Re: [HACKERS] ANSI-strict pointer aliasing rules

Zeugswetter Andreas DCP SD wrote:
>
> > > 4. Find the option for disabling strict alias and get configure to
> add
> > > that.
> >
> > You'll still lose performance, but the option is "-qalias=noansi".
>
> My old xlc does not show that option, it is unfortunately version
> specific.
> The currently compatible option to turn it off would be -qnoansialias
>
> So we can use:
> xlc -qnoansialias
>
> The default cc options are: -qlanglvl=extended -qnoro -qnoroconst
> So I guess we could also use (but above is imho clearer/better):
> cc -qro -qroconst -qlanglvl=extc89

OK, patch attached and applied to use -qnoansialias in xlc.  We can
consider backpatching this to 8.1.X.

--
  Bruce Momjian   http://candle.pha.pa.us
  EnterpriseDB    http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +
Index: configure.in
===================================================================
RCS file: /cvsroot/pgsql/configure.in,v
retrieving revision 1.460
diff -c -c -r1.460 configure.in
*** configure.in    22 Apr 2006 00:29:41 -0000    1.460
--- configure.in    27 Apr 2006 14:26:06 -0000
***************
*** 267,272 ****
--- 267,275 ----

    # Disable strict-aliasing rules; needed for gcc 3.3+
    PGAC_PROG_CC_CFLAGS_OPT([-fno-strict-aliasing])
+ elif test ${CC} = "xlc"; then
+   # AIX xlc has to have strict aliasing turned off too
+   PGAC_PROG_CC_CFLAGS_OPT([-qnoansialias])
  fi

  # supply -g if --enable-debug