cmd/internal/gc: add backend ginscmp function to emit a comparison
This lets us abstract away which arguments can be constants and so on
and lets the back ends reverse the order of arguments if that helps.
Change-Id: I283ec1d694f2dd84eba22e5eb4aad78a2d2d9eb0
Reviewed-on: https://go-review.googlesource.com/9810
Reviewed-by: David Chase <drchase@google.com>
diff --git a/src/cmd/internal/gc/go.go b/src/cmd/internal/gc/go.go
index 71bce0b..404dcbb 100644
--- a/src/cmd/internal/gc/go.go
+++ b/src/cmd/internal/gc/go.go
@@ -778,13 +778,26 @@
Expandchecks func(*obj.Prog)
Getg func(*Node)
Gins func(int, *Node, *Node) *obj.Prog
+
+ // Ginscmp generates code comparing n1 to n2 and jumping away if op is satisfied.
+ // The returned prog should be Patch'ed with the jump target.
+ // If op is not satisfied, code falls through to the next emitted instruction.
+ // Likely is the branch prediction hint: +1 for likely, -1 for unlikely, 0 for no opinion.
+ //
+ // Ginscmp must be able to handle all kinds of arguments for n1 and n2,
+ // not just simple registers, although it can assume that there are no
+ // function calls needed during the evaluation, so no in-memory temporaries
+ // are necessary.
+ Ginscmp func(op int, t *Type, n1, n2 *Node, likely int) *obj.Prog
+
// Ginsboolval inserts instructions to convert the result
// of a just-completed comparison to a boolean value.
// The first argument is the conditional jump instruction
// corresponding to the desired value.
// The second argument is the destination.
// If not present, Ginsboolval will be emulated with jumps.
- Ginsboolval func(int, *Node)
+ Ginsboolval func(int, *Node)
+
Ginscon func(int, int64, *Node)
Ginsnop func()
Gmove func(*Node, *Node)
