Fixes are available
April 2013 Update for XL C/C++ for Linux, V12.1
XL C/C++ for Linux Fix Pack 8 (October 2015 Update) for 12.1
XL C/C++ for Linux Fix Pack 4 (October 2013 Update) for 12.1
XL C/C++ for Linux Fix Pack 5 (December 2013 Update) for 12.1
XL C/C++ for Linux Fix Pack 6 (February 2014 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
xlC loads from constant area while it is more efficient to use immediate instructions. Pattern: First 32-bits are zero Next 16-bit start with 1-bit Next 16-bit value does not start with 1-bit Take this sample: extern "C" unsigned long long res() { return 0x82160001ULL; } xlC listing outputs: | 000000 PDEF res 2| PROC 4| 000000 ld E8620008 1 L8 gr3=.+CONSTANT_AREA(gr2,0) 4| 000004 ld E8630000 1 L8 gr3=+CONSTANT_AREA(gr3,0) 5| 000008 bclr 4E800020 1 BA lr | Tag Table | 00000C 00000000 00092000 00000000 0000000C | Instruction count 3 | Straight-line exec time 3 | Constant Area | 000000 00000000 82160001 If using immediate instructions for above example, it would be more efficient: li rx,1 oris rx,rx,0x8216
Local fix
N/A
Problem summary
PROBLEM DESCRIPTION: The compiler is not as efficient as it could be when loading certain constants. USERS AFFECTED: Users who use a constant that starts with 32 zero-bits, has a 0 in the 49th bit, and a 1 for the 33rd bit when represented with 64-bits.
Problem conclusion
Added code to identify these constants and build them instead of loading them from the constant area.
Temporary fix
Comments
APAR Information
APAR number
LI77327
Reported component name
XL C/C++ FOR LI
Reported component ID
5725C7300
Reported release
C10
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2013-04-27
Closed date
2013-04-27
Last modified date
2013-04-27
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
RC10 PSN IV30067
UP06/09/13
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Document Information
Modified date:
14 October 2021