[Bug target/86449] New: GCC 8 compiler generates slower code for spec 2006 calculix on a power9 using -mcpu=power9 than using -mcpu=power8
meissner at gcc dot gnu.org
gcc-bugzilla@gcc.gnu.org
Mon Jul 9 20:29:00 GMT 2018
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86449
Bug ID: 86449
Summary: GCC 8 compiler generates slower code for spec 2006
calculix on a power9 using -mcpu=power9 than using
-mcpu=power8
Product: gcc
Version: 8.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: meissner at gcc dot gnu.org
Target Milestone: ---
I ran spec 2006 on a DD2.2 power9, and I noticed the GCC 8.x branch (subversion
id 26248) generated slower code for calculix when compiled with a -mcpu=power9
option instead of -mcpu=power8.
Note, the trunk actually generates 2% faster code for -mcpu=power9 than for
-mcpu=power8. This issue is only a regression on the GCC 8 branch.
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