578922 - remove wasteful store/load in box_value_for_native_call on x64

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Luke Wagner [:luke]]

TraceRecorder::box_value_for_native_call currently contains the following snippet:

        // TODO: this is very sad; remove when there is a LIR_d2q
        LIns *tmp = lir->insAlloc(sizeof(Value));
        lir->insStore(v_ins, tmp, 0, ACC_OTHER);
        return lir->insLoad(LIR_ldq, tmp, 0, ACC_OTHER);

When bug 574969 is finished, this hack can be removed, which will improve the performance of boxing doubles on x64.

Comment 1

[Laura Thomson :laura]

I think you got the wrong bug in your Depends on - I bet it's not really bug 549153.

Comment 2

[Luke Wagner [:luke]]

Oops, you're right!

Comment 3

[Luke Wagner [:luke]]

Attachment: use LIR_dasq

SS is 2ms (.3%) faster (1ms from each of 3d-cute and crypto-aes).
V8 is 36ms (.7%) faster (from earley-boyer and splay).

Comment 4

[Luke Wagner [:luke]]

http://hg.mozilla.org/tracemonkey/rev/370feb22c8a1

Comment 5

[Robert Sayre]

http://hg.mozilla.org/mozilla-central/rev/370feb22c8a1