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hornos
Beginner
79 Views

Fortran on Xeon X56xx vs Xeon E56xx

Solved: there was an optimization flag difference between one of the source files.
I have a fortran code which I compile with Intel Compiler 12.0.4 on two different machines with Xeon E5620 and X5650. The X machine produces a slightly bigger code. The code generated on the X machine runs well on both machines however the smaller code generated on the E machine produces wrong results on both. The problem is not presented if the code is built by an older 10.2 compiler.
OS: SLES 11.1
Compiler: 12.0.4 Fortran
Flags: -O2 -xSSE4.2 -ip -ftz
Is there any difference in code generation on various Xeon processors from the same family (56xx)?
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2 Replies
Patrick_F_Intel1
Employee
79 Views

Hello hornos,
Can you elaborate on 'produces wrong results on both'?
What are the errors?
I'm not a compiler guy but I'm sure this is one of the first questions the compiler folks will ask.
Thanks,
Pat
TimP
Black Belt
79 Views

You could compare the compiler output files. There shouldn't be any difference, if the compiler installations and options chosen are the same. The -ip option is more likely to expose source code bugs such as data over-runs, as well as increasing the code size. -xSSE4.2 may produce smaller or slightly slower code than -xSSE4.1.
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