[GHC] #5361: regSpill: out of spill slots!

[GHC]

#5361: regSpill: out of spill slots!
-----------------------------------------------------+----------------------
  Reporter:  markwright                              |          Owner:  igloo                    
      Type:  bug                                     |         Status:  closed                   
  Priority:  highest                                 |      Milestone:  7.2.1                    
 Component:  Compiler                                |        Version:  7.1                      
Resolution:  fixed                                   |       Keywords:  regSpill panic impossible
        Os:  Linux                                   |   Architecture:  x86_64 (amd64)           
   Failure:  Compile-time crash                      |     Difficulty:                           
  Testcase:  http://hackage.haskell.org/package/SHA  |      Blockedby:                           
  Blocking:                                          |        Related:                           
-----------------------------------------------------+----------------------
Changes (by Targen):

 * cc: targen@… (added)


Comment:

 This just bit me in 7.7 trying to compile SHA-1.6.1 — same spot, I
 believe:

 {{{
 $ ghc Data/Digest/Pure/SHA.hs -O -fregs-graph
 [1 of 1] Compiling Data.Digest.Pure.SHA ( Data/Digest/Pure/SHA.hs,
 Data/Digest/Pure/SHA.o )
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.7 for i386-unknown-linux):
         regSpill: out of spill slots!
        regs to spill = 1743
        slots left    = 677
 }}}

 The GHC invocation issued by cabal-install was quite longer, of course —
 that’s as minimal as I managed to get it.  There is no error if I remove
 either -O or -fregs-graph.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5361#comment:4>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler