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*From*: Steve Kargl <sgk at troutmask dot apl dot washington dot edu>*To*: "Kaveh R. Ghazi" <ghazi at caip dot rutgers dot edu>*Cc*: Tobias Burnus <burnus at net-b dot de>, fortran at gcc dot gnu dot org, gcc-patches at gcc dot gnu dot org*Date*: Thu, 28 May 2009 21:09:35 -0700*Subject*: Re: [PATCH]: Integrate gfortran with MPC*References*: <B893CE4B787949BDB96C7366FEA4CA8C@glap>

On Thu, May 28, 2009 at 04:04:41PM -0700, Kaveh R. Ghazi wrote: > From: "Kaveh R. Ghazi" <ghazi@caip.rutgers.edu> > > >From: "Steve Kargl" <sgk@troutmask.apl.washington.edu> > >> > >>BTW, once mpc becomes mandatory, I plan to change gfc_expr as > >>follows: > >> > >>troutmask:sgk[225] diff -u gfortran.h.orig gfortran.h > >>--- gfortran.h.orig 2009-05-26 10:06:24.000000000 -0700 > >>+++ gfortran.h 2009-05-26 10:09:03.000000000 -0700 > >>@@ -1613,11 +1613,7 @@ > >> > >> mpfr_t real; > >> > >>- struct > >>- { > >>- mpfr_t r, i; > >>- } > >>- complex; > >>+ mpc_t complex; > >> > >> struct > >> { > > So I toyed with doing this conversion myself and the testcase > gfortran.dg/real_const_3.f90 started failing on lines 45 and 48. I traced > it to the compile-time evaluation of these variables. I think it happens in > gfc_arith_divide. > > complex :: z = (-0.1,-2.2)/(0.0,0.0) > complex :: z2 = (0.1,1)/0 > > The above lines currently transform into NaN in gfortran and that's what the > testcase expects. MPC, MPFR (and C) turn finite/zero into Inf. Only > zero/zero turns into NaN. > > I'm wondering if it was really meant for fortran to be different, or is this > a bug accidentally immortalized in the testcase? I.e. what does the fortran > standard say? > Andrew's correct in that the Fortran standard does not address Inf or NaN unless one is using Fortran 2003's IEEE intrinsic module. I suspect that this is bug that has been immortalized in the testsuite. It should probably be fixed to give the result that an equivalent C program would give. Can you open a bug report and add me to cc? -- Steve

**Follow-Ups**:**Re: [PATCH]: Integrate gfortran with MPC***From:*Steve Kargl

**References**:**Re: [PATCH]: Integrate gfortran with MPC***From:*Kaveh R. Ghazi

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