Re: [GHC] #7814: panic in PPC NCG

5 Apr 2013

      #7814: panic in PPC NCG
--------------------------------+-------------------------------------------
Reporter:  heisenbug            |          Owner:          
    Type:  bug                  |         Status:  new     
Priority:  normal               |      Component:  Compiler
 Version:  7.7                  |       Keywords:          
      Os:  Unknown/Multiple     |   Architecture:  powerpc 
 Failure:  Building GHC failed  |      Blockedby:          
Blocking:                       |        Related:          
--------------------------------+-------------------------------------------

Comment(by heisenbug):

 This function alone triggers the panic:
 {{{
 ==================== Post CPS Cmm ====================
 [stg_sel_0_upd_entry() //  [R1]
          { info_tbl: [(cc,
                        label: stg_sel_0_upd_info
                        rep:tag:23 HeapRep { ThunkSel 0 }),
                       (ce,
                        label: block_ce_info
                        rep:StackRep [])]
            stack_info: arg_space: 4 updfr_space: Just 4
          }
      {offset
        cc: _c1::P32 = R1;
            if ((Sp + -12) < SpLim) goto cj; else goto cl;
        cj: R1 = _c1::P32;
            call (stg_gc_enter_1)(R1) args: 4, res: 0, upd: 4;
        cl: I32[Sp - 8] = stg_upd_frame_info;
            P32[Sp - 4] = _c1::P32;
            _cf::P32 = I32[_c1::P32 + 8];
            if (_cf::P32 & 3 != 0) goto co; else goto cn;
        cn: I32[Sp - 12] = ce;
            R1 = _cf::P32;
            Sp = Sp - 12;
            call (I32[_cf::P32])(R1) returns to ce, args: 4, res: 4, upd:
 12;
        ce: Sp = Sp + 12;
            _cf::P32 = R1;
            goto co;
        co: R1 = I32[_cf::P32 & (-4) + 4];
            Sp = Sp - 8;
            call stg_ap_0_fast(R1) args: 12, res: 0, upd: 12;
      }
  }]

 ==================== Optimised Cmm ====================
 stg_sel_0_upd_entry() //  [R1]
         { [(cb,
             stg_sel_0_upd_info:
                 const 0;
                 const 1507328;),
            (ce,
             block_ce_info:
                 const 0;
                 const 2097152;)]
         }
     {offset
       cb: _cc::P32 = R1;
           if ((Sp + -12) < SpLim) goto cj; else goto cl;
       cj: R1 = _cc::P32;
           call (I32[BaseReg - 12])(R1) args: 4, res: 0, upd: 4;
       cl: I32[Sp - 8] = I32[PicBaseReg + .LC_stg_upd_frame_info-.LCTOC1];
           P32[Sp - 4] = _cc::P32;
           _cf::P32 = I32[_cc::P32 + 8];
           if (_cf::P32 & 3 != 0) goto co; else goto cn;
       cn: I32[Sp - 12] = I32[PicBaseReg + .LC_block_ce_info-.LCTOC1];
           R1 = _cf::P32;
           Sp = Sp - 12;
           call (I32[_cf::P32])(R1) returns to ce, args: 4, res: 4, upd:
 12;
       ce: Sp = Sp + 12;
           _cf::P32 = R1;
           goto co;
       co: R1 = I32[_cf::P32 & (-4) + 4];
           Sp = Sp - 8;
           call (I32[PicBaseReg + .LC_stg_ap_0_fast-.LCTOC1])(R1) args: 12,
 res: 0, upd: 12;
     }
 }
 }}}
 -ddump-asm dies not show anything

-- 
Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/7814#comment:2
GHC http://www.haskell.org/ghc/
The Glasgow Haskell Compiler