r8 flag...

ifort -r8 -D_LINUX -static -openmp -funroll-loops -parallel -ipo -O3 -axS x3.f -o x3_42_omp

I get a seg fault.

I'm using...
$ ifort -v
Version 11.1

on...
$ uname -a
Linux cs04r-sc-com01-40.diamond.ac.uk 2.6.18-92.1.10.el5_lustre.1.6.6smp #1 SMP Tue Aug 26 12:16:17 EDT 2008 x86_64 x86_64 x86_64 GNU/Linux

Has anyone seen this kind of error before? is there a workaround? Am I doing something stupid???

Thanks for any help,

Wes.

[TimP]

If there is an array out-of-bounds problem, it could get much worse with -r8. Or, you may have something in your source which isn't consistent with -r8. Among many possibilities, remember that real*4 is not affected by -r8.

[wesarmour]

Quoting - tim18

If there is an array out-of-bounds problem, it could get much worse with -r8. Or, you may have something in your source which isn't consistent with -r8. Among many possibilities, remember that real*4 is not affected by -r8.

Hi Tim,

Thanks for the response.

I've managed to narrow the problem down. If I use -r8 -parallel the code seg faults. If I just use -parallel I have no problems.
A friend suggested this might be due to Rhel5 using randomised memory mapping. Certainly it wasn't an issue running on a rhel4 kernel.

Thanks again,

Wes.