diff options
Diffstat (limited to 'tools/js-optimizer.js')
| -rw-r--r-- | tools/js-optimizer.js | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/tools/js-optimizer.js b/tools/js-optimizer.js index 99d4581a..ce23b068 100644 --- a/tools/js-optimizer.js +++ b/tools/js-optimizer.js @@ -266,9 +266,12 @@ function simplifyExpressionsPre(ast) { // When there is a bunch of math like (((8+5)|0)+12)|0, only the external |0 is needed, one correction is enough. // At each node, ((X|0)+Y)|0 can be transformed into (X+Y): The inner corrections are not needed // TODO: Is the same is true for 0xff, 0xffff? + // Likewise, if we have |0 inside a block that will be >>'d, then the |0 is unnecessary because some + // 'useful' mathops already |0 anyhow. function simplifyBitops(ast) { - var SAFE_BINARY_OPS = set('+', '-', '*', '/', '%', '|'); + var USEFUL_BINARY_OPS = set('<<', '>>', '|', '&', '^'); + var SAFE_BINARY_OPS = set('+', '-', '*', '/', '%'); var ZERO = ['num', 0]; var rerun = true; while (rerun) { @@ -287,6 +290,8 @@ function simplifyExpressionsPre(ast) { break; // Too bad, we can't } } + } else if (type == 'binary' && node[1] in USEFUL_BINARY_OPS) { + stack.push(1); } else if ((type == 'binary' && node[1] in SAFE_BINARY_OPS) || type == 'num' || type == 'name') { stack.push(0); // This node is safe in that it does not interfere with this optimization } else { |