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powerpc/rs6000 implicit FPU usage
- From: Till Straumann <strauman at slac dot stanford dot edu>
- To: gcc at gcc dot gnu dot org
- Date: Tue, 01 Nov 2005 16:49:18 -0800
- Subject: powerpc/rs6000 implicit FPU usage
The issue of gcc implicitely generating floating point
instructions (i.e., without 'double' or 'float' types
being used in the source code) has come up a few times
in the past (e.g., 2002/10: GCC floating point usage)
Miraculously, I found that gcc-4.0.2 (unlike 3.2 or 3.4)
no longer generates a lfd/stfd pair for something like this:
unsigned long long *px, *py;
*px = *py;
However, I was unable to find any documentation or recent
discussion about the issue.
Has this kind of optimization (using the FPU for
data objects other than double/float) been deliberately
abandoned or is it the side-effect of other changes?
Thanks
-- Till
PS: Please CC me - I'm not on this list