[Bug target/14326] boehm-gc hardcodes to 3DNow! prefetch for x86_64

[Hans dot Boehm at hp dot com]

------- Additional Comments From Hans dot Boehm at hp dot com  2004-02-27 18:37 -------
I'd be inclined to use __builtin_prefetch for both the X86_64 and I386 cases.  
That gets rid of some obscure configuration options for the GC.

This should be guarded by a #ifdef __GNUC__ .  The current assembly code isn't 
going to work for a non-gcc compiler anyway.  (This may still break the Intel 
compiler.  If so, we'll fix it then.)

I assume gcc does the right thing for __builtin_prefetch depending on the 
command line arguments, i.e. generates nothing by default?

I would like to see the I386 and X86_64 cases handled identically, since the 
underlying mess is now unfortunately the same.

If AMD and Intel can't work this out, we should eventually include two near 
clones of the marker code, one using each version, and choose at run-time.  But 
that's real work.

Hans

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14326