Use the correct inputs when checking if inverse operator can be used.

Use the correct inputs when checking if inverse operator can be used.

R=lrn@google.com

Committed: https://code.google.com/p/dart/source/detail?r=13275

[karlklose, 2012-10-04 09:27:57]

I tried to trigger this branch with the following program, but it did not find
the first input to be useful.

main() {
  foo(x) {
    if (x == 0) return x;
    return x;
  }
  var x = 1;
  if (foo(x) == 0) {
    x = 2;
  }
  print(!(1 < x));
}

[ngeoffray, 2012-10-04 09:39:05]

https://chromiumcodereview.appspot.com/11065007/diff/1001/lib/compiler/implem...
File lib/compiler/implementation/ssa/codegen.dart (right):

https://chromiumcodereview.appspot.com/11065007/diff/1001/lib/compiler/implem...
lib/compiler/implementation/ssa/codegen.dart:1806:
!input.inputs[1].isDouble(types)) {
I think all these && make it so that we never reach here. Lasse wrote this code,
so maybe he remembers if there is a test exercising it.

https://chromiumcodereview.appspot.com/11065007/diff/1001/lib/compiler/implem...
lib/compiler/implementation/ssa/codegen.dart:1820: // TODO(ngeoffray): is this
code ever exercised in a test?
Why is that a TODO on me?

[karlklose, 2012-10-04 10:06:08]

Setting Lasse as reviewer.

https://chromiumcodereview.appspot.com/11065007/diff/1001/lib/compiler/implem...
File lib/compiler/implementation/ssa/codegen.dart (right):

https://chromiumcodereview.appspot.com/11065007/diff/1001/lib/compiler/implem...
lib/compiler/implementation/ssa/codegen.dart:1806:
!input.inputs[1].isDouble(types)) {
In the attached test program,  types[input.inputs[0]].isUseful() is false,
because the first argument is unknown.

https://chromiumcodereview.appspot.com/11065007/diff/1001/lib/compiler/implem...
lib/compiler/implementation/ssa/codegen.dart:1820: // TODO(ngeoffray): is this
code ever exercised in a test?
I thought that you wrote the code. I will change it.

[karlklose, 2012-10-04 10:59:33]

PTAL.

[Lasse Reichstein Nielsen, 2012-10-04 11:02:42]

STV!

[floitsch, 2012-10-04 11:35:26]

LGTM.

https://chromiumcodereview.appspot.com/11065007/diff/6001/lib/compiler/implem...
File lib/compiler/implementation/ssa/codegen.dart (right):

https://chromiumcodereview.appspot.com/11065007/diff/6001/lib/compiler/implem...
lib/compiler/implementation/ssa/codegen.dart:1803:
types[input.inputs[1]].isUseful() &&
I really think we should make this input.left, input.right.

https://chromiumcodereview.appspot.com/11065007/diff/6001/tests/compiler/dart...
File tests/compiler/dart2js/inverse_operator_test.dart (right):

https://chromiumcodereview.appspot.com/11065007/diff/6001/tests/compiler/dart...
tests/compiler/dart2js/inverse_operator_test.dart:10: if (x == 0) return x;
this will be too easy to inline. Maybe change to:
int inscrutable(int x) => x == 0 ? 0 : x | inscrutable(x & (x - 1));

[floitsch, 2012-10-04 13:06:57]

LGTM although I would be happy with a different name.

[karlklose, 2012-10-04 13:10:43]

What about this name?

[floitsch, 2012-10-04 16:22:15]

LGTM. thanks.