Re: Build failure, xemacs-21.1.2 on rh6-based linux-alpha-unknown
On 17 Jun 1999 19:58:04 +0200, Jan Vroonhof <vroonhof(a)math.ethz.ch> said:
What is the default? No special aliasing assumptions? What does the
configure script use?
*IF* you compile at -O3 or higher, *and* specify -qansialias, it will
make optimization decisions based on the assumption that there are no
aliasing screws to worry about. Otherwise, it will make pessimistic
assumptions regarding aliasing.
It seems from below that by default it does not use the aliasing
stuff
so the "it works on other compilers argument" does not apply.
Well, the *default* xlc flags don't use aliasing. However, this doesn't
mean that the code is "correct", merely that the compiler doesn't trip
over the problme.
> For what it's worth, I did light testing of a 21.2 built
with "-O3
> -qansialias"
The only "problem" with is that maybe the new gung-ho typing stuff
makes it less sensible to this kind of problem.
Perhaps it's less sensitive because there's no aliasing bugs in the
code. If this is true, then we're home free.
/Valdis
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