Bug 272901 – [WASM] Avoid extraneous move for simple integer arithmetic in BBQ

• Status: RESOLVED
• Resolution: FIXED
• Component: WebAssembly

[David Degazio]

When we emit various simple integer arithmetic instructions in BBQ with a constant operand, we currently use the MacroAssembler API pretty pessimistically, for example in i32.add:

    m_jit.move(ImmHelpers::regLocation(lhsLocation, rhsLocation).asGPR(), resultLocation.asGPR());
    m_jit.add32(Imm32(ImmHelpers::imm(lhs, rhs).asI32()), resultLocation.asGPR());

It's well-supported in our MacroAssembler to perform a three-operand add (and other arithmetic instructions) even on platforms like x86, so we should just use that. It should save us from obviously redundant codegen like the following on ARM:

    mov x1, x0
    add x1, x1, #1

...and allow us to use instructions like lea on x86 to accomplish much the same.

[Radar WebKit Bug Importer]

<rdar://problem/126695575>

[David Degazio]

*** Bug 272902 has been marked as a duplicate of this bug. ***

[David Degazio]

Pull request: https://github.com/WebKit/WebKit/pull/27473

[EWS]

Committed 277770@main (7a2375d28da4): <https://commits.webkit.org/277770@main>

Reviewed commits have been landed. Closing PR #27473 and removing active labels.

[Fujii Hironori]

Regressed: Bug 273048 – REGRESSION(277770@main): [Mac WK1, GTK, WPE, Win] ASSERTION FAILED: v <= 0 under MacroAssemblerX86Common::sub32