2005120 - riscv64: Use Zba `add.uw rd, rs1, zero` (aka `zext.w rd, rs1`) to simplify ZeroExtendWord

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, task, P5)

Description

[Rong Bao [:csmantle]]

Once Bug 2003218 lands, we will have proper feature detection on RV64 and simulator support for Zba, Zbb and Zbs extensions. Then, we could use zext.w (^1) to simplify ZeroExtendWord (^2).

Comment 1

[Rong Bao [:csmantle]]

Attachment: Bug 2005120 - [riscv64] Part 1: Simplify MacroAssemblerRiscv64Compat::ZeroExtendWord with zext.w from Zba extension. r=#spidermonkey-reviewers,m_kato

Comment 2

[Rong Bao [:csmantle]]

Attachment: Bug 2005120 - [riscv64] Part 2: (Drive-by) Rename Zb* assembler functions to existing naming convention. r=#spidermonkey-reviewers,m_kato

Existing functions uses an underscore to replace the dots in instruction
mnemonics to form a valid C identifier. This patch renames newly-added
functions to match this convention.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/8839e907e314
https://hg.mozilla.org/integration/autoland/rev/2609990b8dc1
[riscv64] Part 1: Simplify MacroAssemblerRiscv64Compat::ZeroExtendWord with zext.w from Zba extension. r=m_kato,spidermonkey-reviewers,iain
https://github.com/mozilla-firefox/firefox/commit/864016ce6169
https://hg.mozilla.org/integration/autoland/rev/f4776f7c82ef
[riscv64] Part 2: (Drive-by) Rename Zb* assembler functions to existing naming convention. r=m_kato,spidermonkey-reviewers,iain

Comment 4

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/2609990b8dc1
https://hg.mozilla.org/mozilla-central/rev/f4776f7c82ef