This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug tree-optimization/78604] [7 regression] test case gcc.target/powerpc/p8vector-vectorize-1.c fails starting with r242750
- From: "amker at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 23 Jan 2017 09:15:22 +0000
- Subject: [Bug tree-optimization/78604] [7 regression] test case gcc.target/powerpc/p8vector-vectorize-1.c fails starting with r242750
- Auto-submitted: auto-generated
- References: <bug-78604-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78604
--- Comment #7 from amker at gcc dot gnu.org ---
(In reply to Michael Meissner from comment #6)
> Unless -ffast-math or -fno-honor-nans is used, you cannot invert < to >=,
> because you will get a different result if either operand is a NaN.
> However, the basic code for vector compares hasn't changed much since the
> early power7 days.
I don't know details in power. Though it's vectorized instruction, it has
integer inner type. That's why the "<" is converted to ">=" in tree-ifcvt just
before vectorizer. Is it safe to transform in this case? Thanks.