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does egcs get its sums right?
- To: egcs-bugs at cygnus dot com
- Subject: does egcs get its sums right?
- From: Stefan Schwarzer <sts at ica1 dot uni-stuttgart dot de>
- Date: Wed, 13 Jan 1999 21:36:34 +0100 (MET)
// Hi,
//
// I have been following the egcs history for a while and this compiler bug
// has followed me from gcc-2.8.1 until now.
// I can still reproduce it with egcs-1.1.1 on Ultra, Solaris 2.5.1 and
// Solaris 7, but _not_ on Alpha DUNIX 4.0C. It only occurs in the
// -O2 and -O3 optimization levels.
//
// I dont include the .ii stuff, because apart from line number info it is
// identical to the soiurce attached below.
// I'd really appreciate if this bug would make it into your testsuite
//
// ok, here it comes:
// gcc version egcs-2.91.60 19981201 (egcs-1.1.1 release)
// SunOS boa.ica1.uni-stuttgart.de 5.7 Generic sun4u sparc SUNW,Ultra-1
//
// this is the wrong result:
// 20:57 boa_sts:~/bugs/gnu> g++ -O3 -Wall ini-egcs.cc
// 20:57 boa_sts:~/bugs/gnu> a.out
// 20:58 boa_sts:~/bugs/gnu> echo $status
// 5
// this is the expected result:
// 20:58 boa_sts:~/bugs/gnu> g++ -Wall ini-egcs.cc
// 20:58 boa_sts:~/bugs/gnu> a.out
// 20:58 boa_sts:~/bugs/gnu> echo $status
// 7
//
// Thanks for your nice work on egcs in any case!
//
// Stefan Schwarzer office: +49-(0)711-685-7606 fax: x-3658
// Uni Stuttgart, ICA 1 e-mail: sts@ica1.uni-stuttgart.de
// Pfaffenwaldring 27 pgp public key available on request/finger
// 70569 Stuttgart, Germany http://www.ica1.uni-stuttgart.de/~sts
struct XTVec{
XTVec(){x[0]=x[1] =x[2] =0;}
XTVec(double ax,double y=0.,double z=0.){x[0]=ax;x[1]=y; x[2]=z; }
double& operator[](int);
double x[3];
};
inline
double & XTVec::operator[](int i){
return x[i];
}
inline
XTVec& operator+=(XTVec& lhs, XTVec& rhs){
lhs[0]+=rhs[0];
lhs[1]+=rhs[1];
lhs[2]+=rhs[2];
return lhs;
}
inline
XTVec operator+(XTVec& lhs, XTVec& rhs){
XTVec result(lhs);
return result += rhs;
}
int main()
{
XTVec ur(4.,0.,1.);
XTVec ll(0.,2.,0.);
XTVec initsum(ur + ll);
// avoid i/o, sorry for the cast
return (int) (initsum[0] + initsum[1] + initsum[2]);
}