[commit: ghc] wip/tdammers-7258: Performance improvements linear regAlloc (#7258) (19a2ba3)

[git at git.haskell.org]

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

On branch  : wip/tdammers-7258
Link       : http://ghc.haskell.org/trac/ghc/changeset/19a2ba3ea436b60466fc4022f53a6631e41b87a5/ghc

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

commit 19a2ba3ea436b60466fc4022f53a6631e41b87a5
Author: Tobias Dammers <tdammers at gmail.com>
Date:   Mon Oct 16 14:27:40 2017 +0200

    Performance improvements linear regAlloc (#7258)


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

19a2ba3ea436b60466fc4022f53a6631e41b87a5
 compiler/nativeGen/RegAlloc/Linear/Main.hs | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/compiler/nativeGen/RegAlloc/Linear/Main.hs b/compiler/nativeGen/RegAlloc/Linear/Main.hs
index 171ce88..6171d8d 100644
--- a/compiler/nativeGen/RegAlloc/Linear/Main.hs
+++ b/compiler/nativeGen/RegAlloc/Linear/Main.hs
@@ -809,27 +809,29 @@ allocRegsAndSpill_spill reading keep spills alloc r rs assig spill_loc
 
           -- case (3): we need to push something out to free up a register
          [] ->
-           do   let keep' = map getUnique keep
+           do   let inRegOrBoth (InReg _) = True
+                    inRegOrBoth (InBoth _ _) = True
+                    inRegOrBoth _ = False
+                let candidates' =
+                      flip delListFromUFM keep $
+                      filterUFM inRegOrBoth $
+                      assig
+                      -- This is non-deterministic but we do not
+                      -- currently support deterministic code-generation.
+                      -- See Note [Unique Determinism and code generation]
+                let candidates = nonDetUFMToList candidates'
 
                 -- the vregs we could kick out that are already in a slot
                 let candidates_inBoth
                         = [ (temp, reg, mem)
-                          | (temp, InBoth reg mem) <- nonDetUFMToList assig
-                          -- This is non-deterministic but we do not
-                          -- currently support deterministic code-generation.
-                          -- See Note [Unique Determinism and code generation]
-                          , temp `notElem` keep'
+                          | (temp, InBoth reg mem) <- candidates
                           , targetClassOfRealReg platform reg == classOfVirtualReg r ]
 
                 -- the vregs we could kick out that are only in a reg
                 --      this would require writing the reg to a new slot before using it.
                 let candidates_inReg
                         = [ (temp, reg)
-                          | (temp, InReg reg) <- nonDetUFMToList assig
-                          -- This is non-deterministic but we do not
-                          -- currently support deterministic code-generation.
-                          -- See Note [Unique Determinism and code generation]
-                          , temp `notElem` keep'
+                          | (temp, InReg reg) <- candidates
                           , targetClassOfRealReg platform reg == classOfVirtualReg r ]
 
                 let result