LI76662: MISSING STORE FOR __D128_TO_SIGNED_BCD

XL C/C++ for Linux Fix Pack 9 (August 2013 Update) for 11.1
June 2012 Update for XL C/C++ for Linux, V11.1
October 2012 Update for XL C/C++ for Linux, V11.1
XL C/C++ for Linux Fix Pack 8 (June 2013 Update) for 11.1

APAR status

• Closed as program error.

Error description

• The following demonstrates how the compiler fails to produce a
  store for the __d128_to_signed_BCD() function when using the
  -qdfp option.
  
  ===== COMPILE COMMAND:
  xlC -q64 -O -qarch=pwr7 -qdfp -c load_store_bcd31.C
  
  
  ======= Test case:
  $cat load_store_bcd31.C
  #include <builtins.h>
  
  
  extern "C" void storeBCD(_Decimal128 dfp, unsigned char *cp,
  unsigned
  long long* op)
  {
     __d128_to_signed_BCD (dfp, 1, (unsigned long long *)cp,
  (unsigned
  long long *)(cp+8));
  }
  
  extern "C" void storeBCD_urg(_Decimal128 dfp, unsigned char *cp,
  unsigned long long* op)
  {
     unsigned long long upper;
     unsigned long long lower;
     __d128_to_signed_BCD (dfp, 1, &upper, &lower);
     *((unsigned long long *)cp) = upper;
     *((unsigned long long *)(cp+8)) = lower;
  }
  
  extern "C" _Decimal128 loadBCD(unsigned char *cp)
  {
     return __signed_BCD_to_d128(*(unsigned long long *)cp,
  *(unsigned
  long long *)(cp+8));
  }
  $
  
  
  ===== ACTUAL LISTING:
  
  >>>>> OBJECT SECTION, OPTIMIZATION <<<<<
   GPR's set/used:   ---- ---- ---- ----  ---- ---- ---- ----
   FPR's set/used:   ---- ---- ---- ----  ---- ---- ---- ----
   CCR's set/used:   ---- ----
    VR's set/used:   ---- ---- ---- ----  ---- ---- ---- ----
       | 000000                           PDEF     storeBCD
      0|                                  PROC
  dfp,cp,op,vs2,vs3,gr5,gr6
      9| 000000 bclr     4E800020   1     BA        lr
       |               Tag Table
  
  
  ======= EXPECTED LISTING:
  
  >>>>> OBJECT SECTION, OPTIMIZATION <<<<<
   GPR's set/used:   ---- -u-- ---- ----  ---- ---- ---- ----
   FPR's set/used:   ssuu ---- ---- ----  ---- ---- ---- ----
   CCR's set/used:   ---- ----
    VR's set/used:   ---- ---- ---- ----  ---- ---- ---- ----
       | 000000                           PDEF     storeBCD
      0|                                  PROC
  dfp,cp,op,vs2,vs3,gr5,gr6
      7| 000000 ddedpdq  FC181284   1     CVDFESB
  vs0,vs1=vs2,vs3,1
      7| 000004 stfd     D8250008   1     STFL      (unsigned long
  long;unsigned char)(gr5,8)=vs1
      7| 000008 stfd     D8050000   1     STFL      (unsigned long
  long;unsigned char)(gr5,0)=vs0
      9| 00000C bclr     4E800020   1     BA        lr
       |               Tag Table
  

Local fix

• n/a
  

Problem summary

• USERS AFFECTED:
  Users using -qdfp with the __d128_to_signed_BCD function and
  optimization maybe affected by this issue.
  
  PROBLEM DESCRIPTION:
  The compiler is optimizing out a store that is should not be
  removing due to incorrect symbols for the store.
  

Problem conclusion

• The compiler has now been fixed to avoid removing the stores
  that are needed.
  

Temporary fix

Comments

APAR Information

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

  IV10079

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

Fix information

• Fixed component name

  XL C/C++ FOR LI

• Fixed component ID

  5724X1400

Applicable component levels

• RB10 PSN IV10079

     UP06/09/13