• Russ Cox's avatar
    cmd/internal/gc: inline x := y.(*T) and x, ok := y.(*T) · 4224d81f
    Russ Cox authored
    These can be implemented with just a compare and a move instruction.
    Do so, avoiding the overhead of a call into the runtime.
    
    These assertions are a significant cost in Go code that uses interface{}
    as a safe alternative to C's void* (or unsafe.Pointer), such as the
    current version of the Go compiler.
    
    *T here includes pointer to T but also any Go type represented as
    a single pointer (chan, func, map). It does not include [1]*T or struct{*int}.
    That requires more work in other parts of the compiler; there is a TODO.
    
    Change-Id: I7ff681c20d2c3eb6ad11dd7b3a37b1f3dda23965
    Reviewed-on: https://go-review.googlesource.com/7862Reviewed-by: 's avatarRob Pike <r@golang.org>
    4224d81f
gen.go 25.7 KB