GHC HEAD uses up all memory while compiling `genprimcode`

When attempting to self-bootstrap GHC HEAD I discovered that utils/genprimocode can't be compiled with GHC HEAD.

How to reproduce roughly:

$ cd utils/genprimcode
$ alex --ghc Lexer.x
$ happy --ghc Parser.y
$ ghc-7.11.20151226 --make Main
[1 of 5] Compiling ParserM          ( ParserM.hs, ParserM.o )
[2 of 5] Compiling Lexer            ( Lexer.hs, Lexer.o )
[3 of 5] Compiling Syntax           ( Syntax.hs, Syntax.o )
[4 of 5] Compiling Parser           ( Parser.hs, Parser.o )
[5 of 5] Compiling Main             ( Main.hs, Main.o )
...killed by OS due to running out-of-memory after using up >10GiB ram....

Trac metadata

Trac field	Value
Version	7.11
Type	Bug
TypeOfFailure	OtherFailure
Priority	highest
Resolution	Unresolved
Component	Compiler
Test case
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Architecture