Fixes are available
November 2012 PTF for XL C for AIX, V12.1
November 2012 PTF for XL C/C++ for AIX, V12.1
March 2013 PTF for XL C for AIX, V12.1
March 2013 PTF for XL C/C++ for AIX, V12.1
XL C for AIX Fix Pack 4 (June 2013 PTF) for 12.1
XL C/C++ for AIX Fix Pack 4 (June 2013 PTF) for 12.1
XL C for AIX Fix Pack 5 (September 2013 PTF) for 12.1
XL C/C++ for AIX Fix Pack 5 (September 2013 PTF) for 12.1
Closed as program error.
A performance degradation is seen with the __popcnt4 and __popcnt8 population count functions when POWER7 hardware is targeted with the -qarch/-qtune options, and -qhot/IPA optimization is used. Slower code is generated using the popcntb instruction instead of the popcntw/popcntd instructions.
- Do not use higher -qhot levels, use -qhot=level=0
PROBLEM DESCRIPTION: Performance degradation with popcnt optimization. USERS AFFECTED: Customers who use popcnt instructions on POWER7.
The popcnt optimization on POWER7 has been disabled, since it is not profitable on POWER7.
Reported component name
XL C FOR AIX
Reported component ID
Last modified date
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fixed component name
XL C FOR AIX
Fixed component ID
Applicable component levels
RC10 PSN U856101