diff options
Diffstat (limited to 'tools/js-optimizer.js')
| -rw-r--r-- | tools/js-optimizer.js | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/tools/js-optimizer.js b/tools/js-optimizer.js index 5bf88a33..a317543d 100644 --- a/tools/js-optimizer.js +++ b/tools/js-optimizer.js @@ -149,7 +149,7 @@ function emptyNode() { // Passes // Dump the AST. Useful for debugging. For example, -// echo "HEAP[(a+b+c)>>2]" | node tools/js-optimizer.js dump +// echo "HEAP[(a+b+c)>>2]" | node tools/js-optimizer.js dumpAst function dumpAst(ast) { printErr(JSON.stringify(ast)); } @@ -354,6 +354,7 @@ function simplifyExpressionsPre(ast) { // HEAP[x >> 2] // very often. We can in some cases do the shift on the variable itself when it is set, // to greatly reduce the number of shift operations. +// XXX x << 24 >> 24 - are we breaking that? only optimize small shifts! function optimizeShifts(ast) { traverseGeneratedFunctions(ast, function(fun) { var funMore = true; @@ -508,7 +509,8 @@ function optimizeShifts(ast) { }); traverse(fun, function(node, type, stack) { // replace name with unshifted name, making everything valid again by balancing the assign changes stack.push(node); - if (node[0] == 'name' && !node[2] && vars[node[1]] && vars[node[1]].primaryShift >= 0 && stack[stack.length-2][0] != 'assign') { + if (node[0] == 'name' && !node[2] && vars[node[1]] && vars[node[1]].primaryShift >= 0 && + (stack[stack.length-2][0] != 'assign' || stack[stack.length-2][2] != node)) { // ignore changing VAR in |VAR = something| node[2] = true; return ['binary', '<<', node, ['num', vars[node[1]].primaryShift]]; } |