On 2013/09/09 19:08:22, Jakob wrote:
This does not lgtm. It is very unintuitive why Double vs. Int32
representation
would have anything to do with whether operands are better swapped or not.
Probably this benchmark just happens to create a situation where our
heuristic
makes the wrong decision. Maybe Better{Left,Right}Operand() should be made
smarter? Changing behavior based on representation does not seem right.
Yes, after revisit the issue, I also find that simply removing this feature
for
double value is not correct.
It would be better to make Better{Left,Right}Operand()smarter. And it is
also
possible that the benchmark I used seems to be just a corner case which
enlarges
the negative impact of xmm register move. WIP....
I paste the benchmark here in case you can't access it.
function test_add(x, y) {
var z = 0;
for (var i = 0; i < x; i++)
z += y;
}
test_add(0x3ffffff, 10.5);
function test_mul(x, y) {
var z = 10;
for (var i = 0; i < x; i++)
z = z * y;
}
test_mul(0x3ffffff, 10.5);
https://codereview.chromium.org/23717039/
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