From fb488025aa77c93ef4649a161b1794cf23170545 Mon Sep 17 00:00:00 2001
From: Slava Pestov <slava@shill.local>
Date: Sat, 4 Jul 2009 02:50:50 -0500
Subject: [PATCH] compiler.cfg.value-numbering.rewrite: fix ##compare-imm
 rewrite rule

---
 .../cfg/instructions/instructions.factor      | 10 +++++
 .../value-numbering/rewrite/rewrite.factor    | 39 ++++++++++++-------
 basis/compiler/tests/codegen.factor           |  6 ++-
 3 files changed, 39 insertions(+), 16 deletions(-)

diff --git a/basis/compiler/cfg/instructions/instructions.factor b/basis/compiler/cfg/instructions/instructions.factor
index a2b12300f7..1a1b2fd65c 100644
--- a/basis/compiler/cfg/instructions/instructions.factor
+++ b/basis/compiler/cfg/instructions/instructions.factor
@@ -199,6 +199,16 @@ SYMBOL: cc/=
         { cc/= cc= }
     } at ;
 
+: swap-cc ( cc -- cc' )
+    H{
+        { cc< cc> }
+        { cc<= cc>= }
+        { cc> cc< }
+        { cc>= cc<= }
+        { cc= cc= }
+        { cc/= cc/= }
+    } at ;
+
 : evaluate-cc ( result cc -- ? )
     H{
         { cc<  { +lt+           } }
diff --git a/basis/compiler/cfg/value-numbering/rewrite/rewrite.factor b/basis/compiler/cfg/value-numbering/rewrite/rewrite.factor
index 9fb6e66e9f..8a435135c7 100755
--- a/basis/compiler/cfg/value-numbering/rewrite/rewrite.factor
+++ b/basis/compiler/cfg/value-numbering/rewrite/rewrite.factor
@@ -1,11 +1,11 @@
-! Copyright (C) 2008 Slava Pestov, Doug Coleman.
+! Copyright (C) 2008, 2009 Slava Pestov, Doug Coleman.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: accessors combinators combinators.short-circuit
-arrays compiler.cfg.hats compiler.cfg.instructions
+USING: accessors locals combinators combinators.short-circuit arrays
+fry kernel layouts math namespaces sequences cpu.architecture
+math.bitwise compiler.cfg.hats compiler.cfg.instructions
 compiler.cfg.value-numbering.expressions
 compiler.cfg.value-numbering.graph
-compiler.cfg.value-numbering.simplify fry kernel layouts math
-namespaces sequences cpu.architecture math.bitwise locals ;
+compiler.cfg.value-numbering.simplify ;
 IN: compiler.cfg.value-numbering.rewrite
 
 GENERIC: rewrite ( insn -- insn' )
@@ -70,16 +70,11 @@ M: ##compare-imm-branch rewrite
         dup rewrite-tagged-comparison? [ rewrite-tagged-comparison ] when
     ] when ;
 
-: >compare-imm ( insn swap? -- insn' )
-    [
-        {
-            [ dst>> ]
-            [ src1>> ]
-            [ src2>> ]
-            [ cc>> ]
-        } cleave
-    ] dip [ [ swap ] [ ] bi* ] when
-    [ vreg>constant ] dip
+:: >compare-imm ( insn swap? -- insn' )
+    insn dst>>
+    insn src1>>
+    insn src2>> swap? [ swap ] when vreg>constant
+    insn cc>> swap? [ swap-cc ] when
     i \ ##compare-imm new-insn ; inline
 
 M: ##compare rewrite
@@ -90,6 +85,20 @@ M: ##compare rewrite
         [ drop ]
     } case ;
 
+:: >compare-imm-branch ( insn swap? -- insn' )
+    insn src1>>
+    insn src2>> swap? [ swap ] when vreg>constant
+    insn cc>> swap? [ swap-cc ] when
+    \ ##compare-imm-branch new-insn ; inline
+
+M: ##compare-branch rewrite
+    dup [ src1>> ] [ src2>> ] bi
+    [ vreg>expr constant-expr? ] bi@ 2array {
+        { { f t } [ f >compare-imm-branch ] }
+        { { t f } [ t >compare-imm-branch ] }
+        [ drop ]
+    } case ;
+
 : rewrite-redundant-comparison? ( insn -- ? )
     {
         [ src1>> vreg>expr compare-expr? ]
diff --git a/basis/compiler/tests/codegen.factor b/basis/compiler/tests/codegen.factor
index 36ee5eb94d..82da31b5fe 100644
--- a/basis/compiler/tests/codegen.factor
+++ b/basis/compiler/tests/codegen.factor
@@ -310,4 +310,8 @@ M: cucumber equal? "The cucumber has no equal" throw ;
     }
 ] [
     [ { 1 2 3 } "x" "y" linear-scan-regression ] { } make
-] unit-test
\ No newline at end of file
+] unit-test
+
+! Regression from Doug's value numbering changes
+[ t ] [ 2 [ 1 swap fixnum< ] compile-call ] unit-test
+[ 3 ] [ 2 [ 1 swap fixnum< [ 3 ] [ 4 ] if ] compile-call ] unit-test
\ No newline at end of file