[Bug target/65871] bzhi builtin/intrinsic wrongly assumes bzhi instruction doesn't set the ZF flag

["jamrial at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65871

--- Comment #9 from James Almer <jamrial at gmail dot com> ---
Created attachment 35804
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35804&action=edit
Preprocessed code where a test instruction is still generated

Please look at the attachment.

[jamrial@archVM ~]$ gcc -std=c99 -march=haswell -O3 -c hevc_ps.i

[jamrial@archVM ~]$ objdump --disassemble hevc_ps.o | grep -B2 -A2 bzhi
    5854:       c4 62 22 f7 d6          sarx   %r11d,%esi,%r10d
    5859:       c4 62 22 f7 da          sarx   %r11d,%edx,%r11d
    585e:       c4 e2 70 f5 f6          bzhi   %ecx,%esi,%esi
    5863:       45 89 9e 68 33 00 00    mov    %r11d,0x3368(%r14)
    586a:       41 89 c3                mov    %eax,%r11d
--
    589d:       85 f6                   test   %esi,%esi
    589f:       75 0d                   jne    58ae
<ff_hevc_decode_nal_sps+0x1a6e>
    58a1:       c4 e2 70 f5 d2          bzhi   %ecx,%edx,%edx
    58a6:       85 d2                   test   %edx,%edx
    58a8:       0f 84 5a 03 00 00       je     5c08
<ff_hevc_decode_nal_sps+0x1dc8>

[jamrial@archVM ~]$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/local/lib/gcc/x86_64-unknown-linux-gnu/6.0.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: /home/jamrial/gcc-svn/configure --prefix=/usr/local
--libdir=/usr/local/lib --libexecdir=/usr/local/lib
--mandir=/usr/local/share/man --infodir=/usr/local/share/info
--enable-languages=c,c++,lto --enable-shared --disable-bootstrap
--enable-threads=posix --enable-libmpx --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch
--disable-libssp --enable-gnu-unique-object --enable-linker-build-id
--enable-lto --enable-plugin --enable-install-libiberty
--with-linker-hash-style=gnu --enable-gnu-indirect-function --disable-multilib
--disable-werror
Thread model: posix
gcc version 6.0.0 20150618 (experimental) (GCC)


Not sure why the new model is not working here.