Re: c/1670: HPUX: call through pointer to static function mangles argument values

[Jeffrey A Law <law at redhat dot com>]

The following reply was made to PR c/1670; it has been noted by GNATS.

From: Jeffrey A Law <law@redhat.com>
To: broeker@physik.rwth-aachen.de
Cc: gcc-gnats@gcc.gnu.org
Subject: Re: c/1670: HPUX: call through pointer to static function mangles 
 argument values
Date: Tue, 16 Jan 2001 15:18:23 -0700

   In message <20010116192410.11119.qmail@sourceware.cygnus.com>you write:
   > 
   > >Number:         1670
   > >Category:       c
   > >Synopsis:       HPUX: call through pointer to static function mangles argu
   > ment values
   > >Confidential:   no
   > >Severity:       serious
   > >Priority:       low
   > >Responsible:    unassigned
   > >State:          open
   > >Class:          wrong-code
   > >Submitter-Id:   net
   > >Arrival-Date:   Tue Jan 16 11:26:01 PST 2001
   > >Closed-Date:
   > >Last-Modified:
   > >Originator:     Hans-Bernhard Broeker
   > >Release:        gcc-2.95.2 (release)
   > >Organization:
   > >Environment:
   > HP-UX 10.20 and higher machines
   > >Description:
   > GCC miscompiles 'gnuplot' on HP-UX since version 10.20 of
   > the OS (and associated hardware).
   > 
   > The bug manifests as incorrect passing of (at least) one
   > argument of type 'double' of a function that is called
   > through a function pointer. The 
   > actual parameter is non-zero, in the calling function, but
   > the called function receives zero.
 Is your compiler using the HP assembler?  If so, that is the bug.  The
 HP assembler provides no way to allow GCC to generate proper code for
 calling a static function through a function pointer with a floating
 point parameter.
 
 This works with the compiler from HP simply because it does not use the
 assembler at all.  It emits object files directly and thus can set the
 magic bits to make it work.
 
 Basically stop using the HP assembler.  You'll be happier in the long run.
 
 jeff