src/cpu/sparc/vm/vm_version_sparc.cpp

*** 47,59 ****
      AllocatePrefetchStepSize = cache_line_size;
  
    AllocatePrefetchDistance = allocate_prefetch_distance();
    AllocatePrefetchStyle    = allocate_prefetch_style();
  
!   if (AllocatePrefetchStyle == 3 && !has_blk_init()) {
!     warning("BIS instructions are not available on this CPU");
!     FLAG_SET_DEFAULT(AllocatePrefetchStyle, 1);
    }
  
    UseSSE = 0; // Only on x86 and x64
  
    _supports_cx8 = has_v9();
--- 47,61 ----
      AllocatePrefetchStepSize = cache_line_size;
  
    AllocatePrefetchDistance = allocate_prefetch_distance();
    AllocatePrefetchStyle    = allocate_prefetch_style();
  
!   if (!has_blk_init()) {
!     if (AllocatePrefetchInstr == 1) {
!       warning("BIS instructions required for AllocatePrefetchInstr 1 unavailable");
!       FLAG_SET_DEFAULT(AllocatePrefetchInstr, 0);
!     }
    }
  
    UseSSE = 0; // Only on x86 and x64
  
    _supports_cx8 = has_v9();
*** 86,100 ****
      }
      if (is_niagara_plus()) {
        if (has_blk_init() && UseTLAB &&
            FLAG_IS_DEFAULT(AllocatePrefetchInstr)) {
          // Use BIS instruction for TLAB allocation prefetch.
!         FLAG_SET_ERGO(intx, AllocatePrefetchInstr, 1);
!         if (FLAG_IS_DEFAULT(AllocatePrefetchStyle)) {
!           FLAG_SET_ERGO(intx, AllocatePrefetchStyle, 3);
          }
          if (FLAG_IS_DEFAULT(AllocatePrefetchDistance)) {
            // Use smaller prefetch distance with BIS
            FLAG_SET_DEFAULT(AllocatePrefetchDistance, 64);
          }
        }
        if (is_T4()) {
--- 88,104 ----
      }
      if (is_niagara_plus()) {
        if (has_blk_init() && UseTLAB &&
            FLAG_IS_DEFAULT(AllocatePrefetchInstr)) {
          // Use BIS instruction for TLAB allocation prefetch.
!         FLAG_SET_DEFAULT(AllocatePrefetchInstr, 1);
        }
        if (FLAG_IS_DEFAULT(AllocatePrefetchDistance)) {
+         if (AllocatePrefetchInstr == 0) {
+           // Use different prefetch distance without BIS
+           FLAG_SET_DEFAULT(AllocatePrefetchDistance, 256);
+         } else {
            // Use smaller prefetch distance with BIS
            FLAG_SET_DEFAULT(AllocatePrefetchDistance, 64);
          }
        }
        if (is_T4()) {
*** 105,133 ****
          }
          if (FLAG_IS_DEFAULT(AllocateInstancePrefetchLines)) {
            FLAG_SET_ERGO(intx, AllocateInstancePrefetchLines, AllocateInstancePrefetchLines*2);
          }
        }
-       if (AllocatePrefetchStyle != 3 && FLAG_IS_DEFAULT(AllocatePrefetchDistance)) {
-         // Use different prefetch distance without BIS
-         FLAG_SET_DEFAULT(AllocatePrefetchDistance, 256);
        }
        if (AllocatePrefetchInstr == 1) {
!         // Need extra space at the end of TLAB for BIS, otherwise prefetching
!         // instructions will fault (due to accessing memory outside of heap).
!         // The amount of space is the max of the number of lines to
!         // prefetch for array and for instance allocations. (Extra space must be
!         // reserved to accomodate both types of allocations.)
! 
!         // +1 for rounding up to next cache line, +1 to be safe
!         int lines = MAX2(AllocatePrefetchLines, AllocateInstancePrefetchLines) + 2;
!         int step_size = AllocatePrefetchStepSize;
!         int distance = AllocatePrefetchDistance;
!         _reserve_for_allocation_prefetch = (distance + step_size*lines)/(int)HeapWordSize;
!       }
      }
! #endif
    }
  
    // Use hardware population count instruction if available.
    if (has_hardware_popc()) {
      if (FLAG_IS_DEFAULT(UsePopCountInstruction)) {
--- 109,126 ----
          }
          if (FLAG_IS_DEFAULT(AllocateInstancePrefetchLines)) {
            FLAG_SET_ERGO(intx, AllocateInstancePrefetchLines, AllocateInstancePrefetchLines*2);
          }
        }
      }
+ 
      if (AllocatePrefetchInstr == 1) {
!       // Use allocation prefetch style 3 because BIS instructions
!       // require aligned memory addresses.
!       FLAG_SET_DEFAULT(AllocatePrefetchStyle, 3);
      }
! #endif /* COMPILER2 */
    }
  
    // Use hardware population count instruction if available.
    if (has_hardware_popc()) {
      if (FLAG_IS_DEFAULT(UsePopCountInstruction)) {