cmd/compile: inlining of empty functions computes arguments #4204
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Here is another test case for the issue:
package main
import "fmt"
type Foo struct {
x, y, z, w int
}
func (Foo) Bar() {
}
func main() {
f := new(Foo)
fmt.Println(f)
f.Bar()
400c9d: 48 8b 74 24 30 mov 0x30(%rsp),%rsi
400ca2: 48 8d 7c 24 68 lea 0x68(%rsp),%rdi
400ca7: 48 c7 c1 04 00 00 00 mov $0x4,%rcx
400cae: f3 48 a5 rep movsq %ds:(%rsi),%es:(%rdi)
}
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What about (empty) `bar` inlined here? // http://play.golang.org/p/oh_n16JptE package main var i int func foo() int { i++; return 0 } func bar(n int) {} func main() { bar(foo()) println(i) } |
dvyukov
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rsc
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This should be fixed with the SSA backend at tip. |
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Go tip generates a call to the empty function if the function is only empty e.g. after some dead code elimination (e.g. when used with a compile time debug constant) in the function: #4563 |
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14531:7b037816cd5c tip linux/amd64 The following code: func raceAcquire(addr unsafe.Pointer) { } func (rw *RWMutex) Lock() { raceAcquire(unsafe.Pointer(&rw.readerSem)) } leads to generation of the following machine code: raceAcquire(unsafe.Pointer(&rw.readerSem)) 450e3e: 48 8b 44 24 20 mov 0x20(%rsp),%rax 450e43: 48 83 c0 0c add $0xc,%rax // later %rax is not used I would expect raceAcquire() call to yield no code at all.The text was updated successfully, but these errors were encountered: