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Re: More linpack on i386-linux analysis
- To: Toshiyasu Morita <tm at netcom dot com>
- Subject: Re: More linpack on i386-linux analysis
- From: Toon Moene <toon at moene dot indiv dot nluug dot nl>
- Date: Sun, 12 Jul 98 18:02:30 +0200
- Cc: egcs-bugs at cygnus dot com
- Organization: Moene Computational Physics, Maartensdijk, The Netherlands
- References: <199807121136.EAA27910@netcom8.netcom.com>
> I've been looking at the inner loop of daxpy() in linpack
> for i386-linux:
> Here's the code generated by gcc-2.7.2; the loop counter
> is nicely allocated in a register:
[...]
> Here's the code generated by egcs-19980707: the loop
> counter is allocated to a stack slot:
[...]
This must be a specific failure of the ix86 backend - on
m68k-next-nextstep3 I get for the Fortran equivalent code:
L5:
fmovex fp1,fp0
fmuld a0@+,fp0
faddd a1@,fp0
fmoved fp0,a1@+
dbra d0,L5
which is optimal.
Cheers,
Toon.