diff --git a/basis/checksums/fnv1/authors.txt b/basis/checksums/fnv1/authors.txt
new file mode 100644
index 0000000000..c64bb4e735
--- /dev/null
+++ b/basis/checksums/fnv1/authors.txt
@@ -0,0 +1 @@
+Alaric Snell-Pym
\ No newline at end of file
diff --git a/basis/checksums/fnv1/fnv1-docs.factor b/basis/checksums/fnv1/fnv1-docs.factor
new file mode 100644
index 0000000000..4fbecd2b75
--- /dev/null
+++ b/basis/checksums/fnv1/fnv1-docs.factor
@@ -0,0 +1,67 @@
+USING: help.markup help.syntax ;
+IN: checksums.fnv1
+
+HELP: fnv1-32
+{ $class-description "Fowler-Noll-Vo checksum algorithm, v1, 32-bit." } ;
+
+HELP: fnv1a-32
+{ $class-description "Fowler-Noll-Vo checksum algorithm, v1a, 32-bit." } ;
+
+
+HELP: fnv1-64
+{ $class-description "Fowler-Noll-Vo checksum algorithm, v1, 64-bit." } ;
+
+HELP: fnv1a-64
+{ $class-description "Fowler-Noll-Vo checksum algorithm, v1a, 64-bit." } ;
+
+
+HELP: fnv1-128
+{ $class-description "Fowler-Noll-Vo checksum algorithm, v1, 128-bit." } ;
+
+HELP: fnv1a-128
+{ $class-description "Fowler-Noll-Vo checksum algorithm, v1a, 128-bit." } ;
+
+
+HELP: fnv1-256
+{ $class-description "Fowler-Noll-Vo checksum algorithm, v1, 256-bit." } ;
+
+HELP: fnv1a-256
+{ $class-description "Fowler-Noll-Vo checksum algorithm, v1a, 256-bit." } ;
+
+
+HELP: fnv1-512
+{ $class-description "Fowler-Noll-Vo checksum algorithm, v1, 512-bit." } ;
+
+HELP: fnv1a-512
+{ $class-description "Fowler-Noll-Vo checksum algorithm, v1a, 512-bit." } ;
+
+
+HELP: fnv1-1024
+{ $class-description "Fowler-Noll-Vo checksum algorithm, v1, 1024-bit." } ;
+
+HELP: fnv1a-1024
+{ $class-description "Fowler-Noll-Vo checksum algorithm, v1a, 1024-bit." } ;
+
+ARTICLE: "checksums.fnv1" "Fowler-Noll-Vo checksum"
+  "The Fowler-Noll-Vo checksum algorithm is another simple and fast checksum. It comes in 32, 64, 128, 256, 512 and 1024-bit versions, each in 1 and 1a variants. The 1a variants tend to produce a slightly better result. See http://en.wikipedia.org/wiki/Fowler_Noll_Vo_hash for more details."
+
+  { $subsection fnv1-32 }
+  { $subsection fnv1a-32 }
+
+  { $subsection fnv1-64 }
+  { $subsection fnv1a-64 }
+
+  { $subsection fnv1-128 }
+  { $subsection fnv1a-128 }
+
+  { $subsection fnv1-256 }
+  { $subsection fnv1a-256 }
+
+  { $subsection fnv1-512 }
+  { $subsection fnv1a-512 }
+
+  { $subsection fnv1-1024 }
+  { $subsection fnv1a-1024 }
+ ;
+
+ABOUT: "checksums.fnv1"
diff --git a/basis/checksums/fnv1/fnv1-tests.factor b/basis/checksums/fnv1/fnv1-tests.factor
new file mode 100644
index 0000000000..de665a1547
--- /dev/null
+++ b/basis/checksums/fnv1/fnv1-tests.factor
@@ -0,0 +1,41 @@
+USING: checksums.fnv1 checksums strings tools.test ;
+IN: checksums.fnv1.tests
+
+! A few test vectors taken from http://www.isthe.com/chongo/src/fnv/test_fnv.c
+
+[ HEX: 811c9dc5 ] [ "" fnv1-32 checksum-bytes ] unit-test
+[ HEX: 811c9dc5 ] [ "" fnv1a-32 checksum-bytes ] unit-test
+[ HEX: cbf29ce484222325 ] [ "" fnv1-64 checksum-bytes ] unit-test
+[ HEX: cbf29ce484222325 ] [ "" fnv1a-64 checksum-bytes ] unit-test
+
+[ HEX: 050c5d7e ] [ "a" fnv1-32 checksum-bytes ] unit-test
+[ HEX: e40c292c ] [ "a" fnv1a-32 checksum-bytes ] unit-test
+[ HEX: af63bd4c8601b7be ] [ "a" fnv1-64 checksum-bytes ] unit-test
+[ HEX: af63dc4c8601ec8c ] [ "a" fnv1a-64 checksum-bytes ] unit-test
+
+[ HEX: 050c5d7d ] [ "b" fnv1-32 checksum-bytes ] unit-test
+[ HEX: e70c2de5 ] [ "b" fnv1a-32 checksum-bytes ] unit-test
+[ HEX: af63bd4c8601b7bd ] [ "b" fnv1-64 checksum-bytes ] unit-test
+[ HEX: af63df4c8601f1a5 ] [ "b" fnv1a-64 checksum-bytes ] unit-test
+
+[ HEX: 31f0b262 ] [ "foobar" fnv1-32 checksum-bytes ] unit-test
+[ HEX: bf9cf968 ] [ "foobar" fnv1a-32 checksum-bytes ] unit-test
+[ HEX: 340d8765a4dda9c2 ] [ "foobar" fnv1-64 checksum-bytes ] unit-test
+[ HEX: 85944171f73967e8 ] [ "foobar" fnv1a-64 checksum-bytes ] unit-test
+
+! I couldn't find any test vectors for 128, 256, 512, or 1024 versions of FNV1 hashes.
+! So, just to check that your maths works the same as my maths, here's a few samples computed on my laptop.
+! So they may be right or wrong, but either way, them failing is cause for concern somewhere...
+
+[ 3897470310 ] [ "Hello, world!" fnv1-32 checksum-bytes ] unit-test
+[ 3985698964 ] [ "Hello, world!" fnv1a-32 checksum-bytes ] unit-test
+[ 7285062107457560934 ] [ "Hello, world!" fnv1-64 checksum-bytes ] unit-test
+[ 4094109891673226228 ] [ "Hello, world!" fnv1a-64 checksum-bytes ] unit-test
+[ 281580511747867177735318995358496831158 ] [ "Hello, world!" fnv1-128 checksum-bytes ] unit-test
+[ 303126633380056630368940439484674414572 ] [ "Hello, world!" fnv1a-128 checksum-bytes ] unit-test
+[ 104295939182568077644846978685759236849634734810631820736486253421270219742822 ] [ "Hello, world!" fnv1-256 checksum-bytes ] unit-test
+[ 9495445728692795332446740615588417456874414534608540692485745371050033741380 ] [ "Hello, world!" fnv1a-256 checksum-bytes ] unit-test
+[ 3577308325596719252093726711895047340166329831006673109476042102918876665433235513101496175651226507162015890004121912850661561110326527625579463564626958 ] [ "Hello, world!" fnv1-512 checksum-bytes ] unit-test
+[ 3577308325596719162840652138474318309664256091923081930027929425092517582111473988451078821416039944023089883981242376700859598441397004715365740906054208 ] [ "Hello, world!" fnv1a-512 checksum-bytes ] unit-test
+[ 52692754922840008511959888105094366091401994235075816792707658326855733053286986999719949898492311786648795846192078757217437117165934438286601534984230194601365788544275827382423366672856972872132009691615382991251544423521887009322211754219117294019951276080952271766377222613325328591830596794468813260226 ] [ "Hello, world!" fnv1-1024 checksum-bytes ] unit-test
+[ 52692754922840008511959888105094366091401994235075816792707658326855804920671100511873485674717442819607149127986090276849364757610838433887624184145636764448608707614141109841761957788887305179569455221243999538336208648824673027111352338809582124430199044921035232455717748500524777795242051756321605065326 ] [ "Hello, world!" fnv1a-1024 checksum-bytes ] unit-test
diff --git a/basis/checksums/fnv1/fnv1.factor b/basis/checksums/fnv1/fnv1.factor
new file mode 100644
index 0000000000..f221cefef2
--- /dev/null
+++ b/basis/checksums/fnv1/fnv1.factor
@@ -0,0 +1,106 @@
+! Copyright (C) 2009 Alaric Snell-Pym
+! See http://factorcode.org/license.txt for BSD license.
+
+USING: checksums classes.singleton kernel math math.ranges
+math.vectors sequences ;
+
+IN: checksums.fnv1
+
+SINGLETON: fnv1-32
+SINGLETON: fnv1a-32
+SINGLETON: fnv1-64
+SINGLETON: fnv1a-64
+SINGLETON: fnv1-128
+SINGLETON: fnv1a-128
+SINGLETON: fnv1-256
+SINGLETON: fnv1a-256
+SINGLETON: fnv1-512
+SINGLETON: fnv1a-512
+SINGLETON: fnv1-1024
+SINGLETON: fnv1a-1024
+
+CONSTANT: fnv1-32-prime 16777619
+CONSTANT: fnv1-64-prime 1099511628211
+CONSTANT: fnv1-128-prime 309485009821345068724781371
+CONSTANT: fnv1-256-prime 374144419156711147060143317175368453031918731002211
+CONSTANT: fnv1-512-prime 35835915874844867368919076489095108449946327955754392558399825615420669938882575126094039892345713852759
+CONSTANT: fnv1-1024-prime 5016456510113118655434598811035278955030765345404790744303017523831112055108147451509157692220295382716162651878526895249385292291816524375083746691371804094271873160484737966720260389217684476157468082573
+
+CONSTANT: fnv1-32-mod HEX: ffffffff
+CONSTANT: fnv1-64-mod HEX: ffffffffffffffff
+CONSTANT: fnv1-128-mod HEX: ffffffffffffffffffffffffffffffff
+CONSTANT: fnv1-256-mod HEX: ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
+CONSTANT: fnv1-512-mod HEX: ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
+CONSTANT: fnv1-1024-mod HEX: ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
+
+CONSTANT: fnv1-32-basis HEX: 811c9dc5
+CONSTANT: fnv1-64-basis HEX: cbf29ce484222325
+CONSTANT: fnv1-128-basis HEX: 6c62272e07bb014262b821756295c58d
+CONSTANT: fnv1-256-basis HEX: dd268dbcaac550362d98c384c4e576ccc8b1536847b6bbb31023b4c8caee0535
+CONSTANT: fnv1-512-basis HEX: b86db0b1171f4416dca1e50f309990acac87d059c90000000000000000000d21e948f68a34c192f62ea79bc942dbe7ce182036415f56e34bac982aac4afe9fd9
+CONSTANT: fnv1-1024-basis HEX: 5f7a76758ecc4d32e56d5a591028b74b29fc4223fdada16c3bf34eda3674da9a21d9000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000004c6d7eb6e73802734510a555f256cc005ae556bde8cc9c6a93b21aff4b16c71ee90b3
+
+M: fnv1-32 checksum-bytes ( bytes checksum -- value )
+    drop
+    fnv1-32-basis swap
+    [ swap fnv1-32-prime * bitxor fnv1-32-mod bitand ] each ;
+
+M: fnv1a-32 checksum-bytes ( bytes checksum -- value )
+    drop
+    fnv1-32-basis swap
+    [ bitxor fnv1-32-prime * fnv1-32-mod bitand ] each ;
+
+
+M: fnv1-64 checksum-bytes ( bytes checksum -- value )
+    drop
+    fnv1-64-basis swap
+    [ swap fnv1-64-prime * bitxor fnv1-64-mod bitand ] each ;
+
+M: fnv1a-64 checksum-bytes ( bytes checksum -- value )
+    drop
+    fnv1-64-basis swap
+    [ bitxor fnv1-64-prime * fnv1-64-mod bitand ] each ;
+
+
+M: fnv1-128 checksum-bytes ( bytes checksum -- value )
+    drop
+    fnv1-128-basis swap
+    [ swap fnv1-128-prime * bitxor fnv1-128-mod bitand ] each ;
+
+M: fnv1a-128 checksum-bytes ( bytes checksum -- value )
+    drop
+    fnv1-128-basis swap
+    [ bitxor fnv1-128-prime * fnv1-128-mod bitand ] each ;
+
+
+M: fnv1-256 checksum-bytes ( bytes checksum -- value )
+    drop
+    fnv1-256-basis swap
+    [ swap fnv1-256-prime * bitxor fnv1-256-mod bitand ] each ;
+
+M: fnv1a-256 checksum-bytes ( bytes checksum -- value )
+    drop
+    fnv1-256-basis swap
+    [ bitxor fnv1-256-prime * fnv1-256-mod bitand ] each ;
+
+
+M: fnv1-512 checksum-bytes ( bytes checksum -- value )
+    drop
+    fnv1-512-basis swap
+    [ swap fnv1-512-prime * bitxor fnv1-512-mod bitand ] each ;
+
+M: fnv1a-512 checksum-bytes ( bytes checksum -- value )
+    drop
+    fnv1-512-basis swap
+    [ bitxor fnv1-512-prime * fnv1-512-mod bitand ] each ;
+
+
+M: fnv1-1024 checksum-bytes ( bytes checksum -- value )
+    drop
+    fnv1-1024-basis swap
+    [ swap fnv1-1024-prime * bitxor fnv1-1024-mod bitand ] each ;
+
+M: fnv1a-1024 checksum-bytes ( bytes checksum -- value )
+    drop
+    fnv1-1024-basis swap
+    [ bitxor fnv1-1024-prime * fnv1-1024-mod bitand ] each ;
diff --git a/basis/checksums/fnv1/summary.txt b/basis/checksums/fnv1/summary.txt
new file mode 100644
index 0000000000..2c74cda8cd
--- /dev/null
+++ b/basis/checksums/fnv1/summary.txt
@@ -0,0 +1 @@
+Fowler-Noll-Vo checksum algorithm
diff --git a/basis/compiler/cfg/def-use/authors.txt b/basis/compiler/cfg/def-use/authors.txt
new file mode 100644
index 0000000000..a44f8d7f8d
--- /dev/null
+++ b/basis/compiler/cfg/def-use/authors.txt
@@ -0,0 +1,2 @@
+Slava Pestov
+Daniel Ehrenberg
diff --git a/basis/compiler/cfg/def-use/def-use-tests.factor b/basis/compiler/cfg/def-use/def-use-tests.factor
new file mode 100644
index 0000000000..1153d9ea81
--- /dev/null
+++ b/basis/compiler/cfg/def-use/def-use-tests.factor
@@ -0,0 +1,37 @@
+! Copyright (C) 2009 Daniel Ehrenberg.
+! See http://factorcode.org/license.txt for BSD license.
+USING: kernel tools.test accessors vectors sequences namespaces
+arrays
+cpu.architecture
+compiler.cfg.def-use
+compiler.cfg
+compiler.cfg.debugger
+compiler.cfg.instructions
+compiler.cfg.registers ;
+
+V{
+    T{ ##peek f V int-regs 0 D 0 }
+    T{ ##peek f V int-regs 1 D 0 }
+    T{ ##peek f V int-regs 2 D 0 }
+} 1 test-bb
+V{
+    T{ ##replace f V int-regs 2 D 0 }
+} 2 test-bb
+1 get 2 get 1vector >>successors drop
+V{
+    T{ ##replace f V int-regs 0 D 0 }
+} 3 test-bb
+2 get 3 get 1vector >>successors drop
+V{ } 4 test-bb
+V{ } 5 test-bb
+3 get 4 get 5 get V{ } 2sequence >>successors drop
+V int-regs 2
+    2 get V int-regs 0 2array
+    3 get V int-regs 1 2array
+2array \ ##phi new-insn 1vector
+6 test-bb
+4 get 6 get 1vector >>successors drop
+5 get 6 get 1vector >>successors drop
+
+cfg new 1 get >>entry 0 set
+[ ] [ 0 get compute-def-use ] unit-test
diff --git a/basis/compiler/cfg/def-use/def-use.factor b/basis/compiler/cfg/def-use/def-use.factor
index 1c9ac90f78..8e8fbf3a2d 100644
--- a/basis/compiler/cfg/def-use/def-use.factor
+++ b/basis/compiler/cfg/def-use/def-use.factor
@@ -1,7 +1,7 @@
-! Copyright (C) 2008, 2009 Slava Pestov.
+! Copyright (C) 2008, 2009 Slava Pestov, Daniel Ehrenberg.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: accessors arrays kernel assocs sequences namespaces fry
-sets compiler.cfg.rpo compiler.cfg.instructions ;
+sets compiler.cfg.rpo compiler.cfg.instructions locals ;
 IN: compiler.cfg.def-use
 
 GENERIC: defs-vreg ( insn -- vreg/f )
@@ -80,18 +80,18 @@ SYMBOLS: defs insns uses ;
         ] each-basic-block
     ] keep insns set ;
 
-: compute-uses ( cfg -- )
-    H{ } clone [
-        '[
-            dup instructions>> [
-                uses-vregs [
-                    _ conjoin-at
-                ] with each
-            ] with each
-        ] each-basic-block
-    ] keep
-    [ keys ] assoc-map
-    uses set ;
+:: compute-uses ( cfg -- )
+    ! Here, a phi node uses its argument in the block that it comes from.
+    H{ } clone :> use
+    cfg [| block |
+        block instructions>> [
+            dup ##phi?
+            [ inputs>> [ use conjoin-at ] assoc-each ]
+            [ uses-vregs [ block swap use conjoin-at ] each ]
+            if
+        ] each
+    ] each-basic-block
+    use [ keys ] assoc-map uses set ;
 
 : compute-def-use ( cfg -- )
-    [ compute-defs ] [ compute-uses ] [ compute-insns ] tri ;
\ No newline at end of file
+    [ compute-defs ] [ compute-uses ] [ compute-insns ] tri ;
diff --git a/basis/compiler/cfg/ssa/liveness/liveness-tests.factor b/basis/compiler/cfg/ssa/liveness/liveness-tests.factor
index 02c49d01f4..5493f252c1 100644
--- a/basis/compiler/cfg/ssa/liveness/liveness-tests.factor
+++ b/basis/compiler/cfg/ssa/liveness/liveness-tests.factor
@@ -39,7 +39,6 @@ cfg new 1 get >>entry 4 set
 [ ] [ 4 get precompute-liveness ] unit-test
 
 [ H{ } ] [ back-edge-targets get ] unit-test
-[ H{ } ] [ phi-outs get ] unit-test
 [ t ] [ 1 get R_q { 1 2 3 } [ get ] map unique = ] unit-test
 [ t ] [ 2 get R_q { 2 } [ get ] map unique = ] unit-test
 [ t ] [ 3 get R_q { 3 } [ get ] map unique = ] unit-test
@@ -85,11 +84,9 @@ V{ } 0 test-bb
 V{ } 1 test-bb
 V{ } 2 test-bb
 V{ } 3 test-bb
-V int-regs 2
-    2 get V int-regs 0 2array
-    3 get V int-regs 1 2array
-2array \ ##phi new-insn 1vector
-4 test-bb
+V{
+    T{ ##phi f V int-regs 2 H{ { 2 V int-regs 0 } { 3 V int-regs 1 } } }
+} 4 test-bb
 test-diamond
 
 cfg new 1 get >>entry 5 set
@@ -109,7 +106,7 @@ cfg new 1 get >>entry 5 set
 [ f ] [ V int-regs 1 2 get live-in? ] unit-test
 [ f ] [ V int-regs 2 2 get live-in? ] unit-test
 
-[ t ] [ V int-regs 0 2 get live-out? ] unit-test
+[ f ] [ V int-regs 0 2 get live-out? ] unit-test
 [ f ] [ V int-regs 1 2 get live-out? ] unit-test
 [ f ] [ V int-regs 2 2 get live-out? ] unit-test
 
@@ -118,7 +115,7 @@ cfg new 1 get >>entry 5 set
 [ f ] [ V int-regs 2 3 get live-in? ] unit-test
 
 [ f ] [ V int-regs 0 3 get live-out? ] unit-test
-[ t ] [ V int-regs 1 3 get live-out? ] unit-test
+[ f ] [ V int-regs 1 3 get live-out? ] unit-test
 [ f ] [ V int-regs 2 3 get live-out? ] unit-test
 
 [ f ] [ V int-regs 0 4 get live-in? ] unit-test
@@ -202,8 +199,6 @@ cfg new 1 get >>entry 0 set
 [ f ] [ 10 get back-edge-target? ] unit-test
 [ f ] [ 11 get back-edge-target? ] unit-test
 
-[ f ] [ 1 11 [a,b] [ get phi-outs get at ] any? ] unit-test
-
 [ f ] [ V int-regs 0 1 get live-in? ] unit-test
 [ f ] [ V int-regs 1 1 get live-in? ] unit-test
 [ f ] [ V int-regs 2 1 get live-in? ] unit-test
diff --git a/basis/compiler/cfg/ssa/liveness/liveness.factor b/basis/compiler/cfg/ssa/liveness/liveness.factor
index 8788bc72f5..625639cc73 100644
--- a/basis/compiler/cfg/ssa/liveness/liveness.factor
+++ b/basis/compiler/cfg/ssa/liveness/liveness.factor
@@ -21,10 +21,6 @@ SYMBOL: R_q-sets
 ! Targets of back edges
 SYMBOL: back-edge-targets
 
-! hashtable of nodes => sets of vregs, where the vregs are inputs
-! to phi nodes in a successor node
-SYMBOL: phi-outs
-
 : T_q ( q -- T_q )
     T_q-sets get at ;
 
@@ -34,9 +30,6 @@ SYMBOL: phi-outs
 : back-edge-target? ( block -- ? )
     back-edge-targets get key? ;
 
-: phi-out? ( vreg node -- ? )
-    phi-outs get at key? ;
-
 : next-R_q ( q -- R_q )
     [ ] [ successors>> ] [ number>> ] tri
     '[ number>> _ >= ] filter
@@ -52,27 +45,14 @@ SYMBOL: phi-outs
         [ back-edge-targets get conjoin ] [ drop ] if
     ] each ;
 
-: set-phi-out ( block vreg -- )
-    swap phi-outs get [ drop H{ } clone ] cache conjoin ;
-
-: set-phi-outs ( q -- )
-    instructions>> [
-        dup ##phi? [
-            inputs>> [ set-phi-out ] assoc-each
-        ] [ drop ] if
-    ] each ;
-
 : init-R_q ( -- )
     H{ } clone R_q-sets set
-    H{ } clone back-edge-targets set
-    H{ } clone phi-outs set ;
+    H{ } clone back-edge-targets set ;
 
 : compute-R_q ( cfg -- )
     init-R_q
     post-order [
-        [ set-R_q ]
-        [ set-back-edges ]
-        [ set-phi-outs ] tri
+        [ set-R_q ] [ set-back-edges ] bi
     ] each ;
 
 ! This algorithm for computing T_q uses equation (1)
@@ -97,31 +77,15 @@ SYMBOL: phi-outs
     H{ } T_q-sets set
     [ next-T_q drop ] each-basic-block ;
 
-:: compute-phi-uses ( cfg -- )
-    ! Here, a phi node uses its argument in the block that it comes from.
-    H{ } clone :> use
-    cfg [| block |
-        block instructions>> [
-            dup ##phi?
-            [ inputs>> [ use conjoin-at ] assoc-each ]
-            [ uses-vregs [ block swap use conjoin-at ] each ]
-            if
-        ] each
-    ] each-basic-block
-    use [ keys ] assoc-map uses set ;
-
 PRIVATE>
 
 : precompute-liveness ( cfg -- )
-    ! The first three of these depend only on the graph
-    ! structure of the CFG, and don't need to be recomputed
-    ! if that doesn't change
+    ! Maybe dominance and def-use should be called before this, separately
     {
+        [ compute-dominance ]
+        [ compute-def-use ]
         [ compute-R_q ]
         [ compute-T_q ]
-        [ compute-dominance ]
-        [ compute-defs ]
-        [ compute-phi-uses ]
     } cleave ;
 
 <PRIVATE
@@ -166,7 +130,6 @@ PRIVATE>
     [let | def [ vreg def-of ] |
         {
             { [ node def eq? ] [ vreg uses-of def only? not ] }
-            { [ vreg node phi-out? ] [ t ] }
             { [ def node strictly-dominates? ] [ vreg node (live-out?) ] }
             [ f ]
         } cond