https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78994
Richard Biener changed:
What|Removed |Added
Status|NEW |ASSIGNED
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78994
Wilco changed:
What|Removed |Added
Status|UNCONFIRMED |NEW
Last reconfirmed|
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78994
--- Comment #9 from PeteVine ---
Well, yes, that fixes the -Ofast issue for me:
-mcpu=cortex-a53 -frename-registers
iir:65952 ns per loop
iir_2: 63098 ns per loop
-mcpu=cortex-a57 (-frename-registers)
iir:62839 ns per loop
iir_2:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78994
wilco at gcc dot gnu.org changed:
What|Removed |Added
CC||wilco at gcc dot gnu.org
---
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78994
--- Comment #7 from PeteVine ---
Not affected by -mno-fix-cortex-a53-843419 which gives the issue full validity.
-Ofast pessimizes Cortex A53 codegen somehow and switching to e.g.
-mcpu=cortex-a57 fixes it. (tested on trunk)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78994
--- Comment #6 from PeteVine ---
It's possible I already had that patch included in my build, but
in case I didn't, here's a quick addition to the previous result:
http://openbenchmarking.org/result/1701143-TA-GCCCOMPAR66
The c-ray thunderx
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78994
--- Comment #5 from Andrew Pinski ---
https://gcc.gnu.org/ml/gcc-patches/2017-01/msg00637.html
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78994
--- Comment #4 from PeteVine ---
I'm delighted to report **not** targeting Cortex-A53 actually incurs a
performance penalty sometimes ;)
http://openbenchmarking.org/result/1701128-TA-GCCCOMPAR79
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78994
--- Comment #3 from PeteVine ---
Hey, that works for me too! (62565 vs 70758 in favour of -Ofast). Usefully
strange :)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78994
Andrew Pinski changed:
What|Removed |Added
Summary|-Ofast makes aarch64 C++|-Ofast makes aarch64 C++
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