On Nov 14, 2009, at 4:01 PM, Lisandro Dalcin wrote:

On Fri, Nov 13, 2009 at 11:09 PM, Barry Smith <[email protected]> wrote:

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Good point, I have removed it.

I put it in because I wanted an easy way to test that PETSc double arrays are always 8 byte aligned (and the unaligned struct values were giving me lots of false alarms).

I guess we can test for double align on x86_64 systems.

Barry

The IBM BlueGene doesn't like 4 byte aligned doubles and sends a bus error after a certain number are generated, Thus I was motivated to make PETSc a bit clearer on that.

But then the compiler in the BlueGene does not -malign-double by default? That would be weird and annoying...

BlueGene has two compilers, IBM's XLc and gcc. I do not know if either of them are rigged to 8 byte align by default. Barry

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On Nov 12, 2009, at 9:29 AM, Lisandro Dalcin wrote:

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On Wed, Nov 11, 2009 at 11:02 PM, Barry Smith <[email protected]> wrote:

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Satish,

gcc supports the option -malign-double on some systems. Please add it to the flags that configure checks for c and c++ and have it added if it exists.

Definitely -1. Why are you asking for this? On x86_64 this is the default. In i386, this flag is likely going to break ABI's.

-- Lisandro Dalcín --------------- Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC) Instituto de Desarrollo Tecnológico para la Industria Química (INTEC) Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) PTLC - Güemes 3450, (3000) Santa Fe, Argentina Tel/Fax: +54-(0)342-451.1594

-- Lisandro Dalcín --------------- Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC) Instituto de Desarrollo Tecnológico para la Industria Química (INTEC) Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) PTLC - Güemes 3450, (3000) Santa Fe, Argentina Tel/Fax: +54-(0)342-451.1594