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Re: target/8087: sparc-sun-solaris2.7 C testsuite failures in execute/20020720-1.c w/-m64 or on sparcv9/sparc64


The following reply was made to PR target/8087; it has been noted by GNATS.

From: Richard Henderson <rth@redhat.com>
To: davem@gcc.gnu.org, gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org,
   ghazi@caip.rutgers.edu, nobody@gcc.gnu.org, davem@redhat.com,
   jakub@redhat.com, roger@eyesopen.com, gcc-gnats@gcc.gnu.org
Cc:  
Subject: Re: target/8087: sparc-sun-solaris2.7 C testsuite failures in execute/20020720-1.c w/-m64 or on sparcv9/sparc64
Date: Mon, 30 Sep 2002 16:24:21 -0700

 On Mon, Sep 30, 2002 at 10:52:04PM -0000, davem@gcc.gnu.org wrote:
 >     The problem is, it's REALLY REALLY expensive to set the
 >     float condition codes to a constant value (two FPU synchronizing
 >     memory operations).
 
 Not really.  Zero is easy:
 
 	fzeros	%f0
 	fnot1s	%f1, %f0
 	fcmps	%fcc0, %f1, %f0
 
 (note that ~0 is a NaN).  One is sort of meaningless all on its own.
 You have to know what sort of comparison is going to be used with it.o
 Hum, actually that's true with NaN and UNORDERED as well.  I.e. this
 is all bogus for COMPARE targets.
 
 
 
 r~


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