diff --git a/basis/compiler/cfg/linear-scan/allocation/allocation.factor b/basis/compiler/cfg/linear-scan/allocation/allocation.factor
index d948fe37ff..4a58064582 100644
--- a/basis/compiler/cfg/linear-scan/allocation/allocation.factor
+++ b/basis/compiler/cfg/linear-scan/allocation/allocation.factor
@@ -25,7 +25,7 @@ IN: compiler.cfg.linear-scan.allocation
         _ add-use-position
     ] each ;
 
-: compute-free-pos ( new -- free-pos )
+: register-status ( new -- free-pos )
     dup free-positions
     [ inactive-positions ] [ active-positions ] [ nip ] 2tri
     >alist alist-max ;
@@ -45,7 +45,7 @@ IN: compiler.cfg.linear-scan.allocation
 
 : assign-register ( new -- )
     dup coalesce? [ coalesce ] [
-        dup compute-free-pos {
+        dup register-status {
             { [ dup no-free-registers? ] [ drop assign-blocked-register ] }
             { [ 2dup register-available? ] [ register-available ] }
             [ register-partially-available ]
diff --git a/basis/compiler/cfg/linear-scan/allocation/spilling/spilling.factor b/basis/compiler/cfg/linear-scan/allocation/spilling/spilling.factor
index 2f4130e9ad..8a671d4455 100644
--- a/basis/compiler/cfg/linear-scan/allocation/spilling/spilling.factor
+++ b/basis/compiler/cfg/linear-scan/allocation/spilling/spilling.factor
@@ -1,7 +1,7 @@
 ! Copyright (C) 2009 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 compiler.utilities
+math sequences sets sorting splitting compiler.utilities namespaces
 compiler.cfg.linear-scan.allocation.state
 compiler.cfg.linear-scan.allocation.splitting
 compiler.cfg.linear-scan.live-intervals ;
@@ -10,42 +10,79 @@ IN: compiler.cfg.linear-scan.allocation.spilling
 : find-use ( live-interval n quot -- elt )
     [ uses>> ] 2dip curry find nip ; inline
 
-: spill-existing? ( new existing -- ? )
-    #! Test if 'new' will be used before 'existing'.
-    over start>> '[ _ [ > ] find-use -1 or ] bi@ < ;
-
 : interval-to-spill ( active-intervals current -- live-interval )
     #! We spill the interval with the most distant use location.
-    start>> '[ dup _ [ >= ] find-use ] { } map>assoc
+    #! If an active interval has no more use positions, find-use
+    #! returns f. This occurs if the interval is a split. In
+    #! this case, we prefer to spill this interval always.
+    start>> '[ dup _ [ >= ] find-use 1/0. or ] { } map>assoc
     alist-max first ;
 
+ERROR: bad-live-ranges interval ;
+
+: check-ranges ( live-interval -- )
+    check-allocation? get [
+        dup ranges>> [ [ from>> ] [ to>> ] bi <= ] all?
+        [ drop ] [ bad-live-ranges ] if
+    ] [ drop ] if ;
+
+: trim-before-ranges ( live-interval n -- )
+    [ ranges>> ] [ uses>> last ] bi
+    [ '[ from>> _ <= ] filter-here ]
+    [ swap last (>>to) ]
+    2bi ;
+
+: trim-after-ranges ( live-interval n -- )
+    [ ranges>> ] [ uses>> first ] bi
+    [ '[ to>> _ >= ] filter-here ]
+    [ swap first (>>from) ]
+    2bi ;
+
 : split-for-spill ( live-interval n -- before after )
     split-interval
-    [
-        [ [ ranges>> last ] [ uses>> last ] bi >>to drop ]
-        [ [ ranges>> first ] [ uses>> first ] bi >>from drop ] bi*
-    ]
-    [ [ compute-start/end ] bi@ ]
-    [ ]
-    2tri ;
+    {
+        [ [ trim-before-ranges ] [ trim-after-ranges ] bi* ]
+        [ [ compute-start/end ] bi@ ]
+        [ [ check-ranges ] bi@ ]
+        [ ]
+    } 2cleave ;
 
-: assign-spill ( before after -- before after )
-    #! If it has been spilled already, reuse spill location.
-    over reload-from>>
-    [ over vreg>> reg-class>> next-spill-location ] unless*
-    [ >>spill-to ] [ >>reload-from ] bi-curry bi* ;
+: assign-spill ( live-interval -- live-interval )
+    dup reload-from>>
+    [ dup vreg>> reg-class>> next-spill-location ] unless*
+    >>spill-to ;
+
+: assign-reload ( before after -- before after )
+    over spill-to>> >>reload-from ;
 
 : split-and-spill ( new existing -- before after )
-    swap start>> split-for-spill assign-spill ;
+    swap start>> split-for-spill assign-spill assign-reload ;
+
+: reuse-register ( new existing -- )
+    [ nip delete-active ]
+    [ reg>> >>reg add-active ] 2bi ;
+
+: spill-existing? ( new existing -- ? )
+    #! Test if 'new' will be used before 'existing'.
+    over start>> '[ _ [ > ] find-use -1 or ] bi@ < ;
 
 : spill-existing ( new existing -- )
     #! Our new interval will be used before the active interval
     #! with the most distant use location. Spill the existing
     #! interval, then process the new interval and the tail end
     #! of the existing interval again.
-    [ nip delete-active ]
-    [ reg>> >>reg add-active ]
-    [ split-and-spill [ add-handled ] [ add-unhandled ] bi* ] 2tri ;
+    [ reuse-register ]
+    [ split-and-spill [ add-handled ] [ add-unhandled ] bi* ] 2bi ;
+
+: spill-live-out? ( new existing -- ? )
+    [ start>> ] [ uses>> last ] bi* > ;
+
+: spill-live-out ( new existing -- )
+    #! The existing interval is never used again. Spill it and
+    #! re-use the register.
+    assign-spill
+    [ reuse-register ]
+    [ nip add-handled ] 2bi ;
 
 : spill-new ( new existing -- )
     #! Our new interval will be used after the active interval
@@ -55,6 +92,9 @@ IN: compiler.cfg.linear-scan.allocation.spilling
     [ dup split-and-spill add-unhandled ] dip spill-existing ;
 
 : assign-blocked-register ( new -- )
-    [ dup vreg>> active-intervals-for ] keep interval-to-spill
-    2dup spill-existing? [ spill-existing ] [ spill-new ] if ;
+    [ dup vreg>> active-intervals-for ] keep interval-to-spill {
+        { [ 2dup spill-live-out? ] [ spill-live-out ] }
+        { [ 2dup spill-existing? ] [ spill-existing ] }
+        [ spill-new ]
+    } cond ;
 
diff --git a/basis/compiler/cfg/linear-scan/assignment/assignment.factor b/basis/compiler/cfg/linear-scan/assignment/assignment.factor
index ab03882757..745146b56e 100644
--- a/basis/compiler/cfg/linear-scan/assignment/assignment.factor
+++ b/basis/compiler/cfg/linear-scan/assignment/assignment.factor
@@ -50,8 +50,11 @@ ERROR: already-spilled ;
 : handle-spill ( live-interval -- )
     dup spill-to>> [ [ record-spill ] [ insert-spill ] bi ] [ drop ] if ;
 
+: first-split ( live-interval -- live-interval' )
+    dup split-before>> [ first-split ] [ ] ?if ;
+
 : next-interval ( live-interval -- live-interval' )
-    split-next>> dup split-before>> [ next-interval ] [ ] ?if ;
+    split-next>> first-split ;
 
 : insert-copy ( live-interval -- )
     {
diff --git a/basis/compiler/cfg/linear-scan/linear-scan-tests.factor b/basis/compiler/cfg/linear-scan/linear-scan-tests.factor
index 5d11e2a5a0..65778a3e7b 100644
--- a/basis/compiler/cfg/linear-scan/linear-scan-tests.factor
+++ b/basis/compiler/cfg/linear-scan/linear-scan-tests.factor
@@ -156,6 +156,31 @@ check-assignment? on
     } 0 split-for-spill [ f >>split-next ] bi@
 ] unit-test
 
+[
+    T{ live-interval
+       { vreg T{ vreg { reg-class int-regs } { n 1 } } }
+       { start 0 }
+       { end 0 }
+       { uses V{ 0 } }
+       { ranges V{ T{ live-range f 0 0 } } }
+    }
+    T{ live-interval
+       { vreg T{ vreg { reg-class int-regs } { n 1 } } }
+       { start 20 }
+       { end 30 }
+       { uses V{ 20 30 } }
+       { ranges V{ T{ live-range f 20 30 } } }
+    }
+] [
+    T{ live-interval
+       { vreg T{ vreg { reg-class int-regs } { n 1 } } }
+       { start 0 }
+       { end 30 }
+       { uses V{ 0 20 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 [ f >>split-next ] bi@
+] unit-test
+
 [
     T{ live-interval
         { vreg T{ vreg { reg-class int-regs } { n 1 } } }
@@ -1419,7 +1444,7 @@ USING: math.private ;
     relevant-ranges intersect-live-ranges
 ] unit-test
 
-! compute-free-pos had problems because it used map>assoc where the sequence
+! register-status had problems because it used map>assoc where the sequence
 ! had multiple keys
 [ { 0 10 } ] [
     H{ { int-regs { 0 1 } } } registers set
@@ -1468,7 +1493,7 @@ USING: math.private ;
         { ranges V{ T{ live-range f 8 10 } } }
         { uses V{ 8 10 } }
     }
-    compute-free-pos
+    register-status
 ] unit-test
 
 ! Bug in live spill slots calculation
@@ -1531,18 +1556,16 @@ V{
 SYMBOL: linear-scan-result
 
 :: test-linear-scan-on-cfg ( regs -- )
-    [ ] [
-        cfg new 0 get >>entry
-        compute-predecessors
-        compute-liveness
-        dup reverse-post-order
-        { { int-regs regs } } (linear-scan)
-        flatten-cfg 1array mr.
-    ] unit-test ;
+    cfg new 0 get >>entry
+    compute-predecessors
+    compute-liveness
+    dup reverse-post-order
+    { { int-regs regs } } (linear-scan)
+    flatten-cfg 1array mr. ;
 
 ! This test has a critical edge -- do we care about these?
 
-! { 1 2 } test-linear-scan-on-cfg
+! [ { 1 2 } test-linear-scan-on-cfg ] unit-test
 
 ! Bug in inactive interval handling
 ! [ rot dup [ -rot ] when ]
@@ -1619,7 +1642,7 @@ V{
 
 test-diamond
 
-{ 1 2 3 4 } test-linear-scan-on-cfg
+[ ] [ { 1 2 3 4 } test-linear-scan-on-cfg ] unit-test
 
 ! Similar to the above
 ! [ swap dup [ rot ] when ]
@@ -1705,7 +1728,7 @@ V{
 
 test-diamond
 
-{ 1 2 3 4 } test-linear-scan-on-cfg
+[ ] [ { 1 2 3 4 } test-linear-scan-on-cfg ] unit-test
 
 ! compute-live-registers was inaccurate since it didn't take
 ! lifetime holes into account
@@ -1758,7 +1781,7 @@ V{
 
 test-diamond
 
-{ 1 2 3 4 } test-linear-scan-on-cfg
+[ ] [ { 1 2 3 4 } test-linear-scan-on-cfg ] unit-test
 
 ! Inactive interval handling: splitting active interval
 ! if it fits in lifetime hole only partially
@@ -1791,7 +1814,7 @@ V{
 
 test-diamond
 
-{ 1 2 } test-linear-scan-on-cfg
+[ ] [ { 1 2 } test-linear-scan-on-cfg ] unit-test
 
 USING: classes ;
 
@@ -1830,7 +1853,7 @@ V{
 
 test-diamond
 
-{ 1 2 } test-linear-scan-on-cfg
+[ ] [ { 1 2 } test-linear-scan-on-cfg ] unit-test
 
 [ _spill ] [ 2 get instructions>> first class ] 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 c67a7bb021..ca8140f1c6 100644
--- a/basis/compiler/cfg/linear-scan/live-intervals/live-intervals.factor
+++ b/basis/compiler/cfg/linear-scan/live-intervals/live-intervals.factor
@@ -1,7 +1,7 @@
 ! Copyright (C) 2008, 2009 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: namespaces kernel assocs accessors sequences math math.order fry
-binary-search combinators compiler.cfg.instructions compiler.cfg.registers
+combinators compiler.cfg.instructions compiler.cfg.registers
 compiler.cfg.def-use compiler.cfg.liveness compiler.cfg ;
 IN: compiler.cfg.linear-scan.live-intervals
 
diff --git a/basis/compiler/cfg/linear-scan/resolve/resolve-tests.factor b/basis/compiler/cfg/linear-scan/resolve/resolve-tests.factor
index feb9ac2504..f2d71691aa 100644
--- a/basis/compiler/cfg/linear-scan/resolve/resolve-tests.factor
+++ b/basis/compiler/cfg/linear-scan/resolve/resolve-tests.factor
@@ -40,11 +40,11 @@ T{ live-interval
 }
 
 [ f ] [
-    0 get test-live-interval-1 spill-to
+    test-live-interval-1 0 get spill-to
 ] unit-test
 
 [ 0 ] [
-    1 get test-live-interval-1 spill-to
+    test-live-interval-1 1 get spill-to
 ] unit-test
 
 CONSTANT: test-live-interval-2
@@ -58,11 +58,11 @@ T{ live-interval
 }
 
 [ 0 ] [
-    0 get test-live-interval-2 reload-from
+    test-live-interval-2 0 get reload-from
 ] unit-test
 
 [ f ] [
-    1 get test-live-interval-2 reload-from
+    test-live-interval-2 1 get reload-from
 ] unit-test
 
 [
@@ -136,10 +136,14 @@ T{ live-interval
 ] unit-test
 
 [
-    { T{ _spill { src 4 } { class int-regs } { n spill-temp } } }
+    {
+        T{ _spill { src 3 } { class int-regs } { n 4 } }
+        T{ _reload { dst 2 } { class int-regs } { n 1 } } 
+    }
 ] [
     {
-       T{ register->memory { from 4 } { to 4 } { reg-class int-regs } }
+       T{ register->memory { from 3 } { to 4 } { reg-class int-regs } }
+       T{ memory->register { from 1 } { to 2 } { reg-class int-regs } }
     } mapping-instructions
 ] unit-test
 
diff --git a/basis/compiler/cfg/linear-scan/resolve/resolve.factor b/basis/compiler/cfg/linear-scan/resolve/resolve.factor
index bd7528291d..7681b811c4 100644
--- a/basis/compiler/cfg/linear-scan/resolve/resolve.factor
+++ b/basis/compiler/cfg/linear-scan/resolve/resolve.factor
@@ -25,13 +25,16 @@ SYNTAX: OPERATION:
 
 >>
 
-: reload-from ( bb live-interval -- n/f )
-    2dup [ block-from ] [ start>> ] bi* =
-    [ nip reload-from>> ] [ 2drop f ] if ;
+: insn-in-block? ( insn# bb -- ? )
+    [ block-from ] [ block-to ] bi between? ;
 
-: spill-to ( bb live-interval -- n/f )
-    2dup [ block-to ] [ end>> ] bi* =
-    [ nip spill-to>> ] [ 2drop f ] if ;
+: reload-from ( live-interval bb -- n/f )
+    2dup [ start>> ] dip insn-in-block?
+    [ drop reload-from>> ] [ 2drop f ] if ;
+
+: spill-to ( live-interval bb -- n/f )
+    2dup [ end>> ] dip insn-in-block?
+    [ drop spill-to>> ] [ 2drop f ] if ;
 
 OPERATION: memory->memory spill-to>> reload-from>>
 OPERATION: register->memory reg>> reload-from>>
@@ -39,12 +42,12 @@ OPERATION: memory->register spill-to>> reg>>
 OPERATION: register->register reg>> reg>>
 
 :: add-mapping ( bb1 bb2 li1 li2 -- )
-    bb2 li2 reload-from [
-        bb1 li1 spill-to
+    li2 bb2 reload-from [
+        li1 bb1 spill-to
         [ li1 li2 memory->memory ]
         [ li1 li2 register->memory ] if
     ] [
-        bb1 li1 spill-to
+        li1 bb1 spill-to
         [ li1 li2 memory->register ]
         [ li1 li2 register->register ] if
     ] if ;
@@ -68,10 +71,10 @@ M: memory->memory >insn
     [ from>> ] [ to>> ] bi = [ "Not allowed" throw ] unless ;
 
 M: register->memory >insn
-    [ from>> ] [ reg-class>> ] bi spill-temp _spill ;
+    [ from>> ] [ reg-class>> ] [ to>> ] tri _spill ;
 
 M: memory->register >insn
-    [ to>> ] [ reg-class>> ] bi spill-temp _reload ;
+    [ to>> ] [ reg-class>> ] [ from>> ] tri  _reload ;
 
 M: register->register >insn
     [ to>> ] [ from>> ] [ reg-class>> ] tri _copy ;
@@ -82,10 +85,10 @@ M: memory->memory >collision-table
     [ from>> ] [ to>> ] bi = [ "Not allowed" throw ] unless ;
 
 M: register->memory >collision-table
-    [ from>> ] [ reg-class>> ] bi spill-temp _spill ;
+    [ from>> ] [ reg-class>> ] [ to>> ] tri _spill ;
 
 M: memory->register >collision-table
-    [ to>> ] [ reg-class>> ] bi spill-temp _reload ;
+    [ to>> ] [ reg-class>> ] [ from>> ] tri _reload ;
 
 M: register->register >collision-table
     [ to>> ] [ from>> ] [ reg-class>> ] tri _copy ;