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Re: GCC floating point usage




--On Wednesday, October 16, 2002 10:53:33 PM +0200 Michael Matz <matz@suse.de> wrote:

Hi,

On Wed, 16 Oct 2002, Mark Mitchell wrote:

> (a) Does this affect codegen when the new feature is not enabled?
>     Zack's patch does, and it shouldn't.

I certainly agree that people not using the flag should see no change.

Why does Zack's patch do that, given his caveat that the sense of the
flag would be reversed so that the flag is off by default?
Because it adds an additional insn pattern, with equal predicates as
the following one, but with different constraints.  This means, that in
the case this pattern is activated (which it is by default, given Zacks
changed default proposal) it will be preferred, which means, because it
only lists float regs in constraints, that float regs will be preferred.
That sounds like a problem that needs to be fixed.

We're still hung up on a more basic problem, though; the RS6000
maintainers haven't yet made an up-or-down decision on the idea of
the flag...

--
Mark Mitchell                mark@codesourcery.com
CodeSourcery, LLC            http://www.codesourcery.com


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