https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85103
Bug ID: 85103
Summary: Performance regressions on SPEC with r257582
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: ipa
Assignee: unassigned at gcc dot gnu.org
Reporter: pthaugen at gcc dot gnu.org
CC: dje at gcc dot gnu.org, hubicka at gcc dot gnu.org,
marxin at gcc dot gnu.org, segher at kernel dot
crashing.org,
wschmidt at gcc dot gnu.org
Target Milestone: ---
Host: powerpc64-unknown-linux-gnu
Target: powerpc64-unknown-linux-gnu
Build: powerpc64-unknown-linux-gnu
r257582 is responsible for a 6% degradation in CPU2000 175.vpr and a 12%
degradation in CPU2006 401.bzip2. Both run on a Power7 box.
Very initial look at profile of bzip2 shows degradation is contained to
mainSort(), which showed a 54% increase in run cycles. Appears one of the calls
to mainGtU() is inlined into mainSort in the slow version, but the drop in
cycle counts on mainGtu is no where close to the increase on mainSort.
