diff --git a/basis/compiler/cfg/linear-scan/allocation/allocation.factor b/basis/compiler/cfg/linear-scan/allocation/allocation.factor
index 8951d7a1f1..ae6c375016 100644
--- a/basis/compiler/cfg/linear-scan/allocation/allocation.factor
+++ b/basis/compiler/cfg/linear-scan/allocation/allocation.factor
@@ -1,4 +1,4 @@
-! Copyright (C) 2008, 2009 Slava Pestov.
+! Copyright (C) 2008, 2010 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: accessors assocs heaps kernel namespaces sequences fry math
 math.order combinators arrays sorting compiler.utilities locals
@@ -38,7 +38,8 @@ IN: compiler.cfg.linear-scan.allocation
     ! If the live interval has a usage at 'n', don't spill it,
     ! since this means its being defined by the sync point
     ! instruction. Output t if this is the case.
-    2dup [ uses>> ] dip swap member? [ 2drop t ] [ spill f ] if ;
+    2dup [ uses>> ] dip '[ n>> _ = ] any?
+    [ 2drop t ] [ spill f ] if ;
 
 : handle-sync-point ( n -- )
     [ active-intervals get values ] dip
diff --git a/basis/compiler/cfg/linear-scan/allocation/spilling/spilling.factor b/basis/compiler/cfg/linear-scan/allocation/spilling/spilling.factor
index 845cb14d5c..a914aab4bf 100644
--- a/basis/compiler/cfg/linear-scan/allocation/spilling/spilling.factor
+++ b/basis/compiler/cfg/linear-scan/allocation/spilling/spilling.factor
@@ -1,4 +1,4 @@
-! Copyright (C) 2009 Slava Pestov.
+! Copyright (C) 2009, 2010 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: accessors arrays assocs combinators fry hints kernel locals
 math sequences sets sorting splitting namespaces linked-assocs
@@ -17,13 +17,13 @@ ERROR: bad-live-ranges interval ;
     ] [ drop ] if ;
 
 : trim-before-ranges ( live-interval -- )
-    [ ranges>> ] [ uses>> last 1 + ] bi
+    [ ranges>> ] [ uses>> last n>> 1 + ] bi
     [ '[ from>> _ <= ] filter! drop ]
     [ swap last (>>to) ]
     2bi ;
 
 : trim-after-ranges ( live-interval -- )
-    [ ranges>> ] [ uses>> first ] bi
+    [ ranges>> ] [ uses>> first n>> ] bi
     [ '[ to>> _ >= ] filter! drop ]
     [ swap first (>>from) ]
     2bi ;
@@ -66,7 +66,8 @@ ERROR: bad-live-ranges interval ;
     split-interval [ spill-before ] [ spill-after ] bi* ;
 
 : find-use-position ( live-interval new -- n )
-    [ uses>> ] [ start>> '[ _ >= ] ] bi* find nip 1/0. or ;
+    [ uses>> ] [ start>> '[ n>> _ >= ] ] bi* find nip
+    [ n>> ] [ 1/0. ] if* ;
 
 : find-use-positions ( live-intervals new assoc -- )
     '[ [ _ find-use-position ] [ reg>> ] bi _ add-use-position ] each ;
@@ -88,7 +89,7 @@ ERROR: bad-live-ranges interval ;
     >alist alist-max ;
 
 : spill-new? ( new pair -- ? )
-    [ uses>> first ] [ second ] bi* > ;
+    [ uses>> first n>> ] [ second ] bi* > ;
 
 : spill-new ( new pair -- )
     drop spill-after add-unhandled ;
diff --git a/basis/compiler/cfg/linear-scan/allocation/splitting/splitting.factor b/basis/compiler/cfg/linear-scan/allocation/splitting/splitting.factor
index 1a2b0f2f2b..b3cba3d90d 100644
--- a/basis/compiler/cfg/linear-scan/allocation/splitting/splitting.factor
+++ b/basis/compiler/cfg/linear-scan/allocation/splitting/splitting.factor
@@ -1,4 +1,4 @@
-! Copyright (C) 2009 Slava Pestov.
+! Copyright (C) 2009, 2010 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: accessors arrays assocs combinators fry hints kernel locals
 math sequences sets sorting splitting namespaces
@@ -25,7 +25,7 @@ IN: compiler.cfg.linear-scan.allocation.splitting
     ] bi ;
 
 : split-uses ( uses n -- before after )
-    '[ _ <= ] partition ;
+    '[ n>> _ <= ] partition ;
 
 ERROR: splitting-too-early ;
 
diff --git a/basis/compiler/cfg/linear-scan/assignment/assignment.factor b/basis/compiler/cfg/linear-scan/assignment/assignment.factor
index c79aa36af1..535f4515eb 100644
--- a/basis/compiler/cfg/linear-scan/assignment/assignment.factor
+++ b/basis/compiler/cfg/linear-scan/assignment/assignment.factor
@@ -1,7 +1,7 @@
-! Copyright (C) 2008, 2009 Slava Pestov.
+! Copyright (C) 2008, 2010 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: accessors kernel math assocs namespaces sequences heaps
-fry make combinators sets locals arrays
+fry make combinators combinators.short-circuit sets locals arrays
 cpu.architecture layouts
 compiler.cfg
 compiler.cfg.def-use
@@ -91,8 +91,16 @@ SYMBOL: register-live-outs
 : insert-reload ( live-interval -- )
     [ reg>> ] [ vreg>> rep-of ] [ reload-from>> ] tri _reload ;
 
+: insert-reload? ( live-interval -- ? )
+    ! Don't insert a reload if the register will be written to
+    ! before being read again.
+    {
+        [ reload-from>> ]
+        [ uses>> first type>> +use+ eq? ]
+    } 1&& ;
+
 : handle-reload ( live-interval -- )
-    dup reload-from>> [ insert-reload ] [ drop ] if ;
+    dup insert-reload? [ insert-reload ] [ drop ] if ;
 
 : activate-interval ( live-interval -- )
     [ add-pending ] [ handle-reload ] bi ;
diff --git a/basis/compiler/cfg/linear-scan/linear-scan-tests.factor b/basis/compiler/cfg/linear-scan/linear-scan-tests.factor
index b3fca6bab7..570c7f9aa7 100644
--- a/basis/compiler/cfg/linear-scan/linear-scan-tests.factor
+++ b/basis/compiler/cfg/linear-scan/linear-scan-tests.factor
@@ -91,7 +91,7 @@ H{
        { vreg 1 }
        { start 0 }
        { end 2 }
-       { uses V{ 0 1 } }
+       { uses V{ T{ vreg-use f 0 } T{ vreg-use f 1 } } }
        { ranges V{ T{ live-range f 0 2 } } }
        { spill-to T{ spill-slot f 0 } }
     }
@@ -99,7 +99,7 @@ H{
        { vreg 1 }
        { start 5 }
        { end 5 }
-       { uses V{ 5 } }
+       { uses V{ T{ vreg-use f 5 } } }
        { ranges V{ T{ live-range f 5 5 } } }
        { reload-from T{ spill-slot f 0 } }
     }
@@ -108,7 +108,7 @@ H{
        { vreg 1 }
        { start 0 }
        { end 5 }
-       { uses V{ 0 1 5 } }
+       { uses V{ T{ vreg-use f 0 } T{ vreg-use f 1 } T{ vreg-use f 5 } } }
        { ranges V{ T{ live-range f 0 5 } } }
     } 2 split-for-spill
 ] unit-test
@@ -118,7 +118,7 @@ H{
        { vreg 2 }
        { start 0 }
        { end 1 }
-       { uses V{ 0 } }
+       { uses V{ T{ vreg-use f 0 } } }
        { ranges V{ T{ live-range f 0 1 } } }
        { spill-to T{ spill-slot f 4 } }
     }
@@ -126,7 +126,7 @@ H{
        { vreg 2 }
        { start 1 }
        { end 5 }
-       { uses V{ 1 5 } }
+       { uses V{ T{ vreg-use f 1 } T{ vreg-use f 5 } } }
        { ranges V{ T{ live-range f 1 5 } } }
        { reload-from T{ spill-slot f 4 } }
     }
@@ -135,7 +135,7 @@ H{
        { vreg 2 }
        { start 0 }
        { end 5 }
-       { uses V{ 0 1 5 } }
+       { uses V{ T{ vreg-use f 0 } T{ vreg-use f 1 } T{ vreg-use f 5 } } }
        { ranges V{ T{ live-range f 0 5 } } }
     } 0 split-for-spill
 ] unit-test
@@ -145,7 +145,7 @@ H{
        { vreg 3 }
        { start 0 }
        { end 1 }
-       { uses V{ 0 } }
+       { uses V{ T{ vreg-use f 0 } } }
        { ranges V{ T{ live-range f 0 1 } } }
        { spill-to T{ spill-slot f 8 } }
     }
@@ -153,7 +153,7 @@ H{
        { vreg 3 }
        { start 20 }
        { end 30 }
-       { uses V{ 20 30 } }
+       { uses V{ T{ vreg-use f 20 } T{ vreg-use f 30 } } }
        { ranges V{ T{ live-range f 20 30 } } }
        { reload-from T{ spill-slot f 8 } }
     }
@@ -162,7 +162,7 @@ H{
        { vreg 3 }
        { start 0 }
        { end 30 }
-       { uses V{ 0 20 30 } }
+       { uses V{ T{ vreg-use f 0 } T{ vreg-use f 20 } T{ vreg-use f 30 } } }
        { ranges V{ T{ live-range f 0 8 } T{ live-range f 10 18 } T{ live-range f 20 30 } } }
     } 10 split-for-spill
 ] unit-test
@@ -187,21 +187,21 @@ H{
                  { reg 1 }
                  { start 1 }
                  { end 15 }
-                 { uses V{ 1 3 7 10 15 } }
+                 { uses V{ T{ vreg-use f 1 } T{ vreg-use f 3 } T{ vreg-use f 7 } T{ vreg-use f 10 } T{ vreg-use f 15 } } }
               }
               T{ live-interval
                  { vreg 2 }
                  { reg 2 }
                  { start 3 }
                  { end 8 }
-                 { uses V{ 3 4 8 } }
+                 { uses V{ T{ vreg-use f 3 } T{ vreg-use f 4 } T{ vreg-use f 8 } } }
               }
               T{ live-interval
                  { vreg 3 }
                  { reg 3 }
                  { start 3 }
                  { end 10 }
-                 { uses V{ 3 10 } }
+                 { uses V{ T{ vreg-use f 3 } T{ vreg-use f 10 } } }
               }
           }
         }
@@ -211,7 +211,7 @@ H{
         { vreg 1 }
         { start 5 }
         { end 5 }
-        { uses V{ 5 } }
+        { uses V{ T{ vreg-use f 5 } } }
     }
     spill-status
 ] unit-test
@@ -230,14 +230,14 @@ H{
                  { reg 1 }
                  { start 1 }
                  { end 15 }
-                 { uses V{ 1 } }
+                 { uses V{ T{ vreg-use f 1 } } }
               }
               T{ live-interval
                  { vreg 2 }
                  { reg 2 }
                  { start 3 }
                  { end 8 }
-                 { uses V{ 3 8 } }
+                 { uses V{ T{ vreg-use f 3 } T{ vreg-use f 8 } } }
               }
           }
         }
@@ -247,7 +247,7 @@ H{
         { vreg 3 }
         { start 5 }
         { end 5 }
-        { uses V{ 5 } }
+        { uses V{ T{ vreg-use f 5 } } }
     }
     spill-status
 ] unit-test
@@ -260,7 +260,7 @@ H{ { 1 int-rep } { 2 int-rep } } representations set
            { vreg 1 }
            { start 0 }
            { end 100 }
-           { uses V{ 0 100 } }
+           { uses V{ T{ vreg-use f 0 } T{ vreg-use f 100 } } }
            { ranges V{ T{ live-range f 0 100 } } }
         }
     }
@@ -274,14 +274,14 @@ H{ { 1 int-rep } { 2 int-rep } } representations set
            { vreg 1 }
            { start 0 }
            { end 10 }
-           { uses V{ 0 10 } }
+           { uses V{ T{ vreg-use f 0 } T{ vreg-use f 10 } } }
            { ranges V{ T{ live-range f 0 10 } } }
         }
         T{ live-interval
            { vreg 2 }
            { start 11 }
            { end 20 }
-           { uses V{ 11 20 } }
+           { uses V{ T{ vreg-use f 11 } T{ vreg-use f 20 } } }
            { ranges V{ T{ live-range f 11 20 } } }
         }
     }
@@ -295,14 +295,14 @@ H{ { 1 int-rep } { 2 int-rep } } representations set
            { vreg 1 }
            { start 0 }
            { end 100 }
-           { uses V{ 0 100 } }
+           { uses V{ T{ vreg-use f 0 } T{ vreg-use f 100 } } }
            { ranges V{ T{ live-range f 0 100 } } }
         }
         T{ live-interval
            { vreg 2 }
            { start 30 }
            { end 60 }
-           { uses V{ 30 60 } }
+           { uses V{ T{ vreg-use f 30 } T{ vreg-use f 60 } } }
            { ranges V{ T{ live-range f 30 60 } } }
         }
     }
@@ -316,14 +316,14 @@ H{ { 1 int-rep } { 2 int-rep } } representations set
            { vreg 1 }
            { start 0 }
            { end 100 }
-           { uses V{ 0 100 } }
+           { uses V{ T{ vreg-use f 0 } T{ vreg-use f 100 } } }
            { ranges V{ T{ live-range f 0 100 } } }
         }
         T{ live-interval
            { vreg 2 }
            { start 30 }
            { end 200 }
-           { uses V{ 30 200 } }
+           { uses V{ T{ vreg-use f 30 } T{ vreg-use f 200 } } }
            { ranges V{ T{ live-range f 30 200 } } }
         }
     }
@@ -337,14 +337,14 @@ H{ { 1 int-rep } { 2 int-rep } } representations set
            { vreg 1 }
            { start 0 }
            { end 100 }
-           { uses V{ 0 100 } }
+           { uses V{ T{ vreg-use f 0 } T{ vreg-use f 100 } } }
            { ranges V{ T{ live-range f 0 100 } } }
         }
         T{ live-interval
            { vreg 2 }
            { start 30 }
            { end 100 }
-           { uses V{ 30 100 } }
+           { uses V{ T{ vreg-use f 30 } T{ vreg-use f 100 } } }
            { ranges V{ T{ live-range f 30 100 } } }
         }
     }
@@ -367,28 +367,28 @@ H{
            { vreg 1 }
            { start 0 }
            { end 20 }
-           { uses V{ 0 10 20 } }
+           { uses V{ T{ vreg-use f 0 } T{ vreg-use f 10 } T{ vreg-use f 20 } } }
            { ranges V{ T{ live-range f 0 2 } T{ live-range f 10 20 } } }
         }
         T{ live-interval
            { vreg 2 }
            { start 0 }
            { end 20 }
-           { uses V{ 0 10 20 } }
+           { uses V{ T{ vreg-use f 0 } T{ vreg-use f 10 } T{ vreg-use f 20 } } }
            { ranges V{ T{ live-range f 0 2 } T{ live-range f 10 20 } } }
         }
         T{ live-interval
            { vreg 3 }
            { start 4 }
            { end 8 }
-           { uses V{ 6 } }
+           { uses V{ T{ vreg-use f 6 } } }
            { ranges V{ T{ live-range f 4 8 } } }
         }
         T{ live-interval
            { vreg 4 }
            { start 4 }
            { end 8 }
-           { uses V{ 8 } }
+           { uses V{ T{ vreg-use f 8 } } }
            { ranges V{ T{ live-range f 4 8 } } }
         }
 
@@ -397,7 +397,7 @@ H{
            { vreg 5 }
            { start 4 }
            { end 8 }
-           { uses V{ 8 } }
+           { uses V{ T{ vreg-use f 8 } } }
            { ranges V{ T{ live-range f 4 8 } } }
         }
     }
@@ -413,7 +413,7 @@ H{
            { vreg 1 }
            { start 0 }
            { end 10 }
-           { uses V{ 0 6 10 } }
+           { uses V{ T{ vreg-use f 0 } T{ vreg-use f 6 } T{ vreg-use f 10 } } }
            { ranges V{ T{ live-range f 0 10 } } }
         }
 
@@ -422,7 +422,7 @@ H{
            { vreg 5 }
            { start 2 }
            { end 8 }
-           { uses V{ 8 } }
+           { uses V{ T{ vreg-use f 8 } } }
            { ranges V{ T{ live-range f 2 8 } } }
         }
     }
@@ -558,7 +558,7 @@ H{
         { start 8 }
         { end 10 }
         { ranges V{ T{ live-range f 8 10 } } }
-        { uses V{ 8 10 } }
+        { uses V{ T{ vreg-use f 8 } T{ vreg-use f 10 } } }
     }
     register-status
 ] unit-test
diff --git a/basis/compiler/cfg/linear-scan/live-intervals/live-intervals.factor b/basis/compiler/cfg/linear-scan/live-intervals/live-intervals.factor
index 00d6f73517..221832e41a 100644
--- a/basis/compiler/cfg/linear-scan/live-intervals/live-intervals.factor
+++ b/basis/compiler/cfg/linear-scan/live-intervals/live-intervals.factor
@@ -1,4 +1,4 @@
-! Copyright (C) 2008, 2009 Slava Pestov.
+! Copyright (C) 2008, 2010 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: namespaces kernel assocs accessors sequences math math.order fry
 combinators binary-search compiler.cfg.instructions compiler.cfg.registers
@@ -10,6 +10,12 @@ TUPLE: live-range from to ;
 
 C: <live-range> live-range
 
+SYMBOLS: +def+ +use+ +memory+ ;
+
+TUPLE: vreg-use n type ;
+
+C: <vreg-use> vreg-use
+
 TUPLE: live-interval
 vreg
 reg spill-to reload-from
@@ -50,18 +56,11 @@ M: live-interval covers? ( insn# live-interval -- ? )
     2dup extend-range?
     [ extend-range ] [ add-new-range ] if ;
 
-GENERIC: operands-in-registers? ( insn -- ? )
-
-M: vreg-insn operands-in-registers? drop t ;
-
-M: partial-sync-insn operands-in-registers? drop f ;
-
-: add-def ( insn live-interval -- )
-    [ insn#>> ] [ uses>> ] bi* push ;
-
-: add-use ( insn live-interval -- )
-    ! Every use is a potential def, no SSA here baby!
-    over operands-in-registers? [ add-def ] [ 2drop ] if ;
+: add-use ( insn live-interval type -- )
+    dup +memory+ eq? [ 3drop ] [
+        swap [ [ insn#>> ] dip <vreg-use> ] dip
+        uses>> push
+    ] if ;
 
 : <live-interval> ( vreg -- live-interval )
     \ live-interval new
@@ -73,9 +72,6 @@ M: partial-sync-insn operands-in-registers? drop f ;
 
 : block-to ( bb -- n ) instructions>> last insn#>> ;
 
-M: live-interval hashcode*
-    nip [ start>> ] [ end>> 1000 * ] bi + ;
-
 ! Mapping from vreg to live-interval
 SYMBOL: live-intervals
 
@@ -86,21 +82,29 @@ GENERIC: compute-live-intervals* ( insn -- )
 
 M: insn compute-live-intervals* drop ;
 
-: handle-output ( insn vreg -- )
-    live-interval
-    [ [ insn#>> ] dip shorten-range ] [ add-def ] 2bi ;
+: handle-output ( insn vreg type -- )
+    [ live-interval ] dip
+    [ drop [ insn#>> ] dip shorten-range ] [ add-use ] 3bi ;
 
-: handle-input ( insn vreg -- )
-    live-interval
-    [ [ [ basic-block get block-from ] dip insn#>> ] dip add-range ] [ add-use ] 2bi ;
+: handle-input ( insn vreg type -- )
+    [ live-interval ] dip
+    [ drop [ [ basic-block get block-from ] dip insn#>> ] dip add-range ]
+    [ add-use ]
+    3bi ;
 
 : handle-temp ( insn vreg -- )
     live-interval
-    [ [ insn#>> dup ] dip add-range ] [ add-use ] 2bi ;
+    [ [ insn#>> dup ] dip add-range ] [ +def+ add-use ] 2bi ;
 
 M: vreg-insn compute-live-intervals*
-    [ dup defs-vreg [ handle-output ] with when* ]
-    [ dup uses-vregs [ handle-input ] with each ]
+    [ dup defs-vreg [ +def+ handle-output ] with when* ]
+    [ dup uses-vregs [ +use+ handle-input ] with each ]
+    [ dup temp-vregs [ handle-temp ] with each ]
+    tri ;
+
+M: partial-sync-insn compute-live-intervals*
+    [ dup defs-vreg [ +use+ handle-output ] with when* ]
+    [ dup uses-vregs [ +memory+ handle-input ] with each ]
     [ dup temp-vregs [ handle-temp ] with each ]
     tri ;