DRAFT: try improve perf

[camc314]

#8509 had a massive impact on perf because we are using this trait to compare large amounts of data. Improving the perf of these comparisons should reduce the impact of the perf degregation

the theory:

match generates code something like:

        match (self, other) {
            (Self::A(_), Self::A(_)) => true,
            (Self::B(_), Self::B(_)) => true,
            (Self::C, Self::C) => true,
            (Self::D, Self::D) => true,
            (Self::E, Self::E) => true,
            _ => false
        }

<example::Foo as example::ContentEq>::content_eq::hd04b232e31742fda:
        mov     qword ptr [rsp - 16], rdi
        mov     qword ptr [rsp - 8], rsi
        mov     rax, qword ptr [rsp - 16]
        mov     rcx, qword ptr [rax]
        movabs  rax, -9223372036854775808
        mov     rdx, rcx
        add     rdx, rax
        movabs  rax, -9223372036854775807
        add     rcx, rax
        xor     eax, eax
        sub     rdx, 4
        cmovb   rax, rcx
        mov     qword ptr [rsp - 32], rax
        mov     rax, qword ptr [rsp - 32]
        lea     rcx, [rip + .LJTI12_0]
        movsxd  rax, dword ptr [rcx + 4*rax]
        add     rax, rcx
        jmp     rax
        ud2
.LBB12_2:
        mov     rax, qword ptr [rsp - 8]
        mov     rdx, qword ptr [rax]
        movabs  rax, -9223372036854775808
        sub     rdx, rax
        mov     rcx, rdx
        add     rcx, 1
        xor     eax, eax
        cmp     rdx, 3
        cmovbe  rax, rcx
        cmp     rax, 0
        sete    al
        and     al, 1
        mov     byte ptr [rsp - 17], al
        jmp     .LBB12_7
.LBB12_3:
        mov     rax, qword ptr [rsp - 8]
        mov     rdx, qword ptr [rax]
        movabs  rax, -9223372036854775808
        sub     rdx, rax
        mov     rcx, rdx
        add     rcx, 1
        xor     eax, eax
        cmp     rdx, 3
        cmovbe  rax, rcx
        cmp     rax, 1
        sete    al
        and     al, 1
        mov     byte ptr [rsp - 17], al
        jmp     .LBB12_7
.LBB12_4:
        mov     rax, qword ptr [rsp - 8]
        mov     rdx, qword ptr [rax]
        movabs  rax, -9223372036854775808
        sub     rdx, rax
        mov     rcx, rdx
        add     rcx, 1
        xor     eax, eax
        cmp     rdx, 3
        cmovbe  rax, rcx
        cmp     rax, 2
        sete    al
        and     al, 1
        mov     byte ptr [rsp - 17], al
        jmp     .LBB12_7
.LBB12_5:
        mov     rax, qword ptr [rsp - 8]
        mov     rdx, qword ptr [rax]
        movabs  rax, -9223372036854775808
        sub     rdx, rax
        mov     rcx, rdx
        add     rcx, 1
        xor     eax, eax
        cmp     rdx, 3
        cmovbe  rax, rcx
        cmp     rax, 3
        sete    al
        and     al, 1
        mov     byte ptr [rsp - 17], al
        jmp     .LBB12_7
.LBB12_6:
        mov     rax, qword ptr [rsp - 8]
        mov     rdx, qword ptr [rax]
        movabs  rax, -9223372036854775808
        sub     rdx, rax
        mov     rcx, rdx
        add     rcx, 1
        xor     eax, eax
        cmp     rdx, 3
        cmovbe  rax, rcx
        cmp     rax, 4
        sete    al
        and     al, 1
        mov     byte ptr [rsp - 17], al
.LBB12_7:
        mov     al, byte ptr [rsp - 17]
        and     al, 1
        ret
.LJTI12_0:
        .long   .LBB12_2-.LJTI12_0
        .long   .LBB12_3-.LJTI12_0
        .long   .LBB12_4-.LJTI12_0
        .long   .LBB12_5-.LJTI12_0
        .long   .LBB12_6-.LJTI12_0

This means that it has to loop over all enum varients for a match.

i am thinking that if instead, we early return if the enum varient is not the same, this will be quicker

[camc314]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• DRAFT: try improve perf #8517 👈 (View in Graphite)
• feat(minifier): merge similar if stmts #8509 : 1 other dependent PR (#8514 )
• main

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[codspeed-hq]

CodSpeed Performance Report

Merging #8517 will not alter performance

_{Comparing c/01-15-draft_try_improve_perf (6c978c8) with c/01-15-feat_minifier_merge_similar_if_stmts (62a3dac)}

Summary

✅ 32 untouched benchmarks