LI77973: COMPILER GENERATES INEFFICIENT CODE.

XL C/C++ for Linux Fix Pack 8 (October 2015 Update) for 12.1
XL C/C++ for Linux Fix Pack 7 (May 2014 Update) for 12.1

APAR status

• Closed as program error.

Error description

• Compiler generates code with 2 branches instead of 1 branch
  only. To fix the problem compiler needs to recognize the
  following pattern in the code:
     ...
     C[4|8]  cr300=gr100,a
     BT      CL.2,cr300,0x1/lt
     ...
     C[4|8]  cr500=gr100,b
     BT      CL.2,cr400,0x2/gt
     ...
  and optimize it to more efficient pattern:
      ...
       S  gr200=gr100,a
       S  gr300=b,a
       CL[4|8]  cr500=gr300,gr200
       BT      CL.2,cr400,0x2/gt
  

Local fix

• Not applicable.
  

Problem summary

• Compiler generates code with 2 branches instead of 1 branch only
  

Problem conclusion

• Compiler recognizes the pattern and rewrites the expression and
  branch
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

  IV55361

• 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

• RC10 PSN IV55361

     UP06/09/13