diff --git a/basis/compiler/cfg/write-barrier/write-barrier-tests.factor b/basis/compiler/cfg/write-barrier/write-barrier-tests.factor
new file mode 100644
index 0000000000..7a4b1c488f
--- /dev/null
+++ b/basis/compiler/cfg/write-barrier/write-barrier-tests.factor
@@ -0,0 +1,72 @@
+USING: compiler.cfg.write-barrier compiler.cfg.instructions
+compiler.cfg.registers cpu.architecture arrays tools.test ;
+IN: compiler.cfg.write-barrier.tests
+
+[
+    {
+        T{ ##peek f V int-regs 4 D 0 f }
+        T{ ##copy f V int-regs 6 V int-regs 4 f }
+        T{ ##allot f V int-regs 7 24 array V int-regs 8 f }
+        T{ ##load-immediate f V int-regs 9 8 f }
+        T{ ##set-slot-imm f V int-regs 9 V int-regs 7 1 3 f }
+        T{ ##set-slot-imm f V int-regs 6 V int-regs 7 2 3 f }
+        T{ ##replace f V int-regs 7 D 0 f }
+    }
+] [
+    {
+        T{ ##peek f V int-regs 4 D 0 }
+        T{ ##copy f V int-regs 6 V int-regs 4 }
+        T{ ##allot f V int-regs 7 24 array V int-regs 8 }
+        T{ ##load-immediate f V int-regs 9 8 }
+        T{ ##set-slot-imm f V int-regs 9 V int-regs 7 1 3 }
+        T{ ##write-barrier f V int-regs 7 V int-regs 10 V int-regs 11 }
+        T{ ##set-slot-imm f V int-regs 6 V int-regs 7 2 3 }
+        T{ ##write-barrier f V int-regs 7 V int-regs 12 V int-regs 13 }
+        T{ ##replace f V int-regs 7 D 0 }
+    } eliminate-write-barriers
+] unit-test
+
+[
+    {
+        T{ ##load-immediate f V int-regs 4 24 }
+        T{ ##peek f V int-regs 5 D -1 }
+        T{ ##peek f V int-regs 6 D -2 }
+        T{ ##set-slot-imm f V int-regs 5 V int-regs 6 3 2 }
+        T{ ##write-barrier f V int-regs 6 V int-regs 7 V int-regs 8 }
+    }
+] [
+    {
+        T{ ##load-immediate f V int-regs 4 24 }
+        T{ ##peek f V int-regs 5 D -1 }
+        T{ ##peek f V int-regs 6 D -2 }
+        T{ ##set-slot-imm f V int-regs 5 V int-regs 6 3 2 }
+        T{ ##write-barrier f V int-regs 6 V int-regs 7 V int-regs 8 }
+    } eliminate-write-barriers
+] unit-test
+
+[
+    {
+        T{ ##peek f V int-regs 19 D -3 }
+        T{ ##peek f V int-regs 22 D -2 }
+        T{ ##copy f V int-regs 23 V int-regs 19 }
+        T{ ##set-slot-imm f V int-regs 22 V int-regs 23 3 2 }
+        T{ ##write-barrier f V int-regs 23 V int-regs 24 V int-regs 25 }
+        T{ ##copy f V int-regs 26 V int-regs 19 }
+        T{ ##peek f V int-regs 28 D -1 }
+        T{ ##copy f V int-regs 29 V int-regs 19 }
+        T{ ##set-slot-imm f V int-regs 28 V int-regs 29 4 2 }
+    }
+] [
+    {
+        T{ ##peek f V int-regs 19 D -3 }
+        T{ ##peek f V int-regs 22 D -2 }
+        T{ ##copy f V int-regs 23 V int-regs 19 }
+        T{ ##set-slot-imm f V int-regs 22 V int-regs 23 3 2 }
+        T{ ##write-barrier f V int-regs 23 V int-regs 24 V int-regs 25 }
+        T{ ##copy f V int-regs 26 V int-regs 19 }
+        T{ ##peek f V int-regs 28 D -1 }
+        T{ ##copy f V int-regs 29 V int-regs 19 }
+        T{ ##set-slot-imm f V int-regs 28 V int-regs 29 4 2 }
+        T{ ##write-barrier f V int-regs 29 V int-regs 30 V int-regs 3 }
+    } eliminate-write-barriers
+] unit-test
diff --git a/basis/compiler/cfg/write-barrier/write-barrier.factor b/basis/compiler/cfg/write-barrier/write-barrier.factor
new file mode 100644
index 0000000000..f7e81c8b5c
--- /dev/null
+++ b/basis/compiler/cfg/write-barrier/write-barrier.factor
@@ -0,0 +1,43 @@
+! Copyright (C) 2008 Slava Pestov.
+! See http://factorcode.org/license.txt for BSD license.
+USING: kernel accessors namespaces assocs sets sequences locals
+compiler.cfg compiler.cfg.instructions
+compiler.cfg.instructions.syntax compiler.cfg.copy-prop ;
+IN: compiler.cfg.write-barrier
+
+! Eliminate redundant write barrier hits.
+
+! Objects which have already been marked, as well as
+! freshly-allocated objects
+SYMBOL: safe
+
+! Objects which have been mutated
+SYMBOL: mutated
+
+GENERIC: eliminate-write-barrier ( insn -- insn' )
+
+M: ##allot eliminate-write-barrier
+    dup dst>> safe get conjoin ;
+
+M: ##write-barrier eliminate-write-barrier
+    dup src>> resolve dup
+    [ safe get key? not ]
+    [ mutated get key? ] bi and
+    [ safe get conjoin ] [ 2drop f ] if ;
+
+M: ##copy eliminate-write-barrier
+    dup record-copy ;
+
+M: ##set-slot eliminate-write-barrier
+    dup obj>> resolve mutated get conjoin ;
+
+M: ##set-slot-imm eliminate-write-barrier
+    dup obj>> resolve mutated get conjoin ;
+
+M: insn eliminate-write-barrier ;
+
+: eliminate-write-barriers ( insns -- insns' )
+    H{ } clone safe set
+    H{ } clone mutated set
+    H{ } clone copies set
+    [ eliminate-write-barrier ] map sift ;