[ruby-dev:12387] reducing logical operation

なかだです。

  せっかく構文木があるんだからと思っても、なかなか最適化は難し
いです。とりあえず論理式の簡略化だけしてみましたが、あんまり違
いはなさそうな気も。


Index: parse.y
===================================================================
RCS file: /home/cvs/ruby/src/ruby/parse.y,v
retrieving revision 1.90
diff -u -2 -p -r1.90 parse.y
--- parse.y	2001/03/06 08:17:16	1.90
+++ parse.y	2001/03/07 02:07:33
@@ -113,4 +113,9 @@ static NODE *new_call();
 static NODE *new_fcall();
 static NODE *new_super();
+static NODE *new_if _((NODE* cond, NODE* t, NODE* f));
+#define new_unless(c, t, f) new_if(c, f, t)
+static NODE *new_loop _((enum node_type t, NODE *c, NODE *b, int state));
+#define new_while(c, b, p) new_loop(NODE_WHILE, c, b, p)
+#define new_until(c, b, p) new_loop(NODE_UNTIL, c, b, p)
 
 static NODE *gettable();
@@ -349,5 +354,5 @@ stmt		: kALIAS fitem {lex_state = EXPR_F
 		    {
 			value_expr($3);
-			$$ = NEW_IF(cond($3), $1, 0);
+			$$ = new_if(cond($3), $1, 0);
 		        fixpos($$, $3);
 		    }
@@ -355,5 +360,5 @@ stmt		: kALIAS fitem {lex_state = EXPR_F
 		    {
 			value_expr($3);
-			$$ = NEW_UNLESS(cond($3), $1, 0);
+			$$ = new_unless(cond($3), $1, 0);
 		        fixpos($$, $3);
 		    }
@@ -361,14 +366,9 @@ stmt		: kALIAS fitem {lex_state = EXPR_F
 		    {
 			value_expr($3);
-			if ($1) {
-			    if (nd_type($1) == NODE_BEGIN) {
-				$$ = NEW_WHILE(cond($3), $1->nd_body, 0);
-			    }
-			    else {
-				$$ = NEW_WHILE(cond($3), $1, 1);
-			    }
+			if ($1 && nd_type($1) == NODE_BEGIN) {
+			    $$ = new_while(cond($3), $1->nd_body, 0);
 			}
 			else {
-			    $$ = 0;
+			    $$ = new_while(cond($3), $1, 1);
 			}
 		    }
@@ -376,14 +376,9 @@ stmt		: kALIAS fitem {lex_state = EXPR_F
 		    {
 			value_expr($3);
-			if ($1) {
-			    if (nd_type($1) == NODE_BEGIN) {
-				$$ = NEW_UNTIL(cond($3), $1->nd_body, 0);
-			    }
-			    else {
-				$$ = NEW_UNTIL(cond($3), $1, 1);
-			    }
+			if ($1 && nd_type($1) == NODE_BEGIN) {
+			    $$ = new_until(cond($3), $1->nd_body, 0);
 			}
 			else {
-			    $$ = 0;
+			    $$ = new_until(cond($3), $1, 1);
 			}
 		    }
@@ -912,5 +907,5 @@ arg		: lhs '=' arg
 		    {
 			value_expr($1);
-			$$ = NEW_IF(cond($1), $3, $5);
+			$$ = new_if(cond($1), $3, $5);
 		        fixpos($$, $1);
 		    }
@@ -1206,5 +1201,5 @@ primary		: literal
 		    {
 			value_expr($2);
-			$$ = NEW_IF(cond($2), $4, $5);
+			$$ = new_if(cond($2), $4, $5);
 		        fixpos($$, $2);
 		    }
@@ -1215,5 +1210,5 @@ primary		: literal
 		    {
 			value_expr($2);
-			$$ = NEW_UNLESS(cond($2), $4, $5);
+			$$ = new_unless(cond($2), $4, $5);
 		        fixpos($$, $2);
 		    }
@@ -1223,5 +1218,5 @@ primary		: literal
 		    {
 			value_expr($3);
-			$$ = NEW_WHILE(cond($3), $6, 1);
+			$$ = new_while(cond($3), $6, 1);
 		        fixpos($$, $3);
 		    }
@@ -1231,5 +1226,5 @@ primary		: literal
 		    {
 			value_expr($3);
-			$$ = NEW_UNTIL(cond($3), $6, 1);
+			$$ = new_until(cond($3), $6, 1);
 		        fixpos($$, $3);
 		    }
@@ -1401,5 +1396,5 @@ if_tail		: opt_else
 		    {
 			value_expr($2);
-			$$ = NEW_IF(cond($2), $4, $5);
+			$$ = new_if(cond($2), $4, $5);
 		        fixpos($$, $2);
 		    }
@@ -4580,5 +4575,14 @@ logop(type, left, right)
 {
     value_expr(left);
-    return rb_node_newnode(type, cond1(left, 1), cond1(right, 1), 0);
+    left = cond1(left, 1);
+    right = cond1(right, 1);
+    if (nd_type(left) == NODE_NOT && nd_type(right) == NODE_NOT) {
+	right->nd_2nd = right->nd_body;
+	right->nd_1st = left->nd_body;
+	left->nd_body = right;
+	nd_set_type(right, type ^ (NODE_OR ^ NODE_AND));
+	return left;
+    }
+    return rb_node_newnode(type, left, right, 0);
 }
 
@@ -4629,4 +4633,34 @@ new_super(a)
     }
     return NEW_SUPER(a);
+}
+
+static NODE*
+new_if(cond, iftrue, iffalse)
+    NODE *cond, *iftrue, *iffalse;
+{
+    if (nd_type(cond) != NODE_NOT) {
+	return NEW_IF(cond, iftrue, iffalse);
+    }
+    cond->nd_cond = cond->nd_body;
+    cond->nd_body = iffalse;
+    cond->nd_else = iftrue;
+    nd_set_type(cond, NODE_IF);
+    return cond;
+}
+
+static NODE*
+new_loop(type, cond, body, state)
+    enum node_type type;
+    NODE *cond, *body;
+    int state;
+{
+    if (nd_type(cond) != NODE_NOT) {
+	return rb_node_newnode(type, cond, body, state);
+    }
+    cond->nd_cond = cond->nd_body;
+    cond->nd_body = body;
+    cond->nd_state = state;
+    nd_set_type(cond, type ^ (NODE_WHILE ^ NODE_UNTIL));
+    return cond;
 }
 


-- 
--- 僕の前にBugはない。
--- 僕の後ろにBugはできる。
    中田 伸悦