Optimization flags for G5 and G4

gene

Fri, Apr 22, 2005 4:09 PM #

I tried following Simon's guide to optimization flags, but I'm getting 
stuck.

Here are my compiler versions:
 > gcc -v
Reading specs from 
/usr/local/lib/gcc/powerpc-apple-darwin7.7.0/4.0.0-autovect/specs
Configured with: ../gcc/configure --enable-threads=posix 
--enable-languages=f95
Thread model: posix
gcc version 4.0.0-autovect 20050128 (experimental, 
autovect-merge-20041213)

I downloaded g77 from hps.sourceforge.net:
 > g77 -v
Reading specs from 
/usr/local/lib/gcc/powerpc-apple-darwin6.8/3.4.2/specs
Configured with: ../gcc/configure --enable-threads=posix 
--enable-languages=f77 --disable-shared --enable-static
Thread model: posix
gcc version 3.4.2

Should I be worried that it mentions a different gcc version?


I had to take out some of the optimizer flags Simon lists because they 
were not recognized:
gcc: -falign-jumps-max-skip=15 -falign-loops-max-skip=15
g77: -ftree-vectorize


Finally, after running ./configure --with-blas='-framework vecLib' 
--with-lapack --with-aqua I get:
WARNING: g77 and gcc disagree on int and double

config.log shows a bunch of errors that look like this: ld instruction 
is only for 64-bit implementations (not allowed without 
-force_cpusubtype_ALL option)

Simon Urbanek

Fri, Apr 22, 2005 6:35 PM #

Gene,

On Apr 22, 2005, at 4:07 PM, gene wrote:

Yes. You will need to download the corresponding gfortran from the  
gcc4 suite (also available on the hpc pages).

gcc3 (and hence your g77) has no G5 support - you need gcc4 in order  
to get optimized binaries.

Cheers,
Simon