Commit Graph

2 Commits

Author SHA1 Message Date
H.J. Lu
1da50d4bda x86: Set Prefer_No_VZEROUPPER and add Prefer_AVX2_STRCMP
1. Set Prefer_No_VZEROUPPER if RTM is usable to avoid RTM abort triggered
by VZEROUPPER inside a transactionally executing RTM region.
2. Since to compare 2 32-byte strings, 256-bit EVEX strcmp requires 2
loads, 3 VPCMPs and 2 KORDs while AVX2 strcmp requires 1 load, 2 VPCMPEQs,
1 VPMINU and 1 VPMOVMSKB, AVX2 strcmp is faster than EVEX strcmp.  Add
Prefer_AVX2_STRCMP to prefer AVX2 strcmp family functions.
2021-03-29 07:40:17 -07:00
Florian Weimer
e4933c8a92 x86: Automate generation of PREFERRED_FEATURE_INDEX_1 bitfield
Use a .def file to define the bitfield layout, so that it is possible
to iterate over field members using the preprocessor.
2021-03-02 15:01:06 +01:00