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cabi: remove unsafe load-to-memcpy optimization #1607

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Merged
xushiwei merged 4 commits into from
Feb 5, 2026
Merged

cabi: remove unsafe load-to-memcpy optimization #1607

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643d61e
test:regression for https://github.com/goplus/llgo/issues/1606 https:…
luoliwoshang Feb 3, 2026
42218be
cabi: fix sret return value corruption when source modified after load
luoliwoshang Feb 4, 2026
446b8b0
test: move return-1605 regression test to _demo with validation
luoliwoshang Feb 4, 2026
fcdd096
cabi: add regression test for issue #1608
luoliwoshang Feb 5, 2026
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2 changes: 2 additions & 0 deletions cl/_testgo/return-1605/expect.txt
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2
2
25 changes: 25 additions & 0 deletions cl/_testgo/return-1605/main.go
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package main

type T struct {
data []int
}

func a() []int {
var t = T{data: []int{1, 2}}
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@gemini-code-assist gemini-code-assist bot Feb 3, 2026

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medium

In Go, it is more idiomatic to use the short variable declaration := when declaring and initializing a new variable inside a function. This improves code conciseness and readability.

Suggested change
var t = T{data: []int{1, 2}}
t := T{data: []int{1, 2}}

a := t.data
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@xgopilot xgopilot bot Feb 3, 2026

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The local variable a shadows the function name a. While Go allows this, consider renaming to something more descriptive like slice, result, or originalData for improved readability.

t.data = []int{1, 2, 3}
return a
}

func b() ([]int, bool) {
var t = T{data: []int{1, 2}}
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@gemini-code-assist gemini-code-assist bot Feb 3, 2026

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medium

In Go, it is more idiomatic to use the short variable declaration := when declaring and initializing a new variable inside a function. This improves code conciseness and readability.

Suggested change
var t = T{data: []int{1, 2}}
t := T{data: []int{1, 2}}

a := t.data
t.data = []int{1, 2, 3}
return a, true
}

func main() {
println(len(a()))
c, _ := b()
println(len(c))
}
110 changes: 110 additions & 0 deletions cl/_testgo/return-1605/out.ll
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; ModuleID = 'github.com/goplus/llgo/cl/_testgo/return-1605'
source_filename = "github.com/goplus/llgo/cl/_testgo/return-1605"

%"github.com/goplus/llgo/runtime/internal/runtime.Slice" = type { ptr, i64, i64 }
%"github.com/goplus/llgo/cl/_testgo/return-1605.T" = type { %"github.com/goplus/llgo/runtime/internal/runtime.Slice" }

@"github.com/goplus/llgo/cl/_testgo/return-1605.init$guard" = global i1 false, align 1

define %"github.com/goplus/llgo/runtime/internal/runtime.Slice" @"github.com/goplus/llgo/cl/_testgo/return-1605.a"() {
_llgo_0:
%0 = alloca %"github.com/goplus/llgo/cl/_testgo/return-1605.T", align 8
call void @llvm.memset(ptr %0, i8 0, i64 24, i1 false)
%1 = getelementptr inbounds %"github.com/goplus/llgo/cl/_testgo/return-1605.T", ptr %0, i32 0, i32 0
%2 = call ptr @"github.com/goplus/llgo/runtime/internal/runtime.AllocZ"(i64 16)
%3 = getelementptr inbounds i64, ptr %2, i64 0
store i64 1, ptr %3, align 4
%4 = getelementptr inbounds i64, ptr %2, i64 1
store i64 2, ptr %4, align 4
%5 = insertvalue %"github.com/goplus/llgo/runtime/internal/runtime.Slice" undef, ptr %2, 0
%6 = insertvalue %"github.com/goplus/llgo/runtime/internal/runtime.Slice" %5, i64 2, 1
%7 = insertvalue %"github.com/goplus/llgo/runtime/internal/runtime.Slice" %6, i64 2, 2
store %"github.com/goplus/llgo/runtime/internal/runtime.Slice" %7, ptr %1, align 8
%8 = getelementptr inbounds %"github.com/goplus/llgo/cl/_testgo/return-1605.T", ptr %0, i32 0, i32 0
%9 = load %"github.com/goplus/llgo/runtime/internal/runtime.Slice", ptr %8, align 8
%10 = call ptr @"github.com/goplus/llgo/runtime/internal/runtime.AllocZ"(i64 24)
%11 = getelementptr inbounds i64, ptr %10, i64 0
store i64 1, ptr %11, align 4
%12 = getelementptr inbounds i64, ptr %10, i64 1
store i64 2, ptr %12, align 4
%13 = getelementptr inbounds i64, ptr %10, i64 2
store i64 3, ptr %13, align 4
%14 = insertvalue %"github.com/goplus/llgo/runtime/internal/runtime.Slice" undef, ptr %10, 0
%15 = insertvalue %"github.com/goplus/llgo/runtime/internal/runtime.Slice" %14, i64 3, 1
%16 = insertvalue %"github.com/goplus/llgo/runtime/internal/runtime.Slice" %15, i64 3, 2
%17 = getelementptr inbounds %"github.com/goplus/llgo/cl/_testgo/return-1605.T", ptr %0, i32 0, i32 0
store %"github.com/goplus/llgo/runtime/internal/runtime.Slice" %16, ptr %17, align 8
ret %"github.com/goplus/llgo/runtime/internal/runtime.Slice" %9
}

define { %"github.com/goplus/llgo/runtime/internal/runtime.Slice", i1 } @"github.com/goplus/llgo/cl/_testgo/return-1605.b"() {
_llgo_0:
%0 = alloca %"github.com/goplus/llgo/cl/_testgo/return-1605.T", align 8
call void @llvm.memset(ptr %0, i8 0, i64 24, i1 false)
%1 = getelementptr inbounds %"github.com/goplus/llgo/cl/_testgo/return-1605.T", ptr %0, i32 0, i32 0
%2 = call ptr @"github.com/goplus/llgo/runtime/internal/runtime.AllocZ"(i64 16)
%3 = getelementptr inbounds i64, ptr %2, i64 0
store i64 1, ptr %3, align 4
%4 = getelementptr inbounds i64, ptr %2, i64 1
store i64 2, ptr %4, align 4
%5 = insertvalue %"github.com/goplus/llgo/runtime/internal/runtime.Slice" undef, ptr %2, 0
%6 = insertvalue %"github.com/goplus/llgo/runtime/internal/runtime.Slice" %5, i64 2, 1
%7 = insertvalue %"github.com/goplus/llgo/runtime/internal/runtime.Slice" %6, i64 2, 2
store %"github.com/goplus/llgo/runtime/internal/runtime.Slice" %7, ptr %1, align 8
%8 = getelementptr inbounds %"github.com/goplus/llgo/cl/_testgo/return-1605.T", ptr %0, i32 0, i32 0
%9 = load %"github.com/goplus/llgo/runtime/internal/runtime.Slice", ptr %8, align 8
%10 = call ptr @"github.com/goplus/llgo/runtime/internal/runtime.AllocZ"(i64 24)
%11 = getelementptr inbounds i64, ptr %10, i64 0
store i64 1, ptr %11, align 4
%12 = getelementptr inbounds i64, ptr %10, i64 1
store i64 2, ptr %12, align 4
%13 = getelementptr inbounds i64, ptr %10, i64 2
store i64 3, ptr %13, align 4
%14 = insertvalue %"github.com/goplus/llgo/runtime/internal/runtime.Slice" undef, ptr %10, 0
%15 = insertvalue %"github.com/goplus/llgo/runtime/internal/runtime.Slice" %14, i64 3, 1
%16 = insertvalue %"github.com/goplus/llgo/runtime/internal/runtime.Slice" %15, i64 3, 2
%17 = getelementptr inbounds %"github.com/goplus/llgo/cl/_testgo/return-1605.T", ptr %0, i32 0, i32 0
store %"github.com/goplus/llgo/runtime/internal/runtime.Slice" %16, ptr %17, align 8
%18 = insertvalue { %"github.com/goplus/llgo/runtime/internal/runtime.Slice", i1 } undef, %"github.com/goplus/llgo/runtime/internal/runtime.Slice" %9, 0
%19 = insertvalue { %"github.com/goplus/llgo/runtime/internal/runtime.Slice", i1 } %18, i1 true, 1
ret { %"github.com/goplus/llgo/runtime/internal/runtime.Slice", i1 } %19
}

define void @"github.com/goplus/llgo/cl/_testgo/return-1605.init"() {
_llgo_0:
%0 = load i1, ptr @"github.com/goplus/llgo/cl/_testgo/return-1605.init$guard", align 1
br i1 %0, label %_llgo_2, label %_llgo_1

_llgo_1: ; preds = %_llgo_0
store i1 true, ptr @"github.com/goplus/llgo/cl/_testgo/return-1605.init$guard", align 1
br label %_llgo_2

_llgo_2: ; preds = %_llgo_1, %_llgo_0
ret void
}

define void @"github.com/goplus/llgo/cl/_testgo/return-1605.main"() {
_llgo_0:
%0 = call %"github.com/goplus/llgo/runtime/internal/runtime.Slice" @"github.com/goplus/llgo/cl/_testgo/return-1605.a"()
%1 = extractvalue %"github.com/goplus/llgo/runtime/internal/runtime.Slice" %0, 1
call void @"github.com/goplus/llgo/runtime/internal/runtime.PrintInt"(i64 %1)
call void @"github.com/goplus/llgo/runtime/internal/runtime.PrintByte"(i8 10)
%2 = call { %"github.com/goplus/llgo/runtime/internal/runtime.Slice", i1 } @"github.com/goplus/llgo/cl/_testgo/return-1605.b"()
%3 = extractvalue { %"github.com/goplus/llgo/runtime/internal/runtime.Slice", i1 } %2, 0
%4 = extractvalue { %"github.com/goplus/llgo/runtime/internal/runtime.Slice", i1 } %2, 1
%5 = extractvalue %"github.com/goplus/llgo/runtime/internal/runtime.Slice" %3, 1
call void @"github.com/goplus/llgo/runtime/internal/runtime.PrintInt"(i64 %5)
call void @"github.com/goplus/llgo/runtime/internal/runtime.PrintByte"(i8 10)
ret void
}

; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: write)
declare void @llvm.memset(ptr nocapture writeonly, i8, i64, i1 immarg) #0

declare ptr @"github.com/goplus/llgo/runtime/internal/runtime.AllocZ"(i64)

declare void @"github.com/goplus/llgo/runtime/internal/runtime.PrintInt"(i64)

declare void @"github.com/goplus/llgo/runtime/internal/runtime.PrintByte"(i8)

attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: write) }
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