From ad0a2e78b374e10a74737d55f98b4bfebffe21ff Mon Sep 17 00:00:00 2001
From: Alex Vondrak <ajvondrak@csupomona.edu>
Date: Sat, 18 Jun 2011 15:26:21 -0700
Subject: [PATCH] compiler.cfg.gvn.misc: simplify ##phi rewrite

---
 extra/compiler/cfg/gvn/expressions/expressions.factor | 3 +++
 extra/compiler/cfg/gvn/misc/misc.factor               | 6 ++----
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/extra/compiler/cfg/gvn/expressions/expressions.factor b/extra/compiler/cfg/gvn/expressions/expressions.factor
index e87fe66d89..c656d4ccc0 100644
--- a/extra/compiler/cfg/gvn/expressions/expressions.factor
+++ b/extra/compiler/cfg/gvn/expressions/expressions.factor
@@ -84,5 +84,8 @@ M: ##load-integer >expr val>> <integer-expr> ;
 
 M: ##load-reference >expr obj>> <reference-expr> ;
 
+! TODO experiment with sorting, in case that identifies more
+! phi equivalences
+
 M: ##phi >expr
     inputs>> values [ vreg>vn ] map \ ##phi prefix ;
diff --git a/extra/compiler/cfg/gvn/misc/misc.factor b/extra/compiler/cfg/gvn/misc/misc.factor
index 864af7b0b5..9e23ae3bdd 100644
--- a/extra/compiler/cfg/gvn/misc/misc.factor
+++ b/extra/compiler/cfg/gvn/misc/misc.factor
@@ -16,10 +16,8 @@ M: ##replace rewrite
     ] [ 2drop f ] if ;
 
 M: ##phi rewrite
-    [ dst>> ] [ inputs>> values [ vreg>vn ] map ] bi
-    dup sift
+    [ dst>> ] [ inputs>> values [ vreg>vn ] map sift ] bi
     dup all-equal? [
-        nip
         [ drop f ]
         [ first <copy> ] if-empty
-    ] [ 3drop f ] if ;
+    ] [ 2drop f ] if ;