https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81616
Andrew Roberts <andrewm.roberts at sky dot com> changed:
What |Removed |Added
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CC| |andrewm.roberts at sky dot com
--- Comment #4 from Andrew Roberts <andrewm.roberts at sky dot com> ---
I've been testing on a Ryzen system and also comparing with Haswell and
Skylake. From my testing -mtune=znver1 does not perform well and never has,
including as of last snapshot:
gcc version 8.0.0 20171119 (experimental) (GCC)
-mtune=generic seems a better option for all three systems as a default for
-march=native
This is only with one test case (attached), but I've seen the same across many
other tests.
See the attached testcase (matix.c) and performance logs
Ryzen - znver1-tunebug.txt
Haswell - znver1-tunebug2.txt
Skylake - znver1-tunebug3.txt
