Fixes are available
APAR status
Closed as program error.
Error description
This is a test for the builtin long __fetch_and_swaplp(volatile long*, long); inline intptr_t Atomic::xchg_ptr(intptr_t exchange_value, volatile intptr_t* dest) { long old_value; __lwsync(); old_value = __fetch_and_swaplp(dest, exchange_value); __isync(); return (intptr_t) old_value; } And this is the disassembled code: $ dbx cpp_test Type 'help' for help. reading symbolic information ... (dbx) listi test_xchg_ptr 0x100000c00 (test_xchg_ptr(long,volatile long*)) 7c2004ac sync 0x100000c04 (test_xchg_ptr(long,volatile long*)+0x4) 7c0020a8 ldarx r0,r0,r4 0x100000c08 (test_xchg_ptr(long,volatile long*)+0x8) 7c6021ad stdcx. r3,r0,r4 0x100000c0c (test_xchg_ptr(long,volatile long*)+0xc) 40a2fff8 bne 0x100000c14 (test_xchg_ptr(long,volatile long*)+0x4) 0x100000c10 (test_xchg_ptr(long,volatile long*)+0x10) 4c00012c isync 0x100000c14 (test_xchg_ptr(long,volatile long*)+0x14) 60030000 ori r3,r0,0x0 0x100000c18 (test_xchg_ptr(long,volatile long*)+0x18) 4e800020 blr The problem is the bne at 0x100000c0c. It should branch back to the ldarx at 0x100000c04, if the stdcx fails, but instead it branches forward to 0x100000c14 and then xchg_ptr() returns without having stored exchange_value to dest. The problem seems to occur when mixing inline assembler with built-ins.
Local fix
N/A
Problem summary
USERS AFFECTED: Users who inter-mix asm statements and compiler built-ins may be affected by this issue. PROBLEM DESCRIPTION: The resulting assembler file contained incorrect assembly code for branches, which resulted in incorrect execution of the code at runtime.
Problem conclusion
The compiler has been fixed so that it will generate correct assembly code for branches.
Temporary fix
Comments
APAR Information
APAR number
LI76224
Reported component name
XL C/C++ SLES10
Reported component ID
5724U8300
Reported release
A10
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2011-06-10
Closed date
2011-06-10
Last modified date
2011-06-10
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++ SLES10
Fixed component ID
5724U8300
Applicable component levels
RA10 PSN IZ94262
UP06/09/13
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Document Information
Modified date:
17 October 2021