panic in new integer switch logic with "out-of-range" literals

Compiling this module

module D (f) where
f :: Int -> String
f n = case n of
  0x8000000000000000 -> "yes"
  _ -> "no"

crashes with the error

[1 of 1] Compiling D                ( /tmp/D.hs, /tmp/D.o )
ghc-stage1: panic! (the 'impossible' happened)
  (GHC version 7.11.20150403 for x86_64-unknown-linux):
	Map.findMin: empty map has no minimal element

The constant does not have to be exactly 0x8000000000000000, everything I tested from there up to 0xffffffffffffffff yields the same crash. Also occurs with Word and negative literals.

The bug seems to be tied to the target's word size somehow, though: a 64-bit compiler does not panic on Int32 and 0x80000000, but a 32-bit compiler does.

Trac metadata

Trac field	Value
Version	7.11
Type	Bug
TypeOfFailure	CompileTimeCrash
Priority	high
Resolution	Unresolved
Component	Compiler (CodeGen)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	nomeata, simonmar
Operating system
Architecture