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Re: [PATCH] implement rint{,f,l}, floor{,f,l}. ceil{,f,l}, trunc{,f,l} and nearbyint{,f,l} as x87 built-in functions
- From: Richard Henderson <rth at redhat dot com>
- To: Roger Sayle <roger at eyesopen dot com>
- Cc: Uros Bizjak <uros at kss-loka dot si>, gcc-patches at gcc dot gnu dot org
- Date: Wed, 25 Aug 2004 12:08:40 -0700
- Subject: Re: [PATCH] implement rint{,f,l}, floor{,f,l}. ceil{,f,l}, trunc{,f,l} and nearbyint{,f,l} as x87 built-in functions
- References: <412C7BAF.9060407@kss-loka.si> <Pine.LNX.4.44.0408250651480.3391-100000@www.eyesopen.com>
On Wed, Aug 25, 2004 at 07:56:57AM -0600, Roger Sayle wrote:
> Ideally the OPTIMIZE_MODE_SWITCHING would be used to control
> the placement of the "fldcw" instructions that actually change
> the mode.
You cannot do this until you figure out how to get the x86 backend to
spill fp-stack registers in XFmode. Otherwise the round+store operation
will be done with a non-standard rounding mode.
Of course, spilling in XFmode is a good idea for other reasons as well.
r~
- References:
- [PATCH] implement rint{,f,l}, floor{,f,l}. ceil{,f,l}, trunc{,f,l}and nearbyint{,f,l} as x87 built-in functions
- Re: [PATCH] implement rint{,f,l}, floor{,f,l}. ceil{,f,l}, trunc{,f,l}and nearbyint{,f,l} as x87 built-in functions