bizarre strictness analysis bug

This module:

module Test where

f :: Int -> Int -> Int
f 0 t = t
f i t = f (i-1) (t+1)

g :: Int -> Int -> Int
g 0 t = t
g i t = g (i-1) (t+1)

contains two identical functions, f and g. If we compile with -O2 -dverbose-core2core using HEAD, GHC derives different strictness for them:

Test.f [Occ=LoopBreaker]
  :: GHC.Types.Int -> GHC.Types.Int -> GHC.Types.Int
 ...
 Str=DmdType U(L)U(L)m,

Test.g [Occ=LoopBreaker]
  :: GHC.Types.Int -> GHC.Types.Int -> GHC.Types.Int
  ...
 Str=DmdType U(L)L,

The strictness on g is wrong (it should be strict in both arguments).

What is even more bizarre is that if you DELETE f, then g gets the correct strictness!

Trac metadata

Trac field	Value
Version	7.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	high
Resolution	Unresolved
Component	Compiler
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