[commit: ghc] master: Kill redundant patterns (0dd61fe)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/0dd61fe72144a829a9e5bb87a1094244e53cdebb/ghc

>---------------------------------------------------------------

commit 0dd61fe72144a829a9e5bb87a1094244e53cdebb
Author: Ben Gamari <ben at smart-cactus.org>
Date:   Thu Dec 3 13:43:39 2015 -0500

    Kill redundant patterns
    
    George's new exhaustiveness checker now realizes these are impossible.
    Yay!


>---------------------------------------------------------------

0dd61fe72144a829a9e5bb87a1094244e53cdebb
 compiler/cmm/Hoopl/Dataflow.hs            | 5 -----
 compiler/nativeGen/RegAlloc/Graph/Main.hs | 3 ---
 compiler/nativeGen/RegAlloc/Liveness.hs   | 2 --
 3 files changed, 10 deletions(-)

diff --git a/compiler/cmm/Hoopl/Dataflow.hs b/compiler/cmm/Hoopl/Dataflow.hs
index 29c7afe..beaf6bc 100644
--- a/compiler/cmm/Hoopl/Dataflow.hs
+++ b/compiler/cmm/Hoopl/Dataflow.hs
@@ -163,7 +163,6 @@ arfGraph pass at FwdPass { fp_lattice = lattice,
                 -> Fact e f -> UniqSM (DG f n e C, Fact C f)
              c NothingC (JustO entry)   f = (block entry `cat` body (successors entry) bdy) f
              c (JustC entries) NothingO f = body entries bdy f
-             c _ _ _ = error "bogus GADT pattern match failure"
 
     -- Lift from nodes to blocks
     block BNil            f = return (dgnil, f)
@@ -253,7 +252,6 @@ analyzeFwd FwdPass { fp_lattice = lattice,
       = case (entries, entry) of
          (NothingC, JustO entry)   -> block entry `cat` body (successors entry)
          (JustC entries, NothingO) -> body entries
-         _ -> error "bogus GADT pattern match failure"
      where
        body  :: [Label] -> Fact C f -> Fact C f
        body entries f
@@ -296,7 +294,6 @@ analyzeFwdBlocks FwdPass { fp_lattice = lattice,
       = case (entries, entry) of
          (NothingC, JustO entry)   -> block entry `cat` body (successors entry)
          (JustC entries, NothingO) -> body entries
-         _ -> error "bogus GADT pattern match failure"
      where
        body  :: [Label] -> Fact C f -> Fact C f
        body entries f
@@ -339,7 +336,6 @@ analyzeBwd BwdPass { bp_lattice = lattice,
       = case (entries, entry) of
          (NothingC, JustO entry)   -> body (successors entry)
          (JustC entries, NothingO) -> body entries
-         _ -> error "bogus GADT pattern match failure"
      where
        body  :: [Label] -> Fact C f -> Fact C f
        body entries f
@@ -429,7 +425,6 @@ arbGraph pass at BwdPass { bp_lattice  = lattice,
                 -> Fact C f -> UniqSM (DG f n e C, Fact e f)
              c NothingC (JustO entry)   f = (block entry `cat` body (successors entry) bdy) f
              c (JustC entries) NothingO f = body entries bdy f
-             c _ _ _ = error "bogus GADT pattern match failure"
 
     -- Lift from nodes to blocks
     block BNil            f = return (dgnil, f)
diff --git a/compiler/nativeGen/RegAlloc/Graph/Main.hs b/compiler/nativeGen/RegAlloc/Graph/Main.hs
index 05db68d..8d5a4db 100644
--- a/compiler/nativeGen/RegAlloc/Graph/Main.hs
+++ b/compiler/nativeGen/RegAlloc/Graph/Main.hs
@@ -355,9 +355,6 @@ graphAddCoalesce (r1, r2) graph
         , RegReal _             <- r2
         = graph
 
-graphAddCoalesce _ _
-        = panic "graphAddCoalesce: bogus"
-
 
 -- | Patch registers in code using the reg -> reg mapping in this graph.
 patchRegsFromGraph
diff --git a/compiler/nativeGen/RegAlloc/Liveness.hs b/compiler/nativeGen/RegAlloc/Liveness.hs
index 167197d..c1c2e3c 100644
--- a/compiler/nativeGen/RegAlloc/Liveness.hs
+++ b/compiler/nativeGen/RegAlloc/Liveness.hs
@@ -909,8 +909,6 @@ livenessForward platform rsLiveEntry (li@(LiveInstr instr mLive) : lis)
         in LiveInstr instr (Just live { liveBorn = rsBorn })
                 : livenessForward platform rsLiveNext lis
 
-livenessForward _ _ _             = panic "RegLiveness.livenessForward: no match"
-
 
 -- | Calculate liveness going backwards,
 --   filling in when regs die, and what regs are live across each instruction