[commit: ghc] master: bugfix: coalescing moves from RealReg to VirtualReg got broken at some point (b5c84a1)

[Simon Marlow]

Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/b5c84a16f4f92a486c63d90d0d00796c884b361c

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

commit b5c84a16f4f92a486c63d90d0d00796c884b361c
Author: Simon Marlow <marlowsd at gmail.com>
Date:   Fri Jul 6 13:20:44 2012 +0100

    bugfix: coalescing moves from RealReg to VirtualReg got broken at some point

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

 compiler/nativeGen/RegAlloc/Linear/Main.hs |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/compiler/nativeGen/RegAlloc/Linear/Main.hs b/compiler/nativeGen/RegAlloc/Linear/Main.hs
index 8c38fd1..b2da1f9 100644
--- a/compiler/nativeGen/RegAlloc/Linear/Main.hs
+++ b/compiler/nativeGen/RegAlloc/Linear/Main.hs
@@ -385,7 +385,7 @@ raInsn platform block_live new_instrs id (LiveInstr (Instr instr) (Just live))
         Just (src,dst)  | src `elementOfUniqSet` (liveDieRead live),
                           isVirtualReg dst,
                           not (dst `elemUFM` assig),
-                          Just (InReg _) <- (lookupUFM assig src) -> do
+                          isRealReg src || isInReg src assig -> do
            case src of
               (RegReal rr) -> setAssigR (addToUFM assig dst (InReg rr))
                 -- if src is a fixed reg, then we just map dest to this
@@ -414,6 +414,11 @@ raInsn _ _ _ _ instr
         = pprPanic "raInsn" (text "no match for:" <> ppr instr)
 
 
+isInReg :: Reg -> RegMap Loc -> Bool
+isInReg src assig | Just (InReg _) <- lookupUFM assig src = True
+                  | otherwise = False
+
+
 genRaInsn :: (FR freeRegs, Instruction instr, Outputable instr)
           => Platform
           -> BlockMap RegSet