From 11731f8d485675b6eff6cf18c060256f9cb06a78 Mon Sep 17 00:00:00 2001
From: Slava Pestov <slava@slava-pestovs-macbook-pro.local>
Date: Tue, 14 Jul 2009 20:05:01 -0500
Subject: [PATCH] compiler.cfg.value-numbering: merge in
 compiler.cfg.branch-folding

---
 .../branch-folding-tests.factor               |  89 ------
 .../cfg/branch-folding/branch-folding.factor  |  33 ---
 basis/compiler/cfg/optimizer/optimizer.factor |   2 -
 .../value-numbering/rewrite/rewrite.factor    |  55 +++-
 .../value-numbering-tests.factor              | 263 +++++++++++++++++-
 .../value-numbering/value-numbering.factor    |   2 +
 basis/compiler/tests/codegen.factor           |   5 +-
 7 files changed, 309 insertions(+), 140 deletions(-)
 delete mode 100644 basis/compiler/cfg/branch-folding/branch-folding-tests.factor
 delete mode 100644 basis/compiler/cfg/branch-folding/branch-folding.factor

diff --git a/basis/compiler/cfg/branch-folding/branch-folding-tests.factor b/basis/compiler/cfg/branch-folding/branch-folding-tests.factor
deleted file mode 100644
index 1d43ea0af3..0000000000
--- a/basis/compiler/cfg/branch-folding/branch-folding-tests.factor
+++ /dev/null
@@ -1,89 +0,0 @@
-IN: compiler.cfg.branch-folding.tests
-USING: compiler.cfg.branch-folding compiler.cfg.instructions
-compiler.cfg compiler.cfg.registers compiler.cfg.debugger
-arrays compiler.cfg.phi-elimination compiler.cfg.dce
-compiler.cfg.predecessors compiler.cfg.comparisons
-kernel accessors assocs sequences classes namespaces
-tools.test cpu.architecture ;
-
-V{ T{ ##branch } } 0 test-bb
-
-V{
-    T{ ##peek f V int-regs 0 D 0 }
-    T{ ##compare-branch f V int-regs 0 V int-regs 0 cc< }
-} 1 test-bb
-
-V{
-    T{ ##load-immediate f V int-regs 1 1 }
-    T{ ##branch }
-} 2 test-bb
-
-V{
-    T{ ##load-immediate f V int-regs 2 2 }
-    T{ ##branch }
-} 3 test-bb
-
-V{
-    T{ ##phi f V int-regs 3 { } }
-    T{ ##replace f V int-regs 3 D 0 }
-    T{ ##return }
-} 4 test-bb
-
-4 get instructions>> first
-2 get V int-regs 1 2array
-3 get V int-regs 2 2array 2array
->>inputs drop
-
-test-diamond
-
-[ ] [ cfg new 0 get >>entry fold-branches compute-predecessors eliminate-phis drop ] unit-test
-
-[ 1 ] [ 1 get successors>> length ] unit-test
-[ t ] [ 1 get successors>> first 3 get eq? ] unit-test
-
-[ T{ ##copy f V int-regs 3 V int-regs 2 } ]
-[ 3 get successors>> first instructions>> first ]
-unit-test
-
-[ 2 ] [ 4 get instructions>> length ] unit-test
-
-V{
-    T{ ##peek f V int-regs 0 D 0 }
-    T{ ##branch }
-} 0 test-bb
-
-V{
-    T{ ##peek f V int-regs 1 D 1 }
-    T{ ##compare-branch f V int-regs 1 V int-regs 1 cc< }
-} 1 test-bb
-
-V{
-    T{ ##copy f V int-regs 2 V int-regs 0 }
-    T{ ##branch }
-} 2 test-bb
-
-V{
-    T{ ##phi f V int-regs 3 V{ } }
-    T{ ##branch }
-} 3 test-bb
-
-V{
-    T{ ##replace f V int-regs 3 D 0 }
-    T{ ##return }
-} 4 test-bb
-
-1 get V int-regs 1 2array
-2 get V int-regs 0 2array 2array 3 get instructions>> first (>>inputs)
-
-test-diamond
-
-[ ] [
-    cfg new 0 get >>entry
-    compute-predecessors
-    fold-branches
-    compute-predecessors
-    eliminate-dead-code
-    drop
-] unit-test
-
-[ 1 ] [ 3 get instructions>> first inputs>> assoc-size ] unit-test
\ No newline at end of file
diff --git a/basis/compiler/cfg/branch-folding/branch-folding.factor b/basis/compiler/cfg/branch-folding/branch-folding.factor
deleted file mode 100644
index 04842552b7..0000000000
--- a/basis/compiler/cfg/branch-folding/branch-folding.factor
+++ /dev/null
@@ -1,33 +0,0 @@
-! Copyright (C) 2009 Slava Pestov.
-! See http://factorcode.org/license.txt for BSD license.
-USING: accessors combinators.short-circuit kernel sequences vectors
-compiler.cfg.instructions
-compiler.cfg.comparisons
-compiler.cfg.rpo
-compiler.cfg ;
-IN: compiler.cfg.branch-folding
-
-! Fold comparisons where both inputs are the same. Predecessors must be
-! recomputed after this
-
-: fold-branch? ( bb -- ? )
-    instructions>> last {
-        [ ##compare-branch? ]
-        [ [ src1>> ] [ src2>> ] bi = ]
-    } 1&& ;
-
-: chosen-successor ( bb -- succ )
-    [ instructions>> last cc>> { cc= cc<= cc>= } memq? 0 1 ? ]
-    [ successors>> ]
-    bi nth ;
-
-: fold-branch ( bb -- )
-    dup chosen-successor 1vector >>successors
-    instructions>> [ pop* ] [ [ \ ##branch new-insn ] dip push ] bi ;
-
-: fold-branches ( cfg -- cfg' )
-    dup [
-        dup fold-branch?
-        [ fold-branch ] [ drop ] if
-    ] each-basic-block
-    cfg-changed ;
\ No newline at end of file
diff --git a/basis/compiler/cfg/optimizer/optimizer.factor b/basis/compiler/cfg/optimizer/optimizer.factor
index 5b0892a0ee..e16fb734e1 100644
--- a/basis/compiler/cfg/optimizer/optimizer.factor
+++ b/basis/compiler/cfg/optimizer/optimizer.factor
@@ -9,7 +9,6 @@ compiler.cfg.branch-splitting
 compiler.cfg.alias-analysis
 compiler.cfg.value-numbering
 compiler.cfg.dce
-compiler.cfg.branch-folding
 compiler.cfg.write-barrier
 compiler.cfg.liveness
 compiler.cfg.rpo
@@ -36,7 +35,6 @@ SYMBOL: check-optimizer?
         compute-liveness
         alias-analysis
         value-numbering
-        fold-branches
         compute-predecessors
         eliminate-dead-code
         eliminate-write-barriers
diff --git a/basis/compiler/cfg/value-numbering/rewrite/rewrite.factor b/basis/compiler/cfg/value-numbering/rewrite/rewrite.factor
index 5dd8884a89..3f7173c355 100755
--- a/basis/compiler/cfg/value-numbering/rewrite/rewrite.factor
+++ b/basis/compiler/cfg/value-numbering/rewrite/rewrite.factor
@@ -98,18 +98,31 @@ M: ##compare-imm rewrite-tagged-comparison
     } case
     swap cc= eq? [ [ negate-cc ] change-cc ] when ;
 
+ERROR: bad-comparison ;
+
 : (fold-compare-imm) ( insn -- ? )
     [ [ src1>> vreg>constant ] [ src2>> ] bi ] [ cc>> ] bi
-    pick integer? [ [ <=> ] dip evaluate-cc ] [ 3drop f ] if ;
+    pick integer?
+    [ [ <=> ] dip evaluate-cc ]
+    [
+        2nip {
+            { cc= [ f ] }
+            { cc/= [ t ] }
+            [ bad-comparison ]
+        } case
+    ] if ;
 
 : fold-compare-imm? ( insn -- ? )
     src1>> vreg>expr [ constant-expr? ] [ reference-expr? ] bi or ;
 
-: fold-compare-imm-branch ( insn -- insn/f )
-    (fold-compare-imm) 0 1 ?
+: fold-branch ( ? -- insn )
+    0 1 ?
     basic-block get [ nth 1vector ] change-successors drop
     \ ##branch new-insn ;
 
+: fold-compare-imm-branch ( insn -- insn/f )
+    (fold-compare-imm) fold-branch ;
+
 M: ##compare-imm-branch rewrite*
     {
         { [ dup rewrite-boolean-comparison? ] [ rewrite-boolean-comparison ] }
@@ -132,10 +145,20 @@ M: ##compare-imm-branch rewrite*
     [ vreg>constant ] dip
     \ ##compare-imm-branch new-insn ; inline
 
+: self-compare? ( insn -- ? )
+    [ src1>> ] [ src2>> ] bi [ vreg>vn ] bi@ = ; inline
+
+: (rewrite-self-compare) ( insn -- ? )
+    cc>> { cc= cc<= cc>= } memq? ;
+
+: rewrite-self-compare-branch ( insn -- insn' )
+    (rewrite-self-compare) fold-branch ;
+
 M: ##compare-branch rewrite*
     {
         { [ dup src1>> vreg-small-constant? ] [ t >compare-imm-branch ] }
         { [ dup src2>> vreg-small-constant? ] [ f >compare-imm-branch ] }
+        { [ dup self-compare? ] [ rewrite-self-compare-branch ] }
         [ drop f ]
     } cond ;
 
@@ -152,21 +175,27 @@ M: ##compare-branch rewrite*
     [ vreg>constant ] dip
     i \ ##compare-imm new-insn ; inline
 
-M: ##compare rewrite*
-    {
-        { [ dup src1>> vreg-small-constant? ] [ t >compare-imm ] }
-        { [ dup src2>> vreg-small-constant? ] [ f >compare-imm ] }
-        [ drop f ]
-    } cond ;
-
-: fold-compare-imm ( insn -- )
-    [ dst>> ]
-    [ (fold-compare-imm) ] bi
+: >boolean-insn ( insn ? -- insn' )
+    [ dst>> ] dip
     {
         { t [ t \ ##load-reference new-insn ] }
         { f [ \ f tag-number \ ##load-immediate new-insn ] }
     } case ;
 
+: rewrite-self-compare ( insn -- insn' )
+    dup (rewrite-self-compare) >boolean-insn ;
+
+M: ##compare rewrite*
+    {
+        { [ dup src1>> vreg-small-constant? ] [ t >compare-imm ] }
+        { [ dup src2>> vreg-small-constant? ] [ f >compare-imm ] }
+        { [ dup self-compare? ] [ rewrite-self-compare ] }
+        [ drop f ]
+    } cond ;
+
+: fold-compare-imm ( insn -- insn' )
+    dup (fold-compare-imm) >boolean-insn ;
+
 M: ##compare-imm rewrite*
     {
         { [ dup rewrite-redundant-comparison? ] [ rewrite-redundant-comparison ] }
diff --git a/basis/compiler/cfg/value-numbering/value-numbering-tests.factor b/basis/compiler/cfg/value-numbering/value-numbering-tests.factor
index e808220716..60d23cefb7 100644
--- a/basis/compiler/cfg/value-numbering/value-numbering-tests.factor
+++ b/basis/compiler/cfg/value-numbering/value-numbering-tests.factor
@@ -2,7 +2,9 @@ IN: compiler.cfg.value-numbering.tests
 USING: compiler.cfg.value-numbering compiler.cfg.instructions
 compiler.cfg.registers compiler.cfg.debugger compiler.cfg.comparisons
 cpu.architecture tools.test kernel math combinators.short-circuit
-accessors sequences compiler.cfg vectors arrays layouts namespaces ;
+accessors sequences compiler.cfg.predecessors
+compiler.cfg.phi-elimination compiler.cfg.dce compiler.cfg.liveness
+compiler.cfg assocs vectors arrays layouts namespaces ;
 
 : trim-temps ( insns -- insns )
     [
@@ -943,7 +945,79 @@ cell 8 = [
     } test-value-numbering
 ] unit-test
 
-: test-branch-folding ( insns -- insns' )
+[
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##load-immediate f V int-regs 1 5 }
+    }
+] [
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##compare f V int-regs 1 V int-regs 0 V int-regs 0 cc< }
+    } test-value-numbering
+] unit-test
+
+[
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##load-reference f V int-regs 1 t }
+    }
+] [
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##compare f V int-regs 1 V int-regs 0 V int-regs 0 cc<= }
+    } test-value-numbering
+] unit-test
+
+[
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##load-immediate f V int-regs 1 5 }
+    }
+] [
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##compare f V int-regs 1 V int-regs 0 V int-regs 0 cc> }
+    } test-value-numbering
+] unit-test
+
+[
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##load-reference f V int-regs 1 t }
+    }
+] [
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##compare f V int-regs 1 V int-regs 0 V int-regs 0 cc>= }
+    } test-value-numbering
+] unit-test
+
+[
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##load-immediate f V int-regs 1 5 }
+    }
+] [
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##compare f V int-regs 1 V int-regs 0 V int-regs 0 cc/= }
+    } test-value-numbering
+] unit-test
+
+[
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##load-reference f V int-regs 1 t }
+    }
+] [
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##compare f V int-regs 1 V int-regs 0 V int-regs 0 cc= }
+    } test-value-numbering
+] unit-test
+
+: test-branch-folding ( insns -- insns' n )
     <basic-block>
     [ V{ 0 1 } clone >>successors basic-block set test-value-numbering ] keep
     successors>> first ;
@@ -1008,3 +1082,188 @@ cell 8 = [
     } test-branch-folding
 ] unit-test
 
+[
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##branch }
+    }
+    1
+] [
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##compare-branch f V int-regs 0 V int-regs 0 cc< }
+    } test-branch-folding
+] unit-test
+
+[
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##branch }
+    }
+    0
+] [
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##compare-branch f V int-regs 0 V int-regs 0 cc<= }
+    } test-branch-folding
+] unit-test
+
+[
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##branch }
+    }
+    1
+] [
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##compare-branch f V int-regs 0 V int-regs 0 cc> }
+    } test-branch-folding
+] unit-test
+
+[
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##branch }
+    }
+    0
+] [
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##compare-branch f V int-regs 0 V int-regs 0 cc>= }
+    } test-branch-folding
+] unit-test
+
+[
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##branch }
+    }
+    0
+] [
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##compare-branch f V int-regs 0 V int-regs 0 cc= }
+    } test-branch-folding
+] unit-test
+
+[
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##branch }
+    }
+    1
+] [
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##compare-branch f V int-regs 0 V int-regs 0 cc/= }
+    } test-branch-folding
+] unit-test
+
+[
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##load-reference f V int-regs 1 t }
+        T{ ##branch }
+    }
+    0
+] [
+    {
+        T{ ##peek f V int-regs 0 D 0 }
+        T{ ##compare f V int-regs 1 V int-regs 0 V int-regs 0 cc<= }
+        T{ ##compare-imm-branch f V int-regs 1 5 cc/= }
+    } test-branch-folding
+] unit-test
+
+! More branch folding tests
+V{ T{ ##branch } } 0 test-bb
+
+V{
+    T{ ##peek f V int-regs 0 D 0 }
+    T{ ##compare-branch f V int-regs 0 V int-regs 0 cc< }
+} 1 test-bb
+
+V{
+    T{ ##load-immediate f V int-regs 1 1 }
+    T{ ##branch }
+} 2 test-bb
+
+V{
+    T{ ##load-immediate f V int-regs 2 2 }
+    T{ ##branch }
+} 3 test-bb
+
+V{
+    T{ ##phi f V int-regs 3 { } }
+    T{ ##replace f V int-regs 3 D 0 }
+    T{ ##return }
+} 4 test-bb
+
+4 get instructions>> first
+2 get V int-regs 1 2array
+3 get V int-regs 2 2array 2array
+>>inputs drop
+
+test-diamond
+
+[ ] [
+    cfg new 0 get >>entry
+    compute-liveness
+    value-numbering
+    compute-predecessors
+    eliminate-phis drop
+] unit-test
+
+[ 1 ] [ 1 get successors>> length ] unit-test
+
+[ t ] [ 1 get successors>> first 3 get eq? ] unit-test
+
+[ T{ ##copy f V int-regs 3 V int-regs 2 } ]
+[ 3 get successors>> first instructions>> first ]
+unit-test
+
+[ 2 ] [ 4 get instructions>> length ] unit-test
+
+V{
+    T{ ##peek f V int-regs 0 D 0 }
+    T{ ##branch }
+} 0 test-bb
+
+V{
+    T{ ##peek f V int-regs 1 D 1 }
+    T{ ##compare-branch f V int-regs 1 V int-regs 1 cc< }
+} 1 test-bb
+
+V{
+    T{ ##copy f V int-regs 2 V int-regs 0 }
+    T{ ##branch }
+} 2 test-bb
+
+V{
+    T{ ##phi f V int-regs 3 V{ } }
+    T{ ##branch }
+} 3 test-bb
+
+V{
+    T{ ##replace f V int-regs 3 D 0 }
+    T{ ##return }
+} 4 test-bb
+
+1 get V int-regs 1 2array
+2 get V int-regs 0 2array 2array 3 get instructions>> first (>>inputs)
+
+test-diamond
+
+[ ] [
+    cfg new 0 get >>entry
+    compute-predecessors
+    compute-liveness
+    value-numbering
+    compute-predecessors
+    eliminate-dead-code
+    drop
+] unit-test
+
+[ t ] [ 1 get successors>> first 3 get eq? ] unit-test
+
+[ 1 ] [ 3 get instructions>> first inputs>> assoc-size ] unit-test
\ No newline at end of file
diff --git a/basis/compiler/cfg/value-numbering/value-numbering.factor b/basis/compiler/cfg/value-numbering/value-numbering.factor
index 9e6e058b52..202b3d1e9b 100644
--- a/basis/compiler/cfg/value-numbering/value-numbering.factor
+++ b/basis/compiler/cfg/value-numbering/value-numbering.factor
@@ -11,6 +11,8 @@ compiler.cfg.value-numbering.simplify
 compiler.cfg.value-numbering.rewrite ;
 IN: compiler.cfg.value-numbering
 
+! Local value numbering. Predecessors must be recomputed after this
+
 : number-input-values ( live-in -- )
     [ [ f next-input-expr simplify ] dip set-vn ] each ;
 
diff --git a/basis/compiler/tests/codegen.factor b/basis/compiler/tests/codegen.factor
index 8f7bc077b4..9f573019c2 100644
--- a/basis/compiler/tests/codegen.factor
+++ b/basis/compiler/tests/codegen.factor
@@ -318,4 +318,7 @@ M: cucumber equal? "The cucumber has no equal" throw ;
 
 cell 4 = [
     [ 0 ] [ 101 [ dup fixnum-fast 1 fixnum+fast 20 fixnum-shift-fast 20 fixnum-shift-fast ] compile-call ] unit-test
-] when
\ No newline at end of file
+] when
+
+! Regression from Slava's value numbering changes
+[ 1 ] [ 31337 [ dup fixnum<= [ 1 ] [ 2 ] if ] compile-call ] unit-test
\ No newline at end of file