cross compiling produces worse code

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2 total messages Started by John Romein Tue, 03 Nov 1992 18:58

#29

Author: John Romein
Date: Tue, 03 Nov 1992 18:58

11 lines
986 bytes

I succesfully configured and build gcc 2.3.1 as cross compiler, running on
a sun4, producing code for a sun3.  I also build the compiler to run on a
sun3 and to produce code for a sun3.
However, a program compiled with the cross compiler runs almost twice as slow
as the program compiled with the non-cross compiler (on a sun3)
Both compilers were told to optimize with the -O2 flag.
Both compilers produced hardware floating point instructions.
Is it possible that -O2 does less optimizations on the cross compiler than on
the non-cross compiler ?

John

Re: cross compiling produces worse code

#32

Author: H.J. Lu
Date: Tue, 03 Nov 1992 23:31

19 lines
1375 bytes

In article <Bx5M21.899@cs.vu.nl>, jwromei@cs.vu.nl (John Romein) writes:
|> I succesfully configured and build gcc 2.3.1 as cross compiler, running on
|> a sun4, producing code for a sun3.  I also build the compiler to run on a
|> sun3 and to produce code for a sun3.
|> However, a program compiled with the cross compiler runs almost twice as slow
|> as the program compiled with the non-cross compiler (on a sun3)
|> Both compilers were told to optimize with the -O2 flag.
|> Both compilers produced hardware floating point instructions.
|> Is it possible that -O2 does less optimizations on the cross compiler than on
|> the non-cross compiler ?
|> 
|> John


Same thing happens to me when I cross-compile from Ultrix to i386. Any
solutions? BTW, if I crossc-compile from the different OSes but running
on the same CPU, i.e., i386, everything seems fine.

H.J.

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