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[Bug target/42542] Vectorizer produces incorrect results on max/min of unsigned intergers
- From: "hjl dot tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 12 Jan 2010 00:41:23 -0000
- Subject: [Bug target/42542] Vectorizer produces incorrect results on max/min of unsigned intergers
- References: <bug-42542-5724@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #23 from hjl dot tools at gmail dot com 2010-01-12 00:41 -------
(In reply to comment #22)
> I am looking at this on IA64 and fixing it for V2SI seems simple enough.
> I will attach a patch. But I am not sure what to do for V4HI and V8QI.
> The current code uses an 'unsigned saturating subtraction' and that
> seems to be what x86 is using for V16QI and V8HI. But when I run
> pr42542-2.c and pr42542-3.c (short and char) on IA64 they fail. My
> patch does make pr42542-1.c (int) work. I tried handling V4HI and V8QI
> in the same way as V2SI but that didn't seem to work either.
>
What was the problem with V4HI and V8QI? The existing code works
OK on pr42542-2.c and pr42542-3.c for me.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42542