Using old code generator

Simon Peyton-Jones simonpj at
Fri Apr 12 12:32:36 CEST 2013

I believe that the old codegen is gone altogether.

Please add to the ticket to say that it blocks compilation of a particular package (with instructions for how to reproduce). Is this an important package?

Someone should just fix the codegen!  Any volunteers?  Simon left some breadcrumbs and I'm sure would help.


| -----Original Message-----
| From: glasgow-haskell-users-bounces at [mailto:glasgow-haskell-
| users-bounces at] On Behalf Of Roman Cheplyaka
| Sent: 12 April 2013 11:27
| To: glasgow-haskell-users at
| Subject: Using old code generator
| Hi,
| I'm looking for a workaround for #7574 [1] (I run into it when trying to
| build the 'statistics' package with profiling enabled with GHC HEAD.)
| The symptom is
|   ghc-stage2: panic! (the 'impossible' happened)
|     (GHC version 7.7.20130407 for i386-unknown-linux):
|     allocateRegsAndSpill: Cannot read from uninitialized register
|       %vI_cCdO
| [1]:
| Do I understand correctly that this bug is specific to the new codegen?
| If so, is it possible to ask the compiler to use the old codegen?
| Is it okay to mix together packages compiled with both codegens?
| Thanks,
| Roman
| _______________________________________________
| Glasgow-haskell-users mailing list
| Glasgow-haskell-users at

More information about the Glasgow-haskell-users mailing list