[GHC] #9329: GHC panics when Cmm-compiling `STK_CHK_GEN_N (8);`

18 Jul 2014


      #9329: GHC panics when Cmm-compiling `STK_CHK_GEN_N (8);`
-------------------------------------+-------------------------------------
        Reporter:  hvr               |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:  7.10.1
       Component:  Compiler          |                 Version:  7.8.3
        Keywords:                    |  Differential Revisions:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash                              |              Difficulty:  Unknown
       Test Case:                    |              Blocked By:
        Blocking:                    |         Related Tickets:
-------------------------------------+-------------------------------------
 The following Cmm code snippet compiles fine

 {{{#!c
 foo ()
 {
   STK_CHK_GEN_N (((1)*8)); /* works */
   return (0);
 }
 }}}


 The following one, however, only compiles with `-O0`, but panics with
 `-O1` or more:

 {{{#!c
 foo ()
 {
   STK_CHK_GEN_N (8); /* panics */
   return (0);
 }
 }}}


 {{{
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.8.3 for x86_64-unknown-linux):
         bundle
     c1 foo [(c1,
              label: block{v c1}_info
              rep:StackRep [])]
     [(c0, {}), (c3, {})]
     foo() //  []
             { info_tbl: [(c1,
                           label: block{v c1}_info
                           rep:StackRep [])]
               stack_info: arg_space: 8 updfr_space: Just 8
             }
         {offset
           c0: R1 = 0;
               call (P64[Sp])(R1) args: 8, res: 0, upd: 8;
         }
     }

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
 }}}

--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9329
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