diff --git a/basis/compiler/cfg/linear-scan/live-intervals/live-intervals-docs.factor b/basis/compiler/cfg/linear-scan/live-intervals/live-intervals-docs.factor
index cb9bbfec27..56a86ae2a5 100644
--- a/basis/compiler/cfg/linear-scan/live-intervals/live-intervals-docs.factor
+++ b/basis/compiler/cfg/linear-scan/live-intervals/live-intervals-docs.factor
@@ -8,7 +8,8 @@ HELP: <live-interval>
   { "vreg" "virtual register" }
   { "live-interval" live-interval-state }
 }
-{ $description "Creates a new live interval for a virtual register. Initially the range is empty." } ;
+{ $description "Creates a new live interval for a virtual register. Initially the ranges are empty and it has no uses." }
+{ $see-also vreg>live-interval } ;
 
 HELP: block-from
 { $values { "bb" basic-block } { "n" integer } }
@@ -36,9 +37,9 @@ HELP: find-use
 }
 { $description "Finds the live intervals " { $link vreg-use } " at the given instruction number, if it has one." } ;
 
-HELP: finish-live-intervals
-{ $values { "live-intervals" sequence } }
-{ $description "Since live intervals are computed in a backward order, we have to reverse some sequences, and compute the start and end." } ;
+HELP: finish-live-interval
+{ $values { "live-interval" live-interval-state } }
+{ $description "Reverses the 'ranges' and 'uses' of the live-interval since those are computed in the reverse order." } ;
 
 HELP: from
 { $var-description "An integer representing a sequence number one lower than all numbers in the currently processed block." } ;
@@ -51,6 +52,10 @@ HELP: intervals-intersect?
 }
 { $description "Checks if two live intervals intersect each other." } ;
 
+HELP: last-use?
+{ $values { "insn#" integer } { "uses" sequence } { "use/f" $maybe vreg-use } }
+{ $description "Maybe gets the last " { $link vreg-use } " of a " { $link live-interval-state } "." } ;
+
 HELP: live-interval-state
 { $class-description "A class encoding the \"liveness\" of a virtual register. It has the following slots:"
   { $table
@@ -90,13 +95,13 @@ HELP: record-temp
 { $description "Assigns the interval [n,n] to vreg:s live interval." } ;
 
 HELP: sync-point
-{ $class-description "A location where all registers have to be spilled. For example when garbage collection is run or an alien ffi call is invoked. Figuring out where in the " { $link cfg } " the sync points are is done in the " { $link compute-live-intervals } " step. The tuple has the following slots:"
+{ $class-description "A location where all live registers have to be spilled. For example when garbage collection is run or an alien ffi call is invoked. Figuring out where in the " { $link cfg } " the sync points are is done in the " { $link compute-live-intervals } " step. The tuple has the following slots:"
   { $table
     { { $slot "n" } { "Set from an instructions sequence number." } }
     { { $slot "keep-dst?" } { "Boolean that determines whether registers are spilled around this sync point." } }
   }
 }
-{ $see-also insn } ;
+{ $see-also cfg>sync-points insn } ;
 
 HELP: to
 { $var-description "An integer representing a sequence number equal to the highest number in the currently processed block." } ;
diff --git a/basis/compiler/cfg/linear-scan/live-intervals/live-intervals-tests.factor b/basis/compiler/cfg/linear-scan/live-intervals/live-intervals-tests.factor
index 59787f2f82..4d6b57955b 100644
--- a/basis/compiler/cfg/linear-scan/live-intervals/live-intervals-tests.factor
+++ b/basis/compiler/cfg/linear-scan/live-intervals/live-intervals-tests.factor
@@ -33,6 +33,13 @@ IN: compiler.cfg.linear-scan.live-intervals.tests
     dup finish-live-interval ranges>>
 ] unit-test
 
+! insn>sync-point
+{ f f t } [
+    T{ ##call-gc } insn>sync-point keep-dst?>>
+    T{ ##callback-outputs } insn>sync-point keep-dst?>>
+    T{ ##unbox } insn>sync-point keep-dst?>>
+] unit-test
+
 ! intervals-intersect?
 { t f f } [
     { { 4 20 } } <live-interval-for-ranges>
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 c612129b74..2c506f745b 100644
--- a/basis/compiler/cfg/linear-scan/live-intervals/live-intervals.factor
+++ b/basis/compiler/cfg/linear-scan/live-intervals/live-intervals.factor
@@ -134,22 +134,14 @@ ERROR: bad-live-interval live-interval ;
     dup live-interval-start -1 = [ bad-live-interval ] [ drop ] if ;
 
 : finish-live-interval ( live-interval -- )
-    [ ranges>> reverse! drop ] [ uses>> reverse! drop ] [ check-start ] tri ;
-
-: finish-live-intervals ( live-intervals -- )
-    [ finish-live-interval ] each ;
+    [ ranges>> reverse! ] [ uses>> reverse! ] [ check-start ] tri 2drop ;
 
 TUPLE: sync-point n keep-dst? ;
 
-C: <sync-point> sync-point
-
 GENERIC: insn>sync-point ( insn -- sync-point/f )
 
-M: hairy-clobber-insn insn>sync-point
-    insn#>> f <sync-point> ;
-
 M: clobber-insn insn>sync-point
-    insn#>> t <sync-point> ;
+    [ insn#>> ] [ hairy-clobber-insn? not ] bi sync-point boa ;
 
 M: insn insn>sync-point drop f ;
 
@@ -159,7 +151,7 @@ M: insn insn>sync-point drop f ;
 : cfg>live-intervals ( cfg -- live-intervals )
     H{ } clone live-intervals set
     linearization-order <reversed> [ compute-live-intervals-step ] each
-    live-intervals get values dup finish-live-intervals ;
+    live-intervals get values dup [ finish-live-interval ] each ;
 
 : compute-live-intervals ( cfg -- intervals/sync-points )
     [ cfg>live-intervals ] [ cfg>sync-points ] bi append ;