Fixes are available
May 2010 Update for XL C/C++ Advanced Edition for Blue Gene/P, V9.0
December 2010 Update for XL C/C++ Advanced Edition for Blue Gene/P, V9.0
XL C/C++ Advanced Edition for Blue Gene/P Fix Pack 17 (October 2013 Update) for 9.0
April 2011 Update for XL C/C++ Advanced Edition for Blue Gene/P, V9.0
August 2011 Update for XL C/C++ Advanced Edition for Blue Gene/P, V9.0
April 2012 Update for XL C/C++ Advanced Edition for Blue Gene/P, V9.0
August 2012 Update for XL C/C++ Advanced Edition for Blue Gene/P, V9.0
APAR status
Closed as program error.
Error description
The provided test case produces an incorrect output at runtime due to the incorrect evaluation of !((~max_juint) == 0) within the 'if' statement. ===== COMPILE COMMAND: xlC_r -q64 test.cpp ===== TESTCASE: $ cat test.cpp /********************************/ #include <stdio.h> typedef uint32_t juint; const juint max_juint = (juint)-1; /* 0xFFFFFFFF largest juint */ int main() { printf("max_juint: 0x%x\n", max_juint); printf("~max_juint: 0x%x\n", ~max_juint); printf(" ((~max_juint) == 0) : %d\n", ((~max_juint) == 0)); printf("!((~max_juint) == 0) : %d\n", !((~max_juint) == 0)); if (!((~max_juint) == 0)) { printf("*** error ***\n", max_juint); } else { printf("*** ok ***\n", max_juint); } return 0; } ===== ACTUAL OUTPUT: $ ./a.out max_juint: 0xffffffff ~max_juint: 0x0 ((~max_juint) == 0) : 1 !((~max_juint) == 0) : 0 *** error *** $ ===== EXPECTED OUTPUT: $ ./a.out max_juint: 0xffffffff ~max_juint: 0x0 ((~max_juint) == 0) : 1 !((~max_juint) == 0) : 0 *** ok *** $
Local fix
Assign the value to a temp variable before evaluating the expression within the 'if'. eg: . . uint32_t temp = ~max_juint; if (!(temp == 0)) { printf("*** error ***\n", max_juint); } else { printf("*** ok ***\n", max_juint); } . .
Problem summary
USER AFFECTED: Users using special const iteral type like HEX, in the logical comparison statement. PROBLEM DESCRIPTION: The compiler does not evaluate the non-integral literal type properly, causing the logic relation in the if-else statements is determined incorrectly.
Problem conclusion
xlCentry needs to choose proper routines to convert and evaluate the special const literal type.
Temporary fix
Comments
APAR Information
APAR number
LI75448
Reported component name
XL C/C++ AE BG/
Reported component ID
5799HJE00
Reported release
900
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2010-04-26
Closed date
2010-04-26
Last modified date
2010-04-26
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++ AE BG/
Fixed component ID
5799HJE00
Applicable component levels
R900 PSN IZ65456
UP06/09/13
Document Information
Modified date:
16 October 2021