// If this value is sufficiently large, look through referrers to see if we can
// avoid a load.
func (fr *frame) canAvoidLoad(instr *ssa.UnOp, op llvm.Value) bool {
if fr.types.Sizeof(instr.Type()) < 16 {
// Don't bother with small values.
return false
}
// Keep track of whether our pointer may escape. We conservatively assume
// that MakeInterfaces will escape.
esc := false
// We only know how to avoid loads if they are used to create an interface
// or read an element of the structure. If we see any other referrer, abort.
for _, ref := range *instr.Referrers() {
switch ref.(type) {
case *ssa.MakeInterface:
esc = true
case *ssa.Field, *ssa.Index:
// ok
default:
return false
}
}
var opcopy llvm.Value
if esc {
opcopy = fr.createTypeMalloc(instr.Type())
} else {
opcopy = fr.allocaBuilder.CreateAlloca(fr.types.ToLLVM(instr.Type()), "")
}
fr.memcpy(opcopy, op, llvm.ConstInt(fr.types.inttype, uint64(fr.types.Sizeof(instr.Type())), false))
fr.ptr[instr] = opcopy
return true
}
