1113018 - x86-64 masm.extractObject does what looks like an unnecessary mov

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, defect)

Description

[Boris Zbarsky [:bzbarsky]]

Here's the codegen I see for the masm.extractObject call in CallDOMNative:

    movq       0x0(%rsp), %r11
    movabsq    $0x7fffffffffff, %rsi
    andq       %r11, %rsi

With the patch I'm about to attach this becomes:

    movabsq    $0x7fffffffffff, %rsi
    andq       0x0(%rsp), %rsi

Comment 1

[Boris Zbarsky [:bzbarsky]]

Attachment: Stop manually moving things into ScratchReg in the x86-64 version of extractObject; just rely on unboxNonDouble doing the right thing as needed

Comment 2

[Dan Gohman [:sunfish]]

Comment on attachment 8538290 [details] [diff] [review]
Stop manually moving things into ScratchReg in the x86-64 version of extractObject; just rely on unboxNonDouble doing the right thing as needed

Review of attachment 8538290 [details] [diff] [review]:
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Nice, that eliminates an ugly coupling at the same time!

Comment 3

[Boris Zbarsky [:bzbarsky]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/936b4df54580

Comment 4

[Phil Ringnalda (:philor)]

https://hg.mozilla.org/mozilla-central/rev/936b4df54580