A fix is available
APAR status
Closed as program error.
Error description
In some scenarios, code tuned for POWER8 does not schedule paired addi+stxvd2x instructions together. This may cause less-than-ideal performance. === EXAMPLE === 1863| 00099C ori 60420000 1 ASM 'ori 2,2,0 #7 ,' * 1448| 0009A0 addi 3A400080 1 LI gr18=128 1866| 0009A4 add 7D6BEA14 1 A gr11=gr11,gr29 1867| 0009A8 add 7D4ADA14 1 A gr10=gr10,gr27 * 1448| 0009AC stxvd2x 7C019799 1 VSTQD (gr1,gr18,0)=vs32 1448| 0009B0 xvcpsgnd F0000781 1 LRVS vs32=vs0 The instructions marked with '*' should be scheduled together.
Local fix
Problem summary
PROBLEM DESCRIPTION: addi + stxvd2x instructions were not scheduled together to take advantage of POWER8 instruction fusion. USERS AFFECTED: Users who use -qarch=pwr8 with -O2 and above.
Problem conclusion
An issue with the instruction scheduler missed instruction fusion opportunities for vector store. It has now been fixed.
Temporary fix
Comments
APAR Information
APAR number
LI78451
Reported component name
XL C/C++ FOR LI
Reported component ID
5725C7300
Reported release
D10
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2015-02-25
Closed date
2015-02-25
Last modified date
2015-02-25
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
XL C/C++ FOR LI
Fixed component ID
5725C7300
Applicable component levels
RD10 PSY
UP
[{"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SSXVZZ","label":"XL C\/C++ for Linux"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"13.1","Line of Business":{"code":"LOB57","label":"Power"}}]
Document Information
Modified date:
17 October 2021