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parse.y: optimize conditions

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* parse.y (new_if_gen, logop_gen): simplify constant conditional
  expressions to help the optimizer.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49435 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
nobu 2015-01-29 08:03:24 +00:00
parent a1f8fbd18d
commit 9443203ee8
1 changed files with 43 additions and 5 deletions
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48
parse.y
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@ -374,6 +374,8 @@ static NODE* node_newnode(struct parser_params *, enum node_type, VALUE, VALUE,
static NODE *cond_gen(struct parser_params*,NODE*);
#define cond(node) cond_gen(parser, (node))
static NODE *new_if_gen(struct parser_params*,NODE*,NODE*,NODE*);
#define new_if(cc,left,right) new_if_gen(parser, (cc), (left), (right))
static NODE *logop_gen(struct parser_params*,enum node_type,NODE*,NODE*);
#define logop(type,node1,node2) logop_gen(parser, (type), (node1), (node2))
@ -1144,7 +1146,7 @@ stmt : keyword_alias fitem {lex_state = EXPR_FNAME;} fitem
| stmt modifier_if expr_value
{
/*%%%*/
$$ = NEW_IF(cond($3), remove_begin($1), 0);
$$ = new_if($3, remove_begin($1), 0);
fixpos($$, $3);
/*%
$$ = dispatch2(if_mod, $3, $1);
@ -2373,7 +2375,7 @@ arg : lhs '=' arg
{
/*%%%*/
value_expr($1);
$$ = NEW_IF(cond($1), $4, $8);
$$ = new_if($1, $4, $8);
fixpos($$, $1);
/*%
$$ = dispatch3(ifop, $1, $4, $8);
@ -2825,7 +2827,7 @@ primary : literal
k_end
{
/*%%%*/
$$ = NEW_IF(cond($2), $4, $5);
$$ = new_if($2, $4, $5);
fixpos($$, $2);
/*%
$$ = dispatch3(if, $2, $4, escape_Qundef($5));
@ -3206,7 +3208,7 @@ if_tail : opt_else
if_tail
{
/*%%%*/
$$ = NEW_IF(cond($2), $4, $5);
$$ = new_if($2, $4, $5);
fixpos($$, $2);
/*%
$$ = dispatch3(elsif, $2, $4, escape_Qundef($5));
@ -9654,11 +9656,32 @@ cond_gen(struct parser_params *parser, NODE *node)
return cond0(parser, node);
}
static NODE*
new_if_gen(struct parser_params *parser, NODE *cc, NODE *left, NODE *right)
{
if (!cc) return right;
cc = cond0(parser, cc);
switch (nd_type(cc)) {
case NODE_NIL:
case NODE_FALSE:
return right;
case NODE_TRUE:
case NODE_LIT:
case NODE_STR:
return left;
}
return NEW_IF(cc, left, right);
}
static NODE*
logop_gen(struct parser_params *parser, enum node_type type, NODE *left, NODE *right)
{
value_expr(left);
if (left && (enum node_type)nd_type(left) == type) {
if (!left) {
if (type == NODE_AND) return 0;
/* make NODE_OR not to be "void value expression" */
}
else if ((enum node_type)nd_type(left) == type) {
NODE *node = left, *second;
while ((second = node->nd_2nd) != 0 && (enum node_type)nd_type(second) == type) {
node = second;
@ -9666,6 +9689,21 @@ logop_gen(struct parser_params *parser, enum node_type type, NODE *left, NODE *r
node->nd_2nd = NEW_NODE(type, second, right, 0);
return left;
}
else {
switch (nd_type(left)) {
case NODE_NIL:
case NODE_FALSE:
if (type == NODE_AND) return left;
left = 0;
break;
case NODE_TRUE:
case NODE_LIT:
case NODE_STR:
if (type != NODE_AND) return left;
nd_set_type(left, NODE_TRUE);
break;
}
}
return NEW_NODE(type, left, right, 0);
}