func ginscmp(op int, t *gc.Type, n1, n2 *gc.Node, likely int) *obj.Prog {
if gc.Isint[t.Etype] && n1.Op == gc.OLITERAL && gc.Smallintconst(n1) && n2.Op != gc.OLITERAL {
// Reverse comparison to place constant last.
op = gc.Brrev(op)
n1, n2 = n2, n1
}
// General case.
var r1, r2, g1, g2 gc.Node
if n1.Op == gc.ONAME && n1.Class&gc.PHEAP == 0 || n1.Op == gc.OINDREG {
r1 = *n1
} else {
gc.Regalloc(&r1, t, n1)
gc.Regalloc(&g1, n1.Type, &r1)
gc.Cgen(n1, &g1)
gmove(&g1, &r1)
}
if n2.Op == gc.OLITERAL && gc.Isint[t.Etype] && gc.Smallintconst(n2) {
r2 = *n2
} else {
gc.Regalloc(&r2, t, n2)
gc.Regalloc(&g2, n1.Type, &r2)
gc.Cgen(n2, &g2)
gmove(&g2, &r2)
}
gins(optoas(gc.OCMP, t), &r1, &r2)
if r1.Op == gc.OREGISTER {
gc.Regfree(&g1)
gc.Regfree(&r1)
}
if r2.Op == gc.OREGISTER {
gc.Regfree(&g2)
gc.Regfree(&r2)
}
return gc.Gbranch(optoas(op, t), nil, likely)
}
func ginscmp(op gc.Op, t *gc.Type, n1, n2 *gc.Node, likely int) *obj.Prog {
if t.IsInteger() && n1.Op == gc.OLITERAL && gc.Smallintconst(n1) && n2.Op != gc.OLITERAL {
// Reverse comparison to place constant last.
op = gc.Brrev(op)
n1, n2 = n2, n1
}
// General case.
var r1, r2, g1, g2 gc.Node
// A special case to make write barriers more efficient.
// Comparing the first field of a named struct can be done directly.
base := n1
if n1.Op == gc.ODOT && n1.Left.Type.IsStruct() && n1.Left.Type.Field(0).Sym == n1.Sym {
base = n1.Left
}
if base.Op == gc.ONAME && base.Class != gc.PAUTOHEAP || n1.Op == gc.OINDREG {
r1 = *n1
} else {
gc.Regalloc(&r1, t, n1)
gc.Regalloc(&g1, n1.Type, &r1)
gc.Cgen(n1, &g1)
gmove(&g1, &r1)
}
if n2.Op == gc.OLITERAL && t.IsInteger() && gc.Smallintconst(n2) {
r2 = *n2
} else {
gc.Regalloc(&r2, t, n2)
gc.Regalloc(&g2, n1.Type, &r2)
gc.Cgen(n2, &g2)
gmove(&g2, &r2)
}
gins(optoas(gc.OCMP, t), &r1, &r2)
if r1.Op == gc.OREGISTER {
gc.Regfree(&g1)
gc.Regfree(&r1)
}
if r2.Op == gc.OREGISTER {
gc.Regfree(&g2)
gc.Regfree(&r2)
}
return gc.Gbranch(optoas(op, t), nil, likely)
}