Path: utzoo!yunexus!ists!jarvis.csri.toronto.edu!mailrus!uwm.edu!gem.mps.ohio-state.edu!tut.cis.ohio-state.edu!ucbvax!hplabs!hpfcso!mjs
From: mjs@hpfcso.HP.COM (Marc Sabatella)
Newsgroups: comp.sys.hp
Subject: Re: Possible HP-UX compiler optimizer bug (found while making Perl)
Message-ID: <7370029@hpfcso.HP.COM>
Date: 10 Nov 89 16:36:07 GMT
Article-I.D.: hpfcso.7370029
References: <4413@fmeed1.UUCP>
Organization: Hewlett-Packard, Fort Collins, CO, USA
Lines: 18

>Refer to the chapter of about the C optimizer in your HP-UX 6.5
>Upgradenotes file. The -O flag causes the peephole optimizer to
>use the highest implemented optimize level. This is not properly
>implemented; I've a few pieces of C code that either crash or hang
>the compiler. I always use "+O1", that causes the compiler to use
>the usual (6.2) optimize level.

Don't blame the peephole optimizer, the global optimizer invoked by -O is an
entirely new product for 6.5

And yes, there are known bugs, which have been fixed for 7.0.

But it is not so bad (at 6.5) that you should should always use +O1.

--------------
Marc Sabatella
HP Colorado Language Lab
marc%hpfcrt@hplabs.hp.com