all: make sure *Pointer[T]'s methods are inlined as intended

Updates #50860

Change-Id: I65bced707e50364b16edf4b087c541cf19bb1778
Reviewed-on: https://go-review.googlesource.com/c/go/+/428362
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>

src/cmd/compile/internal/test/inl_test.go

@@ -6,6 +6,7 @@ package test
 
 import (
 	"bufio"
+	"internal/buildcfg"
 	"internal/testenv"
 	"io"
 	"math/bits"
@@ -205,11 +206,7 @@ func TestIntendedInlining(t *testing.T) {
 			"(*Uintptr).Load",
 			"(*Uintptr).Store",
 			"(*Uintptr).Swap",
-			// TODO(rsc): Why are these not reported as inlined?
-			// "(*Pointer[T]).CompareAndSwap",
-			// "(*Pointer[T]).Load",
-			// "(*Pointer[T]).Store",
-			// "(*Pointer[T]).Swap",
+			// (*Pointer[T])'s methods' handled below.
 		},
 	}
 
@@ -235,6 +232,14 @@ func TestIntendedInlining(t *testing.T) {
 		// (*Bool).CompareAndSwap is just over budget on 32-bit systems (386, arm).
 		want["sync/atomic"] = append(want["sync/atomic"], "(*Bool).CompareAndSwap")
 	}
+	if buildcfg.Experiment.Unified {
+		// Non-unified IR does not report "inlining call ..." for atomic.Pointer[T]'s methods.
+		// TODO(cuonglm): remove once non-unified IR frontend gone.
+		want["sync/atomic"] = append(want["sync/atomic"], "(*Pointer[go.shape.int]).CompareAndSwap")
+		want["sync/atomic"] = append(want["sync/atomic"], "(*Pointer[go.shape.int]).Load")
+		want["sync/atomic"] = append(want["sync/atomic"], "(*Pointer[go.shape.int]).Store")
+		want["sync/atomic"] = append(want["sync/atomic"], "(*Pointer[go.shape.int]).Swap")
+	}
 
 	switch runtime.GOARCH {
 	case "386", "wasm", "arm":

src/sync/atomic/type.go

@@ -35,6 +35,10 @@ func b32(b bool) uint32 {
 	return 0
 }
 
+// For testing *Pointer[T]'s methods can be inlined.
+// Keep in sync with cmd/compile/internal/test/inl_test.go:TestIntendedInlining.
+var _ = &Pointer[int]{}
+
 // A Pointer is an atomic pointer of type *T. The zero value is a nil *T.
 type Pointer[T any] struct {
 	_ noCopy