From fc595a70750ae5bca462d601d41bd43bc0059e50 Mon Sep 17 00:00:00 2001
From: Slava Pestov <slava@slava-pestovs-macbook-pro.local>
Date: Tue, 30 Jun 2009 22:43:02 -0500
Subject: [PATCH] Fix possible infinite loop in skip-empty-blocks and remove
redundant test in compiler.cfg.useless-conditionals
---
basis/compiler/cfg/cfg.factor | 14 ++++++++++++--
.../useless-conditionals.factor | 1 -
2 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/basis/compiler/cfg/cfg.factor b/basis/compiler/cfg/cfg.factor
index b279c5b6b2..68d7e15a5d 100644
--- a/basis/compiler/cfg/cfg.factor
+++ b/basis/compiler/cfg/cfg.factor
@@ -1,6 +1,6 @@
! Copyright (C) 2008, 2009 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
-USING: kernel arrays vectors accessors
+USING: kernel arrays vectors accessors assocs sets
namespaces math make fry sequences
combinators.short-circuit
compiler.cfg.instructions ;
@@ -28,8 +28,18 @@ M: basic-block hashcode* nip id>> ;
[ first ##branch? ]
} 1&& ;
+SYMBOL: visited
+
+: (skip-empty-blocks) ( bb -- bb' )
+ dup visited get key? [
+ dup empty-block? [
+ dup visited get conjoin
+ successors>> first (skip-empty-blocks)
+ ] when
+ ] unless ;
+
: skip-empty-blocks ( bb -- bb' )
- dup empty-block? [ successors>> first skip-empty-blocks ] when ;
+ H{ } clone visited [ (skip-empty-blocks) ] with-variable ;
: add-instructions ( bb quot -- )
[ instructions>> building ] dip '[
diff --git a/basis/compiler/cfg/useless-conditionals/useless-conditionals.factor b/basis/compiler/cfg/useless-conditionals/useless-conditionals.factor
index 7c32f3f8f8..6f4a6eea55 100644
--- a/basis/compiler/cfg/useless-conditionals/useless-conditionals.factor
+++ b/basis/compiler/cfg/useless-conditionals/useless-conditionals.factor
@@ -6,7 +6,6 @@ IN: compiler.cfg.useless-conditionals
: delete-conditional? ( bb -- ? )
{
- [ instructions>> length 1 > ]
[ instructions>> last class { ##compare-branch ##compare-imm-branch ##compare-float-branch } memq? ]
[ successors>> first2 [ skip-empty-blocks ] bi@ eq? ]
} 1&& ;