diff options
author | nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2015-01-29 08:03:24 +0000 |
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committer | nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2015-01-29 08:03:24 +0000 |
commit | 9443203ee829622ae44e2722df0e14dfeeec2ee3 (patch) | |
tree | 3ce2828df2563ec100a37771676d5a2b398c1c89 /parse.y | |
parent | a1f8fbd18da34473ad27323b11f4ebe06dc43104 (diff) |
parse.y: optimize conditions
* 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
Diffstat (limited to 'parse.y')
-rw-r--r-- | parse.y | 48 |
1 files changed, 43 insertions, 5 deletions
@@ -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)); @@ -9655,10 +9657,31 @@ cond_gen(struct parser_params *parser, NODE *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); } |