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[Bug target/66369] gcc 4.8.3/5.1.0 miss optimisation with vpmovmskb
- From: "marcus.kool at urlfilterdb dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 02 Jun 2015 11:20:56 +0000
- Subject: [Bug target/66369] gcc 4.8.3/5.1.0 miss optimisation with vpmovmskb
- Auto-submitted: auto-generated
- References: <bug-66369-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66369
--- Comment #3 from Marcus Kool <marcus.kool at urlfilterdb dot com> ---
> The intrinsic returns "int", and from the above tree dump, the compiler
> won't even consider to combine the sign-extension with vpmovmskb.
That is the core of the issue: the part of gcc that deals with intrinsics does
not consider to use the 64bit version of the vpmovmskb instruction.
BTW: how is gcc behaving on a system with AVX512 ?