1671996 - Signed right shift 8x16 by constant does not work if src != dest

Status: RESOLVED FIXED

(Core :: JavaScript: WebAssembly, defect, P3)

Description

[Lars T Hansen [:lth]]

An oversight, because both compilers force src == dest and this doesn't currently matter: if src != dest, the code will use the old value of dest. But the protocol for the masm API is that the code generator patterns should work for all register assignments, so let's fix it.

Comment 1

[Lars T Hansen [:lth]]

Attachment: Bug 1671996 - Do not use garbage bits if srcreg not same as destreg. r?jseward

Copy src -> dest if they are unequal; moveSimd128 avoids redundant moves.

Depends on D94003

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/202d806bac14
Do not use garbage bits if srcreg not same as destreg.  r=jseward

Comment 3

[Alexandru Michis [:malexandru]]

Backed out 13 changesets (bug 1641595, bug 1671998, bug 1672770, bug 1641641, bug 1672697, bug 1672911, bug 1671996, bug 1671907, bug 1640662) for causing sm failures in splat-x64-ion-codegen.js

Backout link: https://hg.mozilla.org/integration/autoland/rev/c2c595aa8fe1dc18803bf80df3bca7ca07443038

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/1168298328ee
Do not use garbage bits if srcreg not same as destreg.  r=jseward

Comment 5

[Razvan Maries]

https://hg.mozilla.org/mozilla-central/rev/1168298328ee