🛤 Sign-extension operators

[binji]

This is a tracking issue for a post-MVP feature
It will be updated as the issue progresses.

Topic Sign-extension operators
Champion Ben Smith @binji
Status in progress
Phase standardize the feature
Linked issues
Linked repositories github.com/WebAssembly/sign-extension-ops

Details

This proposal adds five new integer instructions for sign-extending 8-bit, 16-bit, and 32-bit values.

• i32.extend8_s: extend a signed 8-bit integer to a 32-bit integer
• i32.extend16_s: extend a signed 16-bit integer to a 32-bit integer
• i64.extend8_s: extend a signed 8-bit integer to a 64-bit integer
• i64.extend16_s: extend a signed 16-bit integer to a 64-bit integer
• i64.extend32_s: extend a signed 32-bit integer to a 64-bit integer

[lars-t-hansen]

We've implemented this and it's been in Nightly for a long time, with our own test cases and the proposed spec test cases. We're just waiting for this proposal to advance before we ship.
https://bugzilla.mozilla.org/show_bug.cgi?id=1429818

[lars-t-hansen]

Sign extension ops are now riding the trains in Firefox and will likely be in FF62, currently scheduled to ship September 5.

[binji]

Moved to WebAssembly/proposals#9.